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Chad911sc
I have my short block built and I’m ready to set my deck height. It’s 96mm bore with stock 71mm factory crank. This is a 2.0 2056 build. I have a Web 86a cam calling for approx 9:1 compression. I have 60cc heads with 3cc valve reliefs on my flat top pistons. If I plug all this into the calculator, I get 8.3:1 for my compression ratio if I set the deck height to .040 inch
After I set up the piston on the rod and bolt down the cylinder to the block, I get .053 inch from the piston to the top of the cylinder.
My question is, what is the best way to proceed to get the 9:1 ratio with at least .040 inch total deck height.
I am thinking that if I take off 6 total cc’s from the head, that will leave me with 54cc heads with the 3cc valve pocket = total 57cc’s. Bringing me now to the correct 9:1 compression ratio with the .040 inch deck height.

If I am in the right ballpark, this means I need to have my heads fly cut….correct??
If this is correct, how do I go about calculating how many thousands of an inch do I need to have removed by the machine shop to remove 6cc from the head?

I obviously will need to remove at least .013 inch total deck height get to my .040 goal, and that’s with no shims or head gaskets being used.

Thanks for your time, Chad
Chad911sc
I have my short block built and I’m ready to set my deck height. It’s 96mm bore with stock 71mm factory crank. This is a 2.0 2056 build. I have a Web 86a cam calling for approx 9:1 compression. I have 60cc heads with 3cc valve reliefs on my flat top pistons. If I plug all this into the calculator, I get 8.3:1 for my compression ratio if I set the deck height to .040 inch
After I set up the piston on the rod and bolt down the cylinder to the block, I get .053 inch from the piston to the top of the cylinder.
My question is, what is the best way to proceed to get the 9:1 ratio with at least .040 inch total deck height.
I am thinking that if I take off 6 total cc’s from the head, that will leave me with 54cc heads with the 3cc valve pocket = total 57cc’s. Bringing me now to the correct 9:1 compression ratio with the .040 inch deck height.

If I am in the right ballpark, this means I need to have my heads fly cut….correct??
If this is correct, how do I go about calculating how many thousands of an inch do I need to have removed by the machine shop to remove 6cc from the head?

I obviously will need to remove at least .013 inch total deck height get to my .040 goal, and that’s with no shims or head gaskets being used.

Thanks for your time, Chad
technicalninja
You're on the right track.

Altering the cylinder head will NOT change deck height.

You will need to add a .013 shim between the jug and case.

Don't trust a single deck reading. Do it on all 4 and adjust shim to the tightest one.

Use the same shim on all. You want the top of the jugs to be parallel to each other.

Plot the shape of the depression in the head and figure out how much you need to trim off of the heads to achieve 9-1.
CAD is the way to go for this.

If you haven't verified the registers in the case are flat, you should before doing any of this.
This is a known weak spot that "sags" with casting age alone (per Jake Raby).

Also, CC the heads and the valve depression before doing any machining.

I NEVER trust "published" numbers. I've seen too much variation in the past.

I LIKE the trough style of valve depression, but I'd expect more than 3 CCs
930cabman
top of then cylinders MUST be in plane with each other and parallel with the case.

my last build I used Plastigage at quarter points of the cylinder/head connection. No head gasket. 20k miles later she runs great
Shivers
You need to raise the compression, right? If so you can have the chambers cut to make it smaller to cut down on the cc's you are dealing with. But make sure you have someone that knows that job. Not sure how much would need to come off
cgnj
Was your case decked?
Did you check the volume of the valve pockets and heads?
Did you check with each cylinder?
I would trim the one cylinder top .013 if you can take that much off and fully seat it without hitting the fins.
Chad911sc
Thanks for the replies!
I did cc the heads and all 4 were 59-60cc. I haven’t cc the valve pockets yet, but I would agree they are by looks alone probably a little more than the stated 3cc.
On the first reply it was stated that by adding a base shim of .013 that would get me to the needed .040, but wouldn’t a shim add space instead of subtracting it?
I will add the water back into the head and remove the 6cc, mark the line on the valve pocket at the waters crest and have it cut down to that line. That should ballpark me into the right area.
I had the case checked at a local machine shop that did the crank polish, flywheel turn, and case cleaning, and they said the journals and the deck were still within parameters. It is a virgin case with 93,000 miles on it.
I will definitely measure and check the deck height on all of the cylinders before preceding, just wanted to understand the process fully at this juncture before going any further.
Thanks again for your valuable time, Chad
rfinegan
Yes Get your deck hight sorted first...
Then set the Head volume (total) for desired compress
lots of good stuff here



QUOTE(Chad911sc @ Dec 12 2024, 10:38 AM) *

Thanks for the replies!
I did cc the heads and all 4 were 59-60cc. I haven’t cc the valve pockets yet, but I would agree they are by looks alone probably a little more than the stated 3cc.
On the first reply it was stated that by adding a base shim of .013 that would get me to the needed .040, but wouldn’t a shim add space instead of subtracting it?
I will add the water back into the head and remove the 6cc, mark the line on the valve pocket at the waters crest and have it cut down to that line. That should ballpark me into the right area.
I had the case checked at a local machine shop that did the crank polish, flywheel turn, and case cleaning, and they said the journals and the deck were still within parameters. It is a virgin case with 93,000 miles on it.
I will definitely measure and check the deck height on all of the cylinders before preceding, just wanted to understand the process fully at this juncture before going any further.
Thanks again for your valuable time, Chad

technicalninja
QUOTE(Chad911sc @ Dec 12 2024, 09:38 AM) *

Thanks for the replies!
I did cc the heads and all 4 were 59-60cc. I haven’t cc the valve pockets yet, but I would agree they are by looks alone probably a little more than the stated 3cc.
On the first reply it was stated that by adding a base shim of .013 that would get me to the needed .040, but wouldn’t a shim add space instead of subtracting it?
I will add the water back into the head and remove the 6cc, mark the line on the valve pocket at the waters crest and have it cut down to that line. That should ballpark me into the right area.
I had the case checked at a local machine shop that did the crank polish, flywheel turn, and case cleaning, and they said the journals and the deck were still within parameters. It is a virgin case with 93,000 miles on it.
I will definitely measure and check the deck height on all of the cylinders before preceding, just wanted to understand the process fully at this juncture before going any further.
Thanks again for your valuable time, Chad


Du'h... you're RIGHT!
Stupid Ninja!

You need to remove .013" from either the top of the jugs OR the jug registers on the case.

NEVER/NEVER completely trust the machine shop. Ian Karr (lots of good videos) had one to the few VW air-cooled specialist machine shops still in business do the machine work in his Bumble Bee.
They BOTCHED the line boring on the case. He had to "do" the engine twice on that car!

The case registers in your pictures show ZERO machine work (they are still dirty).

Minimum I would do (to verify these are flat) would be to remove the head studs, get a small piece of glass, cover it in 1000 grit wet/dry sandpaper, and "lap" the registers with WD/40 as my "cutting fluid".
I'd want to see nice clean aluminum all the way around the registers.
I'd test the surface with either Dykem blue die or a black sharpie. Lightly coat the surfaces and hit it with the glass/sandpaper lightly. You WILL be able to see any low spots this way.

For the reason why check out this video.
https://www.youtube.com/watch?v=siPS_EBLxLY
930cabman
QUOTE(technicalninja @ Dec 12 2024, 12:08 PM) *

QUOTE(Chad911sc @ Dec 12 2024, 09:38 AM) *

Thanks for the replies!
I did cc the heads and all 4 were 59-60cc. I haven’t cc the valve pockets yet, but I would agree they are by looks alone probably a little more than the stated 3cc.
On the first reply it was stated that by adding a base shim of .013 that would get me to the needed .040, but wouldn’t a shim add space instead of subtracting it?
I will add the water back into the head and remove the 6cc, mark the line on the valve pocket at the waters crest and have it cut down to that line. That should ballpark me into the right area.
I had the case checked at a local machine shop that did the crank polish, flywheel turn, and case cleaning, and they said the journals and the deck were still within parameters. It is a virgin case with 93,000 miles on it.
I will definitely measure and check the deck height on all of the cylinders before preceding, just wanted to understand the process fully at this juncture before going any further.
Thanks again for your valuable time, Chad


Du'h... you're RIGHT!
Stupid Ninja!

You need to remove .013" from either the top of the jugs OR the jug registers on the case.

NEVER/NEVER completely trust the machine shop. Ian Karr (lots of good videos) had one to the few VW air-cooled specialist machine shops still in business do the machine work in his Bumble Bee.
They BOTCHED the line boring on the case. He had to "do" the engine twice on that car!

The case registers in your pictures show ZERO machine work (they are still dirty).

Minimum I would do (to verify these are flat) would be to remove the head studs, get a small piece of glass, cover it in 1000 grit wet/dry sandpaper, and "lap" the registers with WD/40 as my "cutting fluid".
I'd want to see nice clean aluminum all the way around the registers.
I'd test the surface with either Dykem blue die or a black sharpie. Lightly coat the surfaces and hit it with the glass/sandpaper lightly. You WILL be able to see any low spots this way.

For the reason why check out this video.
https://www.youtube.com/watch?v=siPS_EBLxLY


Not much different from doctors, lawyers, you name it
Chad911sc
Very true!!
I actually watched all of Ian’s videos!
Very good for first time type 4 builders like myself.
That sounds like a good idea with the flat glass surface to polish those up. I will do that this weekend and make sure they are nice and flat.
Thank again for all the advice, built several engines over the years and they all have their tricks of the trade to apply. This site has been paramount in the building of this engine. I haven’t had to ask very many questions because all the info is already here.Just couldn’t figure out the deck height thing with all the different ways to do it.
Chad911sc
Spent the day on your recommendation to resurface the deck. Definitely looks much better, and I’m sure will help with the sealing process. Used 1000 grit to knock it down a bit and 1500 to finish.
Thanks Technicalninja for the help!
Jack Standz
This should work fine for a shade tree mechanic rebuild, but for the little extra $$ (say $150), don't you want to have a machinist clean up the decks?

You want them flat (the glass and abrasive probably can get you there). You want them parallel to the crank centerline. You want the decks on both case halfs the same distance from the crank centerline.

As a bonus, the material removed will decrease your deck height and increase your compression ratio, which is what you said you are looking for. (If the cleanup cuts ends up farther than you want for your calculated CR, you can add the right sized spacers to dial-in the CR.

It looks like you've already glued the case half together, but just suggesting you might be happier knowing the motor is as good as you can make it. That's a sunk cost and it's still easy enough to pull apart and send to a good machinist.

The combustion chambers will also likely seal up better and longer if the parts are machined as good as you can get them.
iankarr
All great advice. Glad you found the videos helpful. Reagan’s line “trust but verify” is a mantra here. Very few machine shops are set up to work on these engines, so definitely confirm that the place you’re using is experienced. I’ve found that AA cylinders can be too tall. Assuming your registers are dead flat, I’d take the .013 off the jugs, since that’s a much easier machining task than decking the registers, which requires lots more experience and precision.

You’re well on your way! The only other thing I’d suggest is it’s far easier and less frustrating to backtrack on a build if necessary, than to press ahead with something you’re unsure about and have to start from scratch after a problem presents itself while running. BTDT smile.gif
Jack Standz
I'd assume that your decks aren't flat, nor parallel to the crank centerline, nor consistent from side to side.

As Ian says, verify. That means you need to measure things. I'd pay special attention to whether the decks are parallel to the crank centerline.

Not sure that it's "easier" to have the cylinders cut down, but, it's only $85 plus shipping to have European Motor Works deck a type 4 case. Again, cutting the cylinders down doesn't address sunken decks, inconsistent deck heights from case side to side, non-parallel decks, etc. A properly decked case does.

Would suggest you have them also tap the oil galley plugs while they have your case.

Here's a link:

https://www.europeanmotorworks.com/vw/engin...se-service.html
Jack Standz
One more thought.

Raby in this video says that generally it takes 30 thousandths or more (especially with a 2 liter case) to deck a case. That will fix your deck height issue and allow you to use the right thickness spacers to hit your desired CR without further machine work on your case.

https://m.youtube.com/watch?v=siPS_EBLxLY
technicalninja
agree.gif

Jack is right!

Someone (maybe Jack and I, with help from others) really should make a recipe regarding what to do, at what time, and how to verify thread on T4 builds.

Ian Karr did it pretty well on basic rebuild but there isn't a "make sure to do this" list when you have this stuff apart that I am aware of.

If I had the cases apart there is NO WAY IN HELL that I wouldn't have case line bore, and jug register flatness addressed.

Sorry @Chad911SC but you stated the machine shop checked and "Cleaned" the cases.

The first picture shows enough debris on the top of the case and the registers still dirty that I rate that cleaning job as "Not done. even first stage not correct".

I'll go through at least 3 cleaning stages.
First is mechanical in the parts washer.
This involves scrappers, razors, wire brushes and should leave the cases pretty clean, much more so than your pictures show...
At times I'd be using brass/stainless "tooth brushes" and be working under magnification as my 60-year-old eyes are getting weak. I have "jeweler's lens" up to 10X.

During this first stage I would use the glass trick to verify "how bad" my registers are.
I would still expect to have them machined!

After this initial cleaning I'd detail the case haves (both internal and external) cleaning up casting flash/irregularities.

I'd do the RMS drain mods. I'd look closely at all of the oil system parts, probably buy the Tangerine upgrade parts. I'd choose an oil pump that had O-rings between the pump body and the case.

I'd remove ALL of the pressed in plugs/oil channel block offs and clean all of the oil gallies with gun cleaning equipment. Some of the plugs are difficult to re-seal. Multiple threads on here about sealing issues would need to be investigated/addressed.

I'd use a thread "chaser" (not a tap!) on every threaded hole in the block. B12 and air to finish and then inspection under magnification. Threaded bolt holes would look "NEW" after completion.

Big air (175psi) and B12, WD/40 would be used liberally.

All of this happens BEFORE it goes to machine shop!

I'd want the case halves cleaned in a "hot water" rotisserie parts cleaner and then have machine work done. this is second stage cleaning.

After machined parts returned, I'd want to be in a "clean room" if possible. Doesn't have to be "laboratory" clean but cleaner than the open shop.

After all of my mockup builds (at least two) I'd do a final cleaning (3rd stage) with alcohol and air and then do then do final build. At this point I'd be ANAL about the cleanliness...

On an engine with an iron block, I'll also include a "caustic solution" stage during the first cleaning (cheap oven cleaner) and request a caustic solution "vatting" at the machine shop.

The machine shop commonly ask me "why the cleaning? Your stuffs already clean."
I still have them do it...

Now, in the OPs case he's already back together. His registers look a SHITLOAD better now. If he used a large enough piece of glass and kept it FLAT during lapping his registers SHOULD be better.

Did you VERIFY the flatness via the procedure I provided (Dykem or Sharpie)?

If you did, you're good.

If you didn't...

Now Chad gets to make a decision. Try it or back track


One other point, when I was actively pursuing a T4 build I found SO many rod lengths available that ending up with excessive deck was not going to be a problem.

It was the other way round for me. Pistons were far more likely to be sticking out of the jugs and this required metallic "shims" between the jugs and case. Thick ones!

I bought a set of extended length head studs because of this.
I AM surprised you ended up so far down the bore without reusing the stock rods.

This was part of the reason I got the initial deck adjustment WRONG. All of my computations for a T4 were to increase clearance, not reduce it...

Another thing I'd do automatically.
For ANY performance build nowadays.
Ceramic coating on piston crown, chamber, and exhaust port...




Chad911sc
Thanks for all the replies!
Wish I would have seen that Raby video before starting this build. Now I’m leaning on taking it back apart and sending it off to European Motorworks for the suggested work. There is no one I would trust in the Orlando area to do this type of machining on type 4’s.
After lapping in those registers of mine, I put the pistons and cylinders on #1 and #2 and rechecked my deck height on both cylinders. They were both at .053 before the lapping and now they both measure in at .050 thousands. So that means I removed a total of .003 from the deck mad.gif itself. After watching the Raby video it seems like that is nothing according to him on the 2.0 case. When I lay the piece of glass on the top of the deck and try to put even my .00015 feeler gauge into any spot on the deck between the glass and the deck surface, it will no fit. That middle spot on the register of the 2.0 is considerably thinner than the 1.7, but if it’s flat after only taking off .003 then I still should be good?? Right?
I definitely want to do it right the first time and be done with it. So if I need to break it back apart, I will. So what do you guys think? confused24.gif
And just a side note….Thanks again Ian for making those wonderful videos!
Without those I wouldn’t have even attempted this build. It’s been a fun journey so far and I’m ready to get her back in the car, but if it takes longer, I’m ok with it.
seanpaulmc
A guy local to me rebuilding his 912 built up a 2270. He used a machine shop called Rev Masters to bore out the stock cylinders to the 96mm needed. They are west of John Young Pkwy. He was happy with the cylinder work.

Also, take a look at Advanced Cylinder Heads on Forsyth in Winter Park. I stopped in there once, a few years ago now, to check them out and by coincidence they had just finished up a Type 4 case though I do not know what work was done to it.

Neither is a personal endorsement. I have not had work done. My engine build is sometime off in the future as I still have major sheet metal repairs to complete. It would be great to find others in Orlando with direct experience.

Lastly, check out Stratton Motorsports in Winter Park. They do some really, really nice VW builds. pray.gif

Best,
Sean
Superhawk996
QUOTE(Chad911sc @ Dec 16 2024, 04:39 PM) *

They were both at .053 before the lapping and now they both measure in at .050 thousands. So that means I removed a total of .003 from the deck mad.gif

So what do you guys think? confused24.gif


There is no way you removed 0.003” of material lapping with 1000 & 1500 grit sandpaper

So that means there were localized burrs or high points affecting your initial measurement and/or your measuring tools and technique are highly variable.

Agree with the others. Disassemble case and have the deck registers machined. You will end up with more variability trying to take 0.013” off the cylinders due to the mechanics of how the cylinders will be machined and finding a machine shop that can do that EXACTLY the same on 4 cylinders.

The catch 22 of T4 engines is that rebuilding them is not rocket science. The problem is that they are sensitive to details (like case decking) that most machine shops and I4/V6/V8 builders have no experience dealing with.
Chad911sc
Awesome! Thanks Sean!
I’ve heard of Rev masters, but was unaware they did Type 4 work. I will def check out the VW shop in Winter park. It will go ahead and pull it apart and have it decked properly. I only want to do this once.
Not sure how much metal work you need on your 914, I spent the last 10 months doing all of mine as well. I had to replace both of the longs due to rot from the engine bay eating through them. Also had to repair the Hell Hole, it was a major undertaking! I’m on the other side of it now, and just need to finish the motor and install the Tangerine racing transmission linkage. Hopefully smooth sailing after that.
seanpaulmc
Okay, so where is the build thread? As you may not know yet, we love pictures- especially when documenting the resurrection of another 914.

thisthreadisworthlesswithoutpics.gif

Chad911sc
So I have the case halves back apart and now just need to decide where I’m going to ship it off to. Going to ask them to take .015 thousands off the deck. This should get me into the ballpark of where I need to be. I still need to address the head volume. With all the calculations for compression ratio, I need my head volume to be 57cc instead of the now 63cc that I have with the valve relieved pistons and pocket added together. Along with a .040 total deck height this will put me at the desired 9:1 ration I need for my cam.

I always try to add pictures. This site rejects my posts about 80% of the time. I only try to add one or two pics, but it hardly ever accepts them. After trying 15 times I get pisses and just forget it…lol.
Chad911sc
I think I figured it out with my daughters help…
I am computer illiterate!
Chad911sc
This is the 74 914 that it is going into…one of these days!
Chad911sc
Question….
When I get my heads fly cut, it looks like I need to cut about .025 out to get to my target of 57cc’s total. Does this seem reasonable? 60cc heads with 3cc valve reliefs=63cc.
Take away 6cc from the heads looks to be about .025-.030 cut needed. When I looked at the head surface there is a raised outer circle of aluminum that will need to be milled as well so that it will mate with the head surface. Am I on the right track??
Flying up to Indianapolis in a couple days, taking the heads and the case with me to a shop up there that I know well. Spend Christmas with the family and get my machine work done at the same time! Kill two birds with one stone beerchug.gif
Thanks again guys for the help….super appreciated!

The black line is the amount that needs removed.
The other red arrow is the raised aluminum area I was speaking of needing removed to let the cylinder mate with the surface of the head.
technicalninja
On a bone stock 73 2.0l the depression in the head is 6.5mm and the extension of the jug that fits in it is ALSO 6.5mm.

In stock configuration a fire ring or compression ring was included so there was plenty of clearance.

Without that ring it looks like the upper casting wall (outer surface) should be machined down .010 to .020 anyway.
BEFORE any fly cutting is done!

If you fly cut the head, it will increase the upper surface cut exactly the same amount as the fly cut.

This is on MY stuff...

My stuff is OLD and German but doesn't appear to have been machined before.

You should make measurements yourself!

The ONLY place you want the head to contact is the sealing surface at the top of the cylinder. It touches anywhere else and you're going to have a cylinder to head blow out in your future.
Jack Standz
QUOTE(Chad911sc @ Dec 19 2024, 02:17 AM) *

So I have the case halves back apart and now just need to decide where I’m going to ship it off to. Going to ask them to take .015 thousands off the deck. This should get me into the ballpark of where I need to be. I still need to address the head volume. With all the calculations for compression ratio, I need my head volume to be 57cc instead of the now 63cc that I have with the valve relieved pistons and pocket added together. Along with a .040 total deck height this will put me at the desired 9:1 ration I need for my cam.

I always try to add pictures. This site rejects my posts about 80% of the time. I only try to add one or two pics, but it hardly ever accepts them. After trying 15 times I get pisses and just forget it…lol.


Gonna try one more time on this. Raby says that generally it takes 30 thousandths to clean up the deck on most 1.7/1.8 liter cases, more for 2.0 liter cases. Over the years, most people have come to believe he knows what he's talking about. Not sure why you think your case is so special that you will get away with half that amount? Especially without measuring before and after the machine work. What makes you think your case needs only 15 thousandths removed? Maybe one side needs 30 thousandths and the other side needs 40? Or only 20? How far off parallel does your deck measurements show? Side 1, side2?

Why not have a good and competent machinist cleanup the decks on your case (which, generally will take 30 thousandths or more according to Raby) by removing whatever amount of material necessary to achieve a flat and parallel deck?

After this is done, you will probably need to add a spacer between the case and cylinders to achieve your optimal deck height. Then, after measuring and verifying the machine work, add the right size spacers. Then get the combustion chamber volume right for your desired static compression ratio.

Or, get the case machined, get the heads machined to reduce combustion chamber volume. Then order the spacers based on careful measurement and verifying the machine work, unless somehow the machine work magically comes out to be the perfect combination to meet your CR desires.

Not that I believe a particular CR is all that critical for a street motor (but too high a CR can be a problem). Does 8.8, 9.0, 9.1 mean it's all that problematic? But, good machining is very important, especially for long term performance?




Chad911sc
I understand what you are saying about the deck parallel to the crank is super important, this is why I disassembled it. And I am grateful that you have taken the time to help me see that it was necessary to do so. When I place a level across the deck it only has a .003 of a sag in the middle where Raby says it’s thinner. Some 2.0s need that much, but it doesn’t necessarily mean mine will need that much material to be removed. I also know I will need a shim under each cylinder when I’m done to set it back to .040 for final height. My question was more in the line of does .025 -.030 sound about right to get the head chambers down to the desired cc’s for the ratio I want? And also is that amount of removal typical for a fly cut? I have read through hours and hours of posts and some people say you shouldn’t even fly cut a type 4 head. But how else could you make the pocket smaller to get your required result and keep your deck height at the desired .040?
I don’t want to beat a dead horse, but I am a painter by trade and each and every step matters, which make me a bit OCD.
technicalninja
QUOTE(Chad911sc @ Dec 19 2024, 08:41 AM) *

I understand what you are saying about the deck parallel to the crank is super important, this is why I disassembled it. And I am grateful that you have taken the time to help me see that it was necessary to do so. When I place a level across the deck it only has a .003 of a sag in the middle where Raby says it’s thinner. Some 2.0s need that much, but it doesn’t necessarily mean mine will need that much material to be removed. I also know I will need a shim under each cylinder when I’m done to set it back to .040 for final height. My question was more in the line of does .025 -.030 sound about right to get the head chambers down to the desired cc’s for the ratio I want? And also is that amount of removal typical for a fly cut? I have read through hours and hours of posts and some people say you shouldn’t even fly cut a type 4 head. But how else could you make the pocket smaller to get your required result and keep your deck height at the desired .040?
I don’t want to beat a dead horse, but I am a painter by trade and each and every step matters, which make me a bit OCD.


Just saying "All will require XX amount of machine work" is short-sighted.

Saying "Most require XX amount of machine work" is perfectly fine.

I, personally, don't believe EVERYTHING Jake Raby says. I'd guess at times; he's kept some data "close to his chest" and allowed misinformation to flourish.

There's a BUNCH of stuff that I figured he'd be doing that tuns out he was.
In that engine video, at one point, he says "I'm using expensive Honda rods in everything now."
He WASN"T the first...
I believe The NASCAR guys did the "Will Honda rods work" jump well before him.

The whole Raby "proprietary cam shaft profiles" is sort of BS as well. Adding 20+ degrees to both intake and exhaust and THEN spreading the LSA to 112-114 degrees was a GM trick first. This ALONE got rid of the EGR valve in the second gen small block (LS1) in the late 90s...

I'd ALSO bet he's using asymmetric lobe profiles as well.
I haven't seen "asymmetric lobes" mentioned in ANY camshaft discussions regarding the T4.

Ninja rule ninja.gif
Rules are for fools; wise men use good judgement.
Don't EVER believe everything you read, especially on the Internet.

By the time I had it as individual cases I'd KNOW how much I needed machined.

If you can get away with .015 you SHOULD as this solves the deck height issue.
I believe that you should have a gasket/shim between the cylinders and the case if nothing more than a carrier for sealant. I'd measure how thick the thinnest paper gasket is and have the machining slightly increased to allow for it.

To your question is .025-.030 enough to remove 6ccs.
I'm NOT sure. I have access (through my son, Bryan) to high end 3D scanning and CAD engineering software. A simple scan and CAD computation is the way I'd go now but I did find YOUR suggestion of fill the chamber up with XX amount of fluid and just LOOK at where the level is as an EXCELENT suggestion.

For this I'd want a fluid that had ZERO surface tension and Jack's suggestion of alcohol might be the very best fluid to measure this.

I'd worry about TWO things doing the measurement this way.
Is the head LEVEL and does the measuring fluid create a meniscus.
I'd guess alcohol will have a tiny one.
I'd also expect the alcohol to be an escape artist due to this feature.
I'd wipe a tiny amount of simple candle wax on the valve seats before assembly.

The way you will be going is the OLD SCHOOL way. Machine and then test, re-machine if required. This works FINE if you're the machine shop.

And it's not a requirement to be dead ass on at 9.0-1.
A CC difference will not alter the compression ratio that much.
Now, when you get above 10.5-1 it starts to get critical and anything above 13.0-1 requires accuracy at the less than 0.5 cc range.
Tenths of a CC has been HARD to hit for me.
Just making multiple volume checks on a single cylinder is hard to re-create with fine accuracy.

All important measurements I make at least three times and look at averages.
It's easy to be a tiny little bit off.

Hope this helps!

EDIT: In your case I'd talk with the machine shop. I'd say "I think I'm pretty close to flat, I want you to deck the registers TO THE MAIN BEARNG BORE and take off at least .XXX. If that doesn't clean it up, go further until it does and measure how much you had to remove in total."

That is the best way to skin that cat IMO.
Jack Standz
QUOTE(technicalninja @ Dec 19 2024, 11:37 PM) *


I, personally, don't believe EVERYTHING Jake Raby says. I'd guess at times; he's kept some data "close to his chest" and allowed misinformation to flourish.

The whole Raby "proprietary cam shaft profiles" is sort of BS as well. Adding 20+ degrees to both intake and exhaust and THEN spreading the LSA to 112-114 degrees was a GM trick first. This ALONE got rid of the EGR valve in the second gen small block (LS1) in the late 90s...

EDIT: In your case I'd talk with the machine shop. I'd say "I think I'm pretty close to flat, I want you to deck the registers TO THE MAIN BEARNG BORE and take off at least .XXX. If that doesn't clean it up, go further until it does and measure how much you had to remove in total."

That is the best way to skin that cat IMO.


Yes, don't believe everything Raby says either. But, when someone has built and machined so many type iv cases compared to other of us mortals, I think his comments and rules of thumb are not to be ignored.

Yes, agreed on the proprietary camshafts. For example, one of his camshafts seems to be very close to Webcam 163/86b. Among other things, he added duration to the exhaust to crutch a weakness of the type iv exhaust ports.

And to Chad911sc (BTW 911sc has been my favorite Porsche for a long time), no matter what they tell you, carefully measure everthing yourself. And my apologies if I came off a little gruff this morning. I'm still pulling for you to end up with the motor you wanted to build at the end of the project. And that it lasts for a very long time.
Chad911sc
Thanks guys!
Now worries, no offense taken. Like I said I wouldn’t have even taken this one on if it wasn’t for the help of this site. I did the same thing when I built my LS1 in my C5 a few years back. I ended up with 470 rwhp on a naturally asp small block. I take all advice with a grain of salt, but without all the input I wouldn’t have attempted that either.
I do own a 1979 911sc imported from Germany by its only other owner. I’ve owned it for 23 years and just finished painting it last year. Haven’t put it back together yet because I always get distracted with a new project. Working on a 69 beetle right now as well that I adapted a 2.5l turbo forged STI engine into it. It has been a very challenging project getting the cooling and front end set up for a water motor.
rfinegan
duplicated
rfinegan
Am I missing something...
Machine the case to the centerline of the crank. Doesn't the case split the center of the crank. This make setting up the case ez on the flat case half and clamping each case to the table. Machine both to clean up the spigots and match this setting to the other side.
Please advise if I'm missing something, AS I will be performing this on my 2056 soon on my Bridgeport . Once parallel this can be adjusted to best deck height or shimmed as needed.
technicalninja
The case line SHOULD be centered but...

Where it matters is a center axis of the crankshaft.

This is how shit can go wrong...

One of my other projects is a 91 MR2 Turbo.

After tearing the stock gen 2 engine down (all OK, just never touched and OLD) a built Gen 3 engine showed up on Craigslist here in DFW.
This engine was out of a wrecked car and it was cheap!

Gen 3 engines are SHITLOADS better. They never made it to the USA and this one was seriously built ($10,000 receipt). H-beams, Wisecos, billet cams, adjustable cam gears, whole list of good shit.

I went to look. Took a borescope and leak down stuff.
Minor vertical scoring lines in the bore surface. It had been run an extended time without an airfilter!
Leak downs sucked. All the valves had leakage and "bonking" them didn't improve it much.
It HAD been sitting 9 months.

I bought it for half what he was asking...

The receipt was from a well known shop who specialized in these.
I've purchased many things from them.

So, I've got this bad-assed 2.0l that needs a ring job and cleaning up the valves.

I rip it apart. Check deck height on all 4. I've learned to do this early instead of late.

.006 difference in deck height!!!!!! headbang.gif headbang.gif headbang.gif headbang.gif headbang.gif
I'm used to seeing deck height difference BELOW .001. I'm expecting "tenths" and have results that are HUGE!
I'm PISSED!

What I found, after swapping rods/pistons and then installing the crank out of my gen2 in it was two things.
#4 rod bearing journal was repaired via "off-set" grinding (this is a NORMAL thing for quicky machine shop repair) and the deck seemed to be ground at an angle to the crank.
I told the machine shop what I thought, and Eric documented what they found.
It took .0017" to clean it up. He did a final cut at 2 thousands. It WAS decked at an angle!
The crank journal was off-set ground right at .005"
I used the Gen 2 crank out of the car's original engine (never been machined and not damaged at all). Had it micro-polished/balanced and put it back together.

Deck height differences are .0003 now!

The shop in question is NOT a machine shop. They sub the work out
They OBVIOUSLY didn't check anything when they got it back.

The machine shop in question did a "quick production" job on the crank and they decked it from the oil pan registers instaead of the crank bore.
This is the FASTER way to complete the machine work and everything would have worked absolutely fine on a bone stock build at 200hp.

This build is targeted for 500hp (which as actually conservative) and that level of variation is unacceptable at that power level.

So, on another active build at 2.0L I'm shooting for 500 hp.

And parts for that puppy are CHEAPER than T4 stuff...
rfinegan
great follow up. Thanks for the information
technicalninja
The 911 is COOL!

What's that white car in the background?
Jack Standz
Chad,

Awesome looking 911SC. You should be working on getting that "real Porsche" back on the road! smile.gif smile.gif
Chad911sc
The 911sc is actually a Max Moritz built Porsche. It was bought in Germany by a space engineer that ended up moving to Florida and bringing it with him. She is my baby and as you said deserves to be back on the road. I just get distracted by a new project way too easily…lol.
The white car in the background is a 69 Opel GT that I ended up building a 347 ford stroker motor for and had a 4:10 posi shortened rear end into. That was one of the parts cars I used to steal panels from to fix the other one that’s not in the picture.
technicalninja
Let's see here...

500 hp Vette
Nice NICE NICE 911- power level unknown but due to the history of the OP NOT STOCK!
2.5L BLOWN Suby beetle. (I'd bet that is going to be a HANDFUL to drive).

Stroked small block Ford swapped Opel GT with other serious mods.

I'm going guess you will be "less than impressed" with the acceleration of the 914...

I've got a tip for you.

That STI engine will fit! devil.gif

And it would work better in a mid-engine installation IMO! ninja.gif
Chad911sc
Trust me! That was my first thought when purchasing a 914. Stick a turbo Subi engine into it, but when I seen this Olympic blue 914 on Craigslist, I loved it just as it was. I figured I would leave it original and possibly let my daughter, who just turned 17, have it as her second fun car to sport around on the weekends. I haven’t finished the bug yet, have all the fabrication work done but still have to finish the body work and paint. I can’t wait to drive it! The engine purrs like a kitten. I used the Cobb system to tune it and have it close, but I will go to the local Subaru dyno shop to get the perfect set up once it’s finished.
The 911sc engine is exactly like it came from Max Moritz, I had the local Porsche guru fit the new tensioners and Mahle pistons and cylinders when I purchased it over 20 years ago. I don’t think it had a bunch of extra hp, but when Sid Collins tore it apart to rebuild it, the case halves were polished internally and it’s fuel injectors were longer and different shape than the factory ones. Sid said it was done for better distribution of the fuel for efficiency in the burn. Never had it on the dyno, but it definitely scoots. I have only put about 10k miles on it in the past 23 years.
I bought the Corvette from a man down in Miami who had it stolen from his driveway and purchased a new one with the insurance money. They found it 3 months later in a shipping container bound for overseas. I picked it up for 7k and dropped 7k in the engine and suspension. It’s a Super fun car to drive….endless burnouts for days and Sooo much fun to power slide through long corners…lol.
Chad911sc
Talked to the machine shop today and they ended up taking .010 off of the deck to flatten it out on the crankshaft line, and .030 off of the heads to get me down to the 54cc target for my desired compression ratio. Pretty much what I was thinking.
Can’t wait to get back to Florida and start the assembly process once more!
Thanks again for all your help guys! So glad I listened to your advice and tore it back apart beerchug.gif
technicalninja
Will .010 give you the deck height you needed?

I thought you needed .013 from your initial post...

I'd have gone a little bit deeper allowing for shimming.

If your using cast pistons it will probably work fine at .037 but that is getting close in my book.
Jack Standz
Merry Christmas everyone!

Well, you'll figure out the next step when you measure everthing and do the mock-up.

Fingers crossed that you're not too tight on the deck height. As technicalninja says, you don't want to be too close. Pistons hitting valves do tend to ruin one's day smile.gif . But, sometimes we do tend to push the envelope. And sometimes the envelope pushes us. For a 2056, you don't need to cut it that close anyway and they are a fun motor in a 914.

technicalninja
I always check deck height of ALL of the pistons.

As tight as you are, make SURE you don't have one that is .002 different.

"Pop goes the Weasel" is what you want to avoid at all costs.

I sort of expect you know this already!

It's more for the other folks watching the thread...

I would not release a customer job that tight.

MIGHT use that shit myself...

You WANT to decrease piston to head clearance as much as possible in my book.

Close should be better!

Right up till the point the pistons KISS the head which always hurst the motor and sometimes DESTROYS EVERYTHING...

Have a Merry Christmas!

Rick
Chad911sc
Merry Christmas Everyone!!
After I had hand lapped the registers and rechecked my deck height on 2 of the cylinders I was at .050 total, so I should be right at .040 now that the deck has been decreased by .010
I figured I should be between .038 - .040
I always try to get my squish right at the perfect spot for combustion burn efficiency.
I will definitely clay check it on every cylinder to see exactly what my piston to head clearance is….
Thanks again guys!!
technicalninja
QUOTE(technicalninja @ Dec 24 2024, 01:02 PM) *

Will .010 give you the deck height you needed?

I thought you needed .013 from your initial post...

I'd have gone a little bit deeper allowing for shimming.

If your using cast pistons it will probably work fine at .037 but that is getting close in my book.



The above (and the next post from me) is TOTAL BS!

I even sucked Jack Standz in...

I got the math BACKWARDS AGAIN!!!!

headbang.gif headbang.gif headbang.gif headbang.gif

It looks like he didn't remove ENOUGH material.

This would have put the piston DOWN the bore, not up.

He's NOT tight, he's loose!!!!

I'm happy he rechecked his shit and choose the proper amount to remove.

In my book .040 is OPTIMAL and safe enough to release to non-technical folks.

He's as TECHNICAL as I am...

I still suggest checking all of them and (this might be important!) check to verify the jug fins are NOT hitting the head.

The check I did for him on register depth on my stock junk was eye opening!

It looked like either fly cutting head OR cutting top of jugs would require doing something to the fin section of the jug. Without the original compression ring it looked like they ALMOST touched the head in STOCK form!

And I truly believe, on pump gas, the deck height is the MOST important measurement to get right. Something without quench pads, something using fuel that is not prone to detonate, it's not nearly as critical.

But for the crap we can get out of a commercial pump (besides E/85) deck height is stupid important...

Merry Christmas all!
ninja.gif

Edit: Everyone, even brand-new members, can add good info to the forum.
Chad has given me a small Christmas present (and he didn't even try!).
This guy has a functional turbocharged air-cooled VW (the Sun Bug) at 220 hp!
I want to know ALL about that set up!

I VASTLY prefer to force feed engines below 3.5L It's my NORMAL recipe.
I automatically discounted "turbo" due to the limitations of the T4.
Might have been short sighted...

I hope "Nickies" are not part of the equation; blows budget bigtime.

Chad, we will have PM conversations regarding this after the holidays.

And LOTS of folks on here would be interested in turbocharging the T4.

It would make a KILLER thread on its own!
sixnotfour
OMG...
porschetub
QUOTE(sixnotfour @ Dec 26 2024, 10:24 AM) *

OMG...

agree.gif ,hopefully for the same reason ?,that last reply made little sense to me .
technicalninja
QUOTE(Chad911sc @ Dec 23 2024, 06:24 PM) *

I have a disease…..
Project mania…lol
Love to build stuff and can’t say no when I see something in my reach. I have some of them done, but most are still works in progress.
1) my daily driver, she is my true love. 15 years of daily driver flawless service! 2004 4Runner.
2) My first car from 1986 that I still have. Building it for my now 17 years old daughter. It’s a 74 Sun Super Bettle. Has 2110 turbo, 220 hp on water dyno
3) 1979 911sc Max Moritz German born import. Finished painting about a year ago, but this is how she still sits.
4) 1969 beetle with 2.5L turbo STI forged stuffed into it. Crazy amount of fab work. Done with everything but body and paint.
5) 1998 C5 naturally aspirated 470rwhp on the dyno….so much fun!
6) 1972 CJ5 lifted on 39.5’s with hydraulic assisted steering and 4 wheel disk brakes. First V8 that Jeep made AMC 304.
7) My daughters go kart
8) Dads go kart with forged internals of course..lol
9) 2006 Buell 1250 scg
10) 2006 Screamin’ Eagle V-rod
11-12) YSR 50 and the yellow one is a YSR with a IT 175 2 stroke 6 speed with custom frame and reinforced swing arm. Clocked at 87 mph in a 25 speed limit by local policemen in my neighborhood. He let me go first.gif
13) 1991 FZR 400 with 632 big bore Wiseco motor stuffed into it. Also very fun little corner ripper that I take to the Dragon in Tennessee every couple of years.
I do all my own work on everything and nothing has stickers on them…all paint.
Oh yeah…and last but not least the 74 2.0 Olympic blue 914 that I’m currently building a 2056 for.

Actually, just the math was bad. The rest of the posts were fine.

I do not like to make simple mistakes. "In front of me" I'd have been fine.

Sometimes "over the keyboard" can create confusion.

In the "show us what you've got thread" Chad911sc posted this tidbit

"2) My first car from 1986 that I still have. Building it for my now 17 years old daughter. It’s a 74 Sun Super Bettle. Has 2110 turbo, 220 hp on water dyno"

He's got a bunch of nice stuff but that caught my eye as it is the most Type4 like.

I'd like to know how that was done, how long it's run, and what problems he's had along the way.

I'd stay Type4 on my 75 if I could make that type of power without spending 20K...
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