Inspecting under the tins - here's pics., What do you see? Options

[FlacaProductions]

I've been battling high CHT's and have done nearly everything I could think of to get them lower - but had not inspected under the tins.

A number of years ago - when the car was new to me - I was changing the plugs and pulled out a piece of alternator belt that was wedged under the tins near cylinder #3.

I got to thinking recently, wondering if I had missed more pieces and they were causing my higher CHT's.

These are pics I took today - as good as I could with my endoscope. I don't have any frame of reference for how dirty these are/are not.

I know there are no other pieces of belt that I could see (ok - maybe one very small one) and no nests or dead rodents...but are these clean - or clean enough? Would there be something I could use to clean things up a bit without dropping the motor?

[attachmentid=984
120]

[emerygt350]

Looks ok to me. Do you have a higher compression engine? Can't remember your specs.

I have been swapping in and out my 123 with the stock dizzy and have noticed dramatically higher temps with the worn out stock distributor. It has quite a bit of dwell creep as you give it the gas.

[FlacaProductions]

Interesting. I'm staying with the 123.
Brad Mayer did this to my motor - but it's been a few years:
A “stock performance” rebuild with new, original Mahle European pistons and cylinders, Raby FI cam and lifters new German K&S bearings on a std/std crankshaft. Heads completely rebuilt, new stainless valves and new springs by Tuttle’s Parts Exchange.

So - nothing extreme.

I'm now at the point where - not finding anything obvious under the tins - that i'm just going to run it. I'll watch the oil temp and a glance at the CHT every so often but i'm not going to let it rule my life - like I have been. If it lets go, it lets go.

We're early in the game of building a new house and so when that's done, i'll have a proper place to drop the motor, etc. If it's still alive by then (next fall) I'll deal with it.

[dtmehall]

que sera sera

[porschetub]

It is a bit messy but the cooler is more important IMO .

[Dave_Darling]

Well, it's not more important for CHTs... (IMG:style_emoticons/default/wink.gif)

--DD

[emerygt350]

How hot is it running? I have nearly 9:1 compression and mine runs hot doing highway things but like you said I have just accepted that and I try to limit the time over 390. However, I still see some pretty big timing effects and when I get my new Bluetooth 123 back from Ed I plan on diving into playing with the curve and advance to see what I can do. I suspect I won't be able to do much but it's still a big improvement from what I see with the worn bearings in the old dizzy.

[FlacaProductions]

it runs GREAT. Idles solid. Good pep.

My AFR is in a great place. It just runs between 350-400 too much if you follow the Raby temp guidelines.

But - maybe it's always done this and I didn't notice until I put in the CHT gauge. It's possible.

Oil is and always has been 210-225. Cooler is clean. I didn't snap any frames of it yesterday but it's good. Flaps are good.

This time next year, I should have a 2500sf garage to play in and more than just a few days at a time to mess with it.

[Superhawk996]

Let’s revisit

350-375F
“These temps are standard for a STOCK engine with a stock cam at cruise speed, if it is properly tuned. Generally, if you are cruising at these speeds, as soon as you hit a hill you'll see a spike to a higher level, approaching 400F. If you experience temps of 375 in 5th gear, you may be doing the engine an injustice by keeping the tranny in 5th, hitting a hill with a shift to 4th will keep load off the engine and that reduces engine heat and increases cooling fan speed- 4th gear is a friend to stock engines.”

Worrying about anything around 350-375 is a waste of of time.

The other thing is the nature of air cooled engines is the hotter they get the higher the heat transfer (ie cools more). I’m not going to waste time with the formula but it is linear to temperature difference between the item being cooled and ambient air.

The hotter the item - the faster it transfers heat out.

[emerygt350]

it runs GREAT. Idles solid. Good pep.

My AFR is in a great place. It just runs between 350-400 too much if you follow the Raby temp guidelines.

But - maybe it's always done this and I didn't notice until I put in the CHT gauge. It's possible.

Oil is and always has been 210-225. Cooler is clean. I didn't snap any frames of it yesterday but it's good. Flaps are good.

This time next year, I should have a 2500sf garage to play in and more than just a few days at a time to mess with it.

I suspect precht gauge people would run these crazy hot and just be oblivious till a seat drops. I'm talking 450-500 for extended periods. I think it's tough for those of us with modified engines to know if what we are seeing is a matter of just being beyond the ability of the engine to dissipate the heat from 'the extra omph' or we are in a situation where tuning will help (not detuning, just a better tune). There is a member of the world (jake? not raby) that says with a microsquirt and a creative curve he can keep temperature under 300 in most circumstances with extreme lean and high advance.

I am still holding out for tuning since I see such big changes in temps with a better spark system (123, still not 'cool' but way better than my old dizzy), and changes to exhaust and cold air intake. Currently I have my stock exhaust, stock air cleaner, and wobbly old distributor installed and it shoots up to 400 climbing the hills around here. Comes right back down but it still heats up super fast under load. Way more than when I am running the aftermarket stuff.

[FlacaProductions]

Thanks guys - I may just may be being too hard on myself and too set on "lower is better" - my temps come down FAST when i get out of it. I've never seen 450....hell - I've never seen anything higher than maybe 405????

I love data and I love gauges but this may be a case where too much info is a bad thing - for my brain.

[PCH]

Not to belabor things, but are all your clyinders instrumented for CHT? If so, what is the temperture spread? And who is the hottest and who is the coolest?
Hugely important for the cooling of aircooled cylinders is how well the baffeling is sealing the high pressure side from the low pressure side of the cooling system.

[FlacaProductions]

@PCH - no - just cylinder #3