Can too little compression for a camshaft cause engine heating

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jeff swisher
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Re: Can too little compression for a camshaft cause engine heating

Post by jeff swisher » Wed Oct 18, 2017 7:32 am

He stated he tried other radiators and a single pass and a thermostat but it got worse.

Yes funky header for sure.

Something I do to my headers and my exhaust manifolds that many of my Oldsmobiles had from factory.

I port the header flange where it contacts the head larger than the exhaust port in the head.
This will reduce reversion.
Another reversion reducing step can happen in the intake manifold.

Easy to do with a 2 piece manifold like a tunnel-ram. Where the 2 pieces join together.

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Re: Can too little compression for a camshaft cause engine heating

Post by topradman » Wed Oct 18, 2017 9:35 am

Cam gurus, your opinions on this info please. I realize the numbers are a bit skewed as it was done in the car w/hydraulic lifters on the push rod so some difficulty getting the caliper dead straight with the push rods could be the contributor but would be nice for some more cam guys who are very cam savvy to review this for opinions on any possible correlation to my heating issue.
461 CAM SPECS.jpg
Thanks to all you guys for all your time! I really appreciate it!
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Re: Can too little compression for a camshaft cause engine heating

Post by n2xlr8n » Wed Oct 18, 2017 9:47 am

topradman wrote:
Tue Oct 17, 2017 6:33 pm
( I am very disgusted with this brand new Innovate LM2 as much as the car itself! )

Thoughts????
Yes- on the Innovate. I've not had success with any of their WBO2 products or tech support.

I changed to the Spartan2 (Stinger performance) and love it.

YMMV- some love Innovate, but I'm an outlier, I guess.
He who is in me is greater than he who is in the world.

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Re: Can too little compression for a camshaft cause engine heating

Post by topradman » Wed Oct 18, 2017 10:36 am

topradman wrote:
Wed Oct 18, 2017 9:35 am
Cam gurus, your opinions on this info please. I realize the numbers are a bit skewed as it was done in the car w/hydraulic lifters on the push rod so some difficulty getting the caliper dead straight with the push rods could be the contributor but would be nice for some more cam guys who are very cam savvy to review this for opinions on any possible correlation to my heating issue. 461 CAM SPECS.jpg

Thanks to all you guys for all your time! I really appreciate it!
461 CAM SPECS.jpg

CYLINDER PRESSURE CHECK
#1 149 PSI
#8 151 PSI
#4 156 PSI
#3 151 PSI
#6 151 PSI
#5 149 PSI
#7 149 PSI
#2 150 PSI
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Re: Can too little compression for a camshaft cause engine heating

Post by topradman » Wed Oct 18, 2017 7:31 pm

Ok, took carb off and looked down intake runners and at bottom of carb. No real evidence of reversion, at least not anything dramatic and back into the intake. Still hard to say on the headers themselves though. I really thought I had found the smoking gun when we discovered the homemade perforated cones shoved into the front of the exhaust tips and also the muffler design but with open exhaust, the heating problem is still persists.
willys homemade exhaust cones WTF.jpg

Gonna go back and play with the timing some more and go drive her some more.

Any more thoughts on the cam numbers posted previous would be great to know about if anyone has further opinion on the grind and info on the table I posted.

Thanks guys!
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Re: Can too little compression for a camshaft cause engine heating

Post by travis » Thu Oct 19, 2017 1:24 am

60* initial+mechanical+vacuum seems excessive to me even with the low compression and relatively big cam. I would try pulling 5* out at a time and see if this helps.

If there was any truth in your A/F ratio then that is seriously rich at cruise. How did the plugs look when you did the compression check? Maybe try pulling 4 sizes out of the primaries as a test?

Curious...have you tried driving it without the hood? Could the shape of the car be trapping air under the hood?

Your compression numbers are low, but consistent. I've seen worse that didn't have cooling issues. If you would have had something like 110 psi then that would have thrown up a red flag for me.

Your cam sounds to me like the Lunati 292 BMII

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Re: Can too little compression for a camshaft cause engine heating

Post by BobbyB » Thu Oct 19, 2017 6:46 am

While cruising on the highway, with the engine getting hotter than you want it to, what are the temperatures into the radiator and out of the radiator?

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Re: Can too little compression for a camshaft cause engine heating

Post by topradman » Thu Oct 19, 2017 6:54 pm

travis wrote:
Thu Oct 19, 2017 1:24 am
60* initial+mechanical+vacuum seems excessive to me even with the low compression and relatively big cam. I would try pulling 5* out at a time and see if this helps.

If there was any truth in your A/F ratio then that is seriously rich at cruise. How did the plugs look when you did the compression check? Maybe try pulling 4 sizes out of the primaries as a test?

Curious...have you tried driving it without the hood? Could the shape of the car be trapping air under the hood?

Your compression numbers are low, but consistent. I've seen worse that didn't have cooling issues. If you would have had something like 110 psi then that would have thrown up a red flag for me.

Your cam sounds to me like the Lunati 292 BMII
I agree timing seems excessive but backed it off 5 degrees and heats worse, also doesn't accelerate nearly as good. Backed it off 10 degrees and worse yet, heat and acceleration. ( and yes, that balancer mark is correct with the crank )

A/F ratio at 3100=65mph=11-11.5 now, 2600 rpm=50mph= 11.8-12.5, 2100=40 mph=14-15 if cruising at 60 mph and smash the throttle spike lean then 9.8-10 .... all of this I know is way too rich. It's a Quick Fuel 880 VS and I am not a holley/quickfuel guy so not sure where the best place to start out with fuel changes are on this one. ( I can rebuild and old Q-Jet in my sleep ... but that is not the same thing as "fine tuning" a carb ).

I cannot take the hood of as it is a customer car and whoever built it used too long of screws in the piano hinge type hood hinge and the paint is just starting to star at each screw location as you can see it on the top of the hood. I don't want to be the guy that pops that paint off!

As far as the cam goes, the Lunati 292 BMII does not have enough lift. This one is same as that one but 0.544 lift in/ex.

So what about this?..... Too rich, requires me to run a lot of timing? .... then it cools better because the burn starts earlier but is still rich enough to not detonate and maybe still has some flame travel down the cylinders and into the cooling system because of so much fuel still burning but rich mixture still helps cool down the advanced timing?????

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Re: Can too little compression for a camshaft cause engine heating

Post by CharlieB53 » Thu Oct 19, 2017 7:32 pm

There is another method of reducing exhaust reversion, using a very short section of reduced diameter exhaust pipe right at the manifold inlets. Say 1 7/8 dia by an inch long. This will keep exhaust velocity high leaving the cyl but that slight difference will help quell any reverse pulse, limiting reversion. That is a strange manifold.


You briefly mentioned head gaskets. Curious as to cooling flow, series/parallel, could there be any mismatch there?

Another already asked rad inlet and outlet temps.

IR Temp readings of head and block back to front, are all consistent or varied with position?

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Re: Can too little compression for a camshaft cause engine heating

Post by kirkwoodken » Thu Oct 19, 2017 7:49 pm

There have been many good suggestions to this post, which leads me to think something simple is being overlooked. Are you sure head gaskets are not sticking into the bores causing a hot spot and pre-ignition? I don't know all the effects of pre-ignition, but it WILL make an engine untunable, which seems to be part of your problem. (Looks like I typed too slow.)
Last edited by kirkwoodken on Thu Oct 19, 2017 7:52 pm, edited 1 time in total.
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Re: Can too little compression for a camshaft cause engine heating

Post by CharlieB53 » Thu Oct 19, 2017 7:50 pm

One more thought.

Is the expander spring missing from the lower rad hose? Allowing that high flow pump to suck the hose down, restricting flow?

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Re: Can too little compression for a camshaft cause engine heating

Post by bigblockmopar » Thu Oct 19, 2017 8:02 pm

The fabbed exhaust cone could tell someone has already been busy fighting the overheating.
I don't think I've seen in what car this engine is in?

Some other thoughts that crossed my mind while reading the topic;

- Front air dam / Hood seal over radiator-support;
• As the car only overheats while driving, is it possible to install a (temporary) air dam somewhere under the radiator support, to create a low pressure area behind it. This could help releave and vent hot air from the engine bay better perhaps.
• Most cars have a rubber seal mounted on the inside of the hood, which seals over the radiator/support and prevents hot engine bay air from spilling back over the radiator to the front again.

- Any chance the brakes/drivetrain are/is dragging too much causing the engine to work harder during driving?
What is the engine vacuum while driving a steady speed?

- Perhaps a bit 'very' far fetched; Cylinder wall thickness.
Maybe the walls, even at 0.030" over, are (rusted?) thin (enough) that more combustion heat finds its way into the coolant?
I know it's a lot of work partly disassembling the engine again, but if you have the engine open anyway for some reason soon again, a sonic check could tell something.

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Re: Can too little compression for a camshaft cause engine heating

Post by joe 90 » Thu Oct 19, 2017 8:12 pm

Have you actually measured the valve lift?

You said the lifters were a bit soft.
Are the rockers adjusted right?

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Re: Can too little compression for a camshaft cause engine heating

Post by topradman » Thu Oct 19, 2017 8:15 pm

kirkwoodken wrote:
Thu Oct 19, 2017 7:49 pm
There have been many good suggestions to this post, which leads me to think something simple is being overlooked. Are you sure head gaskets are not sticking into the bores causing a hot spot and pre-ignition? I don't know all the effects of pre-ignition, but it WILL make an engine untunable, which seems to be part of your problem. (Looks like I typed too slow.)
No, the bore is 4.250, the gasket is 4.320.

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Re: Can too little compression for a camshaft cause engine heating

Post by topradman » Thu Oct 19, 2017 8:19 pm

joe 90 wrote:
Thu Oct 19, 2017 8:12 pm
Have you actually measured the valve lift?

You said the lifters were a bit soft.
Are the rockers adjusted right?
Valve lift is 0.544 in/ex ... adjust all valves to 0.040 into the lifter plunger that had 0.160 available travel. 0.040 turns out to be just shy of 1/2 turn from zero lash.

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