Can too little compression for a camshaft cause engine heating

[topradman]

I have ran huge cams with low compression and never had your problems.

I did build a 60 over 350 that ran hot no matter what. 200-215 almost all the time.
I tried different fans and mechanical with electric pushers.

Radiator was a rebuilt 3 core copper brass Larger than factory.
It began leaking and I got a new one from the local parts store.

With the new one it ran 140 F I was amazed..Both of them looked to flow the same amount of water by looking into them with cap off.

So no more rebuilt ones for me.

I assume the fan blades are not all tucked inside the shroud..As you know you need some of the blade to be outside the shroud.

I seen a guy install reverse rotation pump on regular rotation fan.. spun the pump backwards.

I would resort to pulling the back of the water pump cover off and take a look.

Have you tried No thermostat? I boil my thermostats to check them and the flat washer area gets a hole or 3 drilled into it.
My 57 chevy runs warmer than I like down the highway at 85 MPH and I resorted to propping the rear of the hood open 1"

That fixed it. Could not expel the air that was being passed through the radiator with all the inner fenders and the newer style exhaust manifolds blocking the exit.

Lobe separation is 109 on this cam. Duration @ 0.050 230 I/E. Valve lift is nothing great 0.544, intake center line 106.

Radiator is brand new double pass 3 rows of 1" tubes ( = 6 rows of brass radiator core material ), cooling system holds 7 gallons! E fan is well shrouded and has a ring around the outside of the blades so has it's own fan circle 18", pulls 60 amps to start, 3800+ cfm.

Waterpump has correct rotation and is a mechanical Meziere advertising 6-8 gpm more than any competitor at off idle, all machined parts so tightest tolerance you can get. Behaved the same with 2 different 55gpm electric pumps. Not using thermostat bypass hose, heater hoses has shut off so no looping engine coolant. Pump is overdriven w/common size pulleys.

No thermostat, 1 3/4" hoses in and out and 1 3/4" waterneck for intake coolant outlet to match water pump inlet size.

No combustion leaks. No unusual cylinder wear. Correct but improved Cometic MLS head gasket design for coolant flow. ( gasket change/upgrade did make this system cool better but it is not fixed yet.

Running open exhaust w/about 4 feet of pipe on shorty type headers for this last drive.

[user-23911]

Thoughts????

Need less mechanical advance to go with the extra static advance (rework the mech advance).
Should have no vac advance at idle?
It only comes in when off idle.
Never run without a thermostat.
You want 14 to 15 AFR at cruise.
Check for excess pressure in the cooling system after it's cooled down.
A lot of overheating problems are caused by the HG s which won't seal properly.......for whatever reason (knock).
Use a proper knock sensor, the GM resonant ones always work well.
Ears never do.

[tresi]

Electric fans, electric water pump how much other electrical loads? What voltage does it hold at cruise? Have you measured the voltage at the water pump?

[topradman]

Thoughts????

Need less mechanical advance to go with the extra static advance (rework the mech advance).
Should have no vac advance at idle?
It only comes in when off idle.
Never run without a thermostat.
You want 14 to 15 AFR at cruise.
Check for excess pressure in the cooling system after it's cooled down.
A lot of overheating problems are caused by the HG s which won't seal properly.......for whatever reason (knock).
Use a proper knock sensor, the GM resonant ones always work well.
Ears never do.

Ok, so I guess I don't follow. I set base timing w/vacuum advance unattached and best manifold vacuum was 15" with base timing now at 44 btdc at idel. I backed off the base timing and reattached vacuum advance to manifold vacuum then dialed the timing back up to 40 btdc to leave it just a little lower than what base was at with max engine vacuum so now I am idling at 40btdc. I then removed vacuum advance again long enough to double check what mechanical advance was doing and was all in w/o vacuum at 41 btdc @2850 rpm w/new base timing of 21 btdc. I then reattached vacuum advance to manifold vacuum and throttled it back up to the 2850 rpm to give me back total timing available of 60 btdc as suggested might be a sweet sport for this engine combination. Now I should be at about the 60 btdc as a theoretical target timing for light load cruise speed?

I don not trust the Innovate LM2 for accurate AFR so who knows for sure. The meter is acting up every few miles and locking up.

I do not have a combustion leak. ( at least not yet ).

This is a 461 (454 + 0.030) in a 1941 Willys so doesn't have a knock sensor available.

Reversion in stupid design short headers combined w/109 lobe separation???

[topradman]

Electric fans, electric water pump how much other electrical loads? What voltage does it hold at cruise? Have you measured the voltage at the water pump?

Electric fan and carbureted style electric fuel pump. Electric pump has been replaced with a "HERO" Meziere belt driven $400 mechanical pump (with correct rotation and overdriven like oem 454 pulley set up). 14 volts down the highway until cooling fan kicks in, then about 13.5-13.8V ( new 140 amp alternator ).

I feel like if things were right with this engine, the E-fan shouldn't even come on at 65 mph and fan set to come on about 190F/ off at 180F. I can watch the volt meter and see when the fan comes on as it jumps down just a touch. This fan is a duplicate of the discontinued Vintage Air Monster Fan and takes about 60 amp to start the motor! I have used them on many, many projects and never been disappointed with air movement. This car cools wonderfully at idle with ac on.

[jeff swisher]

Some of those double and triple pass radiators state do not use a thermostat.
I had a triple pass 2 core 1" tubes on my Bone stock 283 in my 57 chevy with stock water pump..Got hot in a hurry like 5 minutes.

I learned the pump needs to flow a lot of fluid for a triple pass.

190F is not bad at all ,It is what mine runs with no thermostat on highway at 90+ temps where the cooling is compromised.
Around town if I never get on it It stays in the 145 area. Until I get on it then it settles in at 165.

I have seen where triple and double pass radiators make the car run hotter if flow is not correct.

Another thing I have seen a few times is the thick 3 core aluminum radiators making the engine run hot.

You would think more cores would be better but then you must look at fin count when you get fat.
The first 2 rows cool really well with all the cool air pulling the heat from them but as you get deeper into the radiator you get less cool air and sometimes that third row does nothing but become a restriction.

Some electric fans will leave a lot of radaitor surface bare with no air flow.. that could be an issue when looking for every square inch of cooling area.

[topradman]

Some of those double and triple pass radiators state do not use a thermostat.
I had a triple pass 2 core 1" tubes on my Bone stock 283 in my 57 chevy with stock water pump..Got hot in a hurry like 5 minutes.

I learned the pump needs to flow a lot of fluid for a triple pass.

190F is not bad at all ,It is what mine runs with no thermostat on highway at 90+ temps where the cooling is compromised.
Around town if I never get on it It stays in the 145 area. Until I get on it then it settles in at 165.

I have seen where triple and double pass radiators make the car run hotter if flow is not correct.

Another thing I have seen a few times is the thick 3 core aluminum radiators making the engine run hot.

You would think more cores would be better but then you must look at fin count when you get fat.
The first 2 rows cool really well with all the cool air pulling the heat from them but as you get deeper into the radiator you get less cool air and sometimes that third row does nothing but become a restriction.

Some electric fans will leave a lot of radaitor surface bare with no air flow.. that could be an issue when looking for every square inch of cooling area.

Oh Jeff! IF only it were that simple! I have been in the radiator business since 1981. I was around for the birth of the 1st American made aluminum/plastic radiators installed in Corvettes and I remember how we marveled at how their constructions could ever hold up! More than 75% of all radiator shops are now extinct yet I still have a 7 employee shop up and running so I have accumulated a bit of knowledge on cooling systems in particular. I built this aluminum radiator myself and know exactly what you are talking about on all levels of "2 pass" and "3 pass" radiators. I have built hundreds of all aluminum radiators for all sorts of applications from 1500 hp blown street rods to stationary Cummins powered generators that were 6 feet tall and 5 feet wide. I have only ever had one vehicle kick my butt like this before and it was a 12:71 on a 572 Merlin in a prostreet 57 chevy and the owner refused to address the engine as a possible issue and sold the car at auction.

I will admit that this car has made me second guess everything I thought I knew about cooling. I even put the radiator back to a single pass, installed a drilled thermostat, changed back to just a restrictor and all of those things done separately made it worse so I put it all back like I originally designed the cooling system with 2 pass, no thermostat or restrictor, and changed from E-pump to belt driven, overdriven high end mechanical pump.

I have the most aggressive mechanical water that I can find on this little BBC. I am not running a thermostat and no coolant loops via heater hoses or bypass hose. The electric fan will suck a beach towel up to the grill which is 5" away from the front of the radiator. The E fan is very well shrouded. ( I have built hundreds of those too )

Where I am weak on this kind of problem is in the air/fuel ( I know stoich is 14.7 ), ignition, cam timing, cam profile areas of expertise and how it might cause this engine to suck exhaust back into the cylinders at increase rpm as this is what I am assuming is taking place as there is no other reason I can come up with that explains how in the hell fuel boils in the carburetor at only 190F engine temperature???

[jeff swisher]

Sounds like the bases are covered on the cooling system.
You are many steps from the local monkeys that do not build cooling systems.

So lets talk friction and heat.

One other build that was not mine was a 455 olds it was bored and not honed..ran super hot and eventually locked up.

I run my cast pistons at .0035" piston to wall and much more than that with forged.
.0025" does not run any hotter but I beat on my stuff. and Old long skirt pistons are what I was using.

Too tight maybe.
Now my 57 chevy the fuel lines were about 6" from the exhaust manifold Running E85 with 91 octane or running any ethanol the fuel would get air bubbles in it.
Fuel filter was see through and you would run out of fuel if you waited in line at the track..vapor lock deal.

I built shrouds from shiny aluminum sheet and attached them to the exhaust manifold facing the fuel pump.
And facing the fuel lines.

Rubber fuel lines hold heat much longer and will heat soak the fuel easier.
Electric fuel pumps ran on a return set up will or should I say can heat the entire tank of fuel on hot days.

Probably not your issue as 23 mile trip would not be long enough unless you are in rush hour Cali traffic.

If it has a block mounted mechanical pump there is a gasket made that reduces heat transfer to the pump.
Might look into that.
Every little thing as you know will eventually add up.

I would thing fuel boiling on your deal is started down stream of the fuel supply to the carb.

[hpetew]

Whenever I've run without a thermostat or a restrictor in the water neck the motor eventually overheats.

[amcenthusiast]

Just wanted to stop back by and say sorry for my lack of tact saying 'get a Chilton's Manual' -may have come off like an insult... didn't mean it that way... I've got forty years of wrenching-on-motors experience and I still refer to mine every now and then -could help to keep from 'overthinking it'?

[topradman]

Just wanted to stop back by and say sorry for my lack of tact saying 'get a Chilton's Manual' -may have come off like an insult... didn't mean it that way... I've got forty years of wrenching-on-motors experience and I still refer to mine every now and then -could help to keep from 'overthinking it'?

No worries, not easily offended. Too old for that shit! LOL

[topradman]

Sounds like the bases are covered on the cooling system.
You are many steps from the local monkeys that do not build cooling systems.

So lets talk friction and heat.

One other build that was not mine was a 455 olds it was bored and not honed..ran super hot and eventually locked up.

I run my cast pistons at .0035" piston to wall and much more than that with forged.
.0025" does not run any hotter but I beat on my stuff. and Old long skirt pistons are what I was using.

Too tight maybe.
Now my 57 chevy the fuel lines were about 6" from the exhaust manifold Running E85 with 91 octane or running any ethanol the fuel would get air bubbles in it.
Fuel filter was see through and you would run out of fuel if you waited in line at the track..vapor lock deal.

I built shrouds from shiny aluminum sheet and attached them to the exhaust manifold facing the fuel pump.
And facing the fuel lines.

Rubber fuel lines hold heat much longer and will heat soak the fuel easier.
Electric fuel pumps ran on a return set up will or should I say can heat the entire tank of fuel on hot days.

Probably not your issue as 23 mile trip would not be long enough unless you are in rush hour Cali traffic.

If it has a block mounted mechanical pump there is a gasket made that reduces heat transfer to the pump.
Might look into that.
Every little thing as you know will eventually add up.

I would thing fuel boiling on your deal is started down stream of the fuel supply to the carb.

Don't think too tight. When the heads were off I could move the pistons to one side and see a compression ring gap. Rolling resistance w/heads off & torque converter released was fine ( don't remember what the value was on the wrench but remember it was fine and no major scoring on the piston walls ).

I will take further steps tomorrow to check fuel hose routing but think it is fine ( -8AN front to rear on no restrictions, has new e-pump )

Here's what I have on the camshaft. Bear with the numbers being a little skewed as I had to do it in the car, heads on, hydraulic lifters and was having to work off of the push rods and the springs in the plungers are a little soft, even though low miles. Admittedly, I could have made a mistake on the one cylinder with the one weird value. ANY BODY ELSE PLEASE FEEL FREE TO CHIME IN WITH OPINIONS OR EXPERIENCE WITH A SCREWED UP CAM COMBO LIKE THIS AND THE CHEESY HEADERS SHOWN PLEASE

Here is the best I could do in the car on all 16 lobes. Cam timing is set w/o advance or retard on the chain. The numbers check out reasonably spaced at about 90 degrees across the board so if the cam is ground wrong, it's not WAY wrong anyway.

Note the funky headers with the 2" primaries pointing towards each other in a flat collector and super short, especially the middle. Reversion problem to culminate into an overheating problem with this cam and low CR with big chambers????

[tresi]

It could be possible that the headers are to blame but they're no worse than stock manifolds to me

[topradman]

It could be possible that the headers are to blame but they're no worse than stock manifolds to me

Hard to tell. If you look up inside the collector the primaries are dumping into a big open flat area and pointed at angles towards each other. Unlike a manifold, the primary portions usually don't ever dump into a big fat, wide chamber like this and then expect to be necked back down again to exit through a 2 1/2" collector when primaries are not that much smaller than the collector outlet itself. I could be completely wet here though.

Collector area at the primary entrance is 8" x 2" roughly ( 4-2" primaries in a row, (2"+2"+2"+2") x one pipe thick (2").
Normal headers typically have so much longer primaries and are moving into the collector in a parallel fashion to help each ones pulse help pull on the next firing primary on that bank.

I d'know ..... I am probably reaching?

[Geoff2]

I suggest you look at Tech Tips on the site below. I might cure any desire for yourself [ & others ] to run 2x/3x pass radiators....

www.stewartcomponents.com