Spark Advance versus Overheat

[drolston]

From 30 to 50 mph, my flathead is happy as a clam. On a warm day, it overheats badly in slow traffic and if I push it up in speed or up a long grade. Block was boiled out for recent overhaul; new aluminum radiator; new Carpenter water pumps; 170 degree high flow thermostats, fastened in place. Bored and stroked to 284", mild Schneider 248f cam.

It is commonly noted in the threads I reviewed that having the spark retarded can contribute to overheating. I advanced the spark one tick mark (2 degrees, I think). The engine likes that setting; starts easy; no pinging. In searching the threads, one comment suggested that having the spark too advanced could also cause overheating. I guess I should try retarding, but I hate to disturb such a sweet running engine.

Suggestions?
Take the thermostats out?
Spend a small fortune on a Brassworks radiator?

[1931 flamingo]

Have you tried measuring temp at top of radiator and again at the bottom after the t/stats have opened??
My 40 drops 30* top to bottom with NO stats, new pumps.
Paul in CT

[drolston]

Originally Posted by 1931 flamingo

Have you tried measuring temp at top of radiator and again at the bottom after the t/stats have opened??
My 40 drops 30* top to bottom with NO stats, new pumps.
Paul in CT

I have checked with the IR gun and don't get that much drop.
Why did you decide tor run without thermostats? Also have overheat issues?
My next move is to remove the thermostats and see if it makes a difference.

[swedishsteel]

I have a '36 lb engine with a Potvin 3/4 cam. 2 97's on high rise Eddie Meyer manifold, Eddie Meyer heads, stock distributor rebuilt by Bubba. Bubba sets the timing when he ships them back and marks "where it should be". My engine puked coolant out the radiator at highway speed at that advance. Read all I could find about different timing with different cams. I ended up advancing the distributor to the max-with thermostats it runs cool all day long--sit in line at Back to the 50's for 45 minutes and it gets to about 190. Sarts instantly and keeps pulling as long as I keep my foot in it. Hope this helps. Rod

[flatjack9]

What engine engine and distributor do you have? I doubt you have advanced it enough to cause any overheating. Any way to check spark advance?

[drolston]

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Originally Posted by flatjack9

What engine engine and distributor do you have? I doubt you have advanced it enough to cause any overheating. Any way to check spark advance?

Engine is 59A/B with Pertronix in the crab distributor. I have no electronic way to check timing. I have always done it by ear. The engine was broken in with the timing mark on the side of the distributor at the center mark. I ran fine there. I advanced the timing one mark and it ran fine there also. So I left it there on the theory that the more advance you can run without pinging, the better. I will try advancing another two degrees to see if it starts easily and runs without pinging there. And if it makes overheating better or worse.

[Bored&Stroked]

My guess is that you could use more advance. I run a Vertex Magneto on my 284 cube engine and run about 24 degrees total advance. I'd move the advance up some more - and keep doing so until you have a pinging issue. How did you setup your vacuum brake?

[Tinker]

Curious, I've never had pinging on 87 gas. Octane is too high? Is it it me?

[drolston]

Originally Posted by Bored&Stroked

My guess is that you could use more advance. I run a Vertex Magneto on my 284 cube engine and run about 24 degrees total advance. I'd move the advance up some more - and keep doing so until you have a pinging issue. How did you setup your vacuum brake?

The brake has was initially set with a light touch. Maybe I should give it half a turn in to be sure it is still making enough friction to stabilize the breaker plate?

How would you do it?

[flatjack9]

I am one who does not believe that the disc is there to stabilize the plate. Most of the time the vacuum is keeping the disc off the plate, so how can it stabilize?

[mfirth]

Here's $.02 worth more to think about. I ran 160 stats in my 8ba & changed to 180 stats. It runs cooler over all with the 180s .

[JSeery]

Originally Posted by mfirth

Here's $.02 worth more to think about. I ran 160 stats in my 8ba & changed to 180 stats. It runs cooler over all with the 180s .

The thermostats should not have much of an impact on the maximum operation temperature. They increase the rate the engine warms up and maintains a minimum operating temperature.

[1931 flamingo]

X2
Paul in CT

[G.M.]

You need to fill the radiator with the required 22 quarts
to get a true reading. G.M.

[drolston]

Originally Posted by G.M.

You need to fill the radiator with the required 22 quarts
to get a true reading. G.M.

The core on that Champion aluminum radiator is 19" tall, which is almost 2" shorter than stock, and the tank is also about 2" shorter. So that is maybe 3 quarts less total capacity. The smaller radiator core size surely makes a difference in cooling capability, but I do not believe the total volume of water in the system makes much difference, as long as the core is covered and not sucking air into the tubes.

When I got the car it had a 22" tall, 21" wide radiator part #01T (from a 122" wheelbase truck, 39 -41, I think) wedged into it. It leaked a little but never overheated. If that solves the problem, I will probably spring for the Brassworks or Walker. Ouch!

[Tinker]

Cooling capacity does make a difference. Not to say reduced would not work.


Put two pots of water on the stove at the same heat and time. One is 1 cup of water, One is a 2 cups of water. Which to boil first.


Same if...If you put two 55 gal drums plumbed on the front of your car, you'd be highly unlikely to ever overheat. Maybe timing, block restrictions, over bore,...etc. Certainly a radiator that is restricted would not help.



No matter the temp sensor, even if they can be restrictive in summer or high heat ambient temps.

[Pete]

"If that solves the problem, I will probably spring for the Brassworks or Walker. Ouch!"

Check to see if you have a local radiator shop that is familiar with circle track racing radiators. They can usually make you a radiator cheaper and better than the popular hot rod shops. They will also know how to baffle it to stop aereation. Aluminum is not the way to go for a street driver. Copper cools better. Aluminum is lighter. It lightens your wallet better also.

"Boiling out" a block generally refers to hot tanking. this will NOT remove rust/scale, especially in the bottom of the water jackets.
A block that has been acid stripped will never overheat if the cooling system is working right.

As for spark advance on a mildly modified flathead, lots of numbers have been published but the end result is usually a seat of the pants setting assuming the distributor has been set on a machine. You also have to have a positive way of determining top dead center and have a degreed pulley. If you power time on a chassis dyno, from maximum horsepower, you will need to retard the distributor about 2 degrees for normal street driving.
Total advance should be about 24 to 28 degrees and all in at 2000 rpm.
You do not need the vacuum brake on a modified engine. The weights will take care of the advance curve.

[Tinker]

Pete, maybe a circle track guy can do it for street. Most circles ran 20min at max everything. Drag flatheads could be plumbed from pump to head or less.

Circle track guys would have the skills to make it right.

I do run recored rads from a local. Did a nice job retaining upper and lower tanks. Not cheap but everything fit, important on with early fords.
.

[drolston]

I checked a local old-school radiator shop regarding re-core of the truck radiator I have. The new core is over $700, which, with labor, puts that approach in the same price range as Walker and Brassworks.

Regarding water capacity: If more heat is going in than the radiator can take out, the thing is eventually going to boil, regardless of how much water the system holds.

Also, I checked back with the local shop that built the engine; they know flatheads and swear that the inside of the block was pristine. The engine did not overheat before the overhaul and radiator change, so I believe that the block is okay. But bored and stroked means burning more fuel and creating more heat with each cylinder firing. The cam is pretty mild, but exhaust valve timing could also be dumping more fire through that block.

I will report back after the radiator swap.

[Tinker]

Originally Posted by drolston

Regarding water capacity: If more heat is going in than the radiator can take out, the thing is eventually going to boil, regardless of how much water the system holds.

I will disagree here. It'd be like inner coolers are pointless, if normal air flow is fine. But we can disagree.

It's just volume and heat increments. Cool Volume is always better. But maybe the exhaust should be piped to the intake too, as there is hot fuel charged air there. But we want that out the engine.

drop a gallon of boiling water in a bucket contenting 1 cup of cool water or a 5 gallon bucket of cool water. Which one are you going to stick your hand in right away.

But as you say if your radiator is too small too undersized in volume and can't handle the take out and interchange, it won't discharge heat.


Never heard a bad word about Brassworks or Walker. Pertaining to fit of sheet metal or other. Guess when building a hp motor there is some things to do.




.

[Ol' Ron]

The vacuum break must ride the disk at all times, or the ignition will become erratic. The idle or cruise hi vac will not remove the piston from the disk if set properly. Been there, done that. As a racer, I once removed the piston and had trouble finishing last.

[chap52]

I ran a Champion Radiator in my 52 F1 239 for years, never overheated, got hot but never went volcanic. That includes the Arizona summers. Chap

[drolston]

Originally Posted by chap52

I ran a Champion Radiator in my 52 F1 239 for years, never overheated, got hot but never went volcanic. That includes the Arizona summers. Chap

Yeah, but it is dry heat. (old Arizona joke)

Most users of Champion radiators agree that they work fine, and I am sure I am not the only one running a hopped up engine. It's a mystery that I will eventually solve!

[flatjack9]

Originally Posted by Tinker

Cooling capacity does make a difference. Not to say reduced would not work.


Put two pots of water on the stove at the same heat and time. One is 1 cup of water, One is a 2 cups of water. Which to boil first.


Same if...If you put two 55 gal drums plumbed on the front of your car, you'd be highly unlikely to ever overheat. Maybe timing, block restrictions, over bore,...etc. Certainly a radiator that is restricted would not help.



No matter the temp sensor, even if they can be restrictive in summer or high heat ambient temps.

Naturally 1 cup will boil faster, but before long the second will boil also. Practically speaking, if a radiator has a little more water than another one, if the engine is producing too much heat, both will boil within a short time of each other.

[Bored&Stroked]

Unless you need something custom and/or have original tanks and sheet metal that you want to reuse, I'd get a Walker or Brassworks radiator. I had my original 32 radiator re-cored, cost me $900 -- my main reason for doing it was that I wanted the look of the 100% original tanks, side metal frame, etc.. I had it done locally (was in a hurry). they did a decent job, but my bet is that Brassworks would have done an even nicer job . . . but I'd be paying for shipping both ways, would need to wait a bit, etc..

[Tinker]

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Originally Posted by flatjack9

Naturally 1 cup will boil faster, but before long the second will boil also. Practically speaking, if a radiator has a little more water than another one, if the engine is producing too much heat, both will boil within a short time of each other.

Pete you could say that the volume of ford was designed for a specific amount. Reducing it won't help. But to say previously that it doesn't matter is not productive. Not by you mind it. That qt might be enough to get you through traffic. Granted everything is working.

[retep]

I am a believer in the vacuum gauge.
I don’t have any experience with Pertronix so I am not sure if this negates gauge use.
What reading do you get ?

[drolston]

My vacuum at a slow idle (550 rpm) is around 15 with a little dither. At a more comfortable 650 rpm the vacuum is still around 15 with no dither. I know that vacuum is lower than the advertised normal of 17, but I am running a Schneider 248f cam; pretty mild but the duration is longer and I expect that to lower the vacuum at idle. As far as the Pertronix, it is just a substitute for points, and does not affect vacuum or overheat issues.

I have had too much going on lately to tinker with the car, but later this week I will get back into this overheat challenge.

[tubman]

Have you retimed the car since you put the Pertronix in? I installed one in a 350 SBC I had in a boat years ago and when I tried to start it, it backfired a couple of times, hydro-locked, and broke a rocker arm (one of those cheap aluminum rollers Speedway used to sell). I double checked everything over (thinking I had crossed a couple of plug wires) and everything was correct. The only thng I could think of was that the Pertronix somehow had an effect on the timing. I retarded the spark, and the engine started and ran pretty decent. After I put my timing light on it and moved the timing so the light was flashing on the pointer properly, the boat ran great and I never had another problem with it. I don't know exactly how those crazy electronical things work, but I definitely had to reset the timing after I installed the Pertronix. (And bought another rocker arm.)

[drolston]

Originally Posted by tubman

Have you retimed the car since you put the Pertronix in? I installed one in a 350 SBC I had in a boat years ago and when I tried to start it, it backfired a couple of times, hydro-locked, and broke a rocker arm (one of those cheap aluminum rollers Speedway used to sell). I double checked everything over (thinking I had crossed a couple of plug wires) and everything was correct. The only thng I could think of was that the Pertronix somehow had an effect on the timing. I retarded the spark, and the engine started and ran pretty decent. After I put my timing light on it and moved the timing so the light was flashing on the pointer properly, the boat ran great and I never had another problem with it. I don't know exactly how those crazy electronical things work, but I definitely had to reset the timing after I installed the Pertronix. (And bought another rocker arm.)

The Pertronix decides when to fire the coil depending on how its' sensor sees the bumps on the cam. That relationship could certainly affect timing. After rebuild I set the timing to 3 degrees advance on the distributor adjustment. It started and ran great (except for the overheat issue) so I have not messed with it since then. Next thing on my trial and error method is to check the vacuum advance damper on the distributor, to be sure it is not in too tight. Then I am going to go full advance on that adjustment to see if it pings. Back off from there if necessary.