Overheating in parade - Thoughts??

[Earle]

During an hour-long idling period before the parade yesterday while lining up, the engine overheated, dumped a LOT of coolant on the ground (still had some left) and started running unevenly. It hesitated and bucked in taking power to start rolling. Motometer "mercury" got nearly into the clear circle but not into it. I was keeping it at a higher-medium idle the whole time with spark lever at middle position.

Improved when I pulled into the shade and low power and bucking eased off when I got rolling up to speed (35) on the ride home. Running normally by the time I got home (10 miles).

In garage, I opened rad. cap and steam kept billowing out. I slowly added water while she was at medium idle. Took over a gallon. Idled OK. Steaming stopped. Ran smoothly.


Never had this problem before in years of running slowly down parade routes in 90-plus temperatures. I know what I'll start trouble-shooting for today, but I'll expect to learn a lot if I can hear some of you experienced folks confirm what the problem might be...

Background:

Engine just got new inserted rods, rings and bore-honing 400 miles ago (still in "500-mile 35 mph break-in period" - Schwalm's).

Part of the above work, obviously, was the correct set up of the timing. Plus, valves were adjusted.

Block was flushed and cleaned about 4000 miles ago (Schwalm's)

Radiator was properly cleaned and rodded about 4000 miles ago.

Has had a 160 deg. thermostat for about 4000 miles.

Use 50-50 water and Prestone all the time. Change out every season.

New leakless water pump about 4000 miles ago.

New "Petronics" electronic ignition about 4000 miles ago.

New head gasket during engine work, properly torqued and re-torqued.

New hoses and clemps. no leaks.

Radiator full prior to parade.

No "steam" coming from exhaust pipe during the overheat "event".

No "foam" on dip stick. Only clear, new Rotella oil up to proper level.

New fan belt at proper tension.


My thoughts:

1. More heat is being generated because engine is still "breaking in". This put me "over the edge" in the radiator's cooling capacity.

2. Thermostat has stuck closed or was put back in backwards during recent engine work (?).

3. Rodded radiator that was flowing freely only a couple thousand miles ago has clogged up already!


What else?? - HELP??....

Earle

[1931 flamingo]

If radiator was properly rodded and block was flushed and cleaned and coolant changed out every season, what would "clog" it up? I think if I'd been idling for an hour ( Why?), it wouldn't have been at a fast idle with a newly rebuilt motor. JMO
Paul in CT

[George Miller]

I would never let a engine idle for a hour. With a new engine I can not think of any thing that would be worse than letting a engine idle for a hour in 90 degree heat. New engine make more heat than a old engine.

[peters180a/170b]

Had the same problem Sunday before i had to leave for the FRENCH LICK meet. But i had some brown oil in the radiator ,time and time again after flushing the system out. Head gasket,, water leaked to cylinder 1 and was pushing oil and air to radiator. So Monday nite head and all came off ,Tuesday nite new head gasket went on [hopeing no crack in head] Wed nite ran around the neighborhood for 40 minutes and not a drop or steam came out.Thursday nite loaded the car into the trailer and Friday nite off to the meet. Work always gets in the way ,could of had this all done in 1 afternoon..l.o.l. SCHWALM did a soup to nuts engine job and the gasket was not their fault. I now have 30 miles on the engine and runs fine.

[Bruce Adams]

Hi Earle,
I am a big believer in checking the radiator with an infra red thermometer to check for hot and cool spots indicating blocked tubes, but idling for an hour on a hot day still seems to be looking for problems. I was in a parade yesterday in a 95 degree day, even with my new eight fins per inch radiator, it was hot in the top-down convertible, so I turned the engine off during a long downhill portion just to keep the cockpit cooler. The only down side of that was my horn isn't as good with the engine off, but it certainly cooled the passenger compartment.
The infra red thremo registered less than 180 degrees at all points following the parade, so I guess my eight fins per inch radiator radiated properly.

PETER, I used Costco OIL EATER which removed all that brown gunk, but it found holes in my blocked tubes, causing me to purchase a new radiator when the radiator guy said a new core was needed. Its SO NICE to not have to add coolant anymore with my new radiator.

[V4F]

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never had mine heat in a parade & do about 8 per yr . as others have said , i dont idle mine that long . waiting in line i shut it off . in the parade , if stalled as they all do , i shut it off . mine never gets over 170* on a 160* thermostate . i would check all , compression , sniff the radiator for combustion leaks , etc ... steve

[Ken Ehrenhofer]

You can rod out a radiator and make it perfectly clean but do not forget that there is also an attachment betwen the tube and the fin that must be physically attached or it will still not cool properly. It will look great but not dissapate the heat.
IMHO,
Ken

[Earle]

I just want to be clear that "idle" might be the wrong word here. Y'all are probably thinking that I was sitting for an hour at a dead-slow, chug, chug, chug, "typical" Model A slow idle. I wasn't! The RPM's were stepped up quite a bit to a smooth, "medium" level. I don't have a tach. so I can't guess the RPM. 800 - 1000?? And what's the difference between that kind of higher "idling" and the 3 - 5 MPH extended run time once you're rolling in the parade. You all have done that (you parade-goers).

My bad, I guess. Maybe I should have bugged out when I saw what I was up against in this heat but I had no reason to based on previous no-problems in hot weather parade conditions. And I was in my last 100 miles of the "standard" break-in period! I never had a hint of a problem in previous same conditions so I felt "safe".


Let me play "devil's advocate" here for a minute:

You guys seem to be chalking this up solely to the tightness of an engine that's just been rebuilt? It had over 400 miles on it in the break-in! Though I know there's still some tightness there but way better than when new!

The engine still has to accumulate "mixed-load-condition" run time during the break-in - and extended idling with proper cooling and lubrication would not - should not -be harmful. What did "industrial" 'A' engines do back in the day when they were bolted to an air- compressor or a factory floor in the hottest conditions immaginable and ran all day sitting still?

When you think about it, as far as the components in an engine are concerned, a 95 deg. day is little different from an 80 deg. day - only 15 degrees. That's a drop in the bucket for the metal parts of an engine. And the rest of the non-metallic parts are designed for operating temps way higher than that as well!

It was a very long parade and took a long time slowly feeding the groups into it at the starting point. So it was frequent stop-n-go. I elected to keep the idle high to draw more air through the radiator and keep the oil splashing around good rather than repeated stoping and restarting the engine (not good either!).

Could heat cause a degraded perfoemance of the electronic ignition module and cause overheating?! - Then go back to normal when it cools down?

End devil's advocacy....

I'm not writing off the tight-engine theory altogether. You more-experienced engine folks out there are way smarter than I am.

Please keep the input coming. I really appreciate it and need to continue weighing all the possibilities. - And be told where my "devil's advocacy" ideas are off base!!

Today, I'm topping off the radiator and taking her for a "test drive" (another 95 deg day here in Del.) - and looking into the filler hole to see if I can see water flowing. If I don't see any flow and still have an overheat problem, I'll start by checking and replacing the thermostat (the old submerge-it-in-a-pot-of-boiling-water trick to see if it opens. - Actually, 160-170 deg. water...).

Thank you all. I'll post my findings.

Earle

[MAG]

My "guess" would be a marginal radiator. I don't have to say that the radiator is the heart of the cooling system. If it ain't happy none of the other cooling components will be. No one likes to hear "radiator problems" because they are expensive. Unfortunately, trying to work around a marginal radiator is usually a futile attempt. Poor adhesion of fins to tubes, blocked off tubes, and other undetected obstructions are the enemy to the radiator. It may work most of the time but give it a severe test and it will fail.

[Earle]

Thanks, Gents, especially the comments about the fin-to-tube contact in an old radiator (which mine is) - and the I.R. thermometer idea. Duuhhhh....I have an I.R. thermo (cheapie, but accurate from Harbor Freight) that I never thought of employing here.

There may be light at the end of the tunnel as to finding a cause - UNLESS it's the headlight of a locomotive in the form of a new $600+ radiator!

Thanks again,

Earle

P.S. Can any of you guys cheer me up here and tell me I haven't done any damage to my newly-rebuilt engine! If she runs smoothly, compression is good and no signs of oil in crank case, radiator or exhaust, and no strange noises, shouldn't I be OK?

[skip]

Famous line in TORA TORA TORA,
"My engine is overheating and so am I"

Waiting for the carrier to turn into the wind for take-off.

Kind of like a parade. skip.

As in another post, TIMING TIMING TIMING! Too far advanced or too retarded.

[Tacoma Bob]

Earl, Im relieved to hear others talk about fin to tube contact. I have been saying that for years as it happened to me. Brand new rebuild and marginal radiator. I was ideling on an interchange at the Portland OR meet several years ago. The host hotel was maybe a third of a mile and I couldn' t just shut it off as traffic was creeping. Temp was nuts both outside and in my new engine. I screwed around for over a year and finally ordered a brassworks. Best money I ever spent. I suspect your engine still has a few more miles to go. Personally I don't buy the 500 mile bit. For me 800 to 1000 just makes more sense. So I would wait a bit till your really broken in and then see what happends. You may have a radiator thats on the way out and the engine is revealing it.

[Benson]

Earl,

About parades:

In case no one mentioned it:

If you leave the clutch pedal depressed for longer than a few minutes and do it often enough you will wear out the thrust bearing on your engine.

As wear increases so does the for and aft movement of the crankshaft and the rear main leak will get worse.

[MikeK]

My worthless guess is that the end gap on one of the new rings is insufficient. When idling with a dipper tray engine there is insufficient splash oil to cool the underside of the piston tops, causing both the piston top and rings to expand. Prolonged idling is not a good thing. When just one ring or the piston top starts to lock up it is like running against a brake, causing the engine to run rough and generate a lot of heat.

If you did not scuff the bore it is a miracle. Do a cold compression check, inspect with a bore scope through the plug hole if you can borrow one. If the piston/ bore clearance or one of the rings was set with insufficient gap, it is the engine builder's liability. Document, measure, and photograph everything if you find a piston or ring problem.

[Tony S,Fl.]

Why is your spark lever half way down. I see too much retard which will cause overheating if the engine is timed properly. Tony

[Michael P.]

Earle, My '31 Slant Windshield 4 Door Sedan idles the best and the engine runs the coolest in parades when I have the timing lever all the way down. Maybe it's just my particular Model A but I only have the lever all the way up to start the engine then it's lever all the way down for the rest of the driving whether idleing or full speed. Also, what was the GAV set on the carburetor? I believe a too lean mixture can create overheating. I've seen it happen on one of my Model T's at night. When the carburetor is set too lean the exhaust manifold glows red!

[Old182]

Gentlemen: I'll admit I'm a 15 watt bulb in a 25 watt world, but can someone explain the purpose of a thermostat in a Model A engine? Unless I'm mistaken, a 160 thermostat is closed until the coolant reaches 160, then opens. This is great if you have a water-fed heater and you want it to put out heat sooner than later, but otherwise it's just a restriction in the system. It can't make your engine run cooler than without it; in fact it can only cause the coolant to circulate more slowly. What's the advantage? Thanks for helping a dimwit. BTW, the car handled 90+ degree temps in the Cornwall, NY parade yesterday with 50/50 tap water/antifreeze, no Water Wetter, ~1/2 mph, ~2 miles, spark up all the way with 170F upper tank, 148 lower after a hot soak following the parade. It handled the heat WAY better than the driver!

[Earle]

Tony,

I leave the spark lever only half way down because I've been told by experienced 'A' drivers (and it makes sense when you have detonation occuring more and more before TDC) that the more advanced you go on the spark lever the higher the loading becomes on the rod bearings (I'm a little protective of my new and very expensive rod inserts!).

The Model A Instruction Book says to move the spark lever "about half way down" after the engine starts. and, "Only for high speeds should the spark lever be advanced all the way down..." (whatever "high speeds" means). I take all of this to mean that during idling and normal driving, the spark is to be no farther than "about half way down."

As for the "work-in" (break-in) period, the Instruction Book says, "...during the first few days...a new car should not be driven faster than 30 to 35 miles per hour for the first 500 miles." I'm thinking that the manufacturer would have known best what it took to properly break in the engine in a way that he would then be willing to stand behind the warranty. But I still take it extra easy and stay below, or only briefly at, my favorite cruising speed of 40-45 MPH for well beyond 500 miles.

Mike - Thanks for the good info. on ring gaps (scary...but I'm very inclined to trust a guy like Ora Landis at Schwalm's to do things right. But I'll check that out with him.).
What should the correct ring gap dimension be to allow for all expected high temperature conditions?

Earle

[Michael P.]

OLD182, You are correct in that a thermostadt does not help keep the engine cooler. It is there so the engine warms up faster and stays above a certain temperature so that it runs more efficiently and the gas air mixture combusts properly. The original set up on the Ford Model T does not use a thermostadt and works off the "thermosyphon" principle. On cold days it takes forever for the engine to get up to a good efficient running temperature and on really cold days some folks place pieces of cardboard in front of the radiators to block out some air so the engines run warmer. There were even aftermarket manual and automatic loovers sold for Model T's driven up North.

[J Franklin]

Check for fan belt slippage first before you tear into things.