8BA Flathead overheating on highway

[FlatheadTed]

What fan arrangement Are You running ?You need to run a stock fan like early fords came out with they move a lot more air and this air needs to move through at speed ,don't rely on a electric fan alone you can run a electric fan on the front down low but this can parsley block the air flow so you run the stock fan set up or the equivalent plastic one with mutable blades with even a shroud that will pull the air past it .As been said It sounds like your Radiator is not adequate your motor needs more cooling than the others you compared it with, As a test try and run it at a fast idle until the tempt comes right up then place a 13" house fan in front this should start dropping the temp down if it does that will show you that air flow will do it . Ted

[SonicRaT]

It's running an electric fan -- but at highway speeds, the fan becomes generally irrelevant unless it's a pusher and impeding air flow. I've bumped the idle speed up to about 2K rpm and left it running there and it doesn't overheat -- the fan/thermostats cycle and keep it all within normal range.

I don't think it's a radiator issue, unless there's some internal flaw -- the core size is larger than most of the low boys with flatties and it was built by a fairly reputable manufacturer. I think going up in size would likely just mask whatever the primary culprit is.

Originally Posted by Ronnieroadster

Adding the C-4 transmission heat to the radiator is the first thing you should eliminate when i use the C-4 behind any Flathead an external cooler is used so no heat is added to the engine cooling system. Also another area many builders fall short on is the head gaskets used some head gaskets have very small water holes located in five critical areas. These small water holes reduce the amount of coolant that will flow from the block to the head this reduced flow allows the coolant to be super heated by the exhaust ports.
This lack of coolant flow especially when driving at highway speeds only gets worse since the exhaust ports are now getting hotter since the engine is turning higher RPM"S.
One thing you can do if your not already doing it is just run straight water not any mixture containing antifreeze. Straight water will dissipate heat better than anything else During my experience dealing with poor radiator core issue the only change i was able to make was adding just water doing that lowered the temp 10 degrees its not a fix for other issues but its a little something non the less.
Looking at the picture the lower tank seems large it would be better if the radiator core was longer to help cool. A thick radiator core is great however the thicker it gets the less those inner tubes can drop temp. Since heat from the front tubes is making it hard for cool air to reach those rear tubes.
All the above is from my actual experience dealing with similar heat issues seems to me no one thing is going to help its going to be a number of things to help you get the engine running cooler at highway speeds.
Ronnieroadster

I'm getting near the point of pulling the heads to inspect for any signs of leaks or issues, as I'm running out of possible causes. I'm not sure why they went with the radiator tank that large -- but as I've said, it still has a core larger than a lot of the lowboys and some other flattie radiators that don't have these types of issues.

Would I be able to get away with running just the heat sink cooler on the C4 until I can get a bar/plate setup installed? I'm not all that familiar with them. I've been meaning to go pick up some distilled water so I can run less anti-freeze -- but I felt like that was another of the "bandaid" type approaches of trying to treat symptoms without finding the root cause.


I'm going to go pull the 94 off and see if I can figure out whats causing it to act a fool with that idle circuit.

[FlatheadTed]

You can put a cloth over the radiator or keep the fans of and let the house fan do its thing At speed the motor generates a lot more heat relying on just the air flow sometime just will not do it you need to drag the air through so the fan is very relevant ,if you reflect on the original set up Ford had the fan running continually not at random .Pulling the heads is a wast of time and gaskets unless you are topping up the water every few miles in other words its dumping water, If a Radiator is to small or inefficient you can compensate by increased air flow .As a test You should be able to run the heat sink cooler unless you are towing its not working that hard .Try real Shop experiments .Ted

[Mart]

Heven't read every single post. Here's my take.

Relatively heavy vehicle. Poor aerodynamics. Tall axle ratio. Big diameter tyres. Automatic trans. No lockup in the torque converter. Cooler in the radiator.

I'm guessing the torque converter is generating lots of slip. Slip means heat. That heat is being pumped into the cooling system, reducing the ability to cool the engine. The engine is working hard, (poor aero, tall axle, big tyres) so wants to get hot and needs a good cooling system.

I don't think you will fix this.

You can't do anything about the aerodynamics, and don't really want smaller wheels.

The options:
Drive slower.
Fit a separate trans cooler.
Fit an axle with lower gears, or change the gears.
Fit a manual transmission.
Is it possible to fit a bigger radiator??

You need to look at the whole package.

Just my 10 cents worth.

Mart.

[FlatheadTed]

If he disconnect the tranz cooler and retests that will eliminate that ,if the water level drops after its run at 210 then yes you may have a leak but if the water level is the same after cooling then there's no issue .By doubling up electric fans you may be able to do the same but ,I know the other option works ,Ted

[FlatheadTed]

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Its also a matter of experimenting taking into consideration all the previous posts and try the simplest first ,Ted

[1931flathead]

Originally Posted by Mart

Heven't read every single post. Here's my take.

Relatively heavy vehicle. Poor aerodynamics. Tall axle ratio. Big diameter tyres. Automatic trans. No lockup in the torque converter. Cooler in the radiator.

I'm guessing the torque converter is generating lots of slip. Slip means heat. That heat is being pumped into the cooling system, reducing the ability to cool the engine. The engine is working hard, (poor aero, tall axle, big tyres) so wants to get hot and needs a good cooling system.

I don't think you will fix this.

You can't do anything about the aerodynamics, and don't really want smaller wheels.

The options:
Drive slower.
Fit a separate trans cooler.
Fit an axle with lower gears, or change the gears.
Fit a manual transmission.
Is it possible to fit a bigger radiator??

You need to look at the whole package.

Just my 10 cents worth.

Mart.

if it he is at 50mph he running around 2000 rpm and at 60mph he running around 2400 the torque converter should be locked up unless they put a stall converter in it
put a temp gauge in the inlet line going into the trany cooler to see how hot it is getting
I'm thinking must be something wrong with the cooling part of the system
I would try to put a stock fan with more blades and a shroud on it

[FlatheadTed]

That's already been covered, actually there are a couple more things you can do but I will send you a PM

[1931flathead]

I don't think the converter in transmission is slipping it should be locked in around 1400 to 1600

[SonicRaT]

The transmission was installed with a flat-o-matic kit. The stall should be around 1200-1400. There's quite a few vehicles running around out there with a similar weight, tire, and gear size to what I've got, so I wouldn't think I'd be stressing it that much just trying to maintain a low cruising speed down the highway.

I pulled the carburetor apart and it was immaculate -- no debris of any kind to be found anywhere. I couldn't find even the slightest hint as to what might be causing the idle screw issue. It does seem to have stopped leaking after reassembly, so that's a plus I guess.

I tested my load-a-matic some more with the mityvac -- the curve seems to be within spec. I'll try to do some testing on the venturi signal tomorrow to see what kind of vac I'm getting from the source to rule out any potential issue there.

Tomorrow I'll try to bypass the transmission cooler in the radiator and run only the heatsink cooler and see how that goes.

[1931flathead]

Only way to get a good plug reading is drive it and push the clutch in and shut it off and cost to the side and check your plugs

I have done this a lot when i was tuning my cars with two four barrels

[Blix]

Does a stock loadomatic dizzy work with a your carb? Are you using the original carb?
if not you may have to late ignition.

[deuce_roadster]

If you can drive it all day at 50 with no heat issues, it probably is a combo of things like odd radiator (that huge lower tank looks weird) , auto trans, carb issues etc.
Next thing I would do is stop sending trans oil up to radiator. IF it still pukes trans oil maybe there is something in the trans that is not adjusted correctly and creates more heat at higher speed.

[Vintage Copper 47]

A lot of advice here.. I would separate the trans cooler from the radiator.. Also, I'm not particularly trusting of electric fans.. try the stock pulley driven fan.. they always work as intended.. I look forward to hearing about your solution to the heat problem..

[SonicRaT]

Originally Posted by Vintage Copper 47

A lot of advice here.. I would separate the trans cooler from the radiator.. Also, I'm not particularly trusting of electric fans.. try the stock pulley driven fan.. they always work as intended.. I look forward to hearing about your solution to the heat problem..

I have a Derale hyper-cooler on the way for the trans.

The stock fan wouldn't fit. I set a high idle of 2K RPM and let it sit for about 30 minutes while I was fixing other things -- the temperature gauge didn't move off 185. I don't think the fan is the culprit, especially at the speeds where the problems occur.

Originally Posted by Blix

Does a stock loadomatic dizzy work with a your carb? Are you using the original carb?
if not you may have to late ignition.

It's an Edelbrock 94 -- clone of the original equipment from what I know -- it's supposed to work with this distributor. I did some testing with the venturi signal, and I wonder if I'm getting too much advance...

I hooked the mityvac up and let the car idle -- if I pull 4" i'm at about 16 degrees ahead of the timing mark -- at 5" i'm at around 21 degrees ahead. By 7" I'm at 25 degrees.

I was having a hard time gauging the WOT readings and I have no way of loading the engine, so I'm not sure how accurate it is, but I'm seeing around 22 degrees by 1500 RPM and it seems to top out at about 33 degrees past 2K RPM -- isn't that way too much? I've tried adjusting the spring tension and it made very little difference.

For what it's worth, when I let the car fast idle, at 1.5K RPM it was at roughly 23 degrees, and the 2K RPM fast idle was at 32 degrees. After setting the spring tension as tight as it'll go, those have dropped to 17 and 28, with about 11 degrees of advance at 4" and 22 around 7", maxing out around 26 degrees at 10"+

[rotorwrench]

Most flatheads don't need much advance due to all the turbulence in the cylinder. They get a pretty complete burn around 22 degrees at the higher rpms. I'm not sure what the vacuum should be on the 8BA type carb since all my books are for the model 885 on the Mercury cars. They will have very near 3.7 inches of HG vacuum at 2000-rpm from the venturi port on the carb.

I have no experience with the Edelbrock 94 carbs. I have some experience with a stock 8BA 94 but not with the repro stuff. It may have smaller passages in the idle circuit that require the screws to be backed out more but I have no certainty on that. If it idles good then that may be where they are going to end up. Edelbrock's copy of the Rochester Quadrajet was pretty close to OEM and I can use the standard carb kits on those.

[Kurt in NJ]

A mitevac isn't good enough, the advance starts at something like 1/2 inch vacuum, and is all in at something like 2-3, you need a big easy to read accurate vacuum gauge ------having a ported vacuum port isn't the same as the venturi based vacuum for the load a matic

[SonicRaT]

Originally Posted by rotorwrench

Most flatheads don't need much advance due to all the turbulence in the cylinder. They get a pretty complete burn around 22 degrees at the higher rpms. I'm not sure what the vacuum should be on the 8BA type carb since all my books are for the model 885 on the Mercury cars. They will have very near 3.7 inches of HG vacuum at 2000-rpm from the venturi port on the carb.

I have no experience with the Edelbrock 94 carbs. I have some experience with a stock 8BA 94 but not with the repro stuff. It may have smaller passages in the idle circuit that require the screws to be backed out more but I have no certainty on that. If it idles good then that may be where they are going to end up. Edelbrock's copy of the Rochester Quadrajet was pretty close to OEM and I can use the standard carb kits on those.

It's "supposed" to be a fairly close replica, but who knows... I'm seeing around 3-4" in the 1000-2000 rpm range, over 2k I'm seeing around 7-8" which by that point is "all in" on my dizzy and pushing 34 degrees of advance over the stock mark. Yikes. I adjusted the advance posts, and I've got total advance down to about 25 degrees now, but it still seems to be coming on way too early.

Originally Posted by Kurt in NJ

A mitevac isn't good enough, the advance starts at something like 1/2 inch vacuum, and is all in at something like 2-3, you need a big easy to read accurate vacuum gauge ------having a ported vacuum port isn't the same as the venturi based vacuum for the load a matic

My mityvac has a vacuum only gauge which is fairly easy to read -- at idle I'm typically seeing about 0.25-0.5" and around 1-2 degrees of advance with it hooked up. The problem is that by 1k rpm I'm seeing 5", which is pushing 17 degrees of advance.

Looking at the factory specs I can find, I'm not seeing anywhere where it's all in at only 3" -- most seem to suggest that 3.7" should yield roughly 7-8 degrees of advance around 2K RPM at WOT -- I seem to be fairly close with the vacuum readings, but my resulting advance seems way ahead and I can't seem to get it within reason.

I thought maybe the springs were installed backwards, but flipping them around just produced even more advance in the earlier RPM range.

[JSeery]

One easy way out of the distributor issues is to install one of the converted Chevy units. Then you get mechanical advance and vacuum advance. They do need to be modified to the correct flathead advance curve.

[SonicRaT]

Originally Posted by JSeery

One easy way out of the distributor issues is to install one of the converted Chevy units. Then you get mechanical advance and vacuum advance. They do need to be modified to the correct flathead advance curve.

I've been trying to reach Bubba, but haven't had any luck yet. There's the CRT Performance units on eBay, but nobody seems to know what the curve looks like.