Flathead overheating,,, suggestions?

Hey guys,,, I've got the notorious flathead. I know they are pretty common to run hot. Here's what I've got. My radiator is a chopped down 32 radiator (5 inches). I've got washers in my bottom hose with a 11/16 hole. My themorstats have been popped open. I also tried replacing my thermostats with a copper washer with a 5/8 hole. Idling temp is 210 and running down the road temp is 230-240. I just need your suggestions.

 

Watching this as I am debating what to do for a radiator.

From what I read, Walker may be needed.

Stock water pumps???? Meaning that they have all of the impellers and none removed?

 

Pull all the washers, put good stats in, check timing and fuel delivery, Timing is critical to a cool running flathead..............

 

Make sure the block is fully flushed. Check your belt tension. Belt could be slipping on the pumps. Put 180' T-stats back in.

 

First run a "Block check" to make sure you do not have a combustion gas leak into the cooling system. Second if that checks OK loose the wahers in the lower hose,5/8 to 3/4 in the upper ,prefer stats though. Check timing and for too lean. If the above check OK I would be shopping for a radiator.

 

Same as above, may be okay with the 5/8" washers in the top, but I would just put thermostats back in and never put anything in the bottom hoses. Remember retarded timing = hot, not enough fuel = hot and not sure if the pipes are new or what, but I have seen a stock type exhaust pipe with the double layer pipe come apart and restrict flow out of the engine making it run hot. You have to get the exhaust out as fast as possible since it runs through the water jacket. Good luck!

 

How do I do the combustion gas leak test? I am new to this. I measured the cubic inches on my radiator and it was roughly 444 inches. I measured the stock truck radiator that the engine came out of and it was roughly 666 cubic inches. I will try and take out the bottom washers. I already disassembled the thermostates so that makes the top a 1 1/4 hole.

 

I forgot to add that I have had my timing at 4 degrees 2 degress and 0 degrees and all have had the same results of overheating. 2 degress was about the best though. Also, I have two stromberg 97s. I have a holly fuel pump with a holley regulator set at slightly over 2 psi. Do I need to drop this down slightly or keep it?

 

Send your water pumps to Skip Haney in Florida for a rebuild. That made a big difference on my flathead's cooling.

 

I have a Mustang radiator, no stats, no washers, Bob Drake pumps and a bottle of Purple Ice in my AV8. It never runs over 180 degrees. When I was building it I blew the water jackets out with a water blaster (pressure washer) and got a bit of crap out.

 

I've got speedway water pumps. Just gonna try some things today.

 

Assuming no combustion leaks and proper timing, there are only ever two things to increase cooling:

More water flow

Bigger radiator

The nonsense about slowing water down, removing vanes on the pumps and overly restricting water is hogwash. You've cut down your radiator decreasing its thermal efficiency by at least 1/3. You will likely struggle to cool a hopped up flathead well. Not to say it can't be done, but the AV8 radiator is always going to be a wee bit on the small side - and that's assuming it's in good shape and cooling well. You might be able to re-core it with a modern high-efficiency core and obtain better results without spending what a Walker would cost. But you need to eliminate the simple and easy stuff first.

 

My stock original Deuce radiator cooled my flathead perfectly with factory thermostats and a factory mechanical fan. But is was full size. 5" is a lot to remove and still get factory results. The first thing that I would do is restore the capacity of the radiator. Maybe a thicker core? A radiator expert would be needed here.

Don't believe the wives tales. They are just repeated stories by poor mechanics that were working with junkyard parts and worn out stuff.

When my engine of unknown mileage started to run about 190*, I knew some coolant had evaporated and a top off fixed the problem for at least another year.

 

For a combustion gas leak test you can get a test kit from napa auto or other places sell them. It's an easy test that involves your radiator and a bulb, a tube with colored liquid . You run the car with the rad cap off and get the water moving. Pour the liquid into the test tube, place the test tube into the neck of the rad get a good seal, put the buld onto the test tube and compress the bulb pushing air into the tube for about a minute I think. If the liquid in the tube turns from blue to yellow you have combustion gases if the water stays blue you have no leak.its fairly easy and accurate

 

I tried everything from hi-flow pumps, new head gaskets, timing changes and new exhaust. Heating up going down the road suggests not enough cooling from the radiator. If you haven't got a spare grand laying around for a Walker, try these guys

www.cgj.com

Brice Thomas aluminum radiators are made to order and had it on my doorstep in a week. Cools great and $370 including shipping

 

What fan are you running? Does it have a shroud? Also make sure you are getting maximum air through the radiator.....

 

Never put any junk in the lower hoses! Holy crap!
Up top remove washers and stats for now, you will want 180 or so stats after the car is cooling right.
If stock distributor...setting initial timing is meaningless and it is very difficult to find out what advance is actually doing...I think I have posted some ways. The stock setup is VERY prone to limited advance when running and running retarded wth a FH dumps all the heat right into the water jacket rather than into moving the car.
If you do not measure and verify ACTUAL advance ON THE ROAD, revving the stock distributor in driveway does not measure working advance, try a catious temporary experiment: Bump initial timing substantially, to at least 10 degrees, and see if behavior improves. If it pings stop, but I suspect you will see nothing but good because your automatic advance isn't...

 

You didn't mention the radiator cap..... If you are running 15 lb. cap, then 220 degrees is in the ballpark.

Each 1 psi will raise the boiling point of a 50% water/ antifreeze mix by 3 degrees.
Using that info, then 15 lb x 3 degrees = 45 degrees. That raises the boiling point to around 255 degrees.
Ditto to the timing issues as well.

Happy Roddin' 4TTRUK

 

But...it shouldn't be getting anywhere near those numbers just chugging around. Something needs fixing here!

 

Ditch that crummy electric fan and get a mechanical fan and a good shroud.

 

Know a guy that has a 29 RPU that cut down in every way including the radiator. He runs aluminum heads and states that his RPU begins to over heat just idling for 5 mins, so I've driven it several miles on a hot day. It runs about 195-215 rolling on a (90 degree day).
He has a 7" old style electric fan (not like a hayden or anything) that I don't feel pulls enough air through its severely chopped radiator. He stated that when it had stock heads it ran cool and he could leave it idling all day long with fan off-"I don't think so".
Kinda wondering if because he bought this rpu with it's chopped radiator if he really doesn't know what a flathead does, Mind you his other cars are air cooled 911's & 12's. I never heard it run with cast iron heads and can't confirm his complaint not having the cooling system performing as it was originally designed, ????

 

I have borrowed the combustion leak tester from a local shop (buddies with these guys) and I've got nothing so far. I even reved the engine up to get some more rpm and nothing. I took the washers out but haven't done a road test. Thanks for this link 41fordor.

 

I've got a 4 psi radiator cap with a flex-a-lite electric pull style fan. What whould the water level be like. Right now it's not really spitting anything out. I have measured how much I have in there and it is 3 3/4 gallons worth of water and a bottle of water wetter.

 

My distributor is a bubba's hot rod distributor.

 

Have you verified your temp gauge as being accurate?

Have you popped the rad cap and physically looked to make sure you have a bunch of water swirling round in the rad?

Can you check the top and bottom hoses with an infra red temp gun and see much different between them? You can buy them pretty cheap nowadays.

 

I also have an 8CM that WILL NOT cool. It's run hot in 2 different cars. I've tried everything, including: water wetter, new Speedway pumps, new hoses, new t-stats, new electronic ignition (w/ different settings), new head gaskets, blah, blah, blah,...
The only thing left is to completely tear the engine down & try to clean out the water passages. Apparently, it is common for them to still have casting flash, core sand, etc., inside & you are supposed to run distilled water to avoid the mineral deposits from tap water.
I'm sure the overheating problem is why several people choose to go w/ a SBC. I'm not there yet...

 

I am running stock 32 radiator 180 stats. and I run between 170 and 180 it will go up if I push it or a long up grade 190/195 but comes right down. I did have the rad professionally cleaned and I flushed out the block.

 

It seems unlikely to me to be a fan problem if it's running cooler sitting, than running down the road. I recently fought a similar issue. I finally solved it with a new core,this was after the radiator was cleaned and flow tested good twice. Come to find out it was just not transferring the heat out. I was told this happens to old radiators as a thin build up on the inside of the tubes works as insulation preventing the heat transfer. So now after all kinds of remedies that didn't work a simple recore fixed it. Now it seldom runs over 180.

 

Does the distributor have a vacuum advance? And is the carb it hooks to, the right model to run a normal advance? The 8BA flathead had the vacuum only dist., with a wierd ported vacuum setup that won't work with a mechanical/vacuum advance dist. A modern style setup will work with manifold vacuum to it.

 

Flat washers cause lots of cavitation (air bubbles) in the coolant. Don't use them.