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Overheating

4K views 24 replies 18 participants last post by  xcdriver 
#1 ·
I have a fresh modified 351 Cleveland in a 67 Mustang Show Car. It is having a overheating problem. I have installed a new Slant 13469 195 degree (Cleveland) thermostat and it has not helped. I hear that a Robertshaw 180 is teh way to go. Any thoughts? The brass bypass is in place. Cooling is being done by a 4 row aluminum radiator with 2 10 inch electric pull fans with a shroud. I have also added Redline Water Wetter.

I keep hearing that the head gaskets can be installed backwards which will cause what I am experiencing. Is this true and what is happening? Closing off water jackets? Is there a way to check this without pulling the heads?

What other areas should I investigate?
 
#2 ·
feel the front of the heads for a tab, all windsor head gaskets have a tab that pokes out the front alittlebit , it basically says front with an arrow <=====. Im not certain about Clev gaskets tho mate ...
As you stated mate if it is backwards your blocking off water passages, mind you one would think you would also be blocking off oil galleries also???
Good Luck & let us know how you get on.
 
#5 ·
Yeah, the clevelands have the little "tab" at the front on both sides. Get a torch and have look rite at the front where the head bolts onto the block. The "tab" is about 10mm wide and sticks out about 5mm. I would go a bit cooler in the thermostat too. I run a 160 deg to keep cool. I may change now as i have a row aussie cooler and it runs so cool now...
 
#6 ·
i have had success with plugging the brass bypass hole then redrilling with a smaller hole.also i caught up with a mate the other day and while dialling a cam for him we got to talking on this subject.he was running a so called "proper" ???? cleveland thermostat that looked like a normal brass one but had a small extension that came from it with a ring of steel and a rubber seal around this ring.so when it got to op temp the ring would come down and seal off bypass completely.he does alot of main street idle cruising in summer and has not had any problems since he fitted this thermostat,which got recomended to him by someone else that came across it.
i hope this post makes some sense to you if not i will try to get some pics of it, if no one else can shed some light on this thermostat.
 
#7 ·
Is it bored out more than 30 thou
How high is the compression.
If auto, what stall speed are you running. ( car might be revving high all the time )

Does it overheat on idle or when cruising ( different problem associated with each )

A bigger radiator can sometimes aggravate the problem as a standard Water pump just can't shift the additional volume of HOT water around.

The guys at ECOTRANS in Melbourne make a good modified Water pump for the clevo. Better Impeller design with less potential for cavitation.

Check your bottom hose to see if it is being squeezed under mid throttle.
( hose may not have a spring in it !!!!!!!!!!! )
This will stop waterflow and contribute to the problem.

Aluminium radiators also have a BAD tendency to corrode inside real quick if the car is not earthed REAL well. You may find that the inside of the RAD ain't all that healthy. It acts as the sacrificial anode and electrolysis will kill it real fast. ( It may still look OK on the outside and have trashed cores on the inside )

Let us know how you go
 
#8 ·
Yeah, i had the option of alloy when i bought my 4 row a few months ago. The guy who builds them said you cant repair the alloys ones as easy as the standard ones so that made up my mind. The only running of my motor so far is running in the cam, and it didnt go over 180 deg in the 20 minutes.
 
#9 ·
ESP said:
A bigger radiator can sometimes aggravate the problem as a standard Water pump just can't shift the additional volume of HOT water around.
I can relate to that. Was running a standard 2 core on mine and it would overheat badly on the highway but wasn't so bad in traffic. Upgraded to a 50mm 3 core and all of a sudden it was great on the highway but really bad in traffic.
 
#10 ·
Two 10 inch thermos arent going to do the job of drawing enough air through a 4 core radiator IMO. I think a 160deg thermostat works best. Redline watter wetter is definately a good thing. Do you use it with distilled watter?
Also, make sure the cooling system is bled properly.
 
#12 ·
I'll be buggered. I ran mine for 10-20 minutes today @ idle (900-1500rpm). I reversed it out and left it running while I swept out the garage. Hottest it got was 90deg and that's running no fans at all. I actually think my mech temp is not working properly either. I reckon it reads high. I haven't wired the switches up yet. Thats a 4 core radiator, stock water pump, full of green coolant. Thats a 30thou over clevo. Never had any issues with the cast irons heads either.

Yours really shouldn't even get hot. I'd be suspect of the water pump cavitating due to possible corrosion of the impellar.

Brenden
 
#15 ·
this could be a long shot................maybe the block had some sediment in it if it had been sitting for a while. when fired up the coolant flow might have put the sediment into the radiator core therefore reducing capacity. may be worth doing another radiator flush. like i said a long shot.
 
#16 ·
I had the same problem with the stroker i built some years ago. Tried every thing i could think of, I even made the wholes in the head gaskets bigger but still no help.
What did fix it was the factory 7 blade fan. This was in an XC Fairmont Sedan with a three row radiator and 16" thermo.
 
#18 ·
i always thought the colder the better? or was that just for ambient temps?
 
#19 ·
XDman said:
i always thought the colder the better? or was that just for ambient temps?
Depending on how cold you are talking. The colder 180 deg is better than the hotter 220 degree. The colder 130 deg is "not" better than the hotter 180 degree. I would aim at being atleast 170 -180 degrees. If you are too cold or dont run a thermostat, the extended time it takes to warm up the motor causes excessive bore wear over time.
 
#20 ·
I've just driven my car upto heathcote and back over 400k's. I Turned the fans on in Bendigo and in Cranbourne. The rest of the way I was running nothing but the water pump and air coming into the radiator as I drove. I run a 160F thermostat. Engine sat on 75-80deg C all the way.

I'd try a colder thermostat and a radiator clean.

Brenden
 
#22 ·
you know i had the same drama a few months ago with my rebuild
i fixed it easy with some experamental changing of the pully ratio i had some spare clevos and i took the pullys of an old f100 engine witch made the ratio 1 to 1 from crank to water pump
from the old 2 to 1 ratio and it worked everyone i know said no way but it worked hey give it a go
i only have a 3 core radiator with a stinken hot 351
 
#23 ·
Make sure you have a CLEVELAND thermostat. People will tell you there is not a difference but they are wrong!

There is a distinct lip on a genuine cleveland thermostat that is not present on non-cleveland ones, like a windsor thermostat. The lip is there to funnel water from the restrictor plate in the block into the top pipe. If it doesn't go into the thermostat (when opened) it gets recirculated back into the block, bypassing the radiator and also not pushing cool water out of the radiator (worst of both worlds).

If you have the correct thermostat then its likely a problem with your radiator, waterpump or your fans are inadequate. Fisrt off i'd bin the waterpump.
 
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