1973 351 C running hot issues

[Carolina_Mountain_Mustangs]

We have had several discussions on the Forum about the cooling system on the 351 and how it has two flow paths depending on if thermostat is open or closed.

My 1973 Mustang vert has a 351 H code that the PO had put and Edelbrock performer 4-V to 2-V head and holley 4-V carb. on. He had let the car set for 25 years so when I got it I spent another year taking apart detailing and cleaning. I did not tear into the engine it started and ran and he said he had his pit crew put cam, MSD ignition on the do some other performance items. He was a winning sprint car driver in California.

Well I have only driven the car maybe a little over 100 miles in last 11 months. Each time the temp would climb almost to the H on gauge and when you cut it off would blow coolant out.

I have the correct Stant 192 deg. thermostat and the correct Ford baffle under it. I even changed to another big radiator I had that was spotless clean and still running too hot.

I had seen this if the past in 289 302 engines that the person building the engine put the head gaskets on backwards. You can verify them through the core plug holes in the front of the head without pulling the head, no core plugs there on C engines. I had searched the net and ask on this and other forums if there was a way to check a 351 C and all said not you had to pull the heads. We all know that the gaskets are min. of $85 to well over $100 to do that.

So this morning I decided to go into engineer mode. Went to the garage pulled out a bare 351 Q code block and I figured out a way to check if gasket is on correct on the passenger side but could not find a way on the drivers side.

You pull the thermostat housing off and run a piece of metal coat hanger or weld rod down beside the baffle under the thermostat and go through the opening in the block and should go into the head if on correct, see pics. When I check the engine in the car the gasket was on backwards.

So I pulled the R.H. head and sure enough gasket backwards. That prevents the water from flowing from the rear to the front of the head except through some tiny holes. That is the reason it blows water out when you cut it off comes back through the water pump from percolation of the coolant.

So I am off to get some gaskets and got to remove the other head also will not take the chance that both are not wrong.

BTW since he races for a living and has experts for mechanics they can also do incorrect things. The gaskets will come stamped FRONT in big letters but people just do not look. I think he races Chevy engines so SBC does not have a front or back will go either way.

Here are some pictures of the wire in the bare block and on a scale if you want to make one. Also showing how I went into the engine in the car. Pics of the gasket on the car and it was almost erodinghole where it needed one.

When I get back together I will post results. I was at Dr. yesterday will be going for MRI and maybe spine surgery so taking the heads off is pure torture but I have to know.

I did pretty good stated looking at 10:00 and had it apart at 12:30. Darn heads are heavy.

The inside of the engine is very clean and still shows great hone marks on cylinders so I guess the 48,000 miles is correct for the car.

Cheers,

David

 

[73pony]

that's a great bit of detective work.

 

[tony-muscle]

Good job figuring it out.

I have two extra sets of head gaskets if interested. One from the Felpro kit and another from the Mr Gasket kit.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[c9zx]

Very innovative and effective approach, well done. "FRONT" being stamped on the gasket assumes the "mechanic" can read. Indications are he couldn't or didn't. Chuck

 

[midlife]

Why are the gaskets so expensive?

 

[Carolina_Mountain_Mustangs]

You tell me on the gasket price. The racing gaskets are stupid expensive. I went to Auto zone and they will be here tomorrow for heads on Monday for intake. $68.00 for both for Fel Pro.

Now another eye opener. I have heard and assume that .040" is what is considered the safe limit for a 351 overbore. I was in the garage cleaning the deck and this engine is .060" over. I will be shocked if it runs cool when put together correctly. I do not have access to ultrasonic thickness tester at this time but will see if I can borrow one tomorrow. I would be interested in the cylinder wall thickness. You would need a perfect cast block to go that far.

He changed the valves not Ford and has the good valve stem seals not the hats so some work was done better. I have 14 mixed drinks to get through the pain today, lol. That with muscle relaxers makes you superman. Only way I can take the pain to do this maybe one last job.

David

 

[tony-muscle]

The head gaskets cost almost the same as the whole set.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[tony-muscle]

The head gaskets cost almost the same as the whole set.

Sent from my SAMSUNG-SM-G930A using Tapatalk

Which one you want?

$20 plus shipping. I guesstimate that shipping via UPS will be about $12 or so.

If you need an exhaust gasket I have an extra one from the kit as well that I can throw in.

Edit: I have to resend the post from my desktop since the new Tapatalk app wants you to login to share pictures.

 

[tony-muscle]

You tell me on the gasket price. The racing gaskets are stupid expensive. I went to Auto zone and they will be here tomorrow for heads on Monday for intake. $68.00 for both for Fel Pro.

Now another eye opener. I have heard and assume that .040" is what is considered the safe limit for a 351 overbore. I was in the garage cleaning the deck and this engine is .060" over. I will be shocked if it runs cool when put together correctly. I do not have access to ultrasonic thickness tester at this time but will see if I can borrow one tomorrow. I would be interested in the cylinder wall thickness. You would need a perfect cast block to go that far.

He changed the valves not Ford and has the good valve stem seals not the hats so some work was done better. I have 14 mixed drinks to get through the pain today, lol. That with muscle relaxers makes you superman. Only way I can take the pain to do this maybe one last job.

David

I also have a SCE 152108 intake gasket for Blue Thunder 2V. I bought it by mistake. I will throw that one in for an additional $10 if you are interested.

http://scegaskets.com/store/ford/ford-small-block/sb-ford-intakes/sce-gaskets-part-number-152108/

 

[turtle5353]

I had custom MLS head gaskets made for my Cleveland and they ran me around $200 for the set if I remember correctly. But supposedly they can be reused.

 

[Carolina_Mountain_Mustangs]

The other information that I found online on how to detect if backwards was to look at the front lower corner of the gasket. You can look at the pics that Tony posted. The bottom front of the gasket will have the square corner sticking out from head and block and the curved corner will be in the back. On my car it was impossible for me to see the drivers side with PS and Air in the way but could see the passenger side with a mirror. Some gaskets are cut a little different but most have the rounded and square corner.

I would suggest that anyone having any issues with overheating go check your head gaskets. Not a difficult weekend project just lots of clean up and prep.

I also run taps in all the screw holes and blow them out before going back together. I also use anti seize on the header bolts so they do not lock up.

I got the passenger side cleaned up last night and will go pull the drivers side off and get started cleaning there.

Parts house called and the head gaskets did not come in on morning truck but I do not need yet anyway. I am still using the full steel pan gasket under the intake to keep a little heat off the manifold.

Go check your gaskets.

Cheers,

 

[mbrew2]

The other information that I found online on how to detect if backwards was to look at the front lower corner of the gasket. You can look at the pics that Tony posted. The bottom front of the gasket will have the square corner sticking out from head and block and the curved corner will be in the back. On my car it was impossible for me to see the drivers side with PS and Air in the way but could see the passenger side with a mirror. Some gaskets are cut a little different but most have the rounded and square corner.

I would suggest that anyone having any issues with overheating go check your head gaskets. Not a difficult weekend project just lots of clean up and prep.

I also run taps in all the screw holes and blow them out before going back together. I also use anti seize on the header bolts so they do not lock up.

I got the passenger side cleaned up last night and will go pull the drivers side off and get started cleaning there.

Parts house called and the head gaskets did not come in on morning truck but I do not need yet anyway. I am still using the full steel pan gasket under the intake to keep a little heat off the manifold.

Go check your gaskets.

Cheers,

Thank for the tip on checking gaskets! By the way, was that the 48000 mile motor in your car that's .60 over or your spare block.

 

[Carolina_Mountain_Mustangs]

The other information that I found online on how to detect if backwards was to look at the front lower corner of the gasket. You can look at the pics that Tony posted. The bottom front of the gasket will have the square corner sticking out from head and block and the curved corner will be in the back. On my car it was impossible for me to see the drivers side with PS and Air in the way but could see the passenger side with a mirror. Some gaskets are cut a little different but most have the rounded and square corner.

I would suggest that anyone having any issues with overheating go check your head gaskets. Not a difficult weekend project just lots of clean up and prep.

I also run taps in all the screw holes and blow them out before going back together. I also use anti seize on the header bolts so they do not lock up.

I got the passenger side cleaned up last night and will go pull the drivers side off and get started cleaning there.

Parts house called and the head gaskets did not come in on morning truck but I do not need yet anyway. I am still using the full steel pan gasket under the intake to keep a little heat off the manifold.

Go check your gaskets.

Cheers,

Thank for the tip on checking gaskets! By the way, was that the 48000 mile motor in your car that's .60 over or your spare block.

That is the 48,000 mile, lol. He was a racer in California. Guess he went all out to get as much as he could. I will check the VIN# on the block today he might have changed engines.

The gasket was on correct on the drivers side probably only way it stayed cool at all. So no gaskets yet they say one today and another tomorrow. Claim they had never sold one at this store for 351 C..

 

[Carolina_Mountain_Mustangs]

Well gaskets got here yesterday and I got the heads back on and intake installed and my back said no more. Will try to get Alternator, PS and Air back on today and get all the vacuum hoses back right.

I did verify that the VIN# on the block does match the body so it is the original engine. I sent the PO a note about the gaskets but have not heard anything back.

Nothing special on going back together but is it tough to do the 105 Ft. Lbs. torque on the heads with the engine in the car. Or it is for a 70 year old guy, lol. I will put together some pics and do a thread on doing the work for those that are interested. Is a pretty easy weekend job. Takes longer to clean it all up than do the mechanic work.

Hope to here it rumble again today and see if the over heating issue is solved. I think it will be when you cut all water flow off on one side of the engine has to get hot for sure.

Cheers,

 

[c9zx]

Good to hear you got it back together. Chuck

 

[Don C]

I hear you about old age. I moved some 351c heads yesterday, didn't remember them being that heavy

 

[Carolina_Mountain_Mustangs]

I am a happy guy in pain, lol.

Got it all back together. Took longer to get PS, Air and alternator on that to put the heads and intake on. No third hand to help was a big pain.

Well it cranked right up, no noise and let it run for a while and never got any where near Hot, HURRAY. I had the air cleaner off and noticed the choke never opened all the way. He had put the linkage for the choke baffle on the wrong side of the cam coming off the choke so it could never open all the way. This thing should run much better now. Wide open choke, not hot. I am letting it cool down so I can set the choke and also set the timing.

So to recap the R.H. head gasket was on backwards which closed off most of the water flow to the head on that side. The choke was also unable to open all the way.

Had lots of people say that it was the baffle in the block causing the issue but as I figured not so. Ford spent millions on the development of the Cleveland engine. With all their hot and cold room testing and the I think 40,000 mile minimum federal testing of each engine I just do not see them putting something that cost them money in an engine if it is not needed or does not have a function.

If you put a Cleveland together right you will not have issues. Also remember this engine is .060" overbore and running a hot cam so not your stock Cleveland. If it runs cool than any correctly build Cleveland should run fine and have no overheating issues.

My neck an back are saying quit but going to let it cool down set the choke and timing so I can take out on the road tomorrow and see how it does.

When I shut the engine off no percolation of the coolant which is a great sign.

I did have one bobo. When putting the intake on looks like I moved and tore the paper part of the intake gasket. The silicone must have filled in the gap so not going to pull apart unless I have a vacuum leak.

Will do a summary with pics this coming week. Everyone needs to know what to look for.

Cheers,

 

[mudbilly]

::congratz::

 

[Don C]

That's great David, good luck on your test drive tomorrow.