351C, i think i have another cracked head

[ugly74]

Friday i drove my eb to work. Ran great, no problems. Ran some errands after work, and then on the way home i began to notice a subtle misfire. Not like a bad plug or wire, just as if 1 cylinder isnt working 100%. next time i sat there idling, i noticed water vapor out of the left pipe, but not the right. On the drive home it got steadily worse...
I havent pulled a plug yet...but after 3 seperate cases of cracked heads prior to this...im pretty sure its what im facing....again.

Am i the only one having problems with this series of engine?
Once i confirm it, im gonna order parts to rebuild my 302 ( just needs a hone and rings) and swap 'em out.
I want to love this engine, but i cant. Im done with it (until my mustang is ready for an engine, that is)

Thats it, just sharing my frustration with y'all

 

[Skiddy]

man i hope not again, dang

 

[bmc69]

I can honestly say that in my 35 years of running more Clevelands than I could ever count, I've never once had a head gasket let go or a head crack. In fact, I've been amazed at the severity of overheating some of my engines have suffered and still not let a head gasket go or a head crack.

302s..I've had a few of those that did lose the head gasket.

Yr luck with the Clevelands obviously different than mine. That said, there is a "posted and pinned" mod that the racers used to insist on that they swore prevented a chronic head cracking problem with the C's..but I'm only familiar with it from hearing about it.

 

[ugly74]

I can honestly say that in my 35 years of running more Clevelands than I could ever count, I've never once had a head gasket let go or a head crack. In fact, I've been amazed at the severity of overheating some of my engines have suffered and still not let a head gasket go or a head crack.

302s..I've had a few of those that did lose the head gasket.

Yr luck with the Clevelands obviously different than mine. That said, there is a "posted and pinned" mod that the racers used to insist on that they swore prevented a chronic head cracking problem with the C's..but I'm only familiar with it from hearing about it.

Pinning is how i had the first head crack repaired. D&R Headcasting in Denver. Good work, it didnt fail. All my cracks popped up on a different cylinder each time.
Ill go back to them for this, too. But ultimately this badass, reliablity deficient engine will be happier in the mustang.
Less weight, 5 speed, 4.30 rearend, 28 inch tires.

 

[broncnaz]

While not really a C head by most peoples claims. My brother has had lots of issues with the 351M heads losing valves/breaking valve springs.

 

[Deano]

I also had trouble out of 351M heads and head gaskets on them. 351Cs i have Ben running for about 10yrs with no problems except for the crappy gas we have.

 

[ugly74]

No detonation. Its around 11.5-1, and i put 91 octane in it. It was the most difficult engine ive ever tuned, but it is dialed in.
Im ruling out detonation anyway, cuz my cracks have all been on the port side of the valve. And i think pistons would fail first in that case.
I guess it could be a head gasket....but with less than 1000 miles on the motor?

 

[bmc69]

While not really a C head by most peoples claims. My brother has had lots of issues with the 351M heads losing valves/breaking valve springs.

Other than the AIR porting and associated bumps in the exhaust ports..there is otherwise little/no difference between the 351m/400 heads and the 351C-2V heads.

And yes..the springs (and valves) are notoriously unreliable and I never use the original Ford stuff when I build one. I've personally lost two engines to valve spring failure and a dropped valve.

 

[patterdale]

That many cracked heads on the same engine? You have a bigger problem causing the cracks. The block may need to be trued up or you have a blocked water passage or are improperly installing the head gaskets......

 

[DonaldDouchebag]

Have you ever had the block decked and squared?

 

[wdbowers]

is it the same set of heads that you are having repaired or are you replacing heads. I agree with BMC I have blowed radiator hoses off a race engine and never had cracking problems. If it is the same heads it might be small cracks that are undetectable that are opening up over time.

 

[ugly74]

When i went through the engine originally, i confirmed the block is true. Nice and flat.
The 1st three cracks i dealt with were on the original set of 2v heads. All of them were cracks right underneath the valve seat. I credited those failures to my use of a die grinder on them, smoothing things out. Those heads are in my scrap metal pile now...
The heads i have now are an australian 2v casting. They were decked and rebuilt. Didnt touch em with the die grinder either!
This new issue is coolant in the cylinder, but i havent confirmed whether its a crack or a head gasket.
Both surfaces are true, everything torqued properly, so im doubting its a gasket failure.

 

[Madgyver]

I have a problem in one of my "C"s and it's not in the head. Spinning rod bearings..

No cracked heads yet.. Knock on wood.

 

[bmc69]

I have a problem in one of my "C"s and it's not in the head. Spinning rod bearings..
.

Different journals?...or same one or two oiled off same main bearing failing repeatedly?

Further hijack: I went to my buddy's machine shop yesterday where he does my boring/honing and crank grinding. Picked up two 302 ranks and a Mex 302 block.

He's a second-generation Ford race engine builder and racer. He had recently found and bought a bunch of vintage Yates Cleveland NASCAR engine parts. 377 stroker cranks, rods, pistons..Yates alumimum heads..Yates steel "4v C" heads with the insert "slab" to modify exhaust port geometry..some crazy looking intake manifolds, etc. I've got to go back soon to drop off a 400 block and crank and I'll remember to take the camera. Stand by for some real Cleveland porn!

 

[ugly74]

Update! Well i was wrong when i said i was sure i had coolant in the cylinder. With the miss, and the vapor on one side, i just figured it had to be
Anyways, today i finally got around to pulling plugs and all of them looked great, except for #4, which was totally encrusted with oil and burnt on gunk. Gap was completely closed. So that would explain the miss. I put a good used plug in and she runs good again.
Im very worried about all the oil though.

 

[bmc69]

Update! Well i was wrong when i said i was sure i had coolant in the cylinder. With the miss, and the vapor on one side, i just figured it had to be
Anyways, today i finally got around to pulling plugs and all of them looked great, except for #4, which was totally encrusted with oil and burnt on gunk. Gap was completely closed. So that would explain the miss. I put a good used plug in and she runs good again.
Im very worried about all the oil though.

Great news!

I've got one cylinder that is doing exactly that in the 302 solid-lifter ex-racing motor I have in my Donzi. I just keep changing that plug until I get a chance to swap that motor for one I've built to replace it. Will be interesting to see what is causing it...cuz I have no idea at this point.

 

[Jdgephar]

Oil in the cylinder...could be many things, my vote is a cracked piston ring. Usually that or a bad valve seal.