351C .060" overbore?

[Boss1Ray]

saw this CL ad and it mentioned 351 Cleveland block more thick for '72?

http://kansascity.craigslist.org/pts/3127991926.html

I always heard that about .030" bore was all they could handle???

THX

Ray

 

[will e]

mine is .040" but I had it checked out by a competent machine shop. So far so good. .060 seems a little high.

 

[Tnfastbk]

I belive 71 - 73 blocks are all the same thickness when it comes to the cylinder walls. Would have to see proof to show me otherwise. I have a 60 over 4 bolt main block but decided against uding it. Prob would be ok for racing with hard bock in it.

 

[Jeff73Mach1]

I call bullshit on the ad.

Cleveland blocks are a thin wall casting. while may will handle an .040 overbore, few will handle .060 to the point that most people simply say don't do it.

When walls get thin, bores distort at higher rpm's causing increased friction and heat and at the minimum reducing life and power.

at .040 I would not build a high performance engine in a cleveland block, though standard performance would likely be fine. In my opinion a Cleveland engine at .060 would be suitable for a show car that is trailered and just driven around gently on occasion.

 

[clevelandcoupe]

Guys,

My engine builder, Danbury Competition Engines did not recommend anything over a 30 over bore on a cleveland motor. Cylinder walls get too thin and could cause heating up issues. He has built a lot of these motors and I believe he would be an authority, in my opinion.

If anyone is looking, I have a complete 351 cleveland that is 20 over with forged flat top pistons that was completed by Danbury a few years ago for sale and also 4v closed chamber heads.

Let me know.

Thanks, Jay

 

[will e]

.40 seems to be handling my build (see my sig). I probably poop out around 350 to 400hp. No overheating.

 

[Jeff73Mach1]

Boss 351 probably made 375-385 horsepower at the crank in reality- therefore, your engine is still a stock to very mild build, in my book, at 400 HP

We have improved cooling systems as well. Some blocks are better than others in terms of consistent cylinder wall thickness and bore alignment, so as I have said before each one has to be assessed as an individual.

Yours at .040 over sounds fine for the application, but I doubt you would want to build a stroker with an .060 overbore

 

[Mister 4x4]

I guess we'll find out how well suited .060" works. Mine is bored out that far, and I had no problems finding pistons, rings, etc., for it. I honestly believe that with proper cooling, oil pressures, and tuning, that engine will be fine under 'normal' daily driving conditions. I'd be more worried about racing it, because you know for sure there will definitely be a failure at some point.

And if it blows up - so be it... the thing was seized up solid when I bought the car after all. I'll simply score another 351C block and start all over again. Catastrophic engine failure rarely tears up things like headers, intake manifolds, carbs, etc. - and after spending all that money on things of that nature, it only makes sense to stuff another 351C-2V back in there if it were to go south.

 

[goodnigh]

As far as know all Cleveland blocks are the same, and they are rare in block form.

The Cleveland book mentioned in this forum says never over 030.

I bought a car that had a rebuilt Cleveland supposedly worked on by a good

machine shop. The block ended up with a crack and when we pulled the heads

the cracked cylinder wall was 040 over. Only two cylinders were bored 040 over

but that is the one that cracked. Why only two cylinders; got me.

Guess which cylinder was 040 over...

mike

 

[c9zx]

saw this CL ad and it mentioned 351 Cleveland block more thick for '72?

http://kansascity.craigslist.org/pts/3127991926.html

I always heard that about .030" bore was all they could handle???

THX

Ray

Look up SK and XE blocks on the cleveland forum. They are the only blocks I know of that are supposed to have thicker walls. I think the SK had siamese cylinders. I actually saw a XE block not long ago in OKC. The only way to really know how much core shift the block has is to have a sonic test map done for every cylinder. Mine wouldn't clean up at .020. If it would have I'd have spent the money for quasi-custom Diamond Pistons. As it was I used Mahle power pak pistons for 408C. Chuck

 

[JimNiki]

the aussie falcon xe cars were the last of the clevos. I thought our clevos were made thicker before then?

 

[c9zx]

While I am not 100% certain, I don't believe the XE in this case has anything to do with the Aussie Falcon XE. I believe it stands for experimental. Some of these blocks ended up in NASCAR cars in the early to mid 80s. Chuck

 

[Jeff73Mach1]

As a general rule, bore an engine only as much as the block dictates is absolutely necessary. If 7 cylinders clean up at stock and 1 required .060 to clean up, sleeve the offending cylinder in a cleveland and don't bore the rest. regardless, my original respons should be taken in this manner.

The craigslist poster is full of crap. While there are nascar blocks and some aftermarket blocks here and there, the factory blocks are all pretty much the same and while .060 may be okay on an individual engine that was tested during assembly I sure as hell would not buy one that started out that way; there is no way it is a good thing to start with a block that is at it's last possible useful bore diameter.

If you have it, or it matches your car, of course those change the dynamics of the decision making process.

 

[mustbrad]

mine is .40 over and is fine and I drive it hard only part of the time

 

[Boss1Ray]

So I'll say .040" is the max for a regular production 351C block.

Thanks for everyone's replies!

::goodjob::

Ray

 

[Mister 4x4]

OK - since the lid's still off of this can o' worms, I hafta ask: sleeving cylinders... people avoid doing this for obvious reasons (I liken it to having tires retreaded), but could someone feasibly sleeve all 8 cylinders on an .060" engine to get back to, say, .030"?

I'm asking because at some point down the road (hopefully, many years), I anticipate pulling my current engine and rebuilding because of being driven daily (without any catastrophic failures, of course). I know it sounds crazy to even think like that (considering I haven't even fired mine up yet), but by that time, finding another 351C block might not be even as 'easy' as it is now.

 

[Tnfastbk]

OK - since the lid's still off of this can o' worms, I hafta ask: sleeving cylinders... people avoid doing this for obvious reasons (I liken it to having tires retreaded), but could someone feasibly sleeve all 8 cylinders on an .060" engine to get back to, say, .030"?

I'm asking because at some point down the road (hopefully, many years), I anticipate pulling my current engine and rebuilding because of being driven daily (without any catastrophic failures, of course). I know it sounds crazy to even think like that (considering I haven't even fired mine up yet), but by that time, finding another 351C block might not be even as 'easy' as it is now.

YES if done correctly

 

[Jeff73Mach1]

Sleeves are expensive compared to boring a cylinder. Done properly they are not at all a detriment to using the engine for any particular purpose. Big diesel truck engines are all sleeved. Most aluminum engines are sleeved (all used to be, but there is a new process that uses plasma to spray iron onto the walls-it might even be a way to repair blocks for the public in 20 years or so)

Sleeves installed improperly are akin to bores that are bored off axis. It is a machine shop error that should not be tolerated.

 

[TommyK]

Old usable cores are drying up but there are no less than 2 new aftermarket cleveland blocks coming to the marketplace. No need to sleeve unless you gotta have numbers matching.