Hemi Cylinder Wall Pitted

Even if you bore it to appear smooth the pits will return !! Sleeve it and be done with it !! Ask me how I know !!! >>>>.

 

331's have a cyl. wall of approx. 5/8". Bore the crap out of it. My 331 had a stuck piston and the rings had rusted a big groove in one cyl. I bored them all and put Aries pistons with 10.75 comp. Runs like a HEMI should

 

Years ago i bought a fiat drag car 283 .125 over bore the max it had jans 12 to 1 pistons one piston had blown in to little peaces the rist pin put a deep gouge 1/8 by 1/8 by1.5 inch long. in the cylinder wall. money being tight and needing a drag race fix. had sold my 55 chevy a year ago we slaped it together ran that dam thing 5 years hilborn injected on alcohol RUN IT

 

Shiiit... Who's this Jans guy?

 

I have a pontiac 400 that sat in 71 formula in a dilapidated garage with the hood off for years. It ran like a striped ass ape. upon a teardown after an overheat it was apparent where the rust was. there were some pits from .005 to .030. the rust had been polished off the walls by the rings. It's a very low mileage std bore and I'd like to preserve it and was thinking bout epoxy since it was running fine as is. I found an article some time back where some guys had used some hightemp rockhard epoxy and filled the pits using a single edged razor and never had it burn back out

 

I'd say depends on the depth of the pits but those 331's would take .125" unless it had a great deal of core shift.

 

The problem would be with the temperature variations. Cold freezing startups, to top of the curve thermostat temps.

Metal expands and contracts, and epoxy shrinks as it gets old.

Sooner or later you're left with a pit again, and when the ring finds it, it may or may not make a noise, but you will notice smoke coming from the exhaust.

This smoke in the exhaust is what we, in the industry, call "screwed."

 

Hahahaha, thats funny right there...and true...pictures please!!


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This is a true statement. It essentially becomes the "max bore" for the engine, but it is possible.

A good machinist will be able to look at it and tell you about how deep it is. Then cleanup hones will tell you the rest.

Keep in mind that there are only so many sizes of rings available for these small-bore engines. Doing some weird over-bore may lead you to problems with ring sizes, so work with your machinist to find the best combination and don't overbore the engine anymore than you have to, unless you seriously just don't care about longivity of the engine. Custom pistons are the easy part and can be made to whatever size you need and won't cost you anymore one way or the other.

I checked very recently on sleeves for one of my blocks and it was $100 a hole. Seems to be a standard price.

 

#### This is the Jahns Guy !!! >>>>.

 

#### The only guy I know that can guess if the pits will return and tell you how bad they really are is the AMAZING CARNAC !!! This is cast-iron and it is very unpredictable !!! >>>>.

 

Didn't mean that they would ACTUALLY be able to say "oh, it's about .023" deep in the cylinder wall. Sorry. Just implying that someone with experience might be able to take an educated guess at determining rather or not it's pitting or something creeping in from the water jackets. Didn't mean for that comment to be taken quite so literally.

 

I've got some first hand experience on this. :-( I'll be fine after a sleeve.

 

I knew someone around here would know how to spell.

 

#### No problem scootermad !! I'm just trying to save someone the grief and trouble that will follow. I rebuild about 100 engines a year so I'm just speeking out on what I see !!! >>>>.

 

Yep! I'm with ya' man! Sometimes things just don't get conveyed well when typing. Stupid internet...

 

This was my flathead...



I honed it.

I have over 10K on the motor now, no problems.

 

Worst case you burn a little oil until it wears out, just run a little hotter plug and call it good

 

You could metal spray the inside of the engine like Barney Navarro did while 'spearminting with Oxygen as a fuel on the lakes?! Of course you need a doner carb to vaporize.............

 

That's funny right there!
Mine aint so bad I just have bout 5or 6 of his smallest pitts in my 400

 

As has already been posted, get a competent machinst to sleeve it and you'll never have to worry about it again.

This is why I like .060" over in a 331 Chrysler, which is 3.8725" bore. You can then use 283 Chevrolet rings (3.8750") and file them to fit.

By doing this, if you ever need new pistons and a re-bore, you can simply go up another .010", .020", etc. from there and buy the corresponding 283 Chevrolet ring set. I know for a fact that Summit Racing still carries Sealed Power moly rings in the 283 sizes for about $57.00, because I just had to buy some for my 331.

 

Dont forget bearing juice...
And chinese new year

 

I got a hookup on spellin'

 

It is possible and I have witnessed it. Though it was done on some very rare motorcycles that were being restored. No parts were available and it was welded up and honed. Seemed to work pretty good. Don't really know how it held up. And I doubt that the bikes have gotten run much.

 

wowWWW !! jb wELD ???? epoXYYY ????? i think that guy needs a pill or something ill bet his first attempt at patching a tire the patch went on the outside of the tire and it didnt work all that well ( please accept my appology i couldnt help it )

 

Now that is some serious pitting. The 440 I was describing earlier was nowhere near that bad. Does that motor smoke alot?

 

Nah, fix it right...Sleeve the thing.
What's the price of a gasket set, your labor when the thing smokes and you have to go back into it.

Chances are the other cylinders need boring anyway.

I have J.B. Welded pits on motorcycle fork tubes and worked great, but that's not Hemi cylinders.

 

I'm with the crowd that says, if you're going to sleeve one cylinder, then sleeve them all, That way, performance and wear will be uniform in the future. Just two pennies'-worth.

 

Glad I found this thread, and its not four years old either, lol.

Anyway, I've been looking for guidance on a similar situation on my 392. I'd like to save the forged pistons if I can but there is some rust pitting and scoring. I've honed out two cylinders as a test and while I've made a significant improvement I do still see some pits and super light scores. I cannot feel the scores but can still see them when i put a light at the other end of the bore. The pitting is limited in location, basically where the piston caused condensation during years of storage, in most cases confined to about 1/4 inch up and down. I can just barely feel the pitting. I think with some more honing it might come out completely but then I'm getting more and more piston clearance.

I was told elsewhere that old Jahns forgings could run with as much as .009" . On the honed cylinders I'm at about .007 clearance now(feeler gauge). Bores seem within resonable out of round and taper(about .001, as measuered with snap gauge, I plan on double checking when I get a bore gauge) although so far I haven't found good spec on that issue.

I had heard before that iron rings are forgiving. Any feedback on just HOW forgiving they might be would be great.

I understand about 'do it right' and generally agree but I'm not sure I'd be terribly upset if I had to pull the block at some point later to rebore. Right now money is tight. Next year or two it'll be better so I'd have the cash. If saving a grand now means I could drive it for 'awhile' I might not be too miffed to bore later. If I got 20,000 miles out of just honing, I could live with that. May sound like screwed up thinking but it also might be a practical way to get on the road. Besides, if I rebore later, it'll give me something to do, rather than sit thru more mind numbing episodes of house buyers TV shows(gawd!)

BTW, this will be street motor. I'll try to shoot some pics if needed.

Well, thanks for listening.

 

0.009" ??
Wow, we don't even get close to that in a full-on race engine. The old Jahns pistons of the 60's era do grow a bunch but....
The current crop of Ross pistons that we use are run at about 0.003"
The KB hyper jobs run at about 0.0015"

It's your engine and your money so experiment as you wish, but prices of material and labour are not likely to be any less next year so why not do it right? If your pistons are in good shape then you should be able to sell them and offset the cost of new slugs in the nex o/s, assuming that you are not already at 060. Have you sonic checked the walls? You do know that the 392 has core shift problems, don't you?

And yes, ductile rings (as opposed to cast) are somewhat forgiving, however, at 0.009 can you find a 4.010 ring set or do you go to 4.020 and squeeze the shit out of them?


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