I just picked up a 502 short for my galaxie drag car. Last night after I finish assembling my heads, and get ready to bolt them on I gave the cylinder walls a quick wipe with some oil, as I do this i notice a small pit just above the piston (at bdc). Its about 1/16"(prob a lil less) deep and maybe 1/8" round. Now considering the pistons are already in, and Don't wanna buy new pistons so overboring is out. Anyone got any ideas as to a fix? I'm having a hell of a time trying to fig out how the shop I bought this from, who by the way are a reputable shop, building race engines since the 60's, let this pass. And even harder time getting over the fact I didn't catch it before I bought it. Anyway I think I know I'm screwed but any insight would be appreciated.
Step 1- Get on the phone with who you bought it from. Step 2- If you can't a satisfactory answer at step 1, run it. Piston/piston ring seal is FAR less critical at or near BDC. Many engines have flaws bigger than this and still win a lot of races. Step 3- If you do decide to run it, run the snot out of it. Treat it like a rented mule. This flaw is bigger in your mind than it is in your engine.
This is probably the course I will run, more I think about it, more I feel it shouldn't be a big problem. Just sucks knowing I'm putting the time effort and money in and its not perfect.
i hear you, but it's pretty rare for anything to be perfect. how many flaws go unnoticed or ignored. i had a hairline crack near a headbolt hole and it really annoyed me since i had the block magnafluxed, checked, and i had some cash in the block at that point- it sliped thru. but you know what, no problems came out of it.
Sounds like they did the right thing, it would need a sleeve to fix a pit 1/16" deep. You would not be happy to see a sleeve instead.
That is the area that builds up with carbon from many years of use . That is not a spot to worry about . The machinist was just trying to save someone some money and not re boring and installing new pistons . To have the block bored and have new pistons installed you are looking at another $1000+ for that . I really don't think it will make any difference either ! Personally I wouldn't worry about it at all ! I have seen worst than that things in new blocks before ! Just go and have some fun racing with that engine ! It will hold up just fine for you ! Retro Jim
An old friend told me a story about a motor with rusted cylinders. He bought an International truck that had been left outside with the head off. He overhauled the motor, honed the cylinders and put in new rings. All the cylinders were pitted with rust. It burned a little oil for the first 500 miles then settled down. A few years later he had the head off for a valve job and found all the pits filled with hard carbon, the cylinders polished smooth, the pistons in good repair. As long as the pitted areas are not big enough to snag the rings it should work out OK.
Think I'll just clean up any sharp edges and run it as is, I'll stop by the machine shop anyway and let them know they probably should of told me about it rather than me finding it. Hopefully we'll get a good couple years of some fun out of it. Thanks for the help, hopefully see some of you at the track!
You can get away with what you described and you'll never know the difference. On the other hand, if you paid foir perfect or don't want anything less then I wouldn't blame you for doing something about it. To put this in perspective, I would much rather have the imperfection you described than a sleeved cylinder.
I see inclusions and pits in SBC engines all the time. A fact of life for poured cast iron. That small pit, that far down, I would leave alone. Blending the edges will not help. Run it! Only you will know it's there.
You are not going to have a problem that far down in the cylinder, there will be little to no compression on the rings at that point. As stated do not debur it. Leave it
Although the pressure at the end of the stroke is relatively low compared to TDC, there is still quite a bit of pressure in the cylinder at the bottom. Exhaust noise is that pressure escaping when the exhaust valve opens. But I agree, the defect isn't going to cause a problem.
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