Cylinder ridge

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stroker mike

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There is a ridge at the top of my cylinders, how much ridge can I allow before I have to bore it? I also need to check for taper, I know, but for an emergency rebuild...Please help, I'm in trouble. My primary transpo has messed up on me bad.
 
You can use a ridge cutter to remove the ridge. Alot of times half the ridge is carbon buildup so it's really hard to say how much is allowable. Mic'ing it is the only way to know for sure how bad things are. Since you didn't say what engine it is I can't tell you what it should mic out at but I think the factory serv. manual allows .005" out of round if I remember right. I personally don't like to see over .003" out of round but that's what they say.
 
It's a '70 318. If I take it and have it tanked and mag'd then I'll know, I guess. I have a duster with a 72 block in it now, been having oil pressure issues. thing's gonna go real wrong if I commute with it much longer. Looks like I'm on the bus for now.
 
You should remove the cylinder ridge before removing the pistons or you run the risk of damaging the piston ring lands. Some of the old engine manufactorers built their engines with a tiny bit of taper (.002"-.003" top to bottom) so that the rings open and close as the piston travels through the stroke, which supposedly helps stop carbon buildup. I'm not sure if they still do it but to much taper will screw the rings and they won't seat. How much is to much, can't say for sure but I'd guess .004".
 
You can run it with a ridge, but like Demon said, replacing rings (or removing pistons you need to re-use) and leaving the ridge is asking for issues. The actual "ridge" has aradius as it was worn by the worn rings. Your new rings have a sharp 90° angle and as the fresh ring hits the rounded ridge it twists and can break pistons or itself, in addition to losing ring seal at the most important spot in the piston's travel (TDC). If you have to have the lower end good, I'd suggest you buy a crank kit with bearings and simply replace the crank and leave the rings as is. It's cheaper and safer than trying to make a purse of a sow's ear.
 
My humble $.02
*IF* the engine is not burning oil, leave the bore/ring issue as is.
new crank/rod bearings , agreed.

ALSO (and perhaps the most overlooked) area on low oil pressure issues,
CAM bearings !!

So... some gaskets, crank/rod/cam bearings, bingo!! budget transpo
lives again.
 
Very true. Honestly, sounds like rebuild time.
 
You are right, it is rebuild time. I just didn't want to do it under pressure. I was planning the ultimate 318! Ha! I'll get her going one way or another.
 
mech1nxh said:
My humble $.02
*IF* the engine is not burning oil, leave the bore/ring issue as is.
new crank/rod bearings , agreed.

ALSO (and perhaps the most overlooked) area on low oil pressure issues,
CAM bearings !!

So... some gaskets, crank/rod/cam bearings, bingo!! budget transpo
lives again.
Click to expand...

+1 on Cam bearings.
 
either way this thing is coming out. I'm buying a different engine. I can find a runner cheap I bet. Clean it up and run it. Time is hard to come by when you aint drivin. Thanks guys.
 
A friend of mine texted me this morning.. early 360 with J heads... core motor. Don't know the condition yet, get the details tonight. Sounds like a good candidate! Was talking to Bob Gromm and Vic Anderson this morning, either way if I get it machined we're talking $$$. Bob suggested that if it's an emergency I might drop it in as is, close my eyes and start it! Ha! He's the man...
 
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