Larger bore
- Thread starter TeaBagger2006
- Start date
I have a small amount of pitting in one cylinder in my engine that im building it will be race only and i will be doing all the machine work myself so there will be no added cost just trying to decide if i should fill it and how big to go
There are some guys on here that drive half fills. Maybe they'll chime in with their experiences. I have heard that can promote cracking at the fill level. We ran an unfilled block with our first motor for 3.5 years, bout 70 hooks at roughly 1150 fwhp, never a problem block & crank related. Even stock main caps in that one. It was nice to not have to worry about temps running coolant.
I believe I'm the guy Mr Griffith is talking about that cracked a cylinder. I actually split 6 cylinders in that block they split right at the water jackets allowing the coolant to dump into the cylinders and hydrolock the engine. That was a.060 lly block partial filled, billet mains, girdle and all arp studs so I'm never taking one .060 again unless it's sleeved or something.
Bore
I also split a block that was half filled and std. bore. It cracked just above the block filler and went up from there. I had the block sleeved in all 8 cyl. at the point and fixed the problem.
I also split a block that was half filled and std. bore. It cracked just above the block filler and went up from there. I had the block sleeved in all 8 cyl. at the point and fixed the problem.
How much displacement do you really gain by overboring past .4? I would think its not that much, and prob not worth making the cylinder walls too thin.
The cylinder wall still flexes above the fill line...I've ran 2 different blocks .040 over with no fill on our pulling truck the 5 years before last year... Never had a problem, ran first block 3 season's, cylinder walls got some taper, probably from ingesting dirt from running no air cleaner. So I started with a fresh block and used same pistons and new rings & bearings... And we broke an internally balanced crank is why I tore it down to begin with. Still got the .040 worn block with billet mains...want to have it filled and taken .100" if I ever build another pulling engine of my own, most likely with Aluminum Rods too.
I'm not sure exactly what you guys are talking about with the fill line? Out of the 6 cylinders I cracked number 6 cylinder was the worst. It appears the only thing that held it in was the block filler at the base from the half fill. It split on both coolant jackets from about an inch down from the top clear down below the top off the piston at bottom. I split 3 cylinders on drivers side and 3 on passenger side. The drivers side 3 split towards the inside of the block at the coolant jackets and the passenger side 3 split towards the outside of the block. I'm not sure what caused it but I'm leaning towards excessive drive pressures but really not sure.