390 Boring problem

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Apr 12, 2005 | 12:04 PM

FalconStng

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390 Boring problem

I finally got my 390 block back from the machine shop. It was to be bored .060 over. One of the cylinders has a miscut at the top of the cylinder. I measured and the top ring goes past it. I called the shop and they said bring it back and they'd sleeve it. I'm disgusted with the shop for ruining my engine. Can it be successfully sleeved? If so, I'm going to take it somewhere else to get it fixed.

Thanks,

Tracy

Apr 12, 2005 | 12:30 PM

312

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yes it can be .no problem.

Apr 12, 2005 | 08:13 PM

discman

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From: Murrieta, CA

yea, bad machine shops. _ mine balanced my 390 and welded (blobed) welds on the counterweights and
when I put the motor together, the blobs hit the piston skirts... and they put the cam plug in backwards,
--- supposed to be a machine shop - I should have known by the looks of the place - @#*& everywhere.

Im taking my heads somewhere else -Or I buy edelbrock ones.

Apr 12, 2005 | 08:48 PM

rusty70f100

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Joined: Jan 2003

Posts: 8,600

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From: Iowa

Heh, bad machine shops...

I had one where I took my heads in for hardened seats and new valve guides where needed. They did put in 5 new valve guides, which was ok, but they didn't trim them up inside the port. No big deal, a small annoyance.

The big problem was with the hardened exhaust seats they put in. They were all at different levels! Their explanation was that the tool locates on the bottom (top) of the port. Of course, this left the valve stem heights uneven. The adustable valvetrain I installed compensated for this, but I was not happy. You'd think they would put a stop on those machines, so they'd all be the same height.

Apr 12, 2005 | 08:52 PM

FFR428

Needsmorecoffee.

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From: CT

I've had a few blocks sleeved and all have ran just fine. Plus all aluminum blocks are sleeved. Just be sure the shop you choose does this right. Most production shops use a std 3/32" sleeve which are fine and require one less cut in the block saving them time and money. Also available are 1/8" sleeves leaving room for future rebuild overbore if the other walls are thick enough. At .060 though your about at the limit. What was the bore size before and did they need to go to .060? G.

Apr 13, 2005 | 08:21 AM

FERacing66

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From: Jackassville

I was lucky enough to get a machine shop that did a great job, the were the best price around too. I went to antother machine shop, and saw the dump it was in, I hightailed it back to the one I always use, plus they act like proffesionals, the other places talked like they worked in the junkyard. A bad machine shop can ruin your motor, a good one can make it run perfect.

Apr 14, 2005 | 12:38 PM

FalconStng

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Update. The block was standard bore. It's bored to .060 over standard now. The cylinders wouldn't have needed to be bored .060 except that I believe a ring groove cutter was misused on a previous rebuild. I messed up on the measurements. I'm installing 360 pistons. I believe the 360 pistons must have the ring lower. At any rate, after a test assembly, I found that the ring winds up about 1/16" below the miscut. I'm thinking that this is ok. I know I need to allow for some expansion and stretch. Anybody know how much? I'm thinking that it won't be close to 1/16" but that's just my gut feel.

Thanks,

Tracy

Last edited by FalconStng; Apr 14, 2005 at 12:41 PM.