liner slipped 3/8" and piston shoulder gone to ring

967 Views 3 Replies 2 Participants Last post by scout, Jul 19, 2010

scout

Discussion Starter · Jul 18, 2010

We pulled head today on #4 ----why is #4 mentioned alot? and found piston ring section jammed in intake valve port----and piston edge undercut away down to next ring except in one spot at bottom----4.0 ran fine with slight bad idle---#4 had 25 # of compression---rest ok. 95,000 miles--It was trying to overheat on 90' when it was idling with air on--no coolant loss.
The worst thing i have learned from reading alot of posts--

1---new engine will likely suffer same fate if one thing is wrong on my cooling system--
2--a new block is big bucks--$5k+
3- used engines are a crapshoot
4--this truck would sell for $3500-5000 if it had no problems---
5---I hate to lose----this is my biggest problem----

Thanks-

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dave3d

· #2 · Jul 18, 2010

Without seeing the engine, if the cylinder bore is relatively undamaged you could just replace the one piston - s/h pistons are usually OK to use again - but fit a new set of piston rings all round. Sounds as though you need them anyway. Slight nicks and gouges in the bore can be polished out with fine emery paper if they are not too deep - or get the bores honed.

If the cylinder liners are sound but badly gouged, a rebore and new pistons may be the answer. Cheaper than a new block.

Also check the inlet valve is not bent.

I think maybe crack test the block and the head using a dye spray before you go any further.

Dave

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dave3d

· #3 · Jul 18, 2010

Just re read your post.

Missed the bit about the liner slipped !

Dave

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scout

Discussion Starter · #4 · Jul 19, 2010

Have given this some thought----and seen prices on ebay for this year and model and have decided to put back together ----ir ran fine----and sell as a running parts car to someone who needs a perfectly sound RR and is not put off by the engine work----

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