340 head gasket leaking with sleeves

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BRMiller

BRMiller

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My 340 has sleeves on all eight. The middle on both sides have leaking head gaskets. It seems the sleeves have become slightly uneven with the block. My engine guy says it either needs to be decked but the better solution is a new block. What do you all think?
 
BRMiller said:
My 340 has sleeves on all eight. The middle on both sides have leaking head gaskets. It seems the sleeves have become slightly uneven with the block. My engine guy says it either needs to be decked but the better solution is a new block. What do you all think?
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How did the sleeves move? They should have .001-.0015 press fit and be sitting on a machined fault at the bottom of the bore? The heads then keep them from moving up.

Something is very wrong. I can't tell you exactly how many sleeves I have set but it is well in the hundreds and never had a leak or had one move.

Sleeving is a viable way to save a block. Done correctly you will not see a HP loss but you got issues.
 
I'm not sure how they were installed since it was done before I got the car. At least four of them have just enough difference to catch your fingernail on. I haven't measured it but it seems like they aren't lower than the block evenly all the way around. Could they be moving because of heat or were they not installed properly? When I heard it had sleeves I figured we wouldn't have any trouble so I'm figuring somebody screwed up on the install.
 
I'm with Yellow Rose on this one..........the fact that that a couple of sleeves moves at all tells me they were not properly installed to begin with as in not bottomed out. To be honest, not sure if driving them down onto the step and then decking would work out. Since they have moved, you apparently have lost the press fit. Sucks to be sure!

It's executive decision maker time, re-sleeve the bad cylinders and go forward, or replace the block. I'd be tempted to sleeve and go; sleeves are not bad, just people who do them badly are.

Good luck!!
 
Did the sleeves move at all or werected they never decked properly from the get go. I find it odd that all 8 were sleeved. I was always told if you were putting more than 2 sleeves in the same bank it was time for a new block. I find it hard to believe that a press fit sleeve worked it's way up against the pressing force of the head gasket. I have worked on 8.0 Viper motors which have replaceable wet sleeves. We use a special tool to hold the sleeves in when the head is off and it is removed when we install the heads.
I would recommend trying to drive the sleeve back down. If they goes down easily either replace them with a thicker wall sleeve or new block. If they don't budge and are bottomed out I might just try decking the block to even it up. May have been improper decking by previous machinist..
 
They are actually lower than the block surface. I'm guessing they weren't pressed all the way down before it was decked and over time (probably 10,000 miles) they sank down.
 
BRMiller said:
I believe the previous owner had it sleeved to keep the numbers matching block.
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If this is the case then you need to save the block. Let a COMPETENT machinist look it over. It's easy to remove and replace a sleeve or four. Then surface the block again and go. I'm old skool...I don't throw away a block because it needs a sleeve, or even 8 of them. I have done way too many sleeves to know that they work and do not affect HP.
 
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