V4 block machineing

[Rancherlee]

I got my OMC service manual today but I can't find any specs on how much material is allowed to be machined off the cylinder decks to true up the block on a crossflow V4. My block has a sleeve that was installed a few years ago and its about .012 below the rest of the deck height where it blew the gasket (the whole thing is below deckheight like they pressed it in slightly to far) Is it acceptable to mill .015 off the deck as long as I watch the piston-to-head clearance? I know I'll probibly need run 89 octane or bump the timing back 2* to compensate for the extra compression.

 

[xtraham]

Re: V4 block machineing

check the piston hight, 0.015 should be okay providing the heads have not been milled, do both banks, use the thicker head gaskets upon reassembly..

 

[Dhadley]

Re: V4 block machineing

.015 is a lot to cut. If the block was sleeved it should have been cut then. When we do a sleeve we try to take lees than .005, more like .003. If the sleeve sunk, it wasn't done right. To make the block by-the-book right it'll have to be sleeved again. Even using the thick head gaskets cutting that much is risky.

 

[Rancherlee]

Re: V4 block machineing

ok, thats all I needed to hear. Time to find another block then, are most 88-115hp V4 blocks the same (I have access to a 81' 115hp with broken lower unit for the price of gas and my own labor to remove the engine)

 

[Dhadley]

Re: V4 block machineing

What year is the block you have now?

 

[Rancherlee]

Re: V4 block machineing

mines a 1988 88spl The 81' 115 is a flatback

 

[Dhadley]

Re: V4 block machineing

Yep, that'll work. Some external mounting bosses may be different but it's nothing to worry about. Any V4 crossflow block from 79 & newer will bolt up and accept your crank.

 

[Rancherlee]

Re: V4 block machineing

Score, got the engine home at a cost of about 30$ (gas and buying my bro-in-law lunch for helping). Its a virgin, never been opened, block with nice even wear and no scratches and had between 105-120psi compression. Should clean up nicely with a .020 on all 4 holes (bit too much wear for a quick hone-job).

Next question is about the crank. My 88spl crank had pitting on one rod and rod journal where it looks like it is was improperly stored in the winter and rusted. The 115hp crank looks good but one of the rods has pitting on the bearing surface. The rods look different between the 2 engines (the 81' 115hp rods look "weaker") but I was wondering if I could use one of the 115hp rods along with the 3 good 88spl rods. Both rods have the same 321712 part number but the 115 rods look like they are cast and have alot of flashing on the parting lines and the 88spl rods are smoothed on the parting line, almost looks like a forged rod.