Engine and Transmission Tech

I have my Olds 215 block apart and noticed that the liners are slightly proud. The engine was leaking between two back cylinders, so obviously it didn't cure leaking issues.

I was planning to have the engine line-honed and square-decked by a local shop that has a Rottler F65a.

Question is whether to have the block's head surfaces milled flat or to just dress up the cylinder liners.

Paul, Original, integral cast liners? Leaking coolant? Steel shim head gaskets? "It" didn't cure leaking issues? (re-sleeving)? Need more data, roverman.

Yeah, what he said. It sounds like a new sleeve job?? I'm eager to hear more.

It looks like it's the original sleeves in the block. It's just that they stick up from the rest of the deck of the block. Not a lot, but enough to catch your fingernail on if you try. All the sleeves seem to be this way.

A head gasket was leaking between two cylinders on the head side, not the block side. The head gasket was not the shim type, it was the composite type.

Paul,

Sounds more like a Rover block problem than a BOP block, if you have a coolant leak and it not gasket related then even with my limited knowledge of BOP blocks i would of though that you may have some block cracking issues, you could have it pressure tested before spending money on it but would probably be cheaper to source another sound block from D&D.

The standard liners on a 3.5 bore engine do not seal to the gasket so I don't think the problem is related to the height of the liners.

Kevin

It does indeed. It's got to be an Olds block though, right? Or can you machine a Rover/Buick for the head bolt holes. I don't think so because I think it needs the extra boss on the inside of the lifter gallery. I could be wrong though. If it is the liners slipping in a cast-in-liner block (Buick/Olds) then there are some serious problems with the casting. I hope this isn't the case.

You could have the block decked and see what happens. That's sorta a gamble though because if the liners are slipping it's pretty expensive to fix. Is this Olds one of the high compression versions?

One other thing. I thought the slipping liner problem was a late block issue... ?

Nick,

Yes should be impossible for the cast in liners to move as they are slightly corrogated.

If the the block has been relinered at some stage it's worth Paul checking the bore size as it may have been increased, in which case it may be worth trying to save the block.

Paul, If its purely a gasket failure then a light clean up of the heads may do the job, but have the decks checked to see if they are true.

The slightly proud liners should not prevent the heads seating correctly.

Kevin.

Thanks guys. The block is an original Olds block, and I highly doubt that it has been relinered. (New word.)

The head gasket blew between two adjacent cylinders; the last two cylinders on one side. Both the gasket and the head show were it was leaking. The block side did not show evidence that gasses were leaking there.

I think having the liners sticking up above the surface of the block works like an O-ring to help seal the heads. So what I'll do is find a straightedge and check to see if there's been any erosion of the tops of those liners.

I know a machine shop with a Rottler F65A mill. It uses mandrels in the main and cam bores to align the block and I can get the block square decked. The machinist is a pain in the ass and I'll have to negotiate with him to get what I want done. (Seems that even though I'm paying his high prices, he still wants to do things his way.) If I can get that guy to just barely skim those liners to get a fresh, flat surface, that would be perfect. I think.

There could be a problem if the aluminum surface around the liners is not somewhat flat. I'll have to check to make sure it's not too uneven.

Hopefully the rest of the block will clamp against a composite head gasket.

If I have to mill the deck down to the aluminum, I'll probably opt for steel shim head gaskets.

Paul,

Don't forget that the gasket type will affect compression ratio and lifter preload, the tin gaskets are usually 28 thou. and the composite are as much as 46 thou. Can be useful if you want to adjust compression ratio, ie use composites if it would be helpful to reduce compression a bit.

Using comp gaskets will reduce compression by approx .45/1 on an engine that originally had tin gaskets but will also reduce lifter preload by approx 30 thou. If you have at least 25 thou of preload you should be ok.

Kevin.

Kevin, thanks for that reminder about the pre-load.

My engine has the 534 high compression heads and I'm a little concerned about the CR. I was considering using a dremel to cut dishes into the pistons tops, using the valve reliefs as a guide, to try to reduce the CR.

Paul

Paul, I'm getting you didn;t have a coolant leak, only "cylinder swapping"? If "all" the sleeves are equal "proud", are the composite gaskets clamping their" fire ring" on the the sleeve areas or outside of ? If you straight-edge the decks and the heads and their approx. .002" max. end/end,should be ok. Wild Card is how consistant is "proud" dim. of all sleeves? Can check with depth micrometer or small height gage with indicator on decks. Unless your in, Tim-Buck-3, there should be more than one suitable machine shop? Good Luck, roverman.