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1995 115hp V4 VRO Needs rebuild advice

R

robmcconnell

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"Hi

I have compression t

"Hi

I have compression tested the engine and get ZERO on one, 55 on the cylinder above. The other two cylinders seem fine on 110 each.

I need to rebuild, one liner is quite heavily scored in one area and the other is very lightly scored. Will I need to install new liners or can they be bored out.

Can I have the block bored and oversize pistons and rings fitted. I presume all four pistons must then be oversize?

What parts am I looking at here, set of pistons and rings and a full gasket set? How much is this going to run to.

What would have caused this problem, what should I look for when breaking it open.

I have a friend who will do most of the work, as my knowledge of engines is confined to the simple (Spark/air/fuel) and how to diagnose running faults. Not rebuilds.

Thanks
Rob"
 
"As far as the cost goes, it c

"As far as the cost goes, it cost me just under 700 bucks in parts to rebuild on my 90 hp. V4 that included boring pistons rings and gasket set, and a few other misc. parts... I was told that I could just oversize one piston and that would be fine.. But I did all 4 but one oversized more then the other 3..."
 
"Unlike cars, it is very commo

"Unlike cars, it is very common to bore only one cylinder on an outboard. As a matter of fact, it is good practice--if you ever need to rebuild again down the road, why take off unnecessary life from the other cylinder walls? Apparently the pistons are balanced taking into account the oversize issue, so that there are no balance issues. One bit of advice--the machine shop is everything. Don't make the mistake of using an auto machine shop, you need someone who is very experienced with outboards. I had an actual OMC repair station do the block on my engine. They decided to bore two cylinders, refinish the rest, and did a superb job at about the same cost as an auto machine shop. More importantly, they knew exaclty how to finish the port surfaces, and to do all the other things that only an outboard machine shop would know."
 
"Hi Guys

Thanks for the inp

"Hi Guys

Thanks for the input, that clears up a few questions I had. We are going to strip it down this weekend so I will give you an update.

Any tips on the tear down, handy little pointers to make it easier.

Thanks
Rob"
 
"Watch out for the flywheel, t

"Watch out for the flywheel, the magnets are powerfull. After removal keep it in a separate box, the magnets does not like screws etc. The same goes for the optical sensor, store it in a plastig bag to keep it 'clean'.

Some tips when putting it together again.
Use the original Gel Seal on the cranck case and be sure the surface is properly cleaned. Stay off the Loc Tite Flange sealer with plastic-grains!
This engine has no normal head gasket but uses o-rings. Only use GM silicone (black) around the cooling channels and have as much metallic contact as possible between the head and block (for heat transferr)."
 
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