basic stroker ?s

[rficken42]

hey guys, here are my specs
1999 TJ I6 AX15 NP231 w/sye. 33s. 4.10 gears.
my current engine is burning oil but not leaking any. leading me to believe the piston oil rings are worn out. if im going to tear down & rebuild the engine id like to do a basic stroker kit of using 4.2 crank & rods, to make a 4.5. my jeep sees daily driving, dirt, rocks & highway.
i need ideas or threads to follow so i can research more.

[Cheromaniac]

I recommend that you have the cylinders rebored so that you'll be starting out with round and true cylinders. Then you could go on and build a copy of the modified 4.6L poor man's stroker recipe from my site. If your budget is a bit more generous you could consider the 4.6L low buck recipe instead.

[rficken42]

I don't really want to bore out my block. I was looking at builds where I use stock 4.0 pistons with 4.2 crank and rods.

[Knoxes]

I'm almost done with my 4.2 stroker build. It's back in the jeep - just need to re-install a couple of things and we're ready to turn the key.

You can find my thread in the project section under 4.2ish mini stroker build.

[SilverXJ]

I'm with Cheromaniac on this. I recommend a rebore. Not only will the cylinders have wear, but you will also be pulling the piston lower into unworn bore area.

[rficken42]

I understand what you're saying. But I'd like to use my current stock pistons. Wouldn't just honing the cylinder be enough?

[JPrubo]

I agree with those guys. Basically if oil is getting past your rings it's cause the walls and rings have worn. This means the tolerances are looser around the piston. If you hone you will remove more material allowing even more room. Now add to that the higher pressure from increasing the displacement and compression and you are more likely to experience piston slap or increased wear. I would recommend the rebore for better piston fitment and get the keith black pistons so that you can reuse your stock connecting rods. It will save you from buying new/old rods, give you a better rod, a better fit on your pistons. The piston to rod price may not be a wash but the little extra for switching pistons is probably worth it.

[SilverXJ]

Basically if oil is getting past your rings it's cause the walls and rings have worn.

For some reason I missed that part. In this case there is no way you will have a reliable engine by just dropping a 4.2L crank and rings in.

[rficken42]

I'm not entirely sure where the oil is going. It could be the head or gaskets or position rings. I think I'm going to go with sealed power h802 pistons. See how my cylinder walls are when I open up the engine.

My next concern is does having a manual transmission affect anything?

[SilverXJ]

Not the head gasket. If the engine was burning the oil due to a head gasket leak it would be venting pressure into the crank case.

On the manual just make sure you get the correct pilot bearing.

[MN_luda]

he might mean the head itself, as in bad valve seals/oil getting past the guides. Most companies actually make their engines about .002-.003 clearance from the factory. So add in normal wear and it could be up to .004+, not to mention cylinder taper and ring ridge. definately bore it next size bigger!