rebuild question

fattycrack · Post by **fattycrack** » Thu Mar 22, 2012 10:46 am

Ohk so here's the deal I am rebuilding my motor with about 80xxx on it and a few old school guys were telling me , that with the amount of miles I have I'm going to NEED to have a bored out. I really don't want to just because that is more time and money. So what I was wondering is if i would actually need to or if a good hone would do fine?

Hudson_Neon · Post by **Hudson_Neon** » Thu Mar 22, 2012 11:53 am

you don't really NEED to. the reasoning for that is cause the older engines didn't use aluminum pistons. the cast pistons were much harder on the cylinder walls. but if you're rebuilding it, why not just do it? it should only be an extra week and extra $100 or so... actually, now that i think of it, why are you rebuilding it in the first place?

Danteneon · Post by **Danteneon** » Thu Mar 22, 2012 12:48 pm

Hudson_Neon wrote:it should only be an extra week and extra $100 or so...

Plus the price of over-sized pistons. Instead of having the engine bored, you can have it honed and use your existing pistons (but make sure you use new rings) as long as the bores aren't in horrible shape.

But I would like to know why at 80K you are re-building it too.

fattycrack · Post by **fattycrack** » Thu Mar 22, 2012 1:06 pm

I'm going for more power I'm going thru everything check out my progress log

Hudson_Neon · Post by **Hudson_Neon** » Thu Mar 22, 2012 1:29 pm

Danteneon wrote:
Hudson_Neon wrote:it should only be an extra week and extra $100 or so...
Plus the price of over-sized pistons. Instead of having the engine bored, you can have it honed and use your existing pistons (but make sure you use new rings) as long as the bores aren't in horrible shape.

But I would like to know why at 80K you are re-building it too.

but there's no point in rebuilding if you're using the same pistons really.

fattycrack wrote:I'm going for more power I'm going thru everything check out my progress log

also, there's this. you're gonna buy new pistons anyways

Danteneon · Post by **Danteneon** » Thu Mar 22, 2012 1:34 pm

I wanted to make sure the difference between honing and boring were known to the OP. And you can do a rebuild without pistons. New bearings and rings alone can make a major difference if the bore is still in good shape. You can still see the factory cross hatch in my block at 120K.

But I'm with you, since the OP is going for more power, new larger pistons should be part of the equation anyway.

fattycrack · Post by **fattycrack** » Thu Mar 22, 2012 1:36 pm

I already have the pistons and I don't Wanna bore it fuzz of that reason I have stndrd bore pistons

fattycrack · Post by **fattycrack** » Thu Mar 22, 2012 2:23 pm

Ohk so back to the main qeustion I don't NEED. To bore out the cyls but I probably should?

Danteneon · Post by **Danteneon** » Thu Mar 22, 2012 2:54 pm

You don't need to if the cylinder walls are in good condition and the bore is not out of round. I would have a machine shop check them to make sure before slapping in new pistons.

I didn't check your log, but did you get higher compression pistons?

fattycrack · Post by **fattycrack** » Thu Mar 22, 2012 3:09 pm

No same compression but with boost

Danteneon · Post by **Danteneon** » Thu Mar 22, 2012 3:32 pm

So....lower compression pistons? If going boost you will want lower CR than stock.

fattycrack · Post by **fattycrack** » Thu Mar 22, 2012 4:12 pm

I know that's the general rule when boosting but I have a thicker headgasket and I if I remember correct it should bring the compression to 9.1.1 with the pistons I have

Danteneon · Post by **Danteneon** » Thu Mar 22, 2012 4:15 pm

OK, so you do have a plan for bringing it down then. So yeah, as long as the bores check out OK, you don't need to punch them out (and have to buy different pistons).

fattycrack · Post by **fattycrack** » Thu Mar 22, 2012 4:24 pm

Yeah I was kin day wondering why I would have to since my car was only driven with some spirit for about 8 to 10k

Post by **occasional demons** » Thu Mar 22, 2012 6:20 pm

They will need to hone it to get the new rings to seat properly. You will want to give them the new pistons so they can match them to each bore as well as possible.

They should all be very close to the same size, but it isn't a perfect world. There are tolerances with everything. They will generally only hone it enough to get a good consistent surface.