Tried this over in the Integra forum, but it's not getting looked at too much, so here goes again.

I'm currently running with B16 pistons, Crower Stage 3's, and RC 310's in my GS-R (Tuned on Hondata)/P28. I am considering going turbo, and going back to GS-R pistons with new rings, and then getting some ITR cams. The motor was rebuilt about 18k miles ago, so I'm wondering a few things:

1) While changing out the pistons, do I have to replace the rod bearings? Or am I ok to reuse them since they were installed so recently?

2) Will a stock P28 ECU run a GSR on 310's and ITR cams to break it in safely, or should I get some stock injectors? (will that even work with the cams?)

Alternative is to pay to have it broken in on the dyno, which is ok, but Id prefer to do it driving to make sure everything is ok before I get to the tuner.

Thanks guys!

 

Ok, let me give the best answer I know of then I'll give you an alternative.

To do this right and be 100% sure, you should go up to the next size ie bore and hone.

The alternative is to use a flex hone on the bores and then replace the pistons. I would replace the bearings because a in car piston swap can be a b***h sometimes and you end up damaging the bearings trying to get the caps off especially the 2 and 3 pistons.

No, I would not use a p28 to break in anything but a single vtec swap. You can use it to start the motor and check for leaks etc but that would be the extent of it. Go with your alternative for break in. Also, make sure your tuner is using a load control dyno.

 

in-car rebuilds are an abortion if you have to touch the cylinder walls. all that **** just falls on the journals.

if it were me and it was rebuilt only 18k miles ago, i would yank the head and put a thicker HG on it, or just leave it alone.

but, if you do switch pistons, the cylinder walls are probably in good enough shape to just swap pistons and rings. they are probably not glazed like they are on a 100k mile motor.

 

I should have mentioned that I will be removing the engine from the car to do the piston swap. Given that, do I still have to replace the bearings?

Also, my plan was to check the bore of the block once I have it out, and then go from there on the hone/bore. Am in understanding correctly that I only need to bore it out if it's larger than standard spec? Should a hone be done regardless? I'm guessing if it's a little on the larger size, the hone would put it in the over-sized range anyway?

Perhaps I'm just trying to save money too much, but I'm trying to avoid having to buy oversized pistons from Acura, and rather try to use a set of Std used ones. (That is assuming the current pistons are std sized.

Thanks for your posts guys!

 

if you are removing the engine from the car then you should pull it completly apart and properly bore/hone the cylinders and have it cleaned etc..

and you might as well put all new bearings inside. you are going to go thru all that time, effort and money to pull everything apart to reuse the bearings? no way.....that would be a bad idea....

 

I'm still new to working on internals, I just don't see the point when they've been soon recently replaced. If it's needed, I'll do it...I just don't want to do it just because.

 

If the bearings and rods measure fine, you might get away with it. But at 18k I would replace them. Do not use a flex hone, if the bores are round, and you can get a factory .0015-.002 skirt clearance with a proper hone you will be OK. but i doubt that will happen. Have stuff measured, and fix accordingly.

 

Alright...that's a bummer. I think that's going to put me overbudget on my project...Might have to hang onto the N/A setup!

 

Not really, you have to be careful and make sure you cover the bottom of the bores. It is not something I would recomend for a noob.

 

Question for you guys...What are the chances of being able to hone the stock bore twice and still be able to use stock bore pistons? I just checked with the previous owner (who had the last rebuild done) and he said that it was honed, but not bored. He also as the original pistons which he will give me for free. I'm hoping for a good crosshatch still, and to not have to hone again, but say that I do...do you think I'm going to have to end up boring to .25 over?

I guess another way of asking this would be...how much material is generally taken off with a hone?

 

Bump

 

your answer was given: measure it

no one knows how much was taken off or where the PWC will come in. you can go up to .0020 on a cast piston and be safe. how round the bore is also is something you need to check. if you do overbore you might as well go twenty over and buy the 81.50mm since you get a tiny displacement increase. nippon pistons with rings are something like $130ish on ebay.