I recently installed some 84.5 low comp pistons (10:1) for my turbo application.

Due to external circumstances ... I will not be turboing my Integra anymore. Back to N/A - YAH!

I now want to swap the low comp pistons for some high comp ones.

I only have 60 miles on the new motor with the turbo pistons. Can I just swap them out for the N/A ones without honing the block? I will definately get new rings and everything. I haven't even got past the breakin period.

Right now, money is VERY tight. And would just like to do a straight swap.

What are your guys thoughts.

By the way - this is a NO BULLSHIT motor. I'm shooting for 210+ WHP.

 

Technical things aside...
I'd probably keep it the way it is and just live with it for a while. Your circumstances might change for the better?

I say that because if something does happen it's nice to have some extra money around to put things right.

 

It won't cost my really anything to have the high compression pistons installed. I will sell my turbo ones and buy the N/A pistons with the money.

A friend and I will install them.

The only cost is dyno tuning ... which I still have to do with the 2.0 liter motor. I would rather dyno tune it with the correct (high CR) pistons.

 

check clearances. You never know til you check. but...unless there was an issue in the first place or you blew a head gasket or some other problem....more then likely it'll be a quick swap. Don't forget to check your rod bearings and crank journals while your at it. You may not even need new rings unless they were old as well. but...check ring gaps

 

Let me know how much you'd be planning on selling the pistons. What brand are they?

 

If the rings are the same thickness, you could use the rings currently in the motor, on the new pistons, and save from honing the cylinder walls with the crank in the car (ewww )

Nothing wrong with that. Make sure to check piston/wall clearences, but with forged slugs, you have more leeeway than with cast factory.

 

I will install new rings with the pistons.

The low comp pistons were set up for turbo.

I will set the new slugs for N/A.

So, with such low miles ... do we all agree just swap them in. Of course, checking for clearance.

Adam

 

clearance is not the issue. the conditionof the cyl walls is the issue.
if the rings and the walls have already started to mate, then you will have to
hone them or else you will just smoke and burn oil.

I would ONLY put pistons in if I hone the block first.

 

Thats why I suggested, that if he really wanted to, he could re-use the current rings in the car now. They have already mated to the walls. We've used this before in a pinch, and it works quite well.

Of course, the "right" way of doing it is to break the entire motor down, and start with a hone job

Good luck!

 

yeah yeah yeah/

Honestly, if you only have 10 miles on it..

You can just drop another set of pistons in that have the same installed clearance..

say 3k...

Slike steve said..just look and see how smooth the walls are.

If they are not...

hone to like .0031 thou...and gap new rings accordingly..

etc

Jeff

 

No, that will not work either. To get the current rings to work again you would
have to put them in in EXACTLY the same orientation that they came out, which
would be nearly impossible to do. Many people have tried this, i know of noone
that has succeeded.

 

Rings float in the bores ya know

 

No. the pistons float in the bores and the rings push up against the walls.

 

They are able to rotate.....and they do.

 

I've never rebuilt a motor, but yes it seems to me that if the rings had broken in just a little, and you indexed them to the bore when you removed the pistons, you could get them close enough on the new slugs to fall in their original place..


[Modified by sackdz, 5:03 PM 6/23/2002]

 

i agree. no way that you can guarentee those rings staying stationary when there is a gap at the open end. I think the issue with the cylinder walls was an obvious one. if they are scared etc...you'd most certainly hone.

personally? check clearances and condition of a few things and do the swap if thats what you wanna do with that milage

 

Well, with only 60 miles on the motor ... not even reved it past 3500 ... I guess we'll have to see the condition of the cylinder walls.

I'll keep you guys updated.