Ok, say i'm replacing the pistons/rods in my block,
i've been told by knowledgeable folk that I really need to bore it to get the
cylinders back to being round, instead of oval(unless the block had really low miles or something).
But i'd read posts on ht about this and seems like alot of you guys feel that
just a simple hone to break the glaze so the rings can seat is all thats needed.

So i'd like to know for sure?
is boring neccessary, i'd like an engine thats not going to end up smoking
or burning oil, etc after a while.

It'd probably be higher comp oem honda pistons, with new rings, new bearings,
maybe LS rods, and in a d15b longblock.

I'm still debating what to do,
was about to buy a supercharger this week, but building a motor is so intrigueing that i'm very tempted, so lmk what you guys think.

(this is allmotor so i'm not too worried about "go turbo" comments, but just to be on the safe side, dont make any, i aint gonna listen!)

 

I wouldn't spend the money on a rebuild and not bore it. Why take the chance of it burning oil a couple of months down the road. Just make sure it's done right though.

 

hmm ok yeah,
thats just the info i'm looking for.

I should note though, that i'd be building it myself, so boring it would require taking it to a machine shop, otherwise I might not even have to pull it from my car.

 

I've got a different motor, but my H23 VTEC, as well as every H22 i've seen rebuilt, has not had oval'd cylinders, even after 150k miles.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LudeyKrus &raquo;</TD></TR><TR><TD CLASS="quote">I've got a different motor, but my H23 VTEC, as well as every H22 i've seen rebuilt, has not had oval'd cylinders, even after 150k miles.</TD></TR></TABLE>

so you didnt bore em when you rebuilt them and they came out okay?

 

I don't think cylinder bore taper and out-of-roundness is the issue. I've measured several blocks: one stock, and two that had been rebuilt. None of them had more than .001" of taper or out-of-roundness.

I did, however, find a problem with the JDM ITR std bore pistons I used in place of the stock GS-R pistons on my first rebuild. The piston-to-bore clearance was about twice what it was with with GS-R pistons.

Measure the pistons and bore, or measure the piston and cross-check against the bore with a dial bore gauge and micrometer to see if you need to use oversized pistons or not. That would be cost inefficient tho, if you bought a set of std bore pistons only to find out that you have to use oversized pistons b/c the clearance is too much.

What I've seen might not be universally true, but it I think you should take it into consideration.

 

yeah,
wouldnt i have to worry about that MORE if I had it bored then?

 

Maybe you didn't understand. I just threw the set of standard bore JDM ITR pistons into the block w/o clearancing them first. The cylinders were only ball honed and hten the motor went back together.

The JDM ITR pistons were smaller than my stock GS-R pistons, even with the moly coating on the skirts.

If you have to bore the block, then you can set the clearances.

 

might as well bore it now...if you do it later....it will cost labor just to open up the **** again....so why now....secondly like the guy above said....if ya going to do is pretty a rebuild im sure your engien will give you a smile if you goig to bore it out little

 

well ok,
that raises another question
if I do bore it out, can I use the standard sized pistons or do i have to use overbore pistons?

 

If you want to punch it out, then you have to use an appropriately-sized piston for that bore. Common sizes are .25mm, .5mm, and 1mm.

You pick your overbore piston size and then have the machine shop bore it and set the clearance and wall finish.

Honda offers oversized pistons in at least the .25mm (.010") size. There are some Honda engines where they offer .25mm and .5mm oversized.