sh!ft

so i bought a block with pistons in it and this is what i cane across after honing the walls. is this salvageable? can i still run 81mm pistons if i continue to clean it up?

mind you these were originally complete circles but i honed them and they went away after 6 or so passes



they seem to dip in a tad bit, but nothing that catches my fingernail.





long story short, i took the pistons apart and the ringlands were cracked. and the motor was said to have smoked above 4k, im beginning to believe this was one of the issues that ended up happening as a result

DazeMS

Your best bet would be to take it to a machine shop and have them go over the bores. I would be concerned with taper issues. But obviously, those valleys are not going to seal. hence the smoking.

sh!ft

My only concern is if I can still use it with my new Cp pistons. If not then a new block will be sought out, I don't want any issues at all to happen. I'm building a high comp nitrous motor.

spAdam

iTrader: (1)

I wouldn't risk it. Go oversize. Getting rid of your new pistons will be easier than getting rid of them used, regardless of the teardown & rebuild cost when it doesn't work out.

I had to make a similar judgement call over ten years ago when my block came out near the service limit after honing. I already had the pistons. I still kick myself for it today, but I never order pistons/bearings/etc until machining is done.

sh!ft

these are a 700 dollar set of pistons, not too many people i know will be willing to pay that so thats why i want to keep them. plus it cost me nothing to get them

DazeMS

you need to get it measured.. Why would you even hone someone elses block with damaged pistons and hope this will be fine? Dont count your chickens before they've hatched. Take it to a shop and get it looked at for use of said pistons. I would not use any piston regardless of cost in those bores. I dont know how I can be any more clear.

teggy!

No way..... with all the shavings that came off that I would inspect the crank as well


Posted from Honda-tech.com App for Android

sh!ft

thats the thing! the crank was in ok condition! only main #1 had slight to noticeable markings of copper on the bearing, but there was nothing that caught my finger on the journal. even when i drained the oil, nothing concerning came out besides the oil being black. there is nothing else wrong with the cyls besides these markings posted above. with that being said and sticking to my gut, im already on the hunt for another block as it is just in case.

DazeMS

your justifying measurements via your finger? You can clearly see that your hone did not even touch the black markings. not too mention the pitting i see in a few cylinders. Do it right, or dont do it at all. Then again, its not my money. good luck.

kingofbattle909

iTrader: (6)

$700 pistons?..

lostforawhile

you dont have bore gauges? i would check them for you if you were local, that block might be ok if you have it bored and use oversized pistons, i always see if a block needs to be bored first and then order the pistons to fit the block

98vtec

It was also smoking because there is no cross hatch in the hone. There are obviously other issues which need to be addressed but that caught my eye immediately

Charlie Moua

iTrader: (3)

get the pistons measured
get the each cylinder measured
find out where your p2w clearence is (talk to you engine builder where it should be)


Normally with high milage engine it's completely normal for the bores to become out of round (side to side vs. front to back) & is common to see tapper from top to bottom of the bores.

On old +100,000 mile honda blocks, I've seen anywhere from
.0015 to .0023 (side to size)
.0025 to .0048 (back to front)
.002 to .001 (tapper top to bottom)

This is b18 block which was only honed.
Pictures below are of the back/front of the sleeve
Since more load is on the front has more wear.






A boning bit has limited reach.
Could it be "correct" by just honing? probably could but would take a long time for the machininest to "true out" the bore. The cost effective way (labor wise) is to bore it out.


If your worried that in trying to hone out that marking will get your p2w out of desired range (and refuse to sell your custom $700 pistons) you only have 2 options:

a) sell the block & get new block & make sure sleeves don't have much taper
b) have shop install drop in O.E style replacement sleeves ($500ish) that way you'll get back to 81 & can hone it out to get proper p2w


GL

lostforawhile

Never buy any internal parts until everything is measured and the decision is made on what size to bore the block, actually get the blocck bored first to verify everything, sometimes screwups get made

sh!ft

I never bought the internal parts. I traded a 5 lug conversion for these pistons and 300 bucks cash. Just to clear the confusion up. I've made my mind up that its probably best to get a new block. I'm gonna sell the block and get another one.

teggy!

just because you can't feel anything doesn't mean it didn't wear evenly. get your crank spec'd out by a shop to verify


Posted from Honda-tech.com App for Android

DazeMS

what crazy style pistons are worth a 5-600$ lug conversion and 300$ on top? jeeeeessssuuuussssss... everything that has been said is the exact same process you will have to go through ANYWAY... you need to have the block measured through a reputable machine shop.. period.

spAdam

iTrader: (1)

That's probably your safest bet. There's no sense in putting pistons that nice in a questionable block.

Charlie Moua

iTrader: (3)

live and learn.

Glad that you double checked now rather than farther down the road cause re-doing it would of been PITA & spendy.

I'm not sure how much p2w your going to want with those cp pistons.

Consider this...
It's safe to say that any used USDM B motor will have +.0025 (if not more).

I'm not sure if CP sizes their pistons like Wiseco. Wiseco factors in the p2w with their pistons making them about .0032-.0035 smaller than the actual piston SIZE.

So if you used a old block (after hone), you may end up with +.0045 to .005 for p2w... i don't think that's what you would want for a NA car. (turbo motor would be okay). lol

sh!ft

iirc weisco is infamous(imho) for their sideskirt coatings showing early wear indications of wear. so thats not a fair comparison.


BUT



drum roll
















i fixed an ls transmission(cause thats what i do) and i received a free ls shortblock AAANNNNDDDD a free carbon fiber dc integra hood

Charlie Moua

iTrader: (3)

i'm so jelly... the only time i get stuff cheap is if people on cragislist always want to "trade" their parts for mine. haha





no, no....
i was just saying that you should consider the manufacture cause each manufacture has a different way of doing it. I've never used cp before. Just wanted you to think about that pal.

lohatch

You need to MEASURE YOUR PISTON,THEN MEASURE YOUR BORE.

If you haven't reached the desired piston to wall clearance yet you might be able to get that bore straightened out. If you don't have the proper equipment to do this then you shouldn't be doing it.

You need a micrometer(to measure the piston)
A dial bore gauge (to measure the cylinder)
and a proper honing setup. (such as a sunnen)

DazeMS

but he builds transmissions..
Like I said before, it does not matter what block you get and from who. You can not just hone the block and be good to go. Everything has to be measured to the clearances based on the specs provided with your pistons. This is a very easy concept. You really need to take the current block to a machine shop and have it measured and checked. Chances are, you will have to get it bored and honed ANYWAY. That hone job you did will not cut it even without the scores and pits.

sh!ft

hay now. transmissions are a different ball game. so be nice.


as for the measuring the pistons before i run through the block. i was not aware of that. guess it makes cents.() i got the time to drop off the block and the crank today at the shop and they said that it might not be usable once again! but, now that i know to measure the piston THEN go and measure the block, this opens up a new thought process

Attachment 532714

sh!ft