B18C1
Arias pistons/ Crower rods
420hp at 18psi

Spun a bearing about 18 months ago and am finally getting around for a rebuild. The block is already bored at 81.5 with a GE block guard. Some of the bearing lodged itself on the piston skirt and dug a pretty good scratch on cylinder #4. So i took it to the machine shop and had it honed to try and remove the scratch, which it did somewhat. There is still a slight scratch that i can catch with my nail but it doestnt run the entire length of the cylinder like it did before. It is not bad, but it is definately a scratch. The hone made my p2w .0040 with arias pistons which requires a .0030 clearance. I am kinda at wits end as to what I should do. Since money is a huge issue for me right. I kinda need some advice as what i should do.

Machine shop hone again to see if another .001 will clean it up? leaving me with .005p2w
bore it to 82mm and try to find a good deal on some pistons? Im not real sure this is safe.

Please help...

 

Can your pistons run with a larger clearance? i have like a .006 p2w clearance with my vitara setup. it runs fine, it just sounds like a diesel because the pistons can rattle around.

 

I dont know. I could call arias but i am pretty sure thay will say to go with their clearances or maybe .0035. I doubt they would give me the stamp of approval for .005.

 

.005 isn't too terrible. Granted you don't have a "race" motor, but a lot of guys run around that area in p2w.

 

You can moly coat the skirts which will add material to the diameter.

 

Is there a do it yourself coating or should I send the pistons off? Would swain tech be a good choice?

If I just ran the pistons with the .00050 clearance with out coating them, would there be piston slap even after warm up? Also if I use the same ring set that (new of course)
came with the pistons, would I be able to get proper ring end gap?

Thanks for all the help!

 

Swaintech would be the best choice. Thats where I had mine done. Prices are on their website.

You would def have piston slap, probably even after warm up.

Ring gap is not an issue as you cut those reletive to the cylinder diameter.

 

I know that each ring has to filed for proper gap. What I meant was if the bore was opened up more... would the rings come out of the pack with a ring end gap too big. I guess this shouldnt be problem.

I did call arias and the lady there told me .0035 was the largest clearance I should run at less than 20psi. .0045 would only be acceptable around 40lbs of boost. She also mentioned hard anodized coating the pistons, but later said that wouldnt work because I had used scotchbrite on the skirts to smooth up som light scuffing.

Im wondering now if I should just run it with the scratch? Even if I get the scratch out, leaving me with .0050 p2w and get the pistons moly coated (adds back around .0005) I still will have .0045. What would be the lesser of the two evils?

 

here are some pics of the scratch.



just received this email
Hello There,
I don't think it would be a problem other that the pistons will be a little noisy, specially at start-up, if you can live with the piston slap you'll be fine. in as far as the rings are concerned, with that much boost you should be running about .022" to .024" end gap in the top ring, minimum, a little more wouldn't hurt, but less would destroy the engine.

hope this helps

Beeri Meza

Arias Pistons

 

Looks like its time to get some 83mm pistons.

 

Yes thats a valid concern with the ring gaps being too big unfiled.

 

Well took the block to the machine shop today. Honed the cylinder two more thousandths and the scratch is still there. So there is no using these 81.5 pistons. So now what are my options? I am thinking 82mm, but am a bit concerned about cracking a sleeve. How worried should I be at 400-450hp level?

 

you cant afford to buy a new block for $100ish so you can reuse your pistons but you want to spend 500 on a new set of pistons just to use the block you already have?

 

Find a new block, sell the old one problem solved..

 

yeah, that sounds like a plan.

I have an ls bare block. Could I use that?

 

Dude, this may sound a little shady, but I had a problem similar to yours a few years ago. I had a freshly rebuilt short block, put it in my car, and within 10 mins I had a major problem. The shorter version is my #3 piston had one of the circlips fall out and the wristpin worked its way out and dug a nice grove in the cylinder wall, worse than what you have going on there. I got another new 81mm Wiseco piston and threw it all back together and it ran great and made great power. I thought the occasional smoke that I saw was from the gouge in the cylinder wall, but to be completely honest I dont think it was really that bad from that. It was my turbo going out on me. That was one of the best running engines I have had as of yet.......I beat it to death!

 

i was just gonna run it. By the time I could express my concerns to the machinist he already had the block on the machine with the honing stones in the cylinder. Next thing I know the cylinder was 3.212. Pistons measure 3.205. A little late now. As far as "just get another bare block", that doesnt seem to be the easiest thing to find. I have yet to find one.

Now I kinda wish I would have just put it together and ran it.

 

if you saw the messed up cylinder walls in my block that scratch of yours looks damn near perfect.....

i would run it as is....the compression variance would be so small i doubt it would be measurable between the other cylinders.

 

even with the p2w clearance i have now?

 

what is ur p2w now?

 

it may be to late since it got honed out quite a bit......the engine will be kinda noisey at about .007 p2w clearance...

you can have it overbored to 82mm and as long as your tuning is good it should hold up just fine........or send that sucker off to GE and have it re sleeved.

 

.007 is like a vitara build lol. Actually its even worse than some vitara builds. Piston slap everywhere lol. But it sounds like a diesel and it holds up fine for me.

 

Yeah its at .0070 now. What about a new sleeve on just that cylinder? I did locate a bare b18c5 block. That would work wouldnt it? Using GSR crank, rods and pistons.

As far as running 82mm, I would do it if I could find a little more real world info on this. I can find alot of opinions, but little first hand knowledge. Having never done it before myself I have to rely on everyone elses advise and make my decision from that. I know better than post a "can i run 82mm bore safely on stock sleeves". There have been plenty of those, and plenty of opinions and bashing. I just want to do the right thing this time around.

 

see thats where I dont know. I know my motor is somewhere between .005 and .008. I forgot what it was exactly. But I DD it on boost and its fine. As far as 82mm on stock sleeves, i cant say either way.