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ok, so what i have here is a 180k LC9 gen 4 5.3, i picked up an on3 performance 78/75 turbo to punish it with, thus is a super budget build, as its going in my 1974 gmc 3/4 ton truck i only drive in the summer, and shes real hard on the eyes haha. i am hoping to get 1-2 summers out of this motor before getting a better condition 6.0 for it
so i pulled the motor apart to look at everything and do a dod delete, the bearings look good, the pistons and cylinders are what id call ok, to do the rebuild right, it should be bored and new pistons, but i don't want to. so i was cleaning up the pistons and gapping the rings for the turbo. so i decided to put some degreaser in my lil 2 gallon bucket and fill it up just enough to cover the piston, i forgot about it and left it in for approx 1.5 days, pulled it out, its pretty clean...however it looks like it degreased off the piston skirt coating? its wd-40 brand degreaser and says its safe for aluminum. at about 700$ for oversized pistons and machine work, i might either track down another one or just buy an oem style standard bore set of pistons, the ones i found on summit are approx 350$ or just run it and see what she does
There’s some pretty significant wear on the skirt, that outweighs the fact that the coating is gone. The coating is there basically as a sound reducer in the Oem form. If your comfortable with the engine being a little noisy from skirt wear, and your on a tight budget...run it. Ring seal is everything, so maybe consider new rings and a quick dingleberry hone.
The coating was worn off of the critical area anyway. It would run fine without it now that clearances are larger. If you are stressing over it, yes buy one piston off eBay, but it may be worn off in the same area. Alternatively, there are companies that can re-coat them if you truly want it back to stock, but it sounds like you are going budget basement, so just run it, it will be same as it was.
There’s some pretty significant wear on the skirt, that outweighs the fact that the coating is gone. The coating is there basically as a sound reducer in the Oem form. If your comfortable with the engine being a little noisy from skirt wear, and your on a tight budget...run it. Ring seal is everything, so maybe consider new rings and a quick dingleberry hone.
that makes sense, i might see if i can find a good set of rings and throw them on, i had thought of that, but wasnt sure if that might not be the best for something with that many miles? or maybe its what it needs. recommendation on what kind of rings to use for a turbo application?
The coating was worn off of the critical area anyway. It would run fine without it now that clearances are larger. If you are stressing over it, yes buy one piston off eBay, but it may be worn off in the same area. Alternatively, there are companies that can re-coat them if you truly want it back to stock, but it sounds like you are going budget basement, so just run it, it will be same as it was.
not stressing, i was just surprised it ate the graphite coating off of it, and yeah, the cheaper the better, it was more of a if its not going to work at all type thing
i got on summit and found these, steel top ring with plasma moly coating, 2nd is ductile iron, its what they recommended for my application. any opinions?
i got on summit and found these, steel top ring with plasma moly coating, 2nd is ductile iron, its what they recommended for my application. any opinions?
They are file fit, which is good since you’d want to custom gap for boost. Can you find a set of Sealed Power? I like their rings. Summit brand is prolly ok, but that’s why they suggested them...
You sure you need a 1.5 1.5 3.0? This re-ring and dingleberry touch-hone was just a suggestion. Not trying to spend your money. Sealed Power will likely be cheaper than $99...
They are file fit, which is good since you’d want to custom gap for boost. Can you find a set of Sealed Power? I like their rings. Summit brand is prolly ok, but that’s why they suggested them...
You sure you need a 1.5 1.5 3.0? This re-ring and dingleberry touch-hone was just a suggestion. Not trying to spend your money. Sealed Power will likely be cheaper than $99...
those are the sealed power ones, they are only 8$ cheaper than the summit and not a steel top ring. i am on a tight budget because i want to be, if it were a 6.0 i would probably just do it right. but this 5.3 came to me pretty cheap, as did the turbo and manifold. just trying to keep it lo buck and put some power down.
i was considering the re ring anyways, but i am used to having the block machined etc new pistons rings and all that also
i have never rebuilt an ls motor
i have never built anything for a turbo
i have never tried to build it cheap
so far heres what ive got. I ordered the set of summit rings, and a 400 grit flex ball hone. I found an "OEM" set of pistons from the later model LC9 which have valve reliefs and had a 9.6:1 CR, For about 120$ with shipping, so i picked those up.
i have read both where you hit it with a 240 then a 400 and some with just a 400 hone, is there a need to do the 240?
what do you use to lube the hone and how much? i have found everything from ATF to 10w30, to straight 30 to they make special oil for it
should I Use my fancy rings i bought? or return them and just use the "OEM" rings? I'm thinking use the rings that are on the pistons? might break in easier? as well as i doubt piston rings will be the failing point of this of this motor should it fail.
If it were mine, I'd just hit it with the 400 grit hone. You're just trying to roughen up the finish to get fresh rings to seat. 400 is fine for that. More aggressive grits are for actual material removal which is not what you're aftera fte honing oil, it depends what system your gonna use to apply the oil and recirculate.
A proper honing machine uses real honing oil, and really, really floods the cylinder with it, filters, then recirculates.
My guess is you're gonna do something way more "quick and dirty"! In which case, the most important thing you can do is get the flooding/flushing part right, to keep the stones clean and from loading up with swarf. For that, I'm a fan of a few cans of WD40. Have somebody keep a good spray going the whole time. And for heaven's sake, please clean, clean, clean up after this process because the swarf will really eat an engine...
Last, you need to really pump the hone in and out of the cylinder fast to get a "proper" crosshatch. Recently I've been watching Cleetus Mcfarland do the dingleberry hone and it annoys me how flat his crosshatch comes out on account of too much spindle rpm and running the hone in/out too slow.
or do they make a set of regular ones? all i can find are singles? summit says the Wiesco cw24 should work but not sure, the application guide says they are for small engine pistons
As long as the rings go on the same pistons.... slap them back on there and run it. If the bores look clean and don't have anything you can feel with your fingernail slap it back together.
03-14-2019, 04:11 PM
Did i ruin my piston? 
