bp944

iTrader: (4)

I'm looking at buying a ls1 short block from a guy but there's a catch to it. The guy was running 10 lbs of boost on a decently high compression cylinder. He said there is oil on the #7 piston. He said for sure it wasn't a detonation. He guarantees me its the lower end is fine. My question, what is wrong? Is a seal broken, do I have to rehone or bored the engine?

Carter Hays

Don't buy it.

bp944

iTrader: (4)

Can you explain what could be wrong with it? Telling me not to buy it, doesn't really do me any good at all. For $200, is it still worth it?

09camaro383

iTrader: (2)

Oil can be coming from rings, heads or cylinder wall!! It needs to be open to find the problem if the cylinder wall is good still will spend more then 200 I personally will honed or if required bored and re-ring all pistons install new main and rods bearings new heads gaskets and probably forgetting some other stuff!!

bp944

iTrader: (4)

I am buying it FROM a guy, sorry. I'm thinking of switching it to forged pistons so I can run a higher compression. Its currently 64cc heads with the stock bore. Correct me if I'm wrong, I can get +4cc pistons and run an even higher compression and bore it out a bit. Dumb question, which bearings would I have to replace and why?

cowboysfan

how does he know that #7 has oil on it? or does he mean piston top is black? has mentioned above could be several reasons.... can you hear/see the motor running? any possible way to do a compression check? in a nut shell I would say complete overhaul. if no scrap marks on the wall then honing should do the trick otherwise boreing would be required. kinda hard to explain with just the info you provided. either do a compression check or remove heads to see what condion the cylinders/walls are....

cowboysfan

"I'm looking at buying a ls1 short block "from a guy"
but there's a catch to it. The guy was running 10 lbs of boost on a decently high compression cylinder. He said there is oil on the #7 piston. He said for sure it wasn't a detonation. He guarantees me its the lower end is fine. My question, what is wrong? Is a seal broken, do I have to rehone or bored the engine?"

some people need to read carefully!!!!!!!

SO!! if it's a shortblock as it was stated, look at it!!! what do you see wrong? if you dont know what your looking at cause your learning then take a friend who knows so he can tell you what condition the SHORTBLOCK is in.....

09camaro383

iTrader: (2)

Sorry bp944 everything i said is wrong i was thinking long block not short block i forgot the heads were removed !! Bro Inc and cowboysfan graduated from Sherlock Holmes Academy!! Bro Inc is my spelling correct?? Attention everyone there has been a change on the forum we have a teacher now Bro Inc if you want to edit post delete spell check or any kind of problem feel free to contact him!!

LSXNV

iTrader: (1)

there is so much going wrong here. $200 for a short block is a smokin deal. almost too hot. i am not getting the whole oil on the piston thing and how it relates to detonation. it just doesn't make any damn sense to me, oil on the piston? and to the OP you might be getting in over your head but you need to learn somewhere. books don't always cut it. like what was said before, have someone go with you to check it out. the voice in the back of my head is saying "cracked block" since it is so cheap. but who knows.

and for those who dont know, a shortblock is a block and its rotating assembly, a long block is a shortblock with heads on it. thats it, nothing else.

cowboysfan

BP944. my buddy just overhauled an LS1, #7 piston had a hole in it so with replacing that piston and all bearings, rings, turned crank, block honed he paid about $1200 so if block looks good it's a deal for that price. rotate the crank and it should feel smooth as your rotating, and hard spots or ratcheting then you might need more then honing and depending on crank bearings you couls be looking at a new crank.....

cowboysfan

what do you expect in a newbie forum!!!!!!!!!!!!! if your going look at specifics then dont lurk on here...... I could be like you, but why!!! I'm trying to help this guy not make fun of him or others who see like you see the wording, I'm sure it was a type-O error but people like you should be helping people with experince not in the newbie section..... ggeeeeeeeeeeeeeezzzzz!


my apologize to BP944 but I cant stand these type of forumers!!

bp944

iTrader: (4)

I'll admit, I don't know as much as I should and the seller hasn't exactly filled me in. So here's what I figured out today. It wasn't necessarily oil, the top of the piston was wet. It was a small enough amount that he wasn't sure what it was. Its a short block, so he rotated it and said it turned over nicely and there was no scaring or marks on the cylinder wall. As for the cheap price, its with a whole package. I'm buying a load of parts and that's what it comes out for the block. I'm asking all this because I've usually heard that running a high compression ration with a turbo is a no no. I'm trying to figure out what the worst case scenario is.

LSXNV

iTrader: (1)

detonation is the issue. if thats the issue it results in destroyed pistons, it can unseat rings, it can be rough on bearings. a piston that has been beat on pretty hard with detonation would look almost clean, too clean. oily residue left can come from fuel or a lack of oil control from the rings, or coolant from when the heads have been pulled.

to be sure you need to pull a few rod caps and main caps and let the bearings tell you the story. it would be nice if you could tear it down to know for sure, but at a price like this it seems he wants no hassle and just wants rid of it. so the chance of him letting you tear it down before you buy it is slim.

i am a gambling man, if it were me and i couldn't find any obvious damage i would go ahead and get it. i would look for obvious cracks, hammered piston tops, bearings hangin out of the crank and check the cylinder walls for gouging and anything that don't look right. most cylinders with any miles will have some scuffing. like i said this is a gamble, but at this price, i would go after it if nothing obviously wrong could be seen.

Carter Hays

I said don't buy it because..

1 You said for a guy

2 You seemed like you needed to learn some very basic auto tech, not just ls1 specific stuff, so I did not want you get let down.

3 You never said a "$200" short block

I was not trying to be a jerk I just didn't want you to end up spending $$ on a spun bearing, cracked block etc.. pos.

Have a machine shop check it and make your deal.

Peace and good luck.

SOMbitch

iTrader: (8)

First you cannot bore an LS1 block unless it is sleeved. You can HONE it .005-.010 depending on the year block...

Second you want a NEGATIVE cc piston so you can mill the heads for a compression bump and maintain PTV clearance assuming you are going with a decent sized cam.....