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Hey guys. So I thought I had found a good deal. Guy was selling a ls7 crank & ls7 cam. Both used cuz he upgraded. Long story short, he said that his engine builder told him the motor spun a bearing & needed to be rebuilt. So he payed to go big. Was selling the used parts, but being that he's not mechanically savvy, he wasn't sure if these parts were good or not.
So, I took the gamble. $300 shipped for crank & cam. I am not a professional mechanic nor am I an engine builder, but I have done a lot of reading & from everything I've read, I believe the crank & cam to be bad.
The cam looks like it was good, but for some reason either got dropped or something dropped on it, etc, as there are nicks in the cam where the cam rides on the bearings.
The crank I'm pretty sure is fried. I thought I read somewhere that if the crank has blueing or shows a sign of heat stress (rainbow colors) it's done. It loses it's structural integrity I guess.
Anyways, thought I should get a second opinion before actually junking these or turning them into some sort of furniture or decorations. Let me know what ya'll think. Thanks.
did you not ask for pics before you gave him your money?... did you use paypal?... if so open up a claim and get your money back
I got pics. I knew the crank was damaged. Didn't know the cam was. He told me that he couldn't guarantee if they would be useable or not. According to him, hes not mechanically savvy & does not work on his own car. I knew I was taking a risk. It'd be one thing if he said the parts were good & they weren't, but he was honest. It's hard to tell just by pics alone but it all looked relatively ok. Taking it all to a shop tomorrow to get checked out by a professional.
I got pics. I knew the crank was damaged. Didn't know the cam was. He told me that he couldn't guarantee if they would be useable or not. According to him, hes not mechanically savvy & does not work on his own car. I knew I was taking a risk. It'd be one thing if he said the parts were good & they weren't, but he was honest. It's hard to tell just by pics alone but it all looked relatively ok. Taking it all to a shop tomorrow to get checked out by a professional.
good luck....well look at this way...some people buy 30k cars sight unseen and are miserably surprised. at least this wasn't 30k.
I have to note, however, that I can't sell stuff which is brand new in original packaging on here, but that guy can offer beat pieces and they sell. LOL
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Did you plan on using the crank in an LS1 or 6? The LS7 crank is unique to the LS7 as the LS7 is a dry sump engine and as such, the crank has a longer snout, not to mention a 58X reluctor wheel as opposed to a 24X reluctor wheel.
It'd be one thing if he said the parts were good & they weren't, but he was honest.
Or he knew the cam was chipped and is just playing dumb. "I'm not a mechanic, so there is no guarantee" Hard to believe he didn't realize that thing is trashed.
Or he knew the cam was chipped and is just playing dumb. "I'm not a mechanic, so there is no guarantee" Hard to believe he didn't realize that thing is trashed.
But yeah, at least it was just 300.
Just 300?
With 300 a person could drink Starbucks for a few days!!
Or he knew the cam was chipped and is just playing dumb. "I'm not a mechanic, so there is no guarantee" Hard to believe he didn't realize that thing is trashed.
Stevie Wonder could have known those parts were trashed!!
There used to be a shop known as "Crankshaft Specialties", or something like that, that would grind cranks 0.010" undersize, then hard chrome the journals back to blueprint diameter. I don't know if they're still around, however. If they are, then maybe the crank is salvageable....but for God's sake, even the snout is beat up!
Yup, that engine had bearing failure. For $300, you made out. Think he got the bad end of the deal. Spun main bearing in an alum block is usually the death of it. Doesnt matter for your engine as undersized mains are common. They dont make under/over mains to my knowledge so he's pretty much screwed. Cracked cap rods cannot be resized either so he lost most of the super expensive TI rods
Take them to any machine shop. The crank can be turned. Ask them to spec some bearings to match it as well. Since you're running a C5 and it's GEN III, ask them to cut the snout down to wet sump length and press a 24X reluctor on
If they have a cam polishing machine, then it can be saved as well. The nicks wont affect function or lifetime as long as they're precision ground smooth. Nicks/galling on the lobes and oil galleys is what kills a cam. OTOH, a LS7 cam is pretty mild, so the machine work on it would be more than a good used take-out or half a new bump stick with some real specs
To sum up, non of those issues are big problems and the parts arent scrap. You cant run them as-is but you knew that before hand
Yeah, $300 is a lot to lose. I am hoping the crank is salvageable. If so, that's not too bad a deal. At least from what I've found. A lot of used LS7 cranks go for pretty good money. Anyways, wasn't really interested in the cam, but since he offered to throw it in, I thought why not.
Yes, I am aware the difference's between the LS7 and LS1/6. I was going to build a LS7 wet sump with 24x reluctor to put in my 97. So I knew all what needed to be done. Just tried to go cheap. Bit me in the butt. Oh well.
Even a perfect LS7 crank into a LS1 wouldnt be cheap. Barring the snout and reluctor things, a balance job is usually $500 +/- which would go with any stroker crank as well
Even with the machine work of the one you have, thats still half the cost of an aftermarket crank. Production specs are tighter than most aftermarket, so you'll end up ahead anyways
Yup, that engine had bearing failure. For $300, you made out. Think he got the bad end of the deal. Spun main bearing in an alum block is usually the death of it. Doesnt matter for your engine as undersized mains are common. They dont make under/over mains to my knowledge so he's pretty much screwed. Cracked cap rods cannot be resized either so he lost most of the super expensive TI rods
Take them to any machine shop. The crank can be turned. Ask them to spec some bearings to match it as well. Since you're running a C5 and it's GEN III, ask them to cut the snout down to wet sump length and press a 24X reluctor on
If they have a cam polishing machine, then it can be saved as well. The nicks wont affect function or lifetime as long as they're precision ground smooth. Nicks/galling on the lobes and oil galleys is what kills a cam. OTOH, a LS7 cam is pretty mild, so the machine work on it would be more than a good used take-out or half a new bump stick with some real specs
To sum up, non of those issues are big problems and the parts arent scrap. You cant run them as-is but you knew that before hand
Ok, well that makes me feel a little better. So you think the crank can be saved? What about the rainbowing of the crank? Isn't that bad? I'm not doing anything crazy to this build, just building up a N/A stockish LS7. Going to address the valve/head issues obviously. Maybe some stronger hardware or parts to keep reliability & longevity up.
As far as the crank goes, I was planning on having the snout cut down so the end being chewed up I wasn't worried about. & I knew it needed work, I've heard of cranks being ground down/polished, but the rainbowing scares me. I am going to take it down to a shop to have them check it out, see what they say. If it can be saved, that would be awesome. As for the cam, I don't think it's really worth it to try to save that. Can find a used oem LS7 one for less than $100 shipped. So not too worried there unless it's cheaper to fix. But we'll see.
Color change is normal for steel. Look at the ends of an aftermarket cam to see the heat treatment. Its a minor issue for cranks. They can warp slightly, but shops will bend them true again then grind the damaged journals smooth
Really, just take it to a shop, explain what you want and they'll tell you if it's feasible
I did that about 60 years ago when I was building a Pontiac, had the rods turned to stock size for my smaller motor. Afterwards I found thatthe crank was bent and had to trash it. You'd think that the grinder would have check it before grinding all 8 rod journals.
I loved Leadfoots reply about Stevie Wonder. ILMAO!
05-18-2018, 03:59 PM
This is why I don't gamble... Bad crank & cam?
