When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Thanks for all of the positive comments guys. I started the tear down and got the heads, oil pan, and oil pump off. Like I said, I'm new to this LS stuff. I've been very impressed with my 200,000 mile GMC 6.0 liter truck. But losing this LS7 in less than a couple of weeks had me doubting. I've done several small blocks, I built my 79 L-82 into a 383 LT4 Hot Cam killer, and I've done a 454 big block. But this is my first LS engine build. You can see the 5 & 6 rod caps are discolored, and you can see what the spinning of the rod bearings did to the crank. Can the crank be repaired? Can the two discolored rods be saved. Stupid Question: How do you rotate the crank?
Thanks for all of the positive comments guys. I started the tear down and got the heads, oil pan, and oil pump off. Like I said, I'm new to this LS stuff. I've been very impressed with my 200,000 mile GMC 6.0 liter truck. But losing this LS7 in less than a couple of weeks had me doubting. I've done several small blocks, I built my 79 L-82 into a 383 LT4 Hot Cam killer, and I've done a 454 big block. But this is my first LS engine build. You can see the 5 & 6 rod caps are discolored, and you can see what the spinning of the rod bearings did to the crank. Can the crank be repaired? Can the two discolored rods be saved. Stupid Question: How do you rotate the crank?
Install the balancer bolt and use it to rotate the crankshaft.
Not a bad deal given the grief you had to endure. An LS conversion into a 79 Corvette would be a great build I'd love to follow! Hell, I'd love to make an LS7 coffee table for my office or living room, if I had the spare coin, time, and space!
My Dad bought a new 79 Corvette way back when and a good friend still has a 78 that he bought new. World of difference in the two cars (C4 vs C6 Z06), they were slow as dogs back then. Classic lines, though. Adding an LS7 would necessitate the need to beef up likely the entire drivetrain, including the rear end, brakes, and transmission. Probably want/have to make a wet sump conversion, too.
Is that a 79 in your garage in the picture you posted of the dead motor? Is that light beige or maybe yellow? Only 100hp more, what motor and transmission do you have in it now?
Obviously, power won't be an issue, so I'd concentrate on durability. Given that the engine is already out, a cam swap is easy to do and I'd suggest upgrading the durability of the cam lobes over stock by going with an 8620 core cam. Also, and in particular, a good cam with LS friendly lobes (Cam Motion, TSP, ESP, etc.), with something along the lines of Katech's 116 cam specs. I'm partial to AHP's heads with their Moldstar 90 valve guides, Ferrea exhaust valves, and PSI valve springs. I'd also suggest CHE trunnions, Johnson LS drop in slow leakdown rate (SLR) lifters, and a PowerBond Race Series balancer over stock GM counterparts.
Thanks Biggie Vette 427! That's a lot of info to digest. I'm counting you and others to keep it coming. Yes, that is my '79 back in the garage. I bought it new in 79 and just recently rebuilt the L-82 into a 383 with Scat forged crank, H beam rods, and 9to 1 pistons, and Sniper fuel injection. The ironic thing is that I debated doing an LS conversion at the time. I decided it was too expensive.
I autocross it all the time, so I think I'll keep the dry sump. I have a Moroso Accusump mounted on the passenger side firewall now, so it shouldn't be too hard.
I finished the tear down today. Like I said, the LS engine is different. The engine is tight, even after 7000 miles. It was very difficult to rotate the engine with pistons, rods, and Cam. But after removing the pistons, rods, and camshaft, it still took 60 lb ft to rotate the crank. There are six bolts for every main cap! Take a look at the rod bearings and the crank main bearings. It doesn’t look like the other rod bearings were going to last long. The middle main cap has a larger bearing like what is usually in the back of a gen 1 small block. Is the thrust bearing in the middle of the block?!!!! The two rods that discolored don’t look bad! Can they be reconditioned? The crank looks great except where the rod bearings spun. My next step is to see if the crank can be saved and repaired, and the same for the two rods. Then I’ll have the block lightly honed and cleaned. Look at the tiny rod bolts.
The rods look like the sides are worn. Common issue on later motors. That would mean the rods are not reusable as they have worn through, which probably caused all this in the first place.
The rods look like the sides are worn. Common issue on later motors. That would mean the rods are not reusable as they have worn through, which probably caused all this in the first place.
The same issue I just encountered with my LS7. Have to do a complete rebuild now, as my rods had worn on the faces like these and are unusable. Probably caused lack of proper cylinder oiling and resulted in 2 scuffed pistons with piston slap... the reason I tore into it... and found rod faces eating each other.
The same issue I just encountered with my LS7. Have to do a complete rebuild now, as my rods had worn on the faces like these and are unusable. Probably caused lack of proper cylinder oiling and resulted in 2 scuffed pistons with piston slap... the reason I tore into it... and found rod faces eating each other.
I did noticethe large amount of play between rods, so much I took a picture or two. That is a .016 feeler gauge between rods. I just thought it was another LS trait.
Damn, the crank is bent. 45 thousandths out. Now I know why it was so hard to rotate. They will inspect block, rods, and pistons next. Anyone know of a good LS7 crank for sale? I will probably need the whole reciprocating assembly. Damn.
You might end up being into it for more than you wanted...but hey, $150 isnt a bad place to start.
If the block checks out, you might as well go aftermarket and upgrade the crank, rods, pistons, maybe a mild streetable cam, and of course the heads still need to be addressed.
I have a complete set of LS7 Pistons and pins if you are interested. They did not come out of a bad engine and came out of my engine that I decided to rebuild have rebuild. I reused the crank and rods on a HPR sleeved block and I sold my LS7 block and that is why I have the pistons. They have about 8,000 miles on them.
I have a complete set of LS7 Pistons and pins if you are interested. They did not come out of a bad engine and came out of my engine that I decided to rebuild have rebuild. I reused the crank and rods on a HPR sleeved block and I sold my LS7 block and that is why I have the pistons. They have about 8,000 miles on them.
Thanks. I'll definitely keep that in mind. Maybe instead of boring or honing, maybe I should have the one bad sleeve replaced. Then I can stick with standard bore pistons. Is that something my small town machine shop can handle, I wonder.
02-07-2018, 01:28 PM
