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Hey guys, been a minute since I posted. Been busy moving to Arizona from Colorado. Before I left Colorado I discovered piston 7 let me down on my setup. Pretty much no compression and is leaking out all pressure I put into the cylinder. I pulled valve covers and disconnected rockers while doing leak down to rule out it wasn't a bad valve. I was pushing 730whp on stock rotating assembly with 3.6 pulley on meth, which is just too much.
Haven't starting tearing down yet to see what happened but I'm banking on rings. That aside, I have a modest budget to get it back together. At this point I just want to be able to drive my car for a couple of years without tearing down in hopes of having time to rebuild my ls6 block with forged when money permits. Given I just bought a house and am sinking a lot of money into it for upgrades I don't think budget will permit a forged rotating assembly. I have a good Lq4 block and crank. I was thinking about grabbing a stock set of Lq4 pistons and rods, running less boost/timing and giving it another go. I could probably pull this off for a grand.
What are your thoughts on this approach or ideas on another cost effective route? Thanks guys.
Depending on how bad the teardown is, I would see if i could get away with doing the rings and checking everything else. Go up on the pulley and sit around 6xx hp while you build the lq4 into a 408 ysi beast!
if we can help you out at all let me know, we are the local sponsor and can help you with the build either by supplying the correct parts, labor, or both. Same with the tune portion (nic d is our tuner)
You may be able to just swap a piston, I have done that a handful of times over the years, never an issue. It would be around $100 and a day worth of work.
Been super busy but the teardown has started. Found pieces of a compression ring stuck to my magnetic oil pan drain plug. Any bets on if the heads are salvageable?
I agree on the piston swap, but not sure how the hell the piece or ring got past the piston. This might be bad for the bore if it was drug past the piston so.
Been super busy but the teardown has started. Found pieces of a compression ring stuck to my magnetic oil pan drain plug. Any bets on if the heads are salvageable?
The heads would be the least of my concern. They can be repaired relatively easily. I've welded up a handful of them and had to get new seats installed into a few. Worst case, sell me your old head and buy another stock casting.
Depending on how bad the teardown is, I would see if i could get away with doing the rings and checking everything else. Go up on the pulley and sit around 6xx hp while you build the lq4 into a 408 ysi beast!
More likely a ringland than just a ring.... 730 on a stock bottom end? Been there, done that. Might be possible to clean up the cylinder and put in a new piston but won't know anything until it's disassembled and it's reported here what was found.
I pulled heads today and no damage to them, super thankful. No visible damage to the tops of the pistons. Naturally piston 7 is at the top of the cylinder so I haven't had a chance to inspect that cylinder wall. Hopefully will have the steering rack out of the way tomorrow and I will rotate the Crank by hand and confirm a likely broken ring land.
Last edited by tommypenguin; 09-03-2017 at 12:50 AM.
Thanks Ralph rebuilding the ls6 wasn't something I had planned for, though I would be happy to reuse my block and crank. Just pulled the steering rack and rotated the Crank no visible cylinder damage visible from a tough angle. At this point I just need to pull the Crank pulley, bell housing bolts, couple of sensors, and cradle bolts and the motor will be coming out. Hopefully will have time to pull it out next weekend.
Bump, I finally tore down. Trashed the ringlands on piston 7. Not sure if it was from too much power, incorrect gap on rings for boost or both.
Considering buying a pre-assembled short block instead of assembling myself. Suggestions?
Last edited by tommypenguin; 01-04-2018 at 09:20 AM.
Bump, I finally tore down. Trashed the ringlands on piston 7. Not sure if it was from too much power, incorrect gap on rings for boost or both.
Considering buying a pre-assembled short block instead of assembling myself. Suggestions?
Excellent idea to get a preassembled block. It is tedious and fraught with many chances for problems to do yourself. Also the other 7 pistons are suspect if #7 sustained that damage.
Here is what # 7 looked like on mine also with just under 15K miles of supercharging on it. Looks very similar to yours. For the cost I went to a TSP 402 LS2 for boost. 8K miles later I love it.
Still on my 60 lbs injectors. Removed boost a pump and installed a walbro 450 and also a alky meth kit. Cam went from stock 99 .480ish lift to custom .629/.649 lift cam.
If you are keeping the power around that same level then I would try to spend just a little more money and buy a set of rods and pistons then have the machine work done. You wont need anything special as far rods or pistons and off the shelf stuff would work and be relatively cheap. You are saving a ton by doing the work yourself already.
05-28-2017, 01:42 PM
Back to the drawing board, detuning
