6.2 Block Repair
05-19-2014, 09:40 AM
#1
6.2 Block Repair Try not to beat me up too much. Got my hands on a 6.2 long block and for the price, it's worth the gamble to me to see if it can be saved. It threw a rod through the side of the block as pictured, I spoke with a friend of mine who runs a machine shop that does alot of tig welding and he felt pretty confident in repairing it (he has not seen the block yet). My main concerns would be what potential damage could have been done to the mains on the block itself? If it works out fixing the side, should I be concerned with damage to the main journals? (I would replace the entire rotating assembly before anyone asks). Pic included, any advice is appreciated. Thanks
05-19-2014, 12:36 PM
#2
From the picture it sure looks repairable with a good welder. He may want to preheat the block first.
I have seen some aluminum racing blocks that have had numerous repairs done over the years and they are still in operation.
I have seen some aluminum racing blocks that have had numerous repairs done over the years and they are still in operation.
05-19-2014, 09:12 PM
#6
Just took it apart, besides the hole from the rod cyl 2 piston was destroyed as well, nailed the head. Was missing a valve spring on 2 so it looks like it might have dropped a valve in there. #2 sleeve has light gorging (no cracks) that maybe a .020 over could solve or just re-sleeve it. Its actually not that bad and if Tim's $800 machine cost is right, I'll be thrilled. 6.2's are hard to come by up here and I bought it for next to nothing. I'm going to go forward with it and have the hole tigged, replace the rotating assembly and see how it comes out. Even if I put 2g's into it, its still cheaper than buying a straight out LS3.
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05-20-2014, 06:53 PM
#8
Spoke with our local LSX engine builder, he's resleeved countless LSx blocks without issue (meaning only one or 2 at a time, not all 8 of them), he also has a friend who runs a machine shop about an hour away who can also tig the hole, so I may end up out $400-600, and less if the cranks ok. I'll post up pics and update this thread for future members looking to repair to see how things come out. If all goes well it will be in a PT 67 Firebird w/ an MN12 6 speed.
05-21-2014, 12:12 AM
#9
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Not all holes are bad... I be more concern with the cylinder than the hole in the block and the costs involve should not be too bad.
If done by a competent shop all should be fine, just be sure they pressure test, you don't need water and oil mixing up.
If done by a competent shop all should be fine, just be sure they pressure test, you don't need water and oil mixing up.
05-22-2014, 12:23 PM
#12
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Here's a little personal experience story"
I once blew up a cast iron pressure plate, by the grace of God had a scatter shield 1/4 inch thick, saved my legs for sure but the back of the block I had just finished putting together and which the machine work on it along cost me $1,800 was badly damaged, frankly it looked hopeless except yours truly is a good welder.
The wrecker guy who towed the car back home for me and who new how much I had worked and invested over time in that car asked me, and what are you going to do now? I said -going to take it apart and fix it, seen all the pieces of the back of the block we gathered from scene of the explosion out of the back of the cast iron block he asked, you going to fix that?
Had to go out and buy a life saver UTP8 expensive German welding rod (the only one available at the time which would not cause the cast iron block to crack when weld on it heavily) to weld/ reconstruct the back of the block so the transmission housing bolt holes could have a place to be drilled and tapped and the dowel pins holes re drilled again, the transmission had to be centered to no more than 6 thousands off-center to the block so will work properly, I brought it to within 3 thousands.
Worked a day and a half on the block and made it stronger that it ever was, put my motor back together with a billed aluminum pressure plate, I never broke that motor again.
Still have pieces of that block in my tool box to this day.
I went on to win shows and many races with that car, yeah it was worth fixing it.
I say don't be discourage -go for it.
01-16-2015, 06:12 AM
#13
Just an update as I did not abandon this. After some research for a few months on and off I've decided to repair the hole myself. Since the block and oil pans on LS engines are made up of 319-T5 aluminum, I figured I'd take one of those truck pans I have no use for and cut a square out of it and bevel the piece and the hole in the block to make a nice fitting piece for the block using a dremel. I watched a few videos and read some testimonials on Super Alloy 5 and it looks to be a good way to weld it up using my oxy/acetylene torch. I did end up taking off the pan and heads and checking out the lower end, it spins nice, no lateral play in the crank and honestly I believe with just a new sleeve/rod/piston in cyl #2 it should be good to run. I'm confident in the short block after the repairs but if for some reason it grenades, it wont be a huge surprise. Once I get the crank out and the materials for the repair I'll post up some pics of how it goes.
01-16-2015, 03:27 PM
#15
I'm sorry but you can't get a usable L92 block from a junk yard. The going rate for an L92 complete is about $2500-3500 depending on mileage from a salvage yard. If you happen to find a shortblock in a junkyard...chances are it has the same issue this one has.
05-05-2015, 06:48 AM
#19
Yes, shop heat cycled the block in an oven a few times while doing the welding. I gave them the 319-T5 alum information and they used the appropriate filler rod as close as possible. Apparently the T5 part of these blocks refers to the heat treatment of the block so I figured the repair should be the same way as it was made after casting. While there is no 100% guarantee the block is 100% true, measurements within 100th's were taken before, during and after and no visable changes took place (again, that we could see).
It should work out fine, its a non-pressurized area, just oil being slung at it. I almost had them weld in an AN fitting for a turbo drain but I felt the engine's already had a hard life so I gave her a break.
It should work out fine, its a non-pressurized area, just oil being slung at it. I almost had them weld in an AN fitting for a turbo drain but I felt the engine's already had a hard life so I gave her a break.
