so we tore down my Va Speed LS2 366 turbo motor today
10-03-2009, 10:05 PM
#1
TECH Senior Member
Thread Starter
iTrader: (21)
Join Date: Nov 2001
Location: Cecil County Raceway!!!
Posts: 8,484
Likes: 0
Received 0 Likes
on
0 Posts
so we tore down my Va Speed LS2 366 turbo motor today after the coolant and oil mixing failure a few weeks ago, I finally took the bullet back to shawn for failure analysis.
liners #3 and #5 cracked bad. combustion was leaking thru the liners and blowtorching the block. It was pretty violent
Funny thing was it took time to cause the damage we saw...the 7.99 was on a definately hurt motor 
cyl #3
cyl #5
torched deck
head gaskets were intact.
Slight leakage around the middle 4 cylinders...30+ psi is just too much cyl pressure for regular ARP std size head studs
on to the bottom end....
rod bearings were all PERFECT.
pulled the main caps...factory powdered metal caps held just fine at the ~1700-1800hp level. pinned mains did their job...no cap walk
thrust looks almost new after 40 passes....ATI has their sh%t together when it comes to keeping the converter from pushing on the crank
very minimal crank flex...completely normal for a traditional-counterweighted lightweight crank. It had some light wear on the center main bearings.
bottom line...the moroso pan and melling oil pump work well and showed no evidence of oil starvation...motor was ~8100 rpm at times...
obviously the block is trashed, so we'll be replacing with a used LS2 "****" block I found...plan is to resleeve with heavy-wall liners up the bore size to ~4.125...
liners #3 and #5 cracked bad. combustion was leaking thru the liners and blowtorching the block. It was pretty violent
Funny thing was it took time to cause the damage we saw...the 7.99 was on a definately hurt motor cyl #3
cyl #5
torched deck
head gaskets were intact.
Slight leakage around the middle 4 cylinders...30+ psi is just too much cyl pressure for regular ARP std size head studs
on to the bottom end....
rod bearings were all PERFECT.
pulled the main caps...factory powdered metal caps held just fine at the ~1700-1800hp level. pinned mains did their job...no cap walk
thrust looks almost new after 40 passes....ATI has their sh%t together when it comes to keeping the converter from pushing on the crank
very minimal crank flex...completely normal for a traditional-counterweighted lightweight crank. It had some light wear on the center main bearings.
bottom line...the moroso pan and melling oil pump work well and showed no evidence of oil starvation...motor was ~8100 rpm at times...
obviously the block is trashed, so we'll be replacing with a used LS2 "****" block I found...plan is to resleeve with heavy-wall liners up the bore size to ~4.125...
Last edited by Fireball; 10-05-2009 at 06:37 AM.
10-04-2009, 11:58 AM
#7
Thats crazy, 1700 hp on a stock block with stock mains, people always say a aluminum block cant live like that but I'm sure you would habve been fine at about the 1500 hp level.
What crank did you guys use in that motor?
What crank did you guys use in that motor?
Trending Topics
10-04-2009, 07:50 PM
#13
TECH Junkie
iTrader: (3)
Join Date: May 2003
Location: Clayton, North Carolina
Posts: 3,898
Likes: 0
Received 6 Likes
on
6 Posts
The liner would be fine if the parent material supporting it was strong enough. I think this kind of failure is normally from deck distortion because of the way the LS blocks are designed.
Kurt
Kurt
10-05-2009, 06:18 AM
#15
TECH Senior Member
Thread Starter
iTrader: (21)
Join Date: Nov 2001
Location: Cecil County Raceway!!!
Posts: 8,484
Likes: 0
Received 0 Likes
on
0 Posts
all cracking was on the thrust side...we had the aluminum well supported with hardblok...I'm pretty sure having a ductile sleeve in there will definately help matters...I had many stresscracks on the deck, but only sleeve failures were on 3 and 5.
10-05-2009, 07:32 AM
#16
TECH Junkie
iTrader: (3)
Join Date: May 2003
Location: Clayton, North Carolina
Posts: 3,898
Likes: 0
Received 6 Likes
on
6 Posts
Brian,
I have had the same problem with NA engines with o-rings in the deck. The basic design does not seem to play well with o-rings in the deck, just does not have the strength. We have switched Mike Brown to this design of o-ring, but his block has the bridge repair that seems to stop this type of breakage. You could stop this type of break with a reciever groove in the block deck, but then you will push water. You might want to consider the block bridge from ERL, I think it will stop this problem in the future.
Kurt
I have had the same problem with NA engines with o-rings in the deck. The basic design does not seem to play well with o-rings in the deck, just does not have the strength. We have switched Mike Brown to this design of o-ring, but his block has the bridge repair that seems to stop this type of breakage. You could stop this type of break with a reciever groove in the block deck, but then you will push water. You might want to consider the block bridge from ERL, I think it will stop this problem in the future.
Kurt
