LS3 Head gasket lift (Boost)

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CGT
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Re: LS3 Head gasket lift (Boost)

Post by CGT » Sat Feb 10, 2018 9:54 am

Newold1 wrote:
Sat Feb 10, 2018 9:43 am
You are now a LSA type engine user. Let's not over think this issue!

Simple thought here. How does GM get the LSA engines to take boost at a certain compression level, 9.1 to 1 and an engine equipped with piston oil squirters, etc?

How? It was engineered and built from the beginning to have BOOST!

Trying to take an N/A STOCK LS engine and fit it with significant boost is an exercise in futility in the long run!
You can do some things to crutch the problems but eventually Mr. BAD NEWS is gonna get you!

Band Aids don't stay on forever!

My suggestion is save your money and to lower the boost some, re-tune to lessen timing a peak pressure and just take it a little easy on the engine until you can afford and have the time slot to pull the engine and fit it with some good forged pistons and strong ring set, the correct camshaft profile, a better set of aftermarket head studs and a good tuning program and then have the power and torque you want to twist up the drive line, clutch included and smoke off the tires and make it your E-ticket ride! :wink: JMO
I agree, Its a given that its a matter of time before something real bad happens. The problem is, I've felt what that 15-16lbs feels like. Its hard to go back. Thanks for the input. I'm currently looking at pulleys to maybe slow this thing down some.

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Re: LS3 Head gasket lift (Boost)

Post by randy331 » Sat Feb 10, 2018 11:04 am

From what I could tell when I rode in it is,...... more boost and power just equals more peddling the throttle.
Not sure how you tell it made more power?? LOL

Randy

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Re: LS3 Head gasket lift (Boost)

Post by CGT » Sat Feb 10, 2018 11:24 am

randy331 wrote:
Sat Feb 10, 2018 11:04 am
From what I could tell when I rode in it is,...... more boost and power just equals more peddling the throttle.
Not sure how you tell it made more power?? LOL

Randy
Oh I put a set of tires on it. They helped a lot. Now the car is just always broke(N). :D
Last edited by CGT on Sat Feb 10, 2018 11:56 am, edited 2 times in total.

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Re: LS3 Head gasket lift (Boost)

Post by ptuomov » Sat Feb 10, 2018 11:43 am

CGT wrote:
Sat Feb 10, 2018 11:24 am
randy331 wrote:
Sat Feb 10, 2018 11:04 am
From what I could tell when I rode in it is,...... more boost and power just equals more peddling the throttle.
Not sure how you tell it made more power?? LOL

Randy
Oh I put a set of tires on it. They helped a lot. Now the car is just always broke.
Cars are broken, owners are broke! ;-)
[b]Paradigms often shift without the clutch[/b] -- [url]https://www.youtube.com/watch?v=cxn-LxwsrnU[/url]

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Re: LS3 Head gasket lift (Boost)

Post by joe 90 » Sat Feb 10, 2018 5:18 pm

MTENGINES wrote:
Sat Feb 10, 2018 2:03 am

. but they are fastest at the point of destruction
On more than one occasion I've been thinking to myself while driving......wow this has never ever gone this well before.
Then seconds later.....bang, rattle, rattle.

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Re: LS3 Head gasket lift (Boost)

Post by CGT » Sat Feb 10, 2018 5:33 pm

Resized_20180210_160851.jpeg
Not looking forward to pulling the heads off this 'again' ...last time it was NA. There is alot more crap in the way now. Im still contemplating trying the studs without pulling it completely apart. Maybe Ill try some hits with less timing first.
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Re: LS3 Head gasket lift (Boost)

Post by CGT » Sat Feb 10, 2018 5:46 pm

Screenshot_2015-11-16-18-46-28.png
Screenshot_2015-11-16-18-47-27.png
Screenshot_2015-11-16-18-47-20.png
A few of the many modifications done to the blower.
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Re: LS3 Head gasket lift (Boost)

Post by joe 90 » Sat Feb 10, 2018 6:31 pm

Have you thought about just retorquing the heads and retesting it?

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Re: LS3 Head gasket lift (Boost)

Post by CGT » Sat Feb 10, 2018 6:44 pm

joe 90 wrote:
Sat Feb 10, 2018 6:31 pm
Have you thought about just retorquing the heads and retesting it?
Im certainly open for suggestions before splitting it apart. How would you go about retorquing a tty bolt?

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Re: LS3 Head gasket lift (Boost)

Post by joe 90 » Sat Feb 10, 2018 6:54 pm

Same way you retorque any head........clean the oil off the bolt head. Put paint mark on bolt head facing the front. Crack it loose then retorque to spec taking note of where the paint mark ends up.Work through 1 bolt at a time.
I can guarantee at least one of them is loose and more likely all of them are loose.
Some might require another 90 deg. Don't apply any more than the original torque of last time.

If you don't try you'll never know and knowing is everything.
Then report back.

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Re: LS3 Head gasket lift (Boost)

Post by peejay » Sat Feb 10, 2018 8:01 pm

If they are TTY bolts, you won't be able to judge what the original torque was, since they were not tightened to a torque and you will not be re tightening to a torque.

If you're going to go to the trouble of removing the intake and exhaust manifolds so you can get to the head bolts, you might as well just slap new gaskets and head bolts in while you are in there. At least that way you can also give the pistons a good look over and also check valve seal.

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Re: LS3 Head gasket lift (Boost)

Post by CGT » Tue Feb 20, 2018 6:58 pm

KnightEngines wrote:
Fri Feb 09, 2018 7:22 pm
Seen this a lot with Subaru's, on E85 you can put enough timing into them that even without det/preignition they'll lift the heads, seal up again straight away after a pull.
It's not a tune issue, tune can be perfectly safe from a combustion viewpoint, just the pressure rise with the extra timing that E85 allows is too much for basic head clamping.
Fast pressure rise = HP/TQ, not a bad thing, just gotta hold them heads down!

With the new billet subi cases & using ARP2000 14mm head studs the tune can be pushed even further coz the heads don't lift, there has been no adverse affects (other than faster boost reponse & a buttload more midrange TQ) & teardown says everything is happy, it was never a tune issue, just a materials strength issue.

The next limitation in the line seems to be the head castings, they do lift/distort between the studs, but once the block integrity & clamping was sorted the threshold where the head castings are the limit became much higher. For drag racing it is now possible to push 40psi/1000+hp through them, but for endurance racing the reliable limit seems to be around 34psi & 850hp without going to exotic gas rings or other fancy sealing solutions.

You probably won't get away with just swapping in the studs, once the gaskets have crabon tracked they'll keep leaking under boost.
But thin head gaskets are a plus, not a minus - the less head gasket surface area exposed to combustion the better.
What effect do you think gasoline like av gas would have on it? Is this an E85 thing soley?

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Re: LS3 Head gasket lift (Boost)

Post by n2xlr8n » Wed Feb 21, 2018 3:37 pm

CGT wrote:
Tue Feb 20, 2018 6:58 pm
KnightEngines wrote:
Fri Feb 09, 2018 7:22 pm
Seen this a lot with Subaru's, on E85 you can put enough timing into them that even without det/preignition they'll lift the heads, seal up again straight away after a pull.
It's not a tune issue, tune can be perfectly safe from a combustion viewpoint, just the pressure rise with the extra timing that E85 allows is too much for basic head clamping.
Fast pressure rise = HP/TQ, not a bad thing, just gotta hold them heads down!

With the new billet subi cases & using ARP2000 14mm head studs the tune can be pushed even further coz the heads don't lift, there has been no adverse affects (other than faster boost reponse & a buttload more midrange TQ) & teardown says everything is happy, it was never a tune issue, just a materials strength issue.

The next limitation in the line seems to be the head castings, they do lift/distort between the studs, but once the block integrity & clamping was sorted the threshold where the head castings are the limit became much higher. For drag racing it is now possible to push 40psi/1000+hp through them, but for endurance racing the reliable limit seems to be around 34psi & 850hp without going to exotic gas rings or other fancy sealing solutions.

You probably won't get away with just swapping in the studs, once the gaskets have crabon tracked they'll keep leaking under boost.
But thin head gaskets are a plus, not a minus - the less head gasket surface area exposed to combustion the better.
What effect do you think gasoline like av gas would have on it? Is this an E85 thing soley?
I'll defer to KnightEngines, but I've tuned alot of E85 blown (turbo) engines. Many folks tune E85 like race fuels. I don't. I like to keep the timing conservative and throw the boost at it.

I bet you'll be disappointed with the avgas tune up.
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Re: LS3 Head gasket lift (Boost)

Post by cgarb » Wed Feb 21, 2018 4:17 pm

What about porting or stepping up the heads as a solution? If you lost boost psi because the heads flow more air, wouldn't the HP still be there...just with less boost and pressure?

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Re: LS3 Head gasket lift (Boost)

Post by tt 383 » Wed Feb 21, 2018 5:17 pm

Don't know if this was mentioned but the GM ls9 gaskets are 7 layer and it used a bigger head bolt. Many on ls1tech use the gm instead of the cometic. I also didn't think a tight piston to head was desirable for forced induction...

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