Is a piston upgrade necessary?
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 34
Likes: 0
From: West Hartford, CT
Is a piston upgrade necessary?
I have a '15 z51, main mods are a procharger and a single nozzle 50% meth kit. Anyways, just got the car back from getting tuned and it made 677rwhp at 14.6psi boost. I've seen many people say to change them out around 700. I don't plan (at the moment) to take the car any further, but I was hoping the meth would keep everything cooler and it wouldn't be necessary to change them out.
It's just a street car for fun, no track driving.
Thoughts?
It's just a street car for fun, no track driving.
Thoughts?
Last edited by zcyr10; Apr 18, 2020 at 06:27 PM.
Advanced
Joined: Mar 2010
Posts: 68
Likes: 17
From: Enfield CT
I believe you are are on the ragged edge if not a little beyond it, and are pushing your luck with that amount of boost (power). Yes the meth definitely helps keep it cooler but it can do only so much. If you not really using the power i.e. the quick entrance ramp hit, etc. you may survive. If you make the heavy hits It's probably only a matter of time.
The biggest initial problem is the ring gap is to tight. You make the heavy hit the heat builds up, the top ring expands closing up the gap and the top ring land of the piston fails taking a chunk of the piston off. The first thing you do when installing rings in a boosted applications is open up the ring gap. There have been some that open up the ring gap and stay with the stock pistons, which "helps" them survive longer. But why would you do that with all the effort it took to tear the engine down, why wouldn't you put in a drop in forged piston set.
I'd pull the boost down to under 10psi. Just my thoughts
The biggest initial problem is the ring gap is to tight. You make the heavy hit the heat builds up, the top ring expands closing up the gap and the top ring land of the piston fails taking a chunk of the piston off. The first thing you do when installing rings in a boosted applications is open up the ring gap. There have been some that open up the ring gap and stay with the stock pistons, which "helps" them survive longer. But why would you do that with all the effort it took to tear the engine down, why wouldn't you put in a drop in forged piston set.
I'd pull the boost down to under 10psi. Just my thoughts
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 34
Likes: 0
From: West Hartford, CT
I believe you are are on the ragged edge if not a little beyond it, and are pushing your luck with that amount of boost (power). Yes the meth definitely helps keep it cooler but it can do only so much. If you not really using the power i.e. the quick entrance ramp hit, etc. you may survive. If you make the heavy hits It's probably only a matter of time.
The biggest initial problem is the ring gap is to tight. You make the heavy hit the heat builds up, the top ring expands closing up the gap and the top ring land of the piston fails taking a chunk of the piston off. The first thing you do when installing rings in a boosted applications is open up the ring gap. There have been some that open up the ring gap and stay with the stock pistons, which "helps" them survive longer. But why would you do that with all the effort it took to tear the engine down, why wouldn't you put in a drop in forged piston set.
I'd pull the boost down to under 10psi. Just my thoughts
The biggest initial problem is the ring gap is to tight. You make the heavy hit the heat builds up, the top ring expands closing up the gap and the top ring land of the piston fails taking a chunk of the piston off. The first thing you do when installing rings in a boosted applications is open up the ring gap. There have been some that open up the ring gap and stay with the stock pistons, which "helps" them survive longer. But why would you do that with all the effort it took to tear the engine down, why wouldn't you put in a drop in forged piston set.
I'd pull the boost down to under 10psi. Just my thoughts
That's kind of my feeling here also. I honestly thought I would land around 630ish, but now creeping up on the magic 700 has me a little nervous to really romp on it
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 34
Likes: 0
From: West Hartford, CT
that's some serious power on stock pistons, I believe he was running meth as well which I'm sure helped the longevity and I'm hoping the same in my situation.
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Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,478
From: South Florida
The meth is only going to help the pistons. 800 rwhp on a stock LT1 will eventually eat up the thrust bearings. 14.6psi on a Stock LT1 is also iffy when it comes to longevity. I'm only saying be thankful if it stays together for a long time but don't be upset if it pops early.
Melting Slicks
Joined: Oct 2009
Posts: 2,560
Likes: 485
From: Moberly, Mo
I ran into issues once I reached 16 to 17 psi on the stock Lt1 pistons and eventually broke number 1 and 8 ring land. I should have stopped at about 13-14 lbs. First indication that something was going on when it pushed the front crank seal out at a race in St Louis. Replaced that flimsy *** Lt1 seal with an Ls3 seal. Ls Fest it started leaking from the rear seal but I had one more race planned at St Louis again and did a job on it there. Dumped a lot of oil out in my belly pan diaper and still put some oil on the track. So I'd recommend not exceeding 13 psi or so on the stock pistons. Another thing is crank case ventilation, that's one of the most important things in my opinion and I didn't do my job on that end as I should have. Too much crankcase pressure and your gonna screw some stuff up along with to much PSI in the cylinders.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,478
From: South Florida
Texas Speed just showed a tear down of Cleetus's engine. He spun a main and a rod bearing and had multiple broken pistons. You're on borrowed time on any stock piston LT1 with high boost or big power.
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 34
Likes: 0
From: West Hartford, CT
I ran into issues once I reached 16 to 17 psi on the stock Lt1 pistons and eventually broke number 1 and 8 ring land. I should have stopped at about 13-14 lbs. First indication that something was going on when it pushed the front crank seal out at a race in St Louis. Replaced that flimsy *** Lt1 seal with an Ls3 seal. Ls Fest it started leaking from the rear seal but I had one more race planned at St Louis again and did a job on it there. Dumped a lot of oil out in my belly pan diaper and still put some oil on the track. So I'd recommend not exceeding 13 psi or so on the stock pistons. Another thing is crank case ventilation, that's one of the most important things in my opinion and I didn't do my job on that end as I should have. Too much crankcase pressure and your gonna screw some stuff up along with to much PSI in the cylinders.
Thanks guys looks like I have some more work to do, until then I'll just be easy on it
