Compression test done after Cats fail not good!

[Kiwi_Camaro_2010]

Originally Posted by BigBlock69RS

Definitely a leak down test, pinpoint the issue, rings, exhaust or intake valves etc. If it comes up rings. Removing a spark plug and squirting oil into the cylinder will tell you for sure, provided the compression numbers come up in the low cylinders.

Yes i think I will try the oil down spark plug with compression tester as I don't have access to leak down tester, but I have noticed since it happened my smooth idle has gone & now sounds like I have a mild cam in it, so could be a valve, maybe I 'll pull heads before pulling engine out.

cheers

[East Coast Supercharging]

Just a thought for you if your not ready to go with a fully forged engine and the car will have to sit otherwise, if the bore is fine and the ring gland just cracked, you can just replace a piston and your on the road again quickly.
One of our guys here can have that done in an day, remove the head, drop the pan, install new piston with original rings, and your set.

I'm not saying this is the "ultimate repair" or anything, but we have done this a for few people who had poor gas situations etc and did not either have the means or want to go fully forged at that time.
All the cars we have done this too are still on the road today making boost and being enjoyed.

Just an option for you.



Doug @ ECS

[MudderFinger]

I had a cylinder that was down to 155 and it turned out to be a broken ring land, but the cylinder was still hitting. I drove for two months that way and the broken ring land stayed intact, cannot guarantee yours will be the same. You can see the pictures in my build thread, link in signature. Did you hit the rev limiter alot? Thats what killed mine after putting a stahl converter in and not having tune adjusted soon enough. I have almost a whole set of Pistons(7) & rods(8) with only 7000 miles, I would willing to part with cheap. If you need to wait because of cash you could just replace the bad ones and plan a more exstensive build at another time when it is more practicle.

[MudderFinger]

Also with mine I was able to put compressed air in the cylinder with rockers off and hear air coming out oil fill cap hole. So that made it very clear that either the ring land or rings were cracked.

[simon.w]

welcome to my world!

[Kiwi_Camaro_2010]

Originally Posted by East Coast Supercharging

Just a thought for you if your not ready to go with a fully forged engine and the car will have to sit otherwise, if the bore is fine and the ring gland just cracked, you can just replace a piston and your on the road again quickly.
One of our guys here can have that done in an day, remove the head, drop the pan, install new piston with original rings, and your set.

I'm not saying this is the "ultimate repair" or anything, but we have done this a for few people who had poor gas situations etc and did not either have the means or want to go fully forged at that time.
All the cars we have done this too are still on the road today making boost and being enjoyed.

Just an option for you.



Doug @ ECS

Hi Doug, I have thought seriously bout this but I can't afford to take it to anyone, so have to do it myself, which I am capable but motivation is very low at moment as I spent all my holidays on this project. I do want to go all forged & I don't want to have to pull motor twice. You say removed pan in car? I was under the impression sump would not come out without lifting motor? Or can you leave trans attached & lift enough (off engine mounts) for the pan to come out in car?

cheers

[Kiwi_Camaro_2010]

Originally Posted by MudderFinger

I had a cylinder that was down to 155 and it turned out to be a broken ring land, but the cylinder was still hitting. I drove for two months that way and the broken ring land stayed intact, cannot guarantee yours will be the same. You can see the pictures in my build thread, link in signature. Did you hit the rev limiter alot? Thats what killed mine after putting a stahl converter in and not having tune adjusted soon enough. I have almost a whole set of Pistons(7) & rods(8) with only 7000 miles, I would willing to part with cheap. If you need to wait because of cash you could just replace the bad ones and plan a more exstensive build at another time when it is more practicle.

Been thinkin, might still drive it oh so carefully till have enough funds, If I have same problem as yours I can't see it causing too much a problem unless something breaks away. Did you go stroker on crank or keep it stock? Also what size dish are your pistons & what compression ratio do they give you?

cheers

[stevieturbo]

If you just drive it easy, then chances are any damage that is going to be done, has already been done.

As to whether the block will clean up at a light hone, you will never know until it is apart.

As it's a big lazy engine you could pretty much drive forever and never go above 2000rpm. So it seems that is your only option, and if there are any further consequences, so be it.

But I doubt there will be any more damage than is there already. Just keep an eye on oil levels etc.

[simon.w]

Originally Posted by Kiwi_Camaro_2010

Been thinkin, might still drive it oh so carefully till have enough funds, If I have same problem as yours I can't see it causing too much a problem unless something breaks away. Did you go stroker on crank or keep it stock? Also what size dish are your pistons & what compression ratio do they give you?

cheers

Don't risk that piece of ring land coming loose and scoring a bore beyond repair ... you saw those pieces of my ring land in my rebuild post ... they were the big bits, there were pistons that had ring lands broken into tiny bits. Admittedly I probably drove my car for over a year with that issue and no major damage, but I was lucky!



I looked at going for a stroker crank but came to the conclusion that because the LS3 crank is already capable of handling in excess of 1000HP, I would get better performance gains and reliability spending that money on other things.


Re the pistons, the advice I received was to stay somewhere between 9.5:1 and 10.1:1 and then pulley-down. Whipple advised to keep the compression ratio on the higher side and not to go too small on the pulley to allow the blower to work in its most efficient range. In the end I’m going for 10.1:1 forged pistons with a Whipple 8 rib pulley kit with 10% overdrive and a 3.5” blower pulley.



Good luck!

[VADER SS L99]

I think header mfgs need to start owning up to this issue and offer 1 type of cat for NA and another much better type of cat for FI.

[Kiwi_Camaro_2010]

Originally Posted by simon.w

Don't risk that piece of ring land coming loose and scoring a bore beyond repair ... you saw those pieces of my ring land in my rebuild post ... they were the big bits, there were pistons that had ring lands broken into tiny bits. Admittedly I probably drove my car for over a year with that issue and no major damage, but I was lucky!



I looked at going for a stroker crank but came to the conclusion that because the LS3 crank is already capable of handling in excess of 1000HP, I would get better performance gains and reliability spending that money on other things.


Re the pistons, the advice I received was to stay somewhere between 9.5:1 and 10.1:1 and then pulley-down. Whipple advised to keep the compression ratio on the higher side and not to go too small on the pulley to allow the blower to work in its most efficient range. In the end I’m going for 10.1:1 forged pistons with a Whipple 8 rib pulley kit with 10% overdrive and a 3.5” blower pulley.



Good luck!

Yep been thinkin bout that, gona stick to 376 cu in as I was happy with power level at that, plus other components will need changing if I go for more HP & all I want is reliability now, so may still go for forged matching crank & rods (so fillets match up) & maybe wiseco pistons, add L99 to ls3 conversion & smooth idle blower cam. this engine is only coming out once! Time to see Mr bank manager.

[simon.w]

Originally Posted by Kiwi_Camaro_2010

Yep been thinkin bout that, gona stick to 376 cu in as I was happy with power level at that, plus other components will need changing if I go for more HP & all I want is reliability now, so may still go for forged matching crank & rods (so fillets match up) & maybe wiseco pistons, add L99 to ls3 conversion & smooth idle blower cam. this engine is only coming out once! Time to see Mr bank manager.

Seriously, you don't need to touch the crank ... you can run Callie Comstar rods and Mahle or Wiseco pistons with the iron nodular crank and be good for up to 1000hp.

With the right cam, compression ratio and boost, you will be able to run a very reliable 700rwhp without going for a stroker kit.

Put your money towards an 8 rib pulley kit ($1400) so you can go for a smaller blower pulley ($100-150) without slippage and an ADM twin pump system because your ZL1 pump is only good for up to 600rwhp. ($1000-1300).

THEN ... being a Kiwi ... get yourself a nice set of lambswool seat covers so that every minute you're in the car feels like an orgy!

PS ... I'm an Aussie ... so I can say that! (I live in southern California now)

[Kiwi_Camaro_2010]

Originally Posted by simon.w

Seriously, you don't need to touch the crank ... you can run Callie Comstar rods and Mahle or Wiseco pistons with the iron nodular crank and be good for up to 1000hp.

With the right cam, compression ratio and boost, you will be able to run a very reliable 700rwhp without going for a stroker kit.

Put your money towards an 8 rib pulley kit ($1400) so you can go for a smaller blower pulley ($100-150) without slippage and an ADM twin pump system because your ZL1 pump is only good for up to 600rwhp. ($1000-1300).

THEN ... being a Kiwi ... get yourself a nice set of lambswool seat covers so that every minute you're in the car feels like an orgy!

PS ... I'm an Aussie ... so I can say that! (I live in southern California now)

Haha, thought that might come up when I put Kiwi in my login, but you know the sheep jokes work both ways, you'd be getting withdrawal symptoms by now living in America

On the serious side, I know the cast cranks are strong, but I'm not after any more horsepower & at 10psi on 4"dia I'm happy, I do have 3.875" as well but that's it for me, I had 1969 Camaro with big shot NOS on, but as I get older I'm getting sick of workin on cars, I bought the 2010 believing I would be not have to do anymore, so this engine only comes out once more & I'd rather spend money on bullet proofing than more horsepower plus conversion from L99 to LS3 will give me another 60HP. I don't want to have to add any more fuel mods either (might do the ADM fuel controller mod though), plus I can hardly get space in my shed as my sons Skyline boyracer car takes up all the space with his mates working on that. Getting tired......on it.

[stevieturbo]

Whilst the standard cranks are very strong. For a blower application I would choose a steel crank if possible, purely for extra nose strength.

Although of course even that might be debateble, as Ive heard of a couple of Dragonslayer nose failures....which does give me a little concern, as I have one !
Hopefully the 3.825 is stronger than a 4" though. I think both I seen were 4" cranks

The extra stroke to 4" really isnt needed though