Sorry to hear. Time to remove that Accusump bandaid and get a proper dry sump setup.

 

what are the odds your suspension out-handled your oil system like on the 944 engine?

 

So this is the second engine built by this shop that's blown up? Any chance it's the way the shop is building the motors? Or that you're running into an oiling issue as others have suggested?

I hope I haven't put the whammy on you with my bad luck...

 

I would but the data logging shows no oil pressure issues (on 19 run sessions) until about 2 minutes before the boom. There was no oil pressure drop per-se. But the entire oil pressure chart (all the ups and downs) moved down the scale, then another minute later the whole chart moved down again. Still no pressure below 35psi at 3500rpms. Then boom.

Aside from all that... if I could easily put an oil tank somewhere I would do it 'just because'... But it would have to be in the back of the car.

And I ran the same setup without the Accusump for many years and the rod & main bearings always looked brand new after multiple seasons (before I had any data logging ... on the red car).


But the biggest thing that I can tell, was not the engine, but me....

I did have some too-high down shifts that showed 8000+ rpm (peak on the race the day before was an 8300rpm down shift) on a few occasions is probably what caused the failure.

I just won't know until the engine comes out and apart.

TonyG

 

You mean to tell me that it isn't out of the car yet? :-)

Good luck Tony.

 

ugggg Sorry to hear about the engine issues.

If you intend to stick with 4" stroke you may want to consider the longer sleeves, like a darton sleeved block(ERL, RED, etc). If you have not, look at how far beyond the bottom of the factory skirt the piston hangs out at bottom stroke. This allows piston rock and seems shortened longevity and durability issues.
If you go the darton sleeve route you end up in the 4.125 + bore so you can run the LS3/LS7 top end stuff.

That would be the way I would go on it.
Only issue I could see is if you are class restricted to hp/weight you would have to rev limit

Good luck

 

The engine isn't a 4" stroke engine. It's a LS3 with a 3.825" stroke, for the very reason you stated below.

But that's not the reason the rod came apart. It was due to RPM, not stroke, or piston rock at BDC.

The new block will be an LS7 block, so that won't be an issue. It will also, because of the longer sleeves, allow me to run a very short skirt light weight piston. That with the lightest steel rod that's strong enough for 8500rpms is what the next setup is going to be.

The other thing is that any increase in stroke above 3.825" stroke would require me to use a deeper oil pan (fabricate a deeper oil pan...), which would force me to raise the engine, which would cause the intake manifold to hit the strut brace, etc..... Just not worth the extra 19 cubic inches.

TonyG

 

not sure where I got you were 4' stroke.
anyway it's too bad you can't squeeze the extra .175 of space
In an NA motor that gets into 441 CID with the darton setup.
Then you don't have to turn so much rpm to make power

Agreed 8000+ rpm is too much - and the likely cause

 

BTW... we are going to dry sump it.....

TonyG

 

Are you bored with your chevy, boy?

 

No. Not even close.

Am I happy about these engine failures? No.

However, I intend to throw enough money at the problem to make it go away and pick up more power in the process.

I've come way too far to let up now....

This is where the rubber meets the road.

TonyG

 

Tony,

I am sorry to hear about your recent misfortune.

I do however admire your persistence and determination!

 

<<<@!1!@>>>
Tony
Let me first express my condolences ... I am very sorry for all you have gone through and hope you see an end to these issues (you have put too much into this, for it to not be the best ) Now on a lighter note
This might help ( one of my favorite ads )
With humor, maybe this will help ease the pain some

 

Not you Tony I know you, but I was responding to 2bridges he sold his 951 for a miserable C5

 

That is a lot of rev's! Although I have had a few issues, I too am more than pleased with my V8 vs the original turbo motors.