Engine Failure

[Nigel]

I will post more details as I get them, just passing along my experience.

I have a stock short block, that I have disassembled and checked, reassembled and have run for a while. This has been a hobby and learning experience for me just to qualify. Short block had a 110K miles on it, around 200 plus passes at the drag strip, plus an annual consumption of 15 to 20 gallons of methanol for the past 5 years, lots of street hits.

Today, on the way back from the grocery store, I layed into it, watching scan master. No knock, 10.6 ish afr, and pow . Had it towed home. I have to pull the engine and do the checking, but the block split catty corner at the rear main. Not sure if it is my tuning, which I thought was pretty good, or I just won the lottery on a stock block defect.

I will post up findings as I go. Just thought I would pass along.

 

[HackersDna]

Hate to hear that Nigel.. No 2 ways about it, It sucks. Curious were the mains studded? I know you said stock but you had disassembled it and screwed her back.

 

[Gene Van Horn]

Sorry to hear this, alot of work to take the car all apart again. Had mine rebuilt three times untill it finnally went to the correct engine builder. Your in Nassau take it to Dave Husek, he'll take care of you.

 

[bluegate]

Defect, or was it finally time to go? That's alot ground pounding, right? Sorry to hear about it.

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[Nigel]

Thanks for the comments guys.
The mains and rods used the stock hardware. I'll maybe get to pulling the engine next weekend to see further what happened.

 

[Mr.Spool]

Not sure if it is my tuning, which I thought was pretty good,

were you logging fuel and alky pump pressure?i dont know what afr to target with that alky plate and how much meth gets into each cylinder at say 100psi.10.6 doesn t seem lean to me on a low 11 car,but tearing down the motor will give you more clues as to what got hot or what just let go.

 

[Turbo6inKY]

the block split catty corner at the rear main

Did you magnaflux the block for cracks when you tore it down for the rebuild? I'd be suspecting a small crack that started around one of the rear main cap bolts and finally spread.

 

[Nigel]

were you logging fuel and alky pump pressure?i dont know what afr to target with that alky plate and how much meth gets into each cylinder at say 100psi.10.6 doesn t seem lean to me on a low 11 car,but tearing down the motor will give you more clues as to what got hot or what just let go.

Unfortunately I did not have the computer hooked. I do have an Alky transducer. It reads 130 to 135 on the power logger when I have logged it. I'll post up tear down details.

 

[Nigel]

Did you magnaflux the block for cracks when you tore it down for the rebuild? I'd be suspecting a small crack that started around one of the rear main cap bolts and finally spread.

I did not have the block magnafluxed. I was going to ride the stock short block till it bucked me. On the fresh build, I will get it done.

 

[turbo nasty]

When you reassembled it and got it running again, did you log and tune safely and ease boost back in?

 

[Nigel]

When you reassembled it and got it running again, did you log and tune safely and ease boost back in?

My post is not that clear, I had checked out the short block quite a while ago, I did not write down the mileage when I checked it out, but it was 10K miles ago or so and a bunch of 1/4 mile passes on it since it was put back together.

 

[750H.P.V6]

The cars are over 30 years old and the stock parts have been pushed way past anything they were ever designed for. Cycle life fatigue will come to play at some point and unless you've owned the car since there is no way you can envision what it has been subjected to. You we probably just the guy who owned it when it broke. I hope the damage isn't too bad.

Neal

 

[hensleyt]

That is the best ET and MPH I’ve seen with a 5858 good job .Your going to break stock parts someday at that power level

 

[SCOOBY DOO]

Nigel, I've been racing these engines for years...and you're gonna break parts from time to time no matter how careful you are with tuning. Heat cycles and stress take their toll after 30 years. I apprenticed as an automotive machinist...so the only advice I can give with any further build(s) is to magnaflux the block, crank, rods and heads.

To date I had a .030 over block crack a cylinder wall. I had it sleeved...and 6 months later a different cylinder cracked...but this time almost to the top of the deck...so I scrapped the block. I had a piston pin come loose one time and score a cylinder wall and had it sleeved. I put about 125 passes a year on my GN. Build, ET and MPH are in my sig.

 

[bison]

Post pics. I had the stock block i had in my car for years with over 10 minutes logged of 9 sec power on it. Surprisingly it has no cracks. The number 3 cap was in 2 pieces when I tore it down. It had stock hardware


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[Chuck Leeper]

Jim Ruggles was right, when he told me, my stock block would "live for a while" @ 600HP. And, that was 20 yrs ago.

 

[750H.P.V6]

Without wanting to go too far out on a limb I suspect the crank broke between the #5 and #6 rod journal and the block damage you noted is secondary. Please post more info when you get it.

Neal

 

[Nigel]

I'm on the road for work, car is home in the garage, will be a week or two before I can get to it. I will post pics.

 

[Nigel]

Got a little break, so I pulled the pan, pictures to follow. Thanks to all for the interest so far. Will be another two weeks probably before I can pull the engine. Gotta hit the road again, hopefully that problem will be resolved by the end of week. Company probably would not like me posting details on that, but it is a 500+ x 2 megawatt problem.

 

[Nigel]