'68 Vette, put up in storage in 1974 in New York state. Sold to a Wisconsin buyer in 2005 who wanted to restore it. Frame off, bunch of new and expensive stuff (for example, $992 for a "restored" q-jet, another $512 to have SMI go through it). Body and interior are great.

Engine is the 390 horse version, rebuilt 0.030"-over, incorrect closed chamber heads used (290's, should be 215's), some sort of solid lifter cam. It had been dyno'd, not sure if engine or chassis, but showed about 390 peak HP at 4900 RPMs. Sold it (wanted an '10 Camaro, wife told him something had to go) to a guy in Nebraska earlier this year who flips cars, who listed it on eBay, which is how the former co-worker got it. He trailered it home, put about an hour on it in a couple of sessions, when the engine ate itself - spewed water and parts into places they didn't belong.

Upon pulling the heads, found #1 intake valve head had broken off and busted up the head (intake port was broken through the wall). A piece of metal ended up under the #7 intake valve. Cylinder walls scored & beat up. Pulled the engine, had it on the engine stand when I looked at it today. Evidence that all of the intake valves had been kissing the piston valve reliefs (Speed Pro forged pistons). People had told him the incorrect heads had caused the problem, but I didn't buy that (same type and chamber size as the originals). He pulled the timing cover, and the problem became obvious - the timing gear was advanced one tooth.

All that work, all that money, and something as simple as improperly lining up two dots destroyed an engine.

 

Now THAT is a shame.... Ouch

Just because I'm curious, how many degrees would that have advanced the cams approximately?

 

I didn't count the teeth (double roller timing set), but I'd guess somewhere around 10 degrees.

 

So essentially what happened is the intake valves would open too early, and hit the piston when it was still on the exhaust stroke? Huh, seems like something you would notice before a catastrophic failure like that. But then again, I don't do this for a living. Still a shame though

 

Right. Not something that broke the first time it was turned over, but slowly stressed the valve until it finally broke.

The intake valve is supposed to start opening before the piston gets to TDC on the exhaust stroke, but not too much.

 

So what do you do about that if you have a cam with say, a large degree of overlap? Wouldn't that cause the same issue? Although I suppose you would want a piston with deeper reliefs

 

When you have high compression, large overlap, and high lift, you should verify piston to valve clearance during the build. In this case, it was a mostly stock-like rebuild, which shouldn't have had piston to valve clearance issues.

When I say "10 degrees", that's camshaft degrees. Valve timing is referred to in crankshaft degrees. +/- 4 degrees is typically all you would consider changing the cam when degreeing it in, so this would have been 20 degrees advanced by the same standard.

 

Gotcha. Forgot that crankshaft degrees and cam degrees will be different... Now that makes a lot more sense. Thanks for clearing that up for me

 

One pic he sent me:

 

Holy crap. Seems like a pretty stupid error on the part of the builder. Ive done a few timing belts on jap cars and Im always extremely **** about checking, double checking and triple checking timing alignment. Pretty interesting to see the results of someone not sharing the same attention to detail.

 

Now it can be rebuilt into a 541-cube / 8.9L wonder. Yes, this block can go to 4.375" x 4.500" and be expected to live. Use 6.385" rods only, NO other length.

 

He did say that the failure released him from some of the "pristine" aspects of owning the car. The seller is sending him the 215 castings, but he's looking at aftermarket heads.

He's more into road course racing than brute power, so he's inclined to keep the 3.76" crank. Hood clearance causes intake limitations, so big hairy stuff isn't too likely, either.

As I was about to leave, I said something to the effect of, "If you are willing to depart from the original big block, there are other ways to get to 427 cubic inches." He disappeared and came back with a 3-ring binder of LSx information - he'd already considered it (and an LS7 fits under the stock hood).

 

in a tight autocross, or a parking lot gymkhana, I'd prefer the new LS7, but it'd be cheaper to do it with a new L92 block, then use AFR205cc heads and a truck intake for low-rpm response. A COMP 54-000-11 3707/3707-108 +2 cam would be great. But on faster tracks, a 541 would have much better recovery after each upshift. The main drawback is still the weight, and the 427 could have the same torque if the correct pair of turbos were mounted pretty far back in the car, kind of like how Squires Turbo Systems does it in their patented and overpriced rear-turbo kits.

 

 

That's sad really.
[Short story time] I was working on a ford probe (friend's kid's car) and I had to redo the timing belt probably 10 times because the cams kept moving. A friend of mine kept insisting that it was good enough when it was just about lined up right (one tooth off on the crank). Not good enough for me. It's just not worth destroying and engine just because you have to redo something a few times.[/Short story time]