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They were BT Racing springs with less than 5 track days on them. Not expecting that. Probably did a lap and a 1/2 before I realized what had happened - hence the damage. Not sure what to do now. I hate to trash a $10k motor.
Salvage what you can and rebuild it. But no fun for awhile. Find another engine to run and still rebuild it and save it as a spare. Last choice sell it off. But talk to builder or part supplier see if they are willing to help you out first. You got nothing to lose.
My rev limiter is set at 6900, but I never hit it. Maybe 6700 a couple of times. When you are making 500rwhp and you lose a cylinder, it is hard to tell until the backstretch. Obviously it was too late. It was kicking *** before it broke though.
Hoping to salvage the head as TFS is pretty expensive. I finally talked to my vette guru friend. Motor definitely has to come out and redone. Not sure a piston can be changed from bottom but it would save a lot of work. But after 6 1/2 years of tracking, it probably needs to come out anyway.
So both valve springs broke? And dropped the intake valve into the cylinder? Something went seriously wrong. I would check it over carefully. The broken valve spring may have been the result of something else going wrong. Maybe a lifter twisted or ??? I wouldn't be so sure that the broken valve spring was the cause of that.
Only one valve is broken. The wrenched valve had dual springs and both were broken. The other valve and springs are OK. It would be nice to salvage the heads. The chambers are nicked up pretty bad, I presume from the metal pieces floating around in there. Here is what the other pistons look like:
Not sure if they can be salvaged. As far as the cylinder wall of the bad piston, it is almost to the top, but the 1" exposed wall has no scars or ridges that I can tell.
Just got through listening to NASCAR race on radio. Brad Kezwolowski ran last 1/2 of race on 7 cylinders. Will it hurt to run it on 7 cylinders? It still would have over 430 rwhp. Just thinking out loud.
A sometimes over looked failure is the spring retainer lock. One looks like its embedded in the head. So the locks, retainer, springs and valve should be inspected to see if you can find out what failed . As a former Corvair owner, I can tell you the head can be repaired. The 140s dropped valve seats regularly. The engine needs to be yanked and thoroughly cleaned. You're going to need to check the rod journal to make sure it wasn't hurt when the piston and rod smacked the valve. The oil pump is likely contaminated, too. I know, ugh.
If you plan on re-using things like crank/rods have them magnafluxed to check for cracks. They may visually appear in good shape and not be usable. I have had to throw away several thousands of dollars in parts because of a lousy valve spring in the past.
Get ready to spend serious money on a new valve train. Springs are just the first step. Here's an article I did last year on high performance valve trains.
Finally some good news. Got the passenger head off tonite and it all looks good. No nicks or gouges. Hopefully the other can be repaired. I ran my little magnetic pick up all through the cylinders and there is no metal anywhere. To do all that scarring, you would think there would be traces of it somewhere. Hope to get to engine builder tomorrow to have them check out heads and discuss looking at my block. Somebody gets to tear that down. Long process ahead.
A sometimes over looked failure is the spring retainer lock. One looks like its embedded in the head.
I wonder how the spring retainer lock, or valve keeper, got from the top of the head where oil is got came off and physically make it through the head and into the combustion chamber? After all those are in two completely opposite sides of the head and cannot possibly ever come together. If the keeper did fail, it would wind up in the oil pan at worst.
Dropped heads off by race shop that specializes in head work. Even more good news - he says heads are repairable. He did not seem alarmed at them at all. Said he had repaired worse. Also, said he could do my block also if I could get it too them as they do not remove or install - only build. Now to find out what/who/where to do block.
I'm going through a semi-halfassed rebuild on my LT1 now: wadded up #6 rod bearing and galled the wrist pins to the pistons. Really wanted the cheap way out because of the whole "I'll blow it before I wear it out" mentality. Originally was going to slap in good used crank, pistons, rods, reuse mains/rings, install new rod bearings, call it good. Got to reading some more and realized that, if the ring gaps didn't fall right back where they were, ring seal would be a crapshoot. Dammit. So I honed, went with new rings, then I'm all like well hell, may as well polish the crank and get new mains. So as far as the short block is concerned, the only thing I skimped on was boring/new pistons and new cam bearings. Engine had great oil pressure when I tore it down, so cam bearings don't concern me. Learned a fun fact on cylinder walls, despite the fact that there was a near indiscernible ridge, I still had some wall wear. This was a low mileage engine (~60k), but when I hit it with a 3 stone hone, I could see low spots. The thing that really blew my mind was seeing where the rings slammed against the walls near the top of the cylinder. Had I used a dingleberry hone, I would have never noticed that. Ended up going 320 grit and finishing with a red scotch brite pad, hopefully Vizard knows his shjt and this thing breaks in quick with little ring wear and litter in the oil.
It's supposed to be a garage plateau hone, takes the sharp edges off of the hone scratches. The surface was noticeably smoother afterward. Since there's fewer ridges to chew through, the rings presumably seat more quickly and there's less ring wear during breakin and thus less crap in that first batch of oil. Since I'll break in on the dyno and immediately transition to power pulls, this makes me feel a little better about making those power pulls.
04-25-2015, 01:26 PM
Carnage pics from broken valve spring - what now?
