I made my last run with the 79 before the snows and had just horrible results all night... The last run it pulled an awful 15.21 (stilll took down a little Acura) but it sounded like I ran over some gravel the the end of the track... ...she made it back to the tuning area and let go:
From what I can tell the lifter gallery failed, dropped several pieces into the oilpan, which tripped the the rod which went right through the cam :ball: , bashed a hole in the oilpa. My 76 455 is now being built up to replace this 71...
at least it picked a good time to fail, I've got all winter to get the buildup going... I'm thinking lifter girdle or hardblock *might* be an investment... ou: ou: ou:
Ouch! Is this a stock block/build? What's scary is I don't see a lot of core-shift in the lifter bores. Did you look close for that? Good luck on the new one.
Go To Olds! p Forget core shift. You need a brand switch to Olds. Never seen a lifter bore break on an Olds! :moonu:
nasty MAN,That totally SUCKS. I hate to see this in any racer. Talking about core shift is there anyway to spot a problem like that by looking at the block. What was the build-up in this block?
Re: Go To Olds! That's because Olds doesn't make enough power :laugh: Man that really does suck about your lifter bore. How much lift where you running?
Real Deal? OLDS? Might be the fact that Olds Power IS slow power! Ha! just ribbing you guy's, this is an inherent problem with high Hp Buicks,coreshift is something to lookfor upon purchase of a BBB, I'm no expert at checking this problem, maybe someone that is can enlighten us all as to why this happens, a good friend of mine broke at the Nats,(lifterBore) and is adding a support system to resolve this problem, I understand T/A makes a nice piece for this problem. Bruce
Did you break a connecting rod? I have seen this type of failure, when a rod lets go. If a rod is broken, then that is the cause for the broken cam, which took out that lifter bore. I have never seen, or even heard of breaking a lifter bore out on a motor that looks pretty stock... but then again, I have not seen or heard it all either.. Considering you have holes/dents in the oil pan, I think you need to get it out, and do a full inspection, before drawing any conclusions. I guess it could have happened, if you had some issue that caused excessive load on the bores, but considering the rocker gear on that engine, I highly doubt the lifter bore would be the first thing to fail here. Just an educated guess, nothing more...
Hmm, you don't? I guess I do, the lifter bores you can see are all out of wack, some are thicker and some are very thin and not symetrical at all. What year was this block from? Early '70 I would guess? Scott Coffman(used to have aqua '67 Stage 1 car, 2 different ones) he and I looked a bunch of blocks I had here looking for a good one, and he showed me what not to use! Just my $.02. RV
Hi Guys, Clint.....I agree with Jim W., a rod let go first and took out the camshaft which in turn busted the lifter bore. I've done the exact same thing before and I can pretty much guarantee that's the chain of events that took place! Sorry....I've been there myself....:ball:
Thanks guys, nice to have support in my time of mourning... :ball: What you're seeing here is a stock 71 block/71 heads with 60k miles. It was using a stock stg-1 cam, stage 1 springs, stock rocker arms, hogged out manifolds, recurved HEI 14-33, and (at time of failure) an old Edelbrock intake w/ 800 Quadrajet on pump gas. Driveline is a race prepped SwitchPitch TH400 (stock stalls), 3.25" /.125 driveshaft, 85GN 8.5 posi rear 3.42, 275/65/R15 tires. The Wagon is a 79 Century, roughly 3250 lbs with driver/seats/street junk. This is the first time in 14 years that the wagon has been off the road. I had plans to pull her apart this winter anyways and do a full race buildup on my 76 block. I'll just call this Motivation... :grin: :grin: Gary/Roberta, I think the photos may be a little decieving, I noticed yesterday when shrinking these images that the light reflection makes them look odd... The bores were measured in a heated panic 3 days after I bought the block and was clued in by a buddy. They were OK from what I could tell at the time... o No: I'd kill for advice if anyone wants the full size pics emailed to them... Jim/Kerry, Yes, there is definitely a broken connecting rod in there, its visible right below the hole in the cam. I think you're also dead on that the majority of the lifter damage occurred during cam failure from the rod. I've got 2 questions to consider for the next one (if I can ask your advice): 1. It didn't stop all at once, it began, ran for a few minutes, and then punched the pan. The problem started as a rattle, with my helmet on it sounded like I drove over gravel ath the end of the run. Definitely not a rod knock though, distinctly different. When I got back to the tuning area, I thought it was just a bolt rattling in one of the fenderwells. A few seconds after opening the hood I knew better... it made a lound bang, rattled *much* heavier, and then blew through the oilpan. I ran like hell and shut it off right away after that. Could this have started with a broken rod bolt that led to the full failure? 2. When I pulled the intake/valve covers I found a single broken nylon button and a rocker arm that had broken loose and was flopping around. Could this button have broken during cam failure? My curret guess is that the rod failure occurred after some part of the lifter assembly fell into the crankcase and caught the rod, OR that the rod bearing or one of the bolts let go, follwed a minute later by complete meltdown. (either way, I *should* have shut down as soon as I heard a rattle) ...any advice is appreciated! Hopefully this prevents future meltdowns for everyone!
...one more thing on core shift, I checked it using some PVC pipe about 6" long inserted into the lifter bores. Shows right away how asymetrical they are. Also checked wlee thickness along each unit using a caliper... ...what's the approved method?
I.ve seen this before in my buddy's truck that had a 455 in it and it had a rattle in it just before a rod let go and wiped out the cam and block.Your's look's just like his.Side load and big spring pressure from a big roller cam's breaks lifter bore's not small hydraulic cam set up's.Chris
It's not bulletproof but I had my block magnafluxed AND sonic tested before any machine work was started. Here's a picture of a badly shifted block. I still have it but wouldn't use it for anything but a low rpm cruiser.
how can you tell if you have a good block?? any thickness required?? is there a good year block to go for? THANKS!!!!!!!
I was thinking since I still have 4 cylinders working I'd go find a Honduh for it... :laugh: Hmmm, I'm having my 76 block sonic and MPI checked here within the next few weeks in preparation for the rebuild. I've done my little pipe/measurement check already and am reasonably satisfied... I'll also be checking wall thickness along the cylinders, although the honing is still fresh, it was a 20k mi. block. Gary, can you suggest any further tests?
