The Jalopy Journal
Discussion in 'The Hokey Ass Message Board' started by swade41, Sep 26, 2011.
Thanks TR, that's what i'm doing.
I was surprised to see antifreeze in there.
Pump gas and 4.11 gears, I was planning to drive it for ice cream once in awhile, so much for that.
Unless the cam being to far advanced or retarded and you had Valve-to-piston issues...no, it wouldnt cause this.
This is my take on this too.
There's no valve marks on the pistons and electrodes are open so no collision that way.
Phil, I now see something quite disturbing/interesting. A ridge at the top of the cylinders? These are NOT freshly honed bores are they?
Just drawing a conclusion from the photos would not buy into the "detonation" theory, just doesn't have the "right" look!
List all the parts and clearances if you can?
A 10.5:1 aluminum headed SB will run on 91 with no issues! May even run fine on 89!!! (Due to the heads and the "Ethanol" mix in the N.Y. pump gas)
If they are the KB "hypers" and the (top) gaps are tight, that one photo of the piston with the top separated at the pin bosses, is exactly what happens and it happens in that rpm band you stated! This was mentioned above!
Below are shots of some "detonated" pistons!
Good luck with the "fix"!
Thanks, Gary in N.Y.
P.S. You MUST go the "extra mile" with these type builds, bolt it on the dyno, and "close-in" on the tune up while in the dyno room!! There's no other way really! Even moreso with a "dual-quad/tunnel-ram" deal!!
Everything was fresh, the block was taken to 60 over and the new crank,rods,pistons as a kit. He said there was little downard scrape marks in the very top of the cylinder walls where it is black. It was only like the top 1/8 inch of the bore, but said that was indication of detonation too.
That number two piston did have a break in a V shaped pattern on the side of the piston like that first picture.
Can't tell you why but my opinion would be a piston let go first. To many other things to see but cant and looking at a picture its hard to read every thing just right. Plugs are not lean so I cant say its detionation. Any way you look at it you need to study all the other things and never throw a distributon in and only test it to 3000. Sorry you had the loss and I hate to see a destroyed motor especially a fresh built. Good luck on your nrxt one and please pay attention to the little things.
Phil, when you timined it dd you rev to 3000 and over to see if it stopped advancing?
Post some clear pictures of the spark plugs showing the center electrode, ground strap and porcelain.
If you had detonation the spark plug will have small black specks.
Maybe it's the picture but that piston pin looks to short?
Some things to consider with your next motor:
Mark your balancer at 30 degrees or so, when you check your timing, bring the RPM up until the mark quits moving up. That way, no matter what the advance in the distributor, you not exceed what you think is safe for the motor.
The Hypereutectic pistons do not have ANY reserve strength if you are going to get into detonation. As was said, we have all seen plenty with the bottoms of the pin bosses pulled out and the block get sawed.
If it was detonating, the upper rod bearings with show it, as would the "pepper specks" on the spark plug insulators as was mentioned.
Don't be afraid to advance your cam, just make sure you have Intake valve clearance as it will close it up. It may put your RPM range where you need it.
Take care, K
The piston laying in the valley...could you take a good picture of the bottom looking at the pin tower, and another picture from the side at the ringland Intake pocket side...???
This is what is going to tell the most from the info you have given so far...
That would be the fuel / carbon trace above the top ring...
Sir, 30 plus years of race engine building, thank you I understand that. This to my best knowledge was a fresh build, even the finish of cylinder bores doesn't look correct. Theres way too much to this story than we dont know. I'm sure the O/P is a great and very honest guy. Something is very fishy. Do they look like new rods to you or anyone else here?????????? I thought I read the engine had a new crank, rod, and piston kit installed in the rebuild. I'm done with this thread, something just doesn't add up. I have a pair of 632 BBC's to tune in the morning, I dont have anymore time to speculate about this. I TRULY wish Phil the very best, TR
Phil I'm not buying the detonation excuse either.
The tops of the pistons as well as what's left of the plugs look fairly normal, a tad lean, but fine none the less.
I'm also not buying the ring gap because the cylinder walls just aren't showing it.
When Oddy's did my first build, Billy put the Kieth Black Hyper pistons in and I had no problems. In fact when I had Oddy's redo the engine, for more power, I sold that rotating assembly and the tops of the pistons didn't look too much different than yours. If anything my pistons were a little darker on top.
I'd say that your problem lies with either a defective piston or too tight of piston pin. What ever happend... happened at the piston pin point of the piston.
Either way your engine builder should step up to the plate and go to bat for you.
Because it's not detonation!
TR is correct no sign of detanation on plugs
a possable cause
a piston or the set may have been dropped possably before you receved them
with out having this in my hand to examin its just a guess
ben a engine builder since late 60's quit racing in early 90's due to life chang
I agree with alot of others that detonation had nothing to do with this. Some say that there is no scuffing on the walls so that ring butting could not be the problem, I don't totally buy this as the bad cylinder is so beat up that one cannot tell if that cylinder had a problem or not, and it only takes one. It sure looks like the piston was either defective or was pulled apart at the pin to me.
The engine is at the builders so I can't take any other photos, I told him to save the broken parts, that's the best I can do.
TR he told me today when I ask him what was in the kit was crank, rods and pistons. I really don't know the specs on how it was assembled, I dropped off money and he built the engine.
I originaly went to just get a 350 that was 40 over freshened, the crank was spun so we went with the stroker. I told him that I liked how my buddy with the nova engine ran, he had the same tunnel ram and carbs I had. So he built a duplicate of that engine from the cam to the heads, to the stroker kit. To be honest on the paper work for the work done it just had parts and prices, not specs.
Man that makes me ill just looking at it , really sucks ! I'm thinking how much a bunch of bent valves in my GTI bites , I guess it could be worse . Good luck with the new engine .
My buddy Bob was working the timing light and throttle, I was turning the distibutor.
He stepped up and said if it was something he did he would pay for the damage, I didn't say anything to provoke that either. He stands behind his 32 degrees at 3000 and he did blip the throttle a few times during the process.
He's the guy with that 427 powerd gray 56 chevy, just had his engine redone himself.
The rest of the engine really needs to be gone over to try to locate the cause. I'm not seeing detonation, but a failure in the pin boss of the piston. Maybe the pin clearance was wrong - has to be something to cause that piston failure. Hopefully your bilder will step up and work with you to resolve it. Hope you find the issue.
The rods look like old used stock rods to me, not new?
I don't even think the rod bolts have been replaced for ARP bolts...
i'm sure it's not detonation
if press fit pins/rods could piston been damaged during assembly???
piston siezed in bore due to?>breaking piston &cly wall
core shift in block causing failure/thin cly wall
if it was detonation that bashed that piston to death there will be some hammer marks on the topsides of the rod bearing too.
I'm 99.5% sure that detonation did not kill that motor.
First thing i wanted to see was the plugs- like all the others here-i vote against detonation-
Do yourself a favor- gather all that junk up and take it to another engine builder and drop him some dough to go through it- tell him about the parts you believe it to have (new rods, & such) get his opinion on it so that you know you're not just having misguided guesses.
A motor for a street stock where there's a claimer rule is usually made out of junk that's just good enough to last for the power band the car uses on the track, if the guy built it like he builds those, who knows what you got in there.
Kind of a guess on my part, but maybe things got way lean, combined with possibly too much advance, things got "way hot way fast" in your 1/8th mile run, stuck a ring/piston and carnage....
I don't know why, but I look at that and I just think really hot pistons, The carbonization of the pistons near the intake valves might support my position, (fresh fuel/air hitting really, really hot piston tops causing pre-ignition even before compression.)
I think maybe for things to get that hot that fast, there has to be a lean condition.
You may not want to hear this but I think your engine builder took complete advantage of your ability in trusting him. Those rods are not new and his reasoning for the failure is weak at best. IMHO lick your wounds and move on to another builder and learn from your mistakes. Take the time to check on the build while it's being done to insure that said parts are being installed. If you can't tell by looking , then take a friend along that can. This kind of thing happens way too often due to trust. Good Luck on the next one.
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