Everything said here is correct, and it very well may be the cause. The reason I am leaning towards pin clearance has more to do with human nature than it does with what I have observed in the photos. Swade has stated this guy has built several roundy-round motors with hypers. A guy is not going to get by very long building engines with hypers if he is running excessive wall clearance, or insufficient ring end gaps. He will be blowing them up left right & center. He can skate by for a while if he is not checking pin clearance, but eventually he will get burned. I think Swade has had the dubious privilege of accelerating his engine builders learning curve. Oh, and Traditions, as far as your little spiel as to what we have or havent done with pistons, when I was young (roughly 30-35 years ago), I worked for a guy who built MP and gas class motors, so that should clear that up. And I flycut valve reliefs in a drill press. Oh, and one more thing. It is quite possible that he honed too much clearance into #5, and thought "It'll probably be ok, and no-one will know, I'll just throw it together."
He asked. I know he thought it was a rhetorical question, it wasnt. And I am pretty relaxed. Got my feet up on my computer, and my shoes off...
One of the things we all have to remember is that with todays web communication comes an inability to interpret what the speaker is saying. There is no eye to eye or face to face communication. Simply the typed word. Which can be misinterpreted because there is no tone, inflection or volume to gauge how the sentence was delivered. I personally read all entries as being neutral unless the conversation becomes personal or degrading. On the other hand, this freedom also allows some people to be real jerks with absolutely no censure or social punishment, i.e. "keyboard tough guys" who literally threaten, badger, or demean others because they would never do it in real life. Or face to face. Such is the way of the web. John
I had a very good day today TILL i read this post.Man i hate that for you,that dont just suck it super suck,s.Reading this sure makes you humble knowing any time or place this could be you. Good luck and realy hate this for you...............YG
thanks man, I just hope to rebound, things have been tough with the girlfriends health, t-bucket running like crap and this, got to get better.
Hopefully you guys can see the cylinder finish in these shots, kind of hard to take a picture of and of course that #3 with the hole in it.
Looks like the top of the bore is reamed to big with a ridge reamer. Also the honing looks like it's done with a hand drill, not a nice and consistant cross hatch. Possibly he used a block that already was .060 and removed the ridge, honed it and called it good? And if the block previously had forged pistons the bore would be way to big for the hypers... Beter have someone check the bore size and pistons so you know how much piston to wall clearance it has!
Referring to the pictures in entry #67. The pictures of the machined block appear to show fresh boring, decking and perhaps finishing honing. Again the shop is well lit, floors are clean and the area appears to be relatively uncluttered. Even the cleaner cabinet is clean. The gentleman in the background in the first picture is heavy set with glasses perched on a graying mop of hair who seems both surprised and interested in being part of the picture. All are signs of being the owner, operator of the shop. The extra weight, too many late night hamburgers & burritos. The glasses, have you ever seen a machineist who didn't wear glasses? The gray hair speaks for itself. All of the above would indicate that if those were pictures of swade41's short and long block then I can say with confidence it was not a dingle ball rebuild. Sorry Mr4Speed, your argument is invalid.
That was the same block I dropped off, a 010 020 block and the numbers on the back of the block were the same. It was a 40 over short block with the guts in it.
Here's a cylinder in the slant 6 that I am assembling for my HAMB-style dragster. Stock bore, just honed and the deck is surfaced (by a shop, not by me). Your hone job doesn't look very good and it looks like no cut was made on the deck. The longitudinal scratches are a surprise in a new rebuild too. I'd take the block, pistons, rods and crank to a trusted friend who has some measuring devices and check everything.
My first thought on seeing the block pictures was no cross hatch. Second was the amount of wear on the thrust sides of the bores. I'd guess that the pistons were too loose in the bore. A cast piston loose in the bore will break. If detonation was the problem, there should be a lot more signs of the pistons getting hot. There should be carbon from burned oil on the bottom of the piston head.
Your pictures of the engine on the stand at the shop (before the carnage) sure look like the block was decked. There are a couple pictures of the block after the breakage that clearly show the block is not decked. Are we looking at two different engines here?
The angle of the crosshatch should be 45 degrees, in the pictures i don't see anything that looks close to 45 degrees. I see nothing in the pictures that indicates a fresh machined bore and hone job.
In the pictures on page 4 it looked to me like the cylinders where bored but not honed yet. So maybe bobw is right and they are two different engines???
So maybe the theory that excessive cast piston clearance + cold engine = shattered piston has some validity? In another forum there was much discussion about proper warm up and maintaining that heat in the engine from initial fire up at the strip and on thru the staging lanes. That means 180 degrees for the coolant, the trans equally warmed up and the rear end as well. The perceived loss of an extra tenth of a second for a cold engine doesn't stand up. Circle track cars are always completely warmed up before competing. I think the same should apply to amateur drag race cars. It is quite possible that that short block would have lived in a circle track car if only because of proper and thorough warm up procedures. One of the other forum's participants said that he used more fuel to keep the engine warmed up to proper temps than for the actual racing itself. John P.S. Phil thanks for the pm, I try to keep things light.
Severe detonation to cause that much damage will show on the pistons plugs and head gasket fire rings. I see none of that. A failed piston is sure possible but the bore walls look thin. Core shift and the fact that it is a stroker could indicate that the bore failed. A sound block will tolerate detonation that will pin point a weak point some where else other then a block/piston failure.
Phil, I noticed that in the other thread you said that the temp was 180 degrees after the run. Do you remember what the temp was before, during and after the pre stage burn out? And perhaps what the temp was at the starting line? Also what type and weight oil were you running. And what type of cam? Hydraulic, solid lifter, hydraulic roller or solid roller? Last question, how was the engine broken in and how many miles were on the engine at the time of its' demise? Is your break in philosophy "break it in hard so it will run hard". or a little more gentle to let things work themselves in and let the parts get to know each other. John
The time trials were about an hour apart and the same for the race rounds, maybe even shorter time between. The temp never got over 190 and was somewhere between 160-180 on each pass I'd say. The break in procedure was like any solid lifter cam, 20 minutes at 2000-2200 rpms. This was done in two sessions though, the first was twelve minutes when the temp got to 220, let it cool down and did it again for another 10 minutes. Next day set the timing at 32 degrees at 3000 rpm and let run to try and burp the radiator. Next day drive around the corner to load on trailer, at the track I did not race that day but drove the car around the pits a few times. I took the car down the return road to weigh it and also try and launch it a little to see what happens. That was the first time I noticed the miss in the engine under load. The next week took the car for a front end alignment, after the alignment (good friend doing it) it was driven around the block to test alignment. Next day at the track for the 5 passes before it blew, all passes were shifting at 5000 rpms. Today while at the shop he was using a machine that heats two rods at a time, just the small ends. Once from the machine the pins were slid in like a hot knife in butter, so much for the pressed pin theroy here.
Looked normal color, he said the machine takes the place of heating the rod with a flame and blueing the rod.
Putting pressed rods on with a heater is fine if done properly. I question why this type of race car, a tunnel rammed gasser style, would even have pressed pins though! When it is all back together I would definitely dyno it as some have mentioned. I didn't see where the brand of piston was mentioned, were they Speed-Pro or KB hypers?? Harry
My opinion, You didn't over rev it, it didn't lean out, pin looks good. I think the piston just came apart. peace
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