sad story

[james cear]

The engine on my top flight '63 340hp, had a catastrophic failure this weekend, and the numbers matching block went with it, cracked. The tear down to determine the cause is underway. Since I intend to keep the car for now can someone recommend a source for a direct replacement engine? I see several listed in Driveline and Hemmings. Any recommendations or comments would be appreciated. ( I've had better Labor Day weekends).

[Chuck R.]

Re: That stinks Jim

Where abouts did the block take the hit?

Chuck

[Patrick H.]

Re: sad story

James,

If you just want to get it up and running quickly to drive, I'd think about a GM replacement short block or long block. Paint it orange, install you intake, carb, etc. and get a warranty to boot. 20 years from now someone can hunt for a correct one, or it will give you a while to search on your own.

If you want to look for a "correct" engine, check out Engines Limited: http://www.engineslimited.com

Patrick

[Clem Z.]

Re: sad story

this is why i tell corvette owners with orignal engine cars take out the orignal engine and put in a "crate engine" like doc posted BUT do it before you distroy the orignal engine.

[William C.]

Re: sad story

Depending on the meaning of "catistrophic" the block might be saved. What exactly is wrong?

[Loren L.]

Better figure out the cause before

you repeat it on the next motor......

[Duke W.]

Re: sad story

This is very unfortunate, but I want to take this opportunity to WARN owners that the early SB small bearing connecting rods are WEAK!!!

An inproved design small bearing rod went into production circa 1966, and I consider this okay for up to 300 HP engines, but SHP/FI engines should be rebuilt with even higher strength rods such as the Crower Sportsman. They are cheap insurance!

If you rebuild a pre-'66 SB that still has the original rods, THROW THEM AWAY, and buy a new set of the late design rods for up to 300 HP and Crower Sportsmans for SHP/FI.

With proper rods these engines are essentially indestructible as long as you don't run them out of oil

Let us know what broken parts you find, Jim, and remember that the block can be welded up depending on the severity of the damage.

Duke

[james cear]

Re: Thanks

Thanks to those who responded. Postmortem: looks like wrist pin backed out or the bottom of the KB piston failed. One hole punched in the sleeved cylinder wall which may be slavagable with a complete block inspection. The "why" it happened TBD. Thanks Duke, for the recommendation on the rods for the next rebuild.

[Allan Wicklund]

Re: Thanks

Hi Jim, Poster who suggests replacing the original, correct, coded engine is a wise person. Chevy small blocks are an easy obtain and so nice to work with. As you and all of us know, on a "Top Flight" car the original # engine, etc. is big money stuff! And don't we just love to put our foot in the bucket now and then! Al W.

[Duke W.]

Re: Thanks

Can you give more information? KB piston? Does that mean Keith Black? Is this a forged or cast piston? Press fit or floating pin?

Duke

[Allan Wicklund]

Re: Thanks

Duke, I was present for the "Teardown". The wrist pin was a pressed fit stock small journal rod mated to a cast aluminum piston. (Maybe Jim will add the make). No obvious reason for failure. Looked as if something had grabbed piston while it was up high and held it there while the wrist pin traveled down and out. (No reason found to substantiate this thought). No signs of an old crack working towards failure either. What was left of the piston looked just fine as did the rings. Our feeling is that for some unknown reason piston just failed. Motor had 50 clean uneventful miles and was at low RPM, (below 3000, parked) when this happened. It has a forged crank which is saveable and we may be able to resleeve the cylinder to preserve the correctness of this car. As is always the case the reason for failure is needed to prevent re-doing the same thing again. Will be checking for more posts, Thanks! Al W. BTW,when the wrist pin dumped it punched a hole in the existing sleeve the size of four or five dimes. All sleeves were checked for tolerance and found to be correct, prior to assembly.

[Duke W.]

Re: Thanks

Do I understand correctly that this engie had ONLY 50 MILES on a fresh rebuild???

Tough for me to do a "failure analysis" without looking at the actual parts, but a failure this early is what is called "infant mortality" and is indicative of either a defect in a part or an assembly error.

Duke

[Klaus Friedrich #33362]

Re: Thanks

Gentlemen,

I think the engine is repairable. It costs a lot of money and work. But good machine shops can add a seperate sleeve into the damaged cylinder. Happened to me in 1998 after doing a frame-off resto. On the first travel to a meeting the engine failed.

Klaus Friedrich
#33362

[Clem Z.]

Re: Thanks

it is possible that the wrist pin froze in the pin hole in the piston and this will cause what you saw. this could have been claused by lack of lubrication on assembly or too tight a pin fit. if the pin backed out of the rod this was caused by not a enought interferrence fit in the rod.

[Allan Wicklund]

Re: Thanks

Yes folks, only 50 miles by an extremely meticulous, knowledgable machinist. First time out with this fellow for Jim or I. We've both been around enough to evaluate someones ability and I feel that this guy is the real deal in all respects. That said, I'll post some pictures, or email photos to all interested parties to help solve this mystery. (In a day or so). I'm trying to give this fellow some room. What is obvious is that the piston to wrist pin connection failed some how, some way. BTW, oil pressure was at 50 and above and correct oil level was in place. No audible sounds such as piston slap etc. prior to failure. Jim did report a sound such as exhaust leak prior to failure. Cylinder head, (Combustion chamber), shows no sign of contact between valve or piston to head. Question: Way out thought! If intake valve did not open would the suction created exaserbate an already defective piston component? I know I'm reaching!