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[429CJ]

I took apart my 460 that blew up, I found that a wrist pin had slid out of the rod and wedged against the cylinder wall(can you say ouch) Well as I took several of the other rods and pistons out, the wrist pins just fell out!!!! Here is my question: I bought a new set of trw forged .60 over pistons with pins. I'm having them hung on my 429 rods which will be bolted to my 460 crank. Has anyone ever heard of the pins just sliding out? I did not build the motor, it was in the boat when I bought it. Is this a machinist flaw or am I going to have the same thing happen with the new pistons and pins????? Is this a flaw in ford motors.

[spectras only]

429CJ,sorry to hear about your mishap.Yes it is a machinists flaw.All 460/429 have the wrist pins installed with the rods slightly heated ,and the piston sliding on the pin. The pins should never slide out.You can get aftermarket pistons with floating pins,and circlips.

[429CJ]

Thanks for the replie Spectra. I think I'm just stressing on this motor, don't weant it to shatter like the last one. Have you ever heard of a pin coming out like that. Actually there were three pins loose, they fell out in my hand. The sad thing isd the motor only had thirteen hours on it. The guy I bought the boat from said it was brand new. If the pins are installed correctly they should not come out, and I should not have any problems? Once again thanks for the replie

[058]

CJ, This was a result of using bad rods in the engine. The pin hole was too big for press-fit pins. The rods should have been replaced and the machine shop should have caught it. It isn't a "Ford" problem as this can happen to any rod. When you build the new engine go to full floating pins.

[429CJ]

Only one problem with buying the full floating pin pistons, I already bought new Trw forged with press fit pins. Think I'll have a problem if the machine shop knows what their doing?

[058]

If you reuse those rods I think you will have a problem, the holes are too big. There is suppose to be an interference fit between the pins and the rods. I don't have the specifications for the small end of the rod handy but any good machine shop can tell you what its suppose to be. The 460 in my Lincoln had a pin move and it took out the cyl. wall, engine only had 40K on it. The engine was rebuilt by one of the "budget" rebuilders that reuse as many of the parts as they can. I didn't know this at the time otherwise I wouldn't have bought the engine.

[spectras only]

429 CJ,the pin/piston interference fit is 0.001-0.0015inch.One method is to use a mandrell and press,the other is slightly heating the rod.You have to work quick and precise to get the pin in the rod centered.The piston will absorb the heat quickly and if not centered you have to reheat the rod again for repositioning.When I do an assembly, I put the pistons in the oven to curb this problem by having them expanded.It doesn't require much heat.

[mister460]

Yup, the machine shop that hung those pistons messed up bad or you spun it so high that it stretched the rods(not likely)! It should take at least a ton of pressure to press those pins out. DO NOT reuse those rods! They're only good for paper weights or hammers now. Just make sure that you use a good machine shop and you shouldn't have a problem. The only times I've seen the pins walk out were on full floating pistons installed wrong/or with those stupid c-clips and on motors spun to death. Use the spiral clips if you ever go full-floater.
Oh yeah! Don't use rods that came with square bolt heads. Only use the ones that had the oval bolt heads. They're much stronger!
[This message has been edited by mister460 (edited August 05, 2001).]