Broken wrist pin?

[Todd Simpson]

How common is this and what might cause it? How does oil get to these parts?

[Wayne 962]

Never seen one broken - never heard of one breaking. I think the rod snaps and breaks before the wrist pin does. Or, the piston breaks at the point where the wrist pin is inserted.

-Wayne

[TimT]

Dont look!! scary pic...

Piston breaking at wrist pin

[TimT]

Also, oil gets to the wrist pin via a squirter that is installed in the case. the squirter opens at 3 bar oil pressure I believe, and a stream of oil is sprayed on the underside of the piston..

the squirters werent installed to lube the wrist pin though... this was mainly accomplished by oil just being flung around the case... the squirterswere installed to lower piston crown temps...

I notice in your sig you have a 71T... this could be on the bubble for having squirters...

Some other engine gurus actuallly drill a hole in the connecting rod from the rod bearing to the wrist pin and pressure feed the wrist pin....

A guy who builds 1500HP engine told me that trick..

[Todd Simpson]

Motor is a rebuilt 3.2, and went back to the builder to remedy this problem.

I wondered if the rod was drilled, interesting idea. This motor does have a center drilled crank.

[TimT]

I just saw the'71T in your sig....

so if you have a 3.2 you have the squirters..

The fellow that told me about drilling through the rod to pressure feed the wrist pin builds drag motors...1500 hp etc..

[Todd Simpson]

Wanted to clarify...the wrist pin bushing cracked. It was knocking pretty loudly around 3K RPM.

The shop that built it tore it all the way down, redid the rods and put it back together. All is well so far.

[Wayne 962]

Originally posted by Todsimpson
Wanted to clarify...the wrist pin bushing cracked. It was knocking pretty loudly around 3K RPM.

Got pics?

-Wayne

[Todd Simpson]

Nope...