Has anyone ever put a new set of dowel pins in a type 1 and broken them? We were setting up endplay on GT350Mike's engine. We put them in, tapped very gently with a small hammer, and slid the flywheel on. We put the gland nut on by hand and torqued it to 75 ft lbs to check end play. When we pulled the flywheel back off all 4 dowels where broken off. I've done this multiple times and never had this problem. They all didn't seem to break at quite the same depth. They were fun to remove. We tried drilling them with some HSS drills and then a cobalt drill. They didn't even make a mark on them. We ended up building up a weld on the end of them to be able to grab them. I was just wondering if anyone else has ever seen this.

John

I had a 8 dowell flywheel one time that the 4 extra dowell holes were drilled a little crooked one time. It caused those 4 pins to get mis-shaped, but not break. Maybe you got something similiar going on?

Some dowell pins are longer, designed for cranks with deeper dowell holes, usually aftmkt cranks. Could you have the longer ones in a regular crank and are crushing them with the gland nut? Wouldnt really think so at 75 ft lbs,... but maybe?

Larry

I have never seen this. Mystery 4 sure.

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Buy the best and cry once.

i had a old friend have this happen to him i gave him a new crank and he broke one or 2 off i am not sure i got the crank back but havent looked at it since this happened your buddy is definetley not the only obne this ahs happened too

I'm guessing these weren't hardened correctly. This is a factory crank and flywheel with only the 4 dowels. Were going to try again tonight. I'll let you guys know if we figure it out.

John

Yep, that is my guess. Dowel pins should only be hardened to a short depth from their surface and not all of the way hardened.

You can destructively test some samples, but wear safety glasses. They should bend somewhat and not break when you push on one end with the other end clamped. I do not suggest a hammer, but that is what some people would do.