Author Topic: .061 Big Mig with bent rod (Read 511 times)

Frank Donnelly · « **on:** April 08, 2019, 10:55:39 AM »

I have a .061 Big Mig with a bent connecting rod. This was the result of hydraulic lock when applying a starter motor. I ordered a new rod from NV Engines. In order to remove the old one the wrist pin needed to be pushed out of the piston. The pin was retained by what looks like a cross cut over the hole in the piston. This left some flashing at the point of the cuts preventing the pin from sliding out. I cleaned off that flashing with a #11 x acto blade and was able to slide the pin out.
Here is my question: Once the new rod is in and the wrist pin reinserted how do I retain it? Or is it even necessary? I would think it would drift out and score the cylinder wall. Any tips or suggestions would be greatly appreciated.
Thank you,
Frank

Fredvon4 · « **Reply #1 on:** April 08, 2019, 11:11:25 AM »

You must RE STAKE the piston wrist pin hole that you opened...delicate procedure, need some good proper sized Vee Block ( can make from wood the piston is fairly soft material, just need some stable materiel) to support the piston on it's side with hole to be staked UP.

I used a short length of small diameter Music wire (harder than the piston) laid across the hole in same orientation of the first staking and gently Tapped with the Peen side of a very small brass Ball Peen hammer....distorted just a few Thou into the hole...then test fit piston to cylinder to see If I had a burr raised and I did.... smoothed that down with an arkansas stone ( was already within reach) 600 or 800 grit paper would have worked

Frank Donnelly · « **Reply #2 on:** April 08, 2019, 05:58:46 PM »

Fred,
Thank you the quick reply. I will give that a try.
Frank

Author Topic: .061 Big Mig with bent rod (Read 511 times)

Frank Donnelly

.061 Big Mig with bent rod

Fredvon4

Re: .061 Big Mig with bent rod

Frank Donnelly

Re: .061 Big Mig with bent rod