Help

ken35 · Apr 10, 2011

Help Borrowed my brother in laws tiller and now it is broke.

It is an older Craftsman rear tined tiller 5 hp. The engine started knocking so I shut it down. i let it cool down the took it apart. What I found I had never seen befor. The bolts holding the connecting rod to the crank had backed off one fell out when I touched it. The crank is ok but the end of the connecting rod is scored. Now my question is , is there a bearing between the connecting rod and the crank and if so what happened to it.

Muhammad · Apr 10, 2011

Welcome to TBN.

VE6IAZ · Apr 10, 2011

Hi Ken35
If it's an aluminium con-rod chances are it won't use a con-rod bearing. That is to say the con-rod is the bearing. If the rod is not to badly scored you can very carefully clean up the scores with some fine emery cloth (don't get carried away with the emery cloth)and assemble it and check it for round using an inside micrometer. Then install it on the crank using some plastigauge (available at your local automative supply store) You will need to know what the clearance before you get the plasigauge so you can get the right one. Check the engine manufacturers spec for the right clearance. If the clearance is OK, clean every thing up and assemble the engine. I would install new con-rod bolts because the old ones may be streatched. Use a little blue loctite (blue-berry juice)on the con-rod bolts. Remember to clean everything with varsol and dry it before assembly. Put some engine oil on the con-rod bearing before you torque the bolts up. Hope this helps you. VE6IAZ

irvingj · Apr 10, 2011

Ouch, bummer! Sounds like it was just waiting to happen!

I'll be inetrested to hear how you make out. And- welcome to TBN!

955Lincoln · Apr 10, 2011

Buy a new connecting rod and be done with it. They are not very expensive. Check the piston and rings while you're at it. I'm sure the BIL wouldn't mind forking over a little money to replace some worn parts.