I race primarily at East Lansing, and so far I’ve gone through three sets of engine mount clamps this season. They and the bolt wear so rapidly that I have to use a mallet to drive a ball-end Allen key into the mount bolt to adjust the chain. I’m using the magnesium ones that go all the way around the tube.
Did my track just get much rougher, or do they burn up for everyone else?
I go through at least 1 set a year per kart I’ve forgotten to tighten one set fully and it shredded itself to pieces and the Allen bolt basically welded itself to the clamp. But in general 1 pair per year per kart, (Provided I don’t forget to tighten the bolts fully).
Have you tried the odenthal style that wedge between the frame rails and sit flush on the bottom? I was skeptical until I started using them. Now, I wouldn’t own anything else.
I quit using allround type clamps as on hitting something they would twist and put a dent into the frame tube. Went to flush type or wedge type like Derek - great solution. Havent had any issues with clamps after that.
But continued to have issues with motor mount clamp bolts. The bolt head was flush - at same level with the aluminum clamp - tarmac kept hitting it. The allen key didnt go in as the burs were formed.
So as a solution machined 2-3 millimeters off the bolt head so the head sits a bit deeper. Now its impossible for bolt to touch tarmac. The clamp is always the lowest point
After this mod have never had any problems getting the key to fit or getting the bolt out
Lathe and carbide tooling would do it easily, or if you don’t have access to a lathe, hold the bolt in the chuck of a cordless drill and spin the bolt head in the drill while holding it up to a bench grinder. That will keep it fairly consistent as you’re grinding it down.
8.8 10.8 12.9 bolts are relatively soft materials to turn. Even hss stuff is up to it - Just lower rpms a lot compared to carbide bits, use a sharp tool. Adding constant coolant flow keeps the bolt from hardening/tip burning up if doing a lot of material removal - for example drilling a hole through the whole bolt