Cracked tappet guide

Bottom End (crankcases and crankshaft)
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Snake33
Posts: 33
Joined: Wed May 26, 2004 6:23 pm

Cracked tappet guide

#1

Post by Snake33 »

I have some cracks around the screw holes on one of my tappet guides. I asked around about repairing it and have had conflicting answers. I have been told that since they are cast metal they can't be repaired. I have also been told that they can be heated up and sort of brazed. Anyone have any experience or definitive answer on this? As you can imagine, I haven't been having a lot of luck finding an original replacement that is in good shape.



panfreak
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Re: Cracked tappet guide

#2

Post by panfreak »

Hey Snake,
If you really want to try and fix it:

I had an ear on mine that was cracked too, and although I knew cast material is not very forgiving, I wanted to attempt a repair anyway before throwing in the towel. I usually shy away from brazing, so silver solder was the order of the day, with a small tip on my welding torch so as to control the heat a little better. I was very careful, and afterwards used a countersinking bit in the drill press to clean the hole perfectly round again (do a good job). Thinkng that overtightening would more than likely take me back to my original problem, I was cautious not to do this, and used a gasket sealer to prevent leaks. Worked fine for me, no more crack and after a little paint you can't tell.

Metallurgists will cringe, I know that normally cast can't be welded, but desperate times call for desperate measures, what can I say? At least it wasn't JB!
Chewy.

Snake33
Posts: 33
Joined: Wed May 26, 2004 6:23 pm

Re: Cracked tappet guide

#3

Post by Snake33 »

Panfreak,
That is encouraging. Thanks for the info. How long has this repair held up for you?
Snake

panfreak
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Re: Cracked tappet guide

#4

Post by panfreak »

Hey Snake,
4300 miles and counting!
I don't know exactly how bad yer block is broken, but mine only had a crack right on the corner where the metal is thinnest. I didn't bother grinding a fine valley in the crack like I would do under normal welding conditions on something thicker, but I took a lot of time (as always) ensuring everything was CLEAN as hell, ready to accept the solder. A little paint or chrome will contaminate any kind of welding. Good luck.

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