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linusb212

Stripped drain hole with complications

11 posts in this topic

I stripped my oil drain hole last oil change. I took my drain bolt out to examine the damage. I'm sad to say that I think things might be a lot worse than a simple stripped hole.

When I took the bolt out, it came out with lots of aluminum

threads...which I figured would be normal for a stripped hole. Also on the top half or more of the bolt around the threads was a copper colored metal that seems almost fused to the bolt. I'm thinking that maybe there were heli-coils or similar device used in the past and it has come out with the bolt?

The big problem I see is that when gazing up into the drain hole, there is a portion of where the threads SHOULD(!) be that there is just a hole! Almost like it tore a part of the thread wall out. ARGH! It is maybe 1 square centimeter roughly. I'm pretty sure it ain't supposed to be there.

Here's some photos (full size they are large...500k a piece to retain detail):

http://home.sc.rr.com/linusb212/main/hole/

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Helicoil will fix it did the same thing to mine and all is ok

a 12mm x 175 pitch kit is the ticket

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Yep.... Thats a broken shoulder. Prepare to replace the case half. Just inserting a time Cert or a helicoil will not strengthen the wall, just push it out further, more than likely causing metal faiure then engine failure due to FOD damage.. It appears to have been previously drilled out to the limit and helicoiled.

Bonzai :thumbsup:

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Have a machine shop machine you an aluminum plug out of a lathe, then have them weld it in there. Drill the plug and helicoil it. Thanks what I did, and make suer you let the helicoil sit overnight with red loctite.

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Yep.... Thats a broken shoulder. Prepare to replace the case half. Just inserting a time Cert or a helicoil will not strengthen the wall, just push it out further, more than likely causing metal faiure then engine failure due to FOD damage.. It appears to have been previously drilled out to the limit and helicoiled.

Bonzai :thumbsup:

I'm looking at getting a new case then. Looking at the online parts catalog, it appears that you have to buy the crankcase assembly. It would seem like you should just be able to buy half, eh? The assembly is priced at $300.

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Dude, just have someone machine an aluminum plug like I said. I had this done 6 months ago and works like the day it was done.

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When i bought my 426 it was stripped, just like the picture. I went to the local automotive shop and got a piggyback drain plug. Its a bolt with a smaller bolt in it. I tapped it out and JB Welded the thing into place. It has lasted about 2 years now. No problems whatsoever. The only thing is that its SAE not metric...big deal, need a 5/8 rather than a 12mm...thats it, everything works fine. You don't need a new case! :thumbsup:

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I was just thrown off by the area on the threads where there is that missing area. It looks like that if the hole is drilled bigger, that it will create an even bigger gap. I don't think I'm explaining this too good since in effect there is a hole within a hole (the drain hole). Did you look at the photos?

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I'd just fix it and use the money saved on getting a decent torque wrench (if you didn't use one), so it doesn't happen again.

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