Camshaft seal flange holes stripped

[daveduck]

In the middle of my timing belt job I went to replace the camshaft seals, and as I went to put the retainer back on with the new seals, the bolts would not tighten down. I looked inside the holes and they're totally stripped out. I guess that explains why the flange was completely covered in RTV when I removed it...

So, I'm looking for some guidance on how to fix this. Can I just run a tap through the hole, or do I have to drill it larger then run the tap? I think that would end up having metal shavings go into the engine. Or should I just throw some RTV on it like the last guy?

[daveduck]

So I looked closer and the threads extend further than the bolt, so there are some that aren’t stripped. I’m going to get a couple larger bolts and that should do the trick.

[ForcedFirebird]

It's commoon for those holes to be forgotten when cleaning the heads after machining and/or media blasting. Best way to repair if needed is a heli-coil.

[citizen_insane]

I'm not familiar enough with this feature to know if it's a through hole or blind (sounds like it's through into the valve train area of the head), but if you're not willing to pull the head to fix it, you can machine it in the car using grease to prevent the chips from spreading. If you pack the area behind the hole with a thick grease, it will hold the chips and hopefully prevent them from spreading into the oil system. You still have to be very careful not to spread the chips at all, but it can be done. Like ForcedFirebird said, the best solution would be to go to a heli-coil which would mean drilling the holes larger so you can tap them for the insert.

[daveduck]

Thanks for the suggestions guys. I ended up getting some M6x1 20mm bolts, and those threaded in fine, since it was only the first ~10mm of the hole that was stripped. I'll just fix it in the future when I rebuild the head most likely.

[Andre3127]

I'm not familiar enough with this feature to know if it's a through hole or blind (sounds like it's through into the valve train area of the head), but if you're not willing to pull the head to fix it, you can machine it in the car using grease to prevent the chips from spreading. If you pack the area behind the hole with a thick grease, it will hold the chips and hopefully prevent them from spreading into the oil system. You still have to be very careful not to spread the chips at all, but it can be done. Like ForcedFirebird said, the best solution would be to go to a heli-coil which would mean drilling the holes larger so you can tap them for the insert.

It's a pair of blind holes.

Honestly, I doubt the bolts are even required since the fit of that seal retainer is usually a very tight fit in the bore with a fresh oring. I could be wrong.

[ForcedFirebird]

It's a pair of blind holes.

Honestly, I doubt the bolts are even required since the fit of that seal retainer is usually a very tight fit in the bore with a fresh oring. I could be wrong.

It keeps the cam from pushing out of the front of the head, as well as housing the seals.

[Andre3127]

It keeps the cam from pushing out of the front of the head, as well as housing the seals.

Oh right, my bad. I forgot it was also a thrust surface.