Fixing a mistake: bad threads for vanos mounting bolt on aluminum head :(

[eacmen]

Are you sure that you pulled out a helicoil? If you pull the threads from aluminum and they stay on the bolt it kind of looks like one, either way, you got it done.

easy way to tell if you still have the coil you pulled out is hold it up to a magnet. If its magnetic its helicoil if not its part of the aluminum head

[bmwfnatic]

Are you sure that you pulled out a helicoil? If you pull the threads from aluminum and they stay on the bolt it kind of looks like one, either way, you got it done.

[heinzboehmer]

Sounds like I added an unnecessary step then

[eacmen]

Yeah I've never had to resize the dowel either.

[George Hill]

For anyone who finds this thread in the future needing to do the same repair: skip the helicoil. Do the time sert. It's not hard.

Nice job, not much better feeling than overcoming something like this. And fyi I did not have to resize the dowel on the one I repaired either.

[heinzboehmer]

My guess is that whoever did the helicoil drilled a deeper seat and it worked out perfectly in my favor.

That said, though, even if my time sert was sitting a couple mm shallower, causing more protrusion of the dowel, it seems like there was more than enough grace room on the vanos side of the dowel hole to eat that overage.. was that really not true in your case heinzboehmer ?

Hmm, I think it was necessary for me to resize the dowel, but maybe I was just being overly cautious. My timesert definitely sits further forward than the threads on the other side, though. Sounds like you got lucky and were able to skip a step

[ATB88]

Got it done on Thanksgiving using the standard M6x1.0 time sert kit, the extra M6 tap guide they sell, the nice wratcheting tap wrench that eacmen recommended, and a 12mm insert. Drilled out the old threads by hand.

It was scary at first but I got some good emotional support from mechanically inclined friends that got me through it. It wasn't so bad!

Here's the big plot twist: when I got the bolt out and inspected the hole to size up the job guess what I found... a failed helicoil! Felt somewhat better knowing that it wasn't me who first ruined these threads (though it isn't beneath me to have done so either ). Was initially concerned that the previous helicoil repair might have caused them to drill the original threads out to a larger size than the time sert needed, but that wasn't the case in the end. For some reason, I actually did not need to resize the dowel after inserting the time sert. The depth at which my time sert's lip sits is basically identical in depth to where the threads begin in the identical unruined hole on the right side of the VANOS. My guess is that whoever did the helicoil drilled a deeper seat and it worked out perfectly in my favor.

That said, though, even if my time sert was sitting a couple mm shallower, causing more protrusion of the dowel, it seems like there was more than enough grace room on the vanos side of the dowel hole to eat that overage.. was that really not true in your case heinzboehmer ?

I guess the most surprising thing about this is that I've had this car for 7 years and picked it up at 45k miles. At that mileage I'm really surprised that anyone had taken the VANOS off the head before, especially given that it wasn't to do any VANOS bulletproofing (when I Beisan'd the car at 60k miles all the seals and bits looked 100% stock). I actually have all the BMW dealership service records from the POs (which detail a bunch of other things in its first 45k miles like rod bearings etc) and there is no sign of any job that would have required that. Anyway, used cars I guess.

All said and done, couldn't have asked for it to have gone any better! Thanks again everyone!

For anyone who finds this thread in the future needing to do the same repair: skip the helicoil. Do the time sert. It's not hard.

[heinzboehmer]

I think I'm gonna take a crack at the TimeSert this week, kit ordered.

heinzboehmer do you remember the length of the inserts you used? I ordered the M6x1.0 19mm inserts, as those seemed to be the longest they offer and the FAQ on their web page recommends that for blind holes there be close to a 6mm difference between the length of the insert and the hole, and this is the closest to that. But from what I understand the hole is 35mm? How much does this matter?

I ordered the t-handle wrench from the TimeSert web page. Are there any other special tools I'll need to pull it off the way you did (other than a way of resizing the dowel)? You managed to do it with just the fan shroud removed right?

I definitely measured, but looks like I didn't document that part unfortunately. I trust eacmen and bmwfnatic though, 12 mm sounds about right.

For drilling, I used one of those flat tap wrench handles instead of the style you mentioned. Took a while, but was able to get everything done with just the shroud removed. A tap/drill guide was also super useful for making sure the insert went in straight.

Something like this is what I used:

[bmwfnatic]

Stainless and aluminum are not really friends. Tends to cause galvanic corrosion or something alike.

On my fix with the helicoil I used a 12mm insert.

Don’t worry about the clamping force, it will hold, there is also 3 bolts at the bottom of the VANOS still.

[eacmen]

Ah okay thanks for the clarifications, guys. And for the tool rec eacmen.

Okay so the 19mm inserts are out, the kit also comes with 9.4mm inserts. Will I be okay with those or is the 12mm that eacmen recommended really what I need? If I order the 12mm, does it matter if I get the stainless steel or normal material?

Thanks again!

Never did it with the 9.4 but i suspect it will be ok. That would be more of a question for time sert whether the 9.4 can support the clamping force. Need to understand that the vanos sees very high oil pressure so its pushing against the head a fair amount. Which is why leaks from that area is common.

You don't need (or want) stainless steel in my opinion.

[ATB88]

The hole is definitely not 35mm long, I remember measuring. I do not recall the exact numbers but my memory vaguely reminds me it was in the 20mm range.

The bolt is 35mm long, but obviously the vanos, and the dowel area take up a big portion of it. So it just needs threads at the beginning really.

I recommend using the 12mm insert. You might not have have enough depth to use the 19mm ones as you need to leave some room for the counterbore to make sure the insert is flush with the head to allow for a good gasket seal. 12mm should be more than enough to hold the clamping force required for the VANOS bolts.

Cant be sure but that Time-sert T-handle wrench may be too long to allow for install with the rad in place. This is the wrench I have used successfully:

https://www.amazon.com/GearWrench-3880-Ratcheting-Wrench-Piece/dp/B000HBDW3O/

Ah okay thanks for the clarifications, guys. And for the tool rec eacmen.

Okay so the 19mm inserts are out, the kit also comes with 9.4mm inserts. Will I be okay with those or is the 12mm that eacmen recommended really what I need? If I order the 12mm, does it matter if I get the stainless steel or normal material?

Thanks again!

[bmwfnatic]

The hole is definitely not 35mm long, I remember measuring. I do not recall the exact numbers but my memory vaguely reminds me it was in the 20mm range.

The bolt is 35mm long, but obviously the vanos, and the dowel area take up a big portion of it. So it just needs threads at the beginning really.

[eacmen]

I think I'm gonna take a crack at the TimeSert this week, kit ordered.

heinzboehmer do you remember the length of the inserts you used? I ordered the M6x1.0 19mm inserts, as those seemed to be the longest they offer and the FAQ on their web page recommends that for blind holes there be close to a 6mm difference between the length of the insert and the hole, and this is the closest to that. But from what I understand the hole is 35mm? How much does this matter?

I ordered the t-handle wrench from the TimeSert web page. Are there any other special tools I'll need to pull it off the way you did (other than a way of resizing the dowel)? You managed to do it with just the fan shroud removed right?

I recommend using the 12mm insert. You might not have have enough depth to use the 19mm ones as you need to leave some room for the counterbore to make sure the insert is flush with the head to allow for a good gasket seal. 12mm should be more than enough to hold the clamping force required for the VANOS bolts.

Cant be sure but that Time-sert T-handle wrench may be too long to allow for install with the rad in place. This is the wrench I have used successfully:

https://www.amazon.com/GearWrench-3880-Ratcheting-Wrench-Piece/dp/B000HBDW3O/

[ATB88]

I think I'm gonna take a crack at the TimeSert this week, kit ordered.

heinzboehmer do you remember the length of the inserts you used? I ordered the M6x1.0 19mm inserts, as those seemed to be the longest they offer and the FAQ on their web page recommends that for blind holes there be close to a 6mm difference between the length of the insert and the hole, and this is the closest to that. But from what I understand the hole is 35mm? How much does this matter?

I ordered the t-handle wrench from the TimeSert web page. Are there any other special tools I'll need to pull it off the way you did (other than a way of resizing the dowel)? You managed to do it with just the fan shroud removed right?

[eacmen]

I used the timesert kit and drilled it by hand using the tap wrench. Had to remove the puller fan but was able to it without removing the radiator.