Yabo

Ok, so on the 951 I was almost done at the end of summer, with only the intake left to put on. Of course for some reason none of the bolts, which I am 100% positive are the ones that came from there, wanted to go in easy. I had got some dirt in the holes from standing on the engine but I cleaned them out pretty well and I can't imagine that's the reason.

Anyway, of course one of the bolts sheared as I was working it in and out, and I took the whole thing off again and nothing is getting it to turn. I'm just about done cutting it off flush with the head and going to use a reverse bit on it and hopefully salvage the threads.

Has anyone had to helicoil these threads? If so, do you know what size helicoil I would need? Were you successful???

Any advice or stories would be great!

fortysixandtwo

It should be a M8 - 1.25 X 35mm. If you're careful, the bolt can be drilled out without damaging the head. The goal is to drill straight down the bolts center with a small bit, then continue to step up the drill bit size until nothing but the bolt's threads are left. Then the coil can be removed with a pick and some needle nose pliers. I've been successful with this method on several occasions.

For the remaining holes and bolts, I suggest you get a bottoming tap to chase the holes and a die to chase the bolts. (or buy new bolts).

Tom M'Guinn

+1 on all that. Also, be sure to cover all the intake ports before drilling and use a magnet, vacuum and peper towels to get all the shavings. Heli-coil should work fine for the intake bolts. Graingers has a great heli-coil set. Very strange that all the bolts were so tight. Try the bolts with the intake off and see if they are still tight. Sometimes, when installing the intake (or any part) if the intake is not lined up well, the bolts will feel tight as they make contact with the side walls of the flange hole and/or go into the holes at an angle. Either way, you can use a tap and die for the holes and bolts, so they will turn in freely.

Yabo

Yeah I'm still miffed. It wasn't due to a misalignment of the intake I'm pretty sure, and I can tell from the threads and the holes that nothing is cross threaded, just were really stiff. The bolts were off since like may and we had a pretty wet summer, I'm thinking corrosion maybe, but the car is indoors, I really have no idea.

Yabo

Thanks and I just noticed,
Via RI? Where are you in RI?

fortysixandtwo

I grew up and lived in North Kingstown, then moved to the Saint Louis, MO area, aout 18 months ago. (hence the "via RI")

Chris White

I have helicoiled many an intake bolt hole - even more fuel rail mounts.... easy fix.

General rule - never force anything, if its not going in right then there is a problem!

eniac

I've had many of these break....most commonly it's the bolt for the head coolant passage in the front which is the same as the intake bolts.

Everytime I drill the broken bolt out starting with a smaller bit centered then gradually work up to a larger drill bit thats just a tad smaller then the threads. At this point, the rest of the broken bolt should come out. I generally run a tap through it after to make sure the threads are clean but I have yet to need to use a helicoil on the intake bolts. There is one time on an exhaust bolt that the PO had tried to fix in the car so he had retapped the hole at a slight angle. To fix this I had to retap to an SAE size bolt just slightly larger then the metric threads. This was on my car and I did this 8 years ago and haven't had to touch it since.

If the threads are gone and you have the option of a Helicoil vs. Timesert.........go with the timesert.

choinga

good thread. i stripped out one for the fuel rail a while back and tapped it with a helicoil but I'm not real happy with the holding strength and of course the fuel rail isn't a place you want to wiggle loose.

I was looking at some videos on the Timesert site - one of them mentioned the 'bigsert' which is designed to fill a failed helicoil hole. Anyone know which size I'd need to fill that hole? How do you use the bigserts? do you just bore the hole out with a drill bit with the helicoil still in there, re-tap it then use the tool to put in the bigsert?

http://www.timesert.com/html/bigsert.html

Yabo

Thanks all, I've drilled a lot of bolts out before just was curious if anyone else has saved the threads on these, so it sounds like I might be ok.

BTW, this turbo forum is great for support thanks for making it that way. The combined forum didn't get me hardly any response in a days.