Turbo bolts - ARGH

[unclesam099]

Frustration! I go to port my Evo3 today and one bolt broke, and two stripped out. The threads were nasty from the previous owner, but this is ridiculous.

So, I guess that Helicoils are going to have to be the fix. What type of bolts should I get from the HW store to replace the bolts? I know they're M10 x 1.25. But what length and type?

Man, sometimes I hate this damn thing....

 

[project_tsi]

Grade 8 hardware bolts are not strong enough and are no where near rated high enough for the type of heat you'll be putting to them. When I was in a pinch I used some grade 8 hardware bolts and they stretched in no time. I was constantly tightening them back up, but I was lucky enought that none broke upon removal, but the threads were nasty and I used plenty of copper based anti seazed.

IMO if you have to its OK to use some grade 8 hardware bolts for a few days but you should really get some new OEM bolts. You can get them from the dealer, SBR, JNZ, etc. Make sure you get the locking washers also. Either way use plenty of copper based anti seaze.

If I remember correctly you need 95 or 100mm long bolts.

 

[unclesam099]

I looked at McMaster-Carr, and they don't have M10x1.25 in anything better than grade 8.8.

I gotta get lower injector seals for when I put in my 550s, so I guess I'll spend $22 on new bolts while I'm at it.

I wish I had a money tree....

 

[gsxtacy]

In a pinch, I once used a 3.5" 3/8x16 grade 8 bolt. The next time I had the turbo off I had the turbine housing helicoiled for a new OEM bolt.

The grade 8 harware just isn't designed to stand up to the heat cycling of a turbocharger though.

Good luck,

 

[project_tsi]

I looked at McMaster-Carr, and they don't have M10x1.25 in anything better than grade 8.8.

I gotta get lower injector seals for when I put in my 550s, so I guess I'll spend $22 on new bolts while I'm at it.

I wish I had a money tree....

I haven't seen any problems with the heli coils failing, so 8.8 should be fine there. Its the bolts that are the problem. A small study has shown that a lot of the bolt stretch and thread problems are related to the pulling load and weight put on the turbo. A great idea/concept is to support a aftermarket downpipe like that of a stock support. The studys show that there is no longer the pulling down on the turbo and a great part of the weight has been lifted from the setup by properly supporting it. This can also help w/ manifold cracks also as is has a direct relation with the weight pulling down on the manifold, especially when hot.

 

[unclesam099]

Also while people are reading this thread, I ran the car with the WG arm detatched and an open O2 sensor. I was getting positive boost at 4000rpm, maybe a little higher. Then it would run to ~20psi at redline. Does this mean my porting job sucks?

 

[unclesam099]

Well, I used a milling machine to mill out the holes and remove the bolt that was broken. The bolt was taken care of with a lot of Tap Magic and a carbide bit. It smoked like crazy on the way out.

The holes were then drilled out with a 13/32" bit as per the Heli-Coil instructions and tapped with the provided tap.

Next, I got a set of Heli-Coils for $10.50 on eBay Shipped! Pretty awesome. Anyways, the insertion tool that came with the kit was plastic. I got 3 in just fine before I started having problems because the plastic on the insertion tool was getting severly screwed up. I finally just got the last one in, but it only a few threads. It will work, though.

Where can I get some Copper based anti-seize without having to get it from McMaster-Carr? I didn't find it at Ace Hardware or Autozone. Thanks guys!