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No More Stripped Turbo to TMIC Threads


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As anyone with a TMIC knows, especially those with WI, you have to take it off now and then. But even the first time it is installed it can be a hassle and according to the occasional post too many people either cross-thread or strip the threads on the turbo trying to get the TMIC attached.

 

It is almost always a pain. My procedure is to first insert the TMIC's throttle body exit into the TB boot, fully, and tighten it down securely. Next the TMIC must be levered into position so that, normally, the bolts that attach it to the turbo can be inserted through the TMIC and into the turbo's flange bolt holes. This has always been difficult, involving straining to hold the TMIC while gently trying to screw the bolt into the soft aluminum turbo flange without damaging the threads. I've done it many times, thankfully never ruining the threads but always close to it.

 

Not long ago while reading a thread in which stripped turbo bolt threads were mentioned I posted that I was going to change to studs when I installed my AVO380. This is what I ended up doing:

 

I got two bolts about 1 1/2 inch long, cut the heads off and reshaped the cut end so the threads were good. I got two lock-nuts and two regular nuts for the remaining, headless, bolts. I then threaded the cut end through the turbo bolt hole to a depth of 7/8 inch above the turbo, threaded the lock-nut onto the bottom and tightened it down (using the standard two nuts threaded together up top to hold the bolt/stud), and repeated for the other bolt hole.

 

At first I thought I'd thread the two bolts up through the turbo flange, but there was not enough clearance to do that. Then I figured I'd just get a couple of studs, and did, but I didn't feel they were as strong as having a nice nut underneath making SURE it wouldn't ever be pulled out (there is some thread clearance and it makes a bolt kind of 'loose.' The end result I described is perfect. Oh, and that gasket supplied by AVO with the turbo was a perfect addition to the Perrin's stock O-ring.

 

This modification made reinstalling my Perrin TMIC soooooo much easier it was amazing. I just pulled the TMIC over and onto the two projecting studs, pushed it down enough to get the nuts started, and tightened it down. Voila! Everyone should do it. In fact, turbos should come with similar hardware and instructions.

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uggggghhh my turbo side one is shot....

 

makes putting the TMIC back on a 40 minute exercise instead of a 20 minute ordeal.

 

I'm going FMIC.

 

Seriously, this mod takes very little time or effort. Even damaged threads can be accommodated. Once done there is no 'ordeal' again. It proceeds at the pace I described, minus the few moments ratcheting two nuts down securely. Period.

 

Trust me. I've had my TMIC off many more times than I can remember, for multiple reasons. It was always, as you describe, an ordeal. Never again. It is now a non-issue.

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Sounds like a another good idea from you Seeya. Pics or ban:)

 

Wow, tough audience :lol:.

 

Best I could do at the moment. It's pretty self-explanatory but these give some idea. I thought of pics when I was doing it, but in the middle of what I was in the middle of it dropped off the edge.

 

AutoZone told me the size, an odd number, but I forget. I took the two stock bolts to my local Suby friend so that I could match them up and got some bolts and nuts out of his bolt and nut can.

 

As you can see it is utterly simple.

19992972_SmallTMICStudPic1.jpg.00eb4f9b755b89cff512930c919c85ce.jpg

2000692709_SmallTMICStudPic2.jpg.cd83712fd2412c36819a8b2b633c5286.jpg

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ooooooooooooooooor.....

you could just be like Hogmeat - and not have to "leverage" or "pull" your IC down to your turbo. If you have to do that - your TB boot is not on right.

I've spent a few hours dealing wtih this, and wore out 1 boot (cracked a lip) figuring it out....but, you can get the boot to line up so that it just "falls" on your turbo. Nice n' flat.

I am usually 100x slower than others, and nothing ever goes right - so what took me 2 hours the 1st time, and 2 mins the 2nd time will take others a fraction of that.

I'm pleasantly surprised... It was most certainly worth the couple bucks and 10 mins of my time.

CLICK HERE FOR THE HOGZAUST

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you could just be like Hogmeat - and not have to "leverage" or "pull" your IC down to your turbo. If you have to do that - your TB boot is not on right.

 

Exactly.

 

 

Mine just falls into place, I can do it with one hand.

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  • 1 year later...
my original message still stands. Your alignment isn't right. It's not "loosening" it, it's rotating it. The thing is angled oddly, and whenever you make a SLIGHT adjustment, it is magnified 10x at the end where it bolts up. Try it again. and again. take your time. get pissed. it'll work.
I'm pleasantly surprised... It was most certainly worth the couple bucks and 10 mins of my time.

CLICK HERE FOR THE HOGZAUST

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I'm right there with ya. The turbo I just put on had stripped threads in it and I didn't even notice until we we're putting it on. I have a bolt in the back and a stud with a nut on the bottom in the front right now.

You can get studs from the autoparts store that fit also. You can use GM header studs that are m-8 and m-10's (i'll look for sure and try to get pics) if you have stripped them pretty good and need to tap them out to the next larger size. The studs will screw all the way down in and lock in just like UP studs. If this is done with a little threadlock the first time the TMIC comes off there will be no need for the bottom nuts. Slotting the hole in the TMIC will help save threads also.

Oh and I've had mine on and off of the stock turbo a hundred times and it used to just drop right in. After the turbo swap; not so much. I had to get a leg up and lean on it a little to get it bolted up the first time. I'll go back and mess with it, but I know I'll be tapping new bolt holes and stuff, so I'm in no hurry as long as it's holding for the moment:redface:.

Edited by qikslvr
Let's kick this pig!
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  • 1 year later...
So, I installed my new Perrin TMIC today and as I'm tightening everything down, I get to the turbo flange and I'm able to get one bolt down. As I'm tightening down the second one, it goes almost all the way down and I'm waiting to watch the bolt pull the flange tight, but it keeps turning more than I expect. I look at the flange closely and see about 0.5-1mm gap, so I know it's not tight. I go to turn again and I start to see metal shavings come through said gap. I'm thinking "CRAP!" and back the bolt out only to confirm my fear. The threads inside the turbo have been stripped. The good news: the car runs well, with some boost loss I'm sure, and I found a screw driver I've been looking for for months in my engine bay. Naturally you know the bad news. My buddy is going to bring a tapping kit for me but I just wanted to check on other suggestions. Thanks guys!

Updated parts list since original part-out here.

 

Original Full part-out of my LGT HERE!

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my original message still stands. Your alignment isn't right. It's not "loosening" it, it's rotating it. The thing is angled oddly, and whenever you make a SLIGHT adjustment, it is magnified 10x at the end where it bolts up. Try it again. and again. take your time. get pissed. it'll work.

This worked but since I replaced the VF40 with the VF46 alignment was horrible. Gonna go back later today and try to redo the TB boot again.

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  • 10 months later...

The bolts needed to accomplish the permanent fix to either existing or potential problems with the TMIC/turbo interface, obviously, have the same thread spec as what is on there in the first place. Take one of them to your favorite autoparts store and get a couple long enough to mod like I outline. The fix is PERMANENT, and will be reliable forever.

 

IMO, Helicoils are a fix when nothing better is possible. The bolt solution, done exactly as I show, is better in every way.

 

As mentioned, you cannot thread a bolt from the bottom of the TMIC flange... there isn't enough clearance. That's why the bolt was re-configured for the application. It isn't complicated.

 

The title of this thread says it all. It isn't about the hows and whys of personal issues relating to TMIC removal/installation.

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  • 7 months later...

I am reviving this thread hoping that somebody can tell me what size the turbo bolts are.

My plan is to get a couple GM head studs and put a nut on both ends. Trouble is, I don't know what size I need to buy.

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I am reviving this thread hoping that somebody can tell me what size the turbo bolts are.

These are the bolts included in the Perrin install; is it one of these?

(2) M8x40mm Hex head bolts

(2) M6x25mm SS button head bolts

Tits mcgee
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I also wonder if some of the issue with getting the tmic to line up is caused by the combination of where the turbo, and the up pipeare located in there bolt holes.

 

When I reassemble my engine I will try to move the up pipe and turbo outboard. Then install the tmic to check fit then remove it before I install the engine.

 

My main goal is to have more clearance between the tmic and the clutch master cylinder.

305,000miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. CHECK your oil, these cars use it.

 

Engine Build - Click Here

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