Exhaust Stud tap question

[IslandTSI]

Quick question. What size tap is needed to clean up the threads for the exhaust manifold to head studs? Is 8X1.25 correct?

 

[romeen]

Yes, that's the correct size.

 

[IslandTSI]

Thanks.

 

[IslandTSI]

Also should I use lock tight or anti seize or anything like that? Im putting in a brand new set of studs and just cleaned all the threads. Or should I just use lock tight (high temp red) on the nuts when I tighten them down.

Thanks

 

[romeen]

Also should I use lock tight or anti seize or anything like that? Im putting in a brand new set of studs and just cleaned all the threads. Or should I just use lock tight (high temp red) on the nuts when I tighten them down.

Thanks

I have never found it necessary to use anti-sieze or loctite on the portion of the studs that goes into the head. If you do use loctite only use the medium hold, but again I don't know that it is necessary.

I do recommend using either copper or nickel based anti-seize on the portion where the nut will be. This stuff is more expensive and harder to find than the standard anti-seize that you typically find in auto parts stores but will hold up to the high heat much better. I use it on the mani studs, turbo-manifold bolts, turbo-O2 housing bolts.

The nuts should be lock nuts or you should use high grade lock washers with them.

 

[1stGenRocks]

Dont bother with the loctite its a waste of money on anything thats going to get hot. If you read the directions on the back it says one way to break the bond so it comes apart is to heat it. Just thread the studs into the head bare so they stay put and use copper antisieze and lockwashers on the nuts.

 

[IslandTSI]

The nuts are stainless with stainless lock washers. There is both a normal washer and a lock washer for each stud. Should I put the lock washer closest to the nut or closest to the manifold?

 

[romeen]

The lock washer goes next to the nut. So if you want to use the flat washer as well it will be:

exhaust manifold--flat washer--lock washer--nut

 

[IslandTSI]

Cool thanks, that was something I always wondered.

 

[LamboORG97GSX]

hey just to add to this forum topic: when upgrading the studs to 10 instead of 8s willl that work with stock exhuast manifold stud holes, or do I have to also tap them larger?. being 3 of mine are stripped and I was just wondering if any one has done this yet with any problems I should be aware of! and from what I'm hearing that the studs stripping is a common problem with the dsm heads.

 

[romeen]

hey just to add to this forum topic: when upgrading the studs to 10 instead of 8s willl that work with stock exhuast manifold stud holes, or do I have to also tap them larger?. being 3 of mine are stripped and I was just wondering if any one has done this yet with any problems I should be aware of! and from what I'm hearing that the studs stripping is a common problem with the dsm heads.

I don't know the answer to your question. But you might want to consider using a helicoil which will allow you to use the same size studs as intended. If you use 10mm studs in a location intended for 8mm and then have the misfortune of stripping those then you start worrying about just how large can you continue to drill and tap without running into problems. Plus the helicoils hold great and won't strip (possible but not likely). If you decide to do it you need the M8x1.25 kit.

 

[IslandTSI]

I would also recommend using a helicoil. but if you do drill the hole out and tap the head for a 10mm bolt yes you will also have to drill the matching manifold hole out to 10mm.

 

[LamboORG97GSX]

thanks guys....I had a heilcoil done at the machinest and the damn things didn't hold. But I guess I can retry it myself. I just heard of guys using the 10 so I was thinking about it, I just don't want to pull the head again to take it back to the machinest, for a few bolts.

 

[romeen]

thanks guys....I had a heilcoil done at the machinest and the damn things didn't hold. But I guess I can retry it myself. I just heard of guys using the 10 so I was thinking about it, I just don't want to pull the head again to take it back to the machinest, for a few bolts.

Helicoils are actually quite strong and reliable. They usually end up being stronger than the original tapped hole.

You don't necessarily have to pull the head to helicoil the stud holes. But since you must first drill the hole before tapping it and the drill must obviously be at a right angle to the front of the head you will need something like this:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92187

Otherwise there is no way to get a drill with attached bit at a right angle in that small space. You may still need to remove the fan. I have the slim fans and was able to do it w/out removing anything, but just barely.

If you do helicoil it remember to take your time so you don't make any mistakes. Also use some tape on the drill bit to mark the depth of the hole. DON'T DRILL TOO DEEP INTO THE HEAD! If you wan't any more advice on doing the helicoil let me know.

 

[IslandTSI]

If you are having space issues just pull the rad out. It only takes a minute and your coolant should already be drained anyways. With the rad out there is plenty of room to fit a drill in

 

[chicagoavenger]

I had to take my fan and radiator out.it's a 5 min job to do the helicoil. I don't know why peopel say there a pain in the ass butall I did was drill, tap, insert and voila.

 

[LamboORG97GSX]

I think I'm going to go with that right angle drill deal.
but when I buy the heilcoil kit, get the 8x1.25mm? and any auto supplier will normally carry this?

 

[romeen]

I think I'm going to go with that right angle drill deal.
but when I buy the heilcoil kit, get the 8x1.25mm? and any auto supplier will normally carry this?

Yes that is the correct size you need. Be ready to pay $30-40 for the kit but that will include about a dozen of the inserts, the appropriate sized tap and sometimes the drill bit that you need (I believe 21/64 for this kit).

Remember, take your time and do it right. Especially during the drilling make sure the bit is in line with the existing hole so you don't drill crooked. And as I said before don't drill too deep! Make sure the bit isn't dull and worn. As you know the head is aluminum and you don't need to exert much pressure on the drill.