exhaust studs Q, teh 10mm-8mm step down ones Options

[bd1308]

by tapping and enlarging the hole to 10mm to allow the oversized studs to fit....I would think that these studs would be less likely to pull out, due to teh increased radial surface area that was created through the tapping and drilling.......is it too minor to count, or does it really make a difference?

b

[MecGen]

Hi Britt

I have used a step stud to repair my first 914, if the damaged hole is not too bad, its a good option.

People will argue the fact that the studs walls are not thick anough, and a heli coil is better for expansion and contracion. If you ever workrd on a damged heli coil, you know what a pain in the ass that is.

I retapped the head in place, used step studs, and heated the heat exchanger to notch just a tad more clearance around the nut area. I find that if you are not carefull with the new exhaust nut and stud, it can be damaged on assembley (trying to fit a fucking wrench or socket on it). Everything was tourqued down evenly using aviation grade brass nuts.

Worked for me

Later

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[bd1308]

i have this 2.0 with 4 studs that need attention...they look super funky...kinda like a partial heli-coil in 6 of 9 holes.

it was wierd.

anyway thanks for biting....

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b

[type47]

are you sure of the size? i thought oversize was 9x8mm

[DNHunt]

You might want to consider Time-serts. They are done entirely by hand including reaming the old threads out. I have done this with the engine in the car. It's pretty slick.

The kit is kind of expensive is the only problem I've had.

Dave

[jsteele22]

Glad to see this thread. I've been ignoring my exhaust stud issues for a while, and this sounds like a good chance to learn some more. A few questions for the experts :

1) Where do you get exhaust studs ? Didn't see them listed at PP (though I know they carry more than their website lists). Is there a recommedned brand ?

2) Are these step studs a standard product (like with oversize pistons, etc.) or are they some kind of specialty product ?

3) When I pulled my exhaust I had 7 of the 8 studs unscrew from the heads (nut stayed frozen to stud). Is this a sign of problems w/ the heads, improper installation, use of wrong nuts, or just weird luck ? Should I tap one size larger ? Use some kind of locktite ?

4) If/when I replace the studs, should I replace the 8th one ? If so, how to I get it out ?

TIA,
Jeff

[bd1308]

if you do one, i'd do them all....

to get the 8th out, I would try double nutting the stud, and if that doesnt work, weld a nut to the stud and get it out that way....patience and a welder and you will get that out in no time.

when I needed 2 studs replaced, I let the p-mechanic do it. He did a fine job....I didn't like having a MAPP torch so close to the fuel lines anyway.

as far as step-studs, i would say they are speciality....my father saw some in the AA catalog...some are online, and i think the rabbit or something used step studs. don't quote me though.

DN: If I ever rebuild my 2.0 case...i'll use time-serts. they seem real slick. saw some at flaps. I was going to use them on my head when the #1 plug kept on coming out of the case, but I didn't end up getting to that point.

I think using locktite is a good idea...you DONT want those studs turning unless you want them out. Whether or not locktite stands up to the head temps...i don't know.

I was just wondering if the step-studs hold up better without pulling thhreads. But I guess it doesn't matter, as the choices of stud repair is pretty open.



b