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R & R intake and exhaust studs?

4K views 14 replies 10 participants last post by  r-mm 
#1 ·
So I believe I have managed to follow instructions and and completed my valve adjustment. I ordered three shims to add to the set from the second motor I've been scavenging parts from to give me the range I needed. I've also got the valve cover on now.

Now that's done I'm looking at the manifold studs on both sides and I'm not too happy with the condition. Not to mention that two are missing on the intake side. Most are very rusty and a couple that are out of focal depth in these pictures have very few threads left.

I've already ordered replacements for the exhaust studs but the intakes were on back order at Centerline Alfa. So if anyone can suggest where to look for those I'd be thankful.

The most important thing I'm looking for here would be tips and tricks for removing and replacing these studs. I'm especially nervous as an amateur mechanic considering these are aluminum heads. Should I start saturating with penetrant (PB Blaster?) while waiting for parts? Double nut and turn? What about the one that only has 2-3 threads left, I don't think I can't get two nuts on that? And it looks like I ought to run a tap into the missing intake stud holes, there's a fair amount of iron oxides left in there. Anybody know the thread pitch for that?

Any and all help appreciated, thanks.
 

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#2 · (Edited)
....So if anyone can suggest where to look for those I'd be thankful.
Spruell Motorsports lists these studs on their website. Don't know if they are in stock, but they probably are. See: 8mm Stud Intake Weber Manifold/Head Mounting (5 of 7) - Spruell Motorsport, Inc - Performance and Your Store for Sports Car Performance and Racing Parts

Note that most Alfa intake manifolds require different length studs in the various positions. So don't just order seven of the Spruell part I reference above - measure what you need first.


Anybody know the thread pitch for that?
The fine thread is 8 x 1.0 while the coarse thread is 8 x 1.25

The most important thing I'm looking for here would be tips and tricks for removing and replacing these studs.
You are on the right track: soak with penetrant, double nut, twist, pray. Heating the section of the head around the stud with a propane torch will help as well.

There are stud removal tools on the market (one is pictured below). These tend to mangle the exposed threads, but if your's are stripped/corroded, that might not be an issue.

 
#3 ·
This is by far the best stud extractor I have ever used. The stud will slide all the way through allowing the tool to go right up against the head. I have removed hundreds of studs with it.

I will disclose that the one I have is Hazet brand made in Germany. I paid close to 200.00 for it 10 years ago. The link I posted is another tool company's copy of it. If it works close to or as good as hazet's then it will be money well spent.

Titan 16023 3/8 Drive Universal Stud Extractor
 
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#4 ·
PB blaster as you are doing.

Double nut the studs and back them out slowly so as you can tell if they are about to snap.

Good luck,

Vin
 
#6 · (Edited)
centerline sells replacement (brass) nuts (exhaust), it's worth getting a new set as they are pretty easy to strip, and if you use steel nuts they can rust, weld to the studs. threadlock and plenty of anti-seize
 
#8 ·
Echo JimG comments above. I have the same one and it works great. By grabbing the stud right at the base it minimizes off axis forces . I've removed some nasty nasty frozen studs easily with that tool and my impact gun
 
#11 ·
Okay, this just went from bad to worse. Not beyond repair I assume, just more work, more $.

In the pictures I posted above you can see that two of the intake studs are missing. So I got out a 8 X 1.25 tap to clean them up. First one went fine. Second one had more bits of the old stud stuck in it. Long story short I spent an hour boogering it up with the tap beyond recovering.

So once again I am back looking for guidance. What's the best practice here? Can I get a big enough helicoil in there to still use the 8 X 1.25 stud? Any tips, cautions so I don't make any more novice errors?
 
#13 ·
In the pictures I posted above you can see that two of the intake studs are missing. So I got out a 8 X 1.25 tap to clean them up. First one went fine. Second one had more bits of the old stud stuck in it. Long story short I spent an hour boogering it up with the tap beyond recovering.
Get all of the remaining pieces of the old stud out of that hole before you start pilot drilling and tapping the aluminum head for the helicoil insert. If you don't, your pilot drill could wander causing you more grief. The aluminum head material is much softer than the steel of the embedded stud pieces. You want to drill the pilot hole for the helicoil tap as axially centered in the old stud hole as possible. In fact, once you get the remnants of the old stud out, the pilot bit cleanup needed for the the insert tap should be minimal (and done carefully).

And +1 for the tape marker on the pilot bit tip from goats. You don't want to blast all the way through the wall.
 
#12 ·
yes, helicoil is fine. Don't beat yourself up over this kind of stuff, it happens all the time. When you drill it out for the helicoil, use a piece of tape on the drill bit so you don't go too deep into the blind hole, You only need about .300 " depth or so.
 
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#14 ·
If you haven't already started pulling the studs, use the PB blaster, then tap on the head of the stud gently with a hammer. Helps to loosen the corrosion.

I would suggest that you not use a cutting tap to clean threads, but instead use a cleaning tap. If you don't have that, take a stud, cut a couple of vertical slots in it, double nut it and use it to clean the threads. You don't want to cut the existing threads, it'll only loosen the tolerances on the newly studded installation. In addition, a cutting tap will not clean to the bottom of the existing threads.

These are cleaning taps:
 

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#15 ·
Good advice here. Helicoiling is relatively straightfwd. I did it for the cam cap studs in the head. If you can temporarily install the manifolds and use them as guides to insure you are drilling plumb it will help. Go slow use cutting fluid. Mcmaster sells helicoil kits. Are these those studs with fine thread one side coarse on the other? Alfa loves those. If not you can shop for studs on mcmaster too.
 
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