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What are the studs called...

0

01_XJ

NAXJA Forum User
Location
Emporia, KS
...that are on the 0331 head and are used to secure the exhaust manifold. I just received my new head and as I went to get the manis on there, realized that I didn't keep the studs from my old head. The shop is like 25 miles away and if the studs are cheap enough, I could probably get new ones from the dealership or auto parts store instead.
 
J317 2318 DOWEL, Cylinder Head To Intake
 
01_XJ said:
Awesome, thanks. So, will this most likely be a dealer only part, or would I have a chance getting it at Napa/Kragen?
Click to expand...

Your best bet is the dealer, probably not at a parts store, maybe at an automotive machine shop.

They are just locating pins--find an appropriate sized roll pin, cut to proper length if necessary, put it together and don't worry about it.
 
Uh.. I think he's talking about the threaded studs on both ends of the cylinder head, not intake manifold alignment dowels.

They're just studs- should be able to come up with something comparable at the nearest hardware store.
 
The things I'm talking about are threaded studs that have a nut that goes down over them to help attach the exhaust manifold.
 
joe_peters said:
And that is a horse of a different color...

3/8"-24 studs.

5-90's screw reference page: http://www.kelleyswip.com/screws.html
Click to expand...

Half marks (but thanks for linking!)

The OEM stud is 3/8"-16 where it threads into the head, and 3/8"-24 for the nut. There are actually sound engineering reasons for doing it that way, but they don't really apply here (load's too small.)

Get a stick of 3/8"-16 threaded rod and cut studs about 2" to 2-1/2" long. I use brass rod, can pick it up at the local hardware store, and I don't have to worry about rust or seizing. Pick up nuts with the threaded rod, and make sure to reuse the little "dish" shaped washers that should be under the nuts.
 
5-90 said:
Pick up nuts with the threaded rod, and make sure to reuse the little "dish" shaped washers that should be under the nuts.
Click to expand...
X2, those Belleville washers are real important. They make it so you can't hear the exhaust header gasket leak over the leak from the crack at the collector anymore.
 
kastein said:
X2, those Belleville washers are real important. They make it so you can't hear the exhaust header gasket leak over the leak from the crack at the collector anymore.
Click to expand...

They're not true Bellevilles, but close enough.

Their primary purpose is to help keep the screws/nuts/studs from working loose due to the different rates of thermal expansion between aluminum and iron/steel - aluminum's rate is twice as much as steel, and it will cause the screws/whatever to start backing out!

Even when it's "just steel" or "just aluminum" being clamped, the washer still provides enough "give" to maintain clamping force without stretching the screw overmuch. One of these days, I want to see if real Bellevilles will work better...

If you want to use a threadlocker, LocTite #271 is it. Everything else will break down in short order when subjected to exhaust heat.
 
Chippendale dancers.




<rim shot>
 
Is there any chance that I'd be able to get the old ones out of the head w/o damaging them? I have to go pick up the old head from the shop tomorrow, and being without a vehicle I', hoping to avoid having to go to the hardware store.
 
01_XJ said:
Is there any chance that I'd be able to get the old ones out of the head w/o damaging them? I have to go pick up the old head from the shop tomorrow, and being without a vehicle I', hoping to avoid having to go to the hardware store.
Click to expand...

You can try double-nutting them and backing them out that way. Most stud pullers tend to damage the threads a bit.
 
double nutting them should work, but if it doesn't and you purchase new from NAPA or similar watch the overall length of the stud. 2" is too short and 2 1/2" is just a hair too long....if you screw it into the head until it seats it will interfere with the head bolts at either end of the head (and the front one passes thru a water jacket).

Also, the stock nuts are staked, which prevents them from backing off.

Jeff
 
Looks like I'm going to Napa or the hardware store today before I can go get the head. So is there something I can pick up in place of those dished washers?
 
They're squeezed in on two or three equally spaced flats which makes the hole slightly oval or triangular in shape. Basically an all-metal "nylock" type locknut, they will spin freely onto the stud until the "staked" portion is reached at which point they take a little effort to turn.

Many of the nuts and bolts on the suspension of an XJ are like this, for example the leaf/shackle/LCA bolts and UCA bolts.

EDIT: here is a pic - http://shop1.mailordercentral.com/marshfasteners/images/ALLMETALLOCKNUTMOM.JPG

They're also marketed as "all metal locknuts" or "metal locknuts". You'll see any number of different staking patterns, some are semicircular dents in the top of the nut, others are squeezed on the flats, etc etc.
 
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