Need a Replacement Stud 4 Iron Head LIM Leak Fix

[60dgrzbelow0]

I'm down one (1) of the necessary four (4) "Corner Studs" on a LIM Gasket Repair for an Iron Head 3.4L that was not present during the tear-down and this fact probably explains the leaking LIM gasket. I've looked around high and low on eBay and via Google search combos with no luck in finding anything satisfactory.

I'd appreciate a "heads" up on where I can find one (1) or more to finish the repair and for safe keeping ...or knowing if there is a decent hardened stud replacement that can be installed. If I cannot locate one to complete the set, knowing the thread type/count specifications on these studs might allow me to make one from a bolt. Thanks in advance for any advice on this...

[60dgrzbelow0]

Still need "D'Artangon" with these "Three Musketeers" to finish the LIM with all four bolts... These look to be 8mm X 1.25 X 80mm in dimension with a six point driving end:

[60dgrzbelow0]

Well... I think I may have just found a fair substitute... Although quite drunk and dishevelled, with a new King's Guard outfit and a decent sword...I think this TE-CO 125,000 lb tensile strength Driver Stud that measures M8 X 1,25 X 80MM OAL with a nifty mid-space squared off to accept an install wrench with some Thread-Locker will make a fair stab at playing "D'Artagnon" and complete this "Three Musketeers" Stud Set nicely.... How does it go? Oh...Yessss...

"All For One!...One For All!...And Every Man For HIMSELF!!!"


....Now ...I just have to find a decent "Hat" (err.. Flange Nut) for this fellow...

Ahhh,,, I'm in luck with Amazon.com... Found just the thing...A hardened (10.9) Phosphor treated M8-1,25 Flange Nut...and now to work!

[geoffinbc]

I can send you one. I have tons of extras. But can you not go to a local yard? There are tons of 2.8L/3.1L/3.4L engines out there.

[60dgrzbelow0]

Thanks Geoff... I'll PM you with the information... I should probably get a set of four (4) if you can spare them, but one will be enough to get my over the crisis. Give me your PayPal data in my message data listing so I can pay you fair market value and S&H for this impossible to find hardware... I really appreciate the help on this project.

"So Shines A Good Deed... Upon Weary World..."

[JerryRigg]

Is this it?

GM part # 10070187
eBay: http://www.ebay.com/itm/New-Genuine-...item2a17f56c1b

There's more info if you search the part number

EDIT: this might help too: http://parts.nalleygmc.com/showAssem...roduct=2538194

[60dgrzbelow0]

Is this it?

GM part # 10070187
eBay: http://www.ebay.com/itm/New-Genuine-...item2a17f56c1b

There's more info if you search the part number

EDIT: this might help too: http://parts.nalleygmc.com/showAssem...roduct=2538194

JR...

Thanks for looking into this on my behalf. That stud is too big at M10 X 1.50mm X etc... but the information source you listed will come in handy on other issues. I'm taking Geoff Moore "betterthanyou" up on his generous offer for these stud(s) and I'll post their images side by side with the three that I've shown in this post as soon as they arrive.

[60dgrzbelow0]

Geoff has been good enough to come to my rescue and while I await my handy, "Fasten"-ating package to arrive from "The Great White North", have a look at this interesting web site that has some very interesting information about "Bolt Science" including some VERY handy computer apps to deal with these issues:

http://www.boltscience.com/pages/tighten.htm

[60dgrzbelow0]

Okay... I have a new question and an observation that I may have stumbled upon something that might have some import concerning why so many LIM Gaskets fail. In the process of trying to be as comprehensive as possible and not assume anything from the condition of old fasteners, I took a very close look at the remaining three stock thrust washers and the remaining three nuts and made a serious efforts to find some "fill-ins" that were high quality, hardened steel (either phosphored or Blued Steel). The dimensions I was shooting for were of course for a set of Flat Thrust Washers and Flange Nuts that were appropriate for sizing to the M8 X 1.25 X 80mm Studs. It took some time, by using eBay and Amazon.com searches, I managed to find some "Industrial Strength" ones that were identical to the thickness (1/8th") and OD sized washers made for the GM LIM. When they arrived... I cleaned up the remaining hardware as much as possible and then did a side-by-side photo session to memorialize these images and post them here. It is a happy outcome that in spite of the clarity and precision offered by human sight...in my case, augmented by prescription lens glasses... that the multi-megapixel digital camera can often pick up and make clear things our ordinary vision cannot.

And this is where I discovered a problem with Stock GM Flat Thrust Washers for the LIM... They appear to be manufactured with a hardened Iron or Steel center bottom section enshrouded by what looks like a milder, galvanized steel shell...sort of like an MM Hard Candy Shell Coating. What the side-by-side images showed was that the inner portion of the washer has actually rusted and dissolved away. With these washers in place against the aluminum of the LIM...they could be rotting away inside and never reveal the problem on their exterior portions. Meanwhile...inside the washers' core...that rusting breakdown would serve to relieve any established pre-load between the nuts holding them onto the corner studs...and the subsidance that would follow could allow for the Lower Intake Manifold to lose pressure at those locations and allow the gasket material to likewise loosen, migrate and break down. Look at the last few photos and you'll see exactly what I mean. If you look closely on the outside areas of the stock GM washers, you can see the shape and markings from where the holding nut was turned and torqued down... and on the flip-side...you can see where the matching area underneath is literally "washed" away. It is easy to conclude that this fastener surface has been compromised. So... what I intend for their replacement is to use only the solid, high quilty, hardened treated steel washers of the same dimensions instead.

The question I have is whether or not Locking Flanged Nuts can be used in lieu of the normal, non-locking nuts... and if so...what adaptation must be made in adjusting for their installation torque...since they qualify as "Self-Torqueing Nuts". In the same manner that I found the non-automotive, industrial grade washers...I also found a fifty pack (actually they Gypped me out of one (1)) of High-Tensile Steel, Locking Flange Nuts sized at M8X 1.25 TPI. The side-by-side photos I took will show that the beveled, upper portion of the locking nuts makes them about three thread depths taller and oval at the top that act as the squeezing, locking force these special fasteners use to prevent their vibrating loose or coming undone accidentally. These are similar in design to the familiar adjustable locking nuts used on the rocker arm studs holding rocker arms in place.

[geoffinbc]

I would replace the washers if they are all bad but I would not use the locking nuts. There is no way to get the right torque setting. I have never had a set come loose. I believe the factory torque spec is 23lbs and I just put them to 25lbs in sequence. Do one round at 15~18lbs and then the final round of 25lbs about 3 times to ensure everything is even. Use a bit of oil or assembly lube on the washers and threads.

[60dgrzbelow0]

Will do. I did find it interesting that the bolts to the LIM set have two high quality blue steel washers per bolt to allow for a more fluid distribution of friction during the torque procedures. The only thing I can think of in their other binary metal design is that they were able to buy those in lots at a much cheaper price. Go figure, huh? I hate seeing anything mechanical that fails at any point because of cost-cutting or "clever engineering". By thye way...I only paid $1.60 + S&H for that bag of 50 M8 X 1.25 TPI Locking Flange Nuts and I'm sure to find other non-critical applications for their use. There seem to be many opportunities to buy high quality fasteners in odd lots via eBay and Amazon.com.

I'm taking your advice and using these GM Phosphor M8 X 1.25 Flange Nuts instead:

http://www.ebay.com/itm/400139029766?ru=http%3A%2F%2Fwww.ebay.com%3A80%2Fsch%2Fi.html%3F_from%3DR40%26_trksid%3Dp4712.m570.l1313%26_nkw%3D400139029766%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1