HD C3 IRS build up

[rtj]

I recently assembled one of Tom's 12 bolt kits. He tuned the posi, fitted the stub axles, and blended out the edges on the posi for a reasonable price. The details were posted on another forum.

I get a lot of good info from this site, so I figured I'd post some photos from the build up of the entire IRS. It's the complete Tom's kit, and I'm going to do a few more things.



Final photo of the assembly.


Here's the cross member tig'ed up. Hard to clean real good, and the place I went to get gas pushed an argon mix, when I asked for straight argon. I took the mix, but think it was a mistake.



Another thing going in this is the adjustable toe mentioned in one of the PDF's in the Tech section. I got some grade five 3/4" bolts and nuts and have it mostly machined up. Here's the first couple of pieces. I"ve tried machining grade 8 before, and it was a pain, the grade 5 was not too bad. I'll need to order some extra long through bolts, this short one is just for fitting.



I think this will be far stonger than the standard bolt and shims. I will eventually work on the engine, and figured I'd plan for it.

A few other things on the list, lots of gussets, solid aluminum bushings on the cross member and pinion snubber, new 3.5 in driveshaft with 1350 u joints....

 

[rtj]

Boxed in the strut rod bracket, need to fix the ends to drop the strut rod 0.5 to 1", haven't decided which yet. Parts for toe setting screws pretty much done.


Got the rotors drilled for half inch studs.



Solid dif crossmember spacers started:







Shortened the spring.


Need some of those bands to install back on the spring now

 

[84rzv500r]

nice work... :thumbs:

 

[rtj]

These are finished. They require a lot of fitting. I waited to weld up the supports until after I got it all bolted up. Good thing, as the side to side distance was good, but one bracket is bent up about 10 to 15 degrees. I need to cut one or both brackets loose, bolt up the cross brace with a diff installed bolted to the pinion bracket, and weld up the brackets in the correct location. Someday, all this hardware will probably get transplanted on another car, so the solid bushings seemed like the way to go.

 

[phantomjock]

SOLID WORK there! Very nice job on the "pucks." Just wondering - do you have a preference for the metal spring? Why not opt for the Dual Mount Composite?

Inquiring minds want to know! (Or did I miss it earlier?)

Cheers - Jim

 

[rtj]

SOLID WORK there! Very nice job on the "pucks." Just wondering - do you have a preference for the metal spring? Why not opt for the Dual Mount Composite?

Inquiring minds want to know! (Or did I miss it earlier?)

Cheers - Jim

If you install the "traction bars" like 84rz500r, then maybe the dual mount would okay. My gut feeling is that without the traction bar, the diff may move around more. But, this may or may not happen.

I thought about composite when I bought the last spring, but is was too soon after snapping an axle, so I decided on steel. Luckily I was just coasting to a stop light when the passenger side axle finally let go.

 

[rtj]

The first fitting of the solid bushings was a let down. I could tell one of the perches was tipped at a different angle, and you could see a dent in the frame above where they attach. I've had this car since 97, and think I paid $4200 for it back then. I drove it until 2004 with only small repairs and minor upgrades. But, during that time found the frame damage. So butchering it up a bit has never bothered me too much.

Any way you can see where I sliced the mount and tack welded it back. A nice little digital angle gage from HF and a floor jack and I got the angle matched to the good side and tacked it up in place. Amazingly, when the cross member was bolted up, it all fit real nice. You can see the dent in the frame in the picture.




I think the plan now is to finish welding the gap, grind it down flush and weld on reinforcing plates on both sides with the cross member bolted in.

I was impressed with how solid it ended up. Final assembly will probably include some high temp or black rtv to seal the whole thing up (bushings to hat to cross member).

Decided to machine solid bushings for the pinion mount and reinforce the pinion bracket to the frame as recommended.

 

[MYBAD79]

Nice work !!!

:thumbs::thumbs:

 

[rtj]

Nice work !!!

:thumbs::thumbs:

Thanks for telling the secret on shortening the steel spring. On your spring did you replace the band clamps and if yes, what did you use?

For anyone that didn't see it, the trick is to cut and drill one side. My mind was determined to trim both ends!

 

[MYBAD79]

Nice work !!!

:thumbs::thumbs:

Thanks for telling the secret on shortening the steel spring. On your spring did you replace the band clamps and if yes, what did you use?

For anyone that didn't see it, the trick is to cut and drill one side. My mind was determined to trim both ends!

Hehe.... Yes, just drill a new center hole and only cut one side..... On one spring (two+ years ago) I hammered the band clamp back in place..... Since then I installed the dual mount spring and wow..... I am impressed.....

One huge benefit is that spring does not mount to the diff.....

 

[rtj]

Went with 0.55" drop on these. Used the slots to machine off material.

 

[rtj]

Double post :crap::huh:

 

[rtj]

Part # TY750 - Turbo 400 Chrome Moly (4140) Transmission Yoke (1350 series) - 32 Spline - Billet Removable Straps

I picked up this from moser. Really nice part, and more compact than the factory yoke. I need to order the 1350 3.5 driveshaft on line as I'm told best not to look local.

Made more progress, will post photos later.

 

[MYBAD79]

:thumbs:

Looking really good !!!

 

[rtj]

Thanks MyBad79, my welding needs lot of work, but the only way to improve is to keep practicing. And, since this frame is banged up, I figure it is good for that.



This is what I came up with to brace the diff cross-member mounts.

Here it is welded in place. Big dent on frame evident above weld.



In the process of completely removing the battery box and storage boxes.

touched up the welds on the pinion mount bracket, and boxed the sides with flat stock.



I'm willing to add weight if it is going to prevent breakage. I've had enough failures and can do without more on this car.

 

[rtj]

Picked this up hoping it would work for traction bars. I put one kit on the camaro a while ago.

S&W
DOOR CAR ENGINE LIMITER - DUAL
20-607
Highly recommend for any car using an aluminum front motor plate and engine mid-mount. Engine limiters proved a simple but positive means of eliminating any rearward or forward movement of the engine and transmission during acceleration or deceleration. These limiter eliminate the need for solid transmission mounts which can put excessive loads on the tailshaft housing. Welding required for installation.

 

[rtj]

Billet trans yoke and welded up engine limiters. One thing, they are chrome moly and need to be tig welded with matching rod. I cut off about 4 inches from the tubes, so they were plenty long enough.

 

[rtj]

F



Test fit with old irs diff. There is one on each side. I still need to weld the front brackets to the frame, they are on with a bolt in a tapped hole in the frame. Thanks to 84RZV500R for posting his install.

Now to make solid pinion bushings and install the toe control adjusters.

 

[rtj]

If you were a fan of Monster House years ago, you'll know what I mean when I say I'm about to stamp DONE on this part of the work.



Hacked off the fender flares. They were always to narrow, so I'll extend them 1.5 or 2" before re-attaching them. I'll do this like I did the hood scoop on my Camaro. You have to do some fender cutting anyways to drill the holes for the toe adjustment screws, so I'm doing both at the same time.

Here is the solid pinion bushing pieces. Turned out okay, material was cheap.



Looks like I'll try setting something up for a chrome molly 3" driveshaft. Hopefully they won't mind me sending the trans yoke.

 

[rtj]

sheet metal form.

Rough cut scoop sitting on hood,



Sort of complete hood,



I think this will work with the flares. I'll probably cut the mudflaps off with a radius.