Xschop's 5.3 LM7 build

Arthropraxis wrote:Is it possible/practical to get a new drive shaft made with the Corvette spline?

Yes absolutely and the spline pattern I believe would be 26 by 1.125". The 944 TT bearings and sleeves could easily be modified/changed. Also the pilot tip that is machined onto the shaft could be made to fit a stock GM pilot bearing...

Constantine has manufactured replacement shafts for guys with damaged/worn items.
Ask him about possibly supplying shafts with Corvette splines.

Here is my Email back from Spec.

We extend it to 1.200+ to optimize input shaft stability and keep them from twisting at high tq levels. For comparison a normal spline length would be in the area of .780.



David Norton
P 800-828-4379 Ext: 110
F 205.491.8593

[You must be registered and logged in to see this link.]

That pic in Endernet's gallery would be a .78" spline length.

Then somebody be fibbin.

Alright engineering gurus, before my rebuilt Turbo LSD goes in, I wanna beef the axles now that I know the Type 2 CV's are a go in the 33 spline shafts (couple hundred hard miles so far ) Anyways I was wondering if anyone upgraded their axle shafts and left the inner concave washer out and had any problems?

If it's feasable, there is a set of 4340 chromoloy shafts for sand buggies that fit our CV's and the stronger Type 2 cv's and are 21.375" length. All later manual cars have 21.3125" length axles shafts. Only real question I have is if I leave off the inner concave washers, will the shafts hit inside the stub axles or do the CV joints keep the shaft from high lateral movement?

[You must be registered and logged in to see this image.]

Can't you just take 0.03125" off each end? Doesn't seem like much.

That's not the concern, I don't want to cut a circlip groove into the aftermarket shaft and weaken it (stress riser problem). The Dune buggy guys are running these shafts with no problems and their control arms have larger articulation degrees than our 944 will see.

BTW I have been running Pex #10-204 type 2 CV's on the driver's side for a while now. They are a direct fit for VW# 211-501-331-B or EMPI #87-9917

I mic'd the 944 CV balls at 17.5mm Dia. and the Type 2's are 19.05mm brand new and ARE HEAT TREATED... So I suspect that the BlindChicken writeup had a rebuilt Type 2 that they used as mock-up.

If you want 100,000 miles plus out of these shafts, install a washer to put pre-load on the CV . I don't think any of us expect to get that much out of any drive line component in these things.

I think the Type 2 CV's have a little less plunge action than the OEM 944 CV's. If that is true then you would have less of a chance of the shaft hitting the inner sections of the flange. I would be more concerned about not enough plunge; thats how the cages break.

You know, if anyone was using a G31 and steel (early) trailing arms you can bolt on 930 CV's. The VW guys make Chrome Moly 930 stub shafts and the late 915/930 transaxle output shafts bolt onto a G31.

Stock CV's are 100mm and the 930 is 108mm diameter. The Type 2 CV's are 2mm thinner than the 944's.

Hey 948 what do you mean by "preload"? The buggy guys say the axle shafts are kept in place by the self centering action of the CV's.

And yes the Type 2 cv's have +- 1mm less plunge axially than the type 4's because the outer race is 32mm whereas the type 4 cv is 34mm. However the inner races are both 28mm and fit perfectly on the 944 shafts with inner and outer snap rings installed. The cages are beefier too on the type 2's

As to V8 carrera, I saw a G31 (non turbo) tranny up close a few days ago and wondered how the pinion gear and ring gear rotate and are situated on the back?

The concave washer works like a spring. When installing a stock CV you usually have to push down on the CV axially a little to install the clip (Pre-load). IMO, the intended purpose of the concave washer is to prevent sliding of the mating splines, to improve life reduce wear etc. Again I don't think it will matter too much to our application but in 30,000 miles or so I would inspect them.

Also, check the range of articulation, IIRC the Type 2's have less than the OE ones had.....but IIRC they were still fine for the 944 arm movement.

I originally saw your post over on Gestapoville about the 944 rear control arm articulation not being anywhere near type 2 cv's 17 degree max. The Appletree rep said that 17 degrees is from parallel in all directions, is that the case?

At any rate I will lathe a Circlip groove 2mm wide only to the spline valley depth and stick on new inner stop rings. The factory stop rings are 33 spline and full circular and stop on an inner catch base that creates a stress riser area in the shaft. I'll post dims shortly so you can see what I'm saying.

[You must be registered and logged in to see this image.]

xschop wrote:I originally saw your post over on Gestapoville about the 944 rear control arm articulation not being anywhere near type 2 cv's 17 degree max. The Appletree rep said that 17 degrees is from parallel in all directions, is that the case?

At any rate I will lathe a Circlip groove 2mm wide only to the spline valley depth and stick on new inner stop rings. The factory stop rings are 33 spline and full circular and stop on an inner catch base that creates a stress riser area in the shaft. I'll post dims shortly so you can see what I'm saying.

IIRC the angle I measured was something like 8 dgrees in one directon and 10 in the other, either way is lower than the quoted angle. (You can measure on the bench to be sure).

You could try to cut a pocket, with a large radius, at the base of the shoulder you machine into the spline? A radius would help reduce any stresses.

As to V8 carrera, I saw a G31 (non turbo) tranny up close a few days ago and wondered how the pinion gear and ring gear rotate and are situated on the back?

If you compare both transaxles you will see that both shafts spin the same directions but the pinion gear is on the front of the lower shaft on the 016 and the pinion gear is on the rear of the lower shaft on the G31. The ring gears are on opposite sides of the cases. Because pinion gears drive the ring gears from the outside edge you need the ring gears on opposite sides for each type to drive the same direction.

Been wanting to do this for a while, so finally got around to setting up so I can do these. I will make a lockdown plate on the next one that attaches to the steering rack mounts so I can repeat without alot of set-up...but it's a done deal.....First thing the X-member got is an base wash and a fresh coat of paint. Dried a day or so and set it up on the Bridgeport and Fly-cut the base so it would lock down perfectly perpendicular when drilling the control arm bolt holes exactly 1" upwards....

[You must be registered and logged in to see this image.]

The way the factory should have done it.....

[You must be registered and logged in to see this image.]

Clamp it in and use a dial indicator to get it 100% true...
[You must be registered and logged in to see this image.]

And pre-drill with a locator first. Drill with 12mm bit, then pre-drill bottom and repeat for both sides...

[You must be registered and logged in to see this image.]

Then clean-up the new bolt area for new washers to seat nicely...

[You must be registered and logged in to see this image.]

Then I milled the motor mount locations for 1/2" setback for the V8 install...

[You must be registered and logged in to see this image.]

Then I lathed out 4 brand new 1.00" billet X-member spacers to complete the mod....

[You must be registered and logged in to see this image.]

Nice job, great pictures.
Question, I'm curious about you elongating the engine mount holes, I have just done a trial engine fit and I have 1/2 inch between the driver's side head and the firewall reinforcing plate. How can you use that elongation?

How much are you going to charge for the x-member mods and 1" spacers? I assume that one must use the bump steer units you manufacture.

V8 setback mounts....
[You must be registered and logged in to see this image.]

And I'm going to post this one for sale as a complete kit with TPC engine mounts with AC capability. You would have to get the TPC Bump-steer kit as I don't want to be mailing spindles, especially M030 stuff that I can't trust USPS with ....LOL.....

[You must be registered and logged in to see this link.]

Rob,
I see from your picture that you offset transmission mount controls the setback of the engine.

I queried the engine setback as you can see from my photo that the drivers side cylinder head is touching the nut retaining the firewall stiffener plate. (Will change that to a coach bolt). There is 1/2 inch between head and firewall.

You said in an earlier PM that things vary by the quality of the techs on the day. LOL
Is there variation on the distance from the crossmember to the firewall?

[You must be registered and logged in to see this image.]

Yes, you need a button head or coach bolt as you say on the brake plate for the V8 trans mount to adjust as far back as possible. I got extra hood clearance, and header clearance, along with truck crank pulley clearance with the extra 1/2" - 5/8" setback

Somehow my message is not getting across here.......LOL
How can one move the engine back when there is only 1/2 inch firewall clearance and the engine mounts are in the stock crossmember mounting holes. If I elongate the crossmember holes the engine will touch the firewall. Does your car have different engine bay dimensions?
I just don't see what I'm missing.

I was just trying to post before you did....
More than likely there is some slight variation between the X-member to firewalls as you can see the X-member to frame holes are slotted from the factory. Between the X-member/frame slotted holes and the X-member/engine mount slotting and the V8 trans mount, you have ultimate adjustability.


Also the main point is that even 3/8" set back of the engine gives you an extra 1/2" or so throttle body to hood clearance because the LS throttle body is right in the curvature of the hood, not to mention if you have the hood latch, your air intake boot will also not be touching....check out CFjoija's thread after he installed his V8 mount.

DID you already install your V8 mount? Because the thinner steel reinforcement plate will actually have about 3/8"-1/2" seperation from rear driver's head whereas the 1/4" thick billet brake plate (what I run) has 1/4" seperation....make sense?

I'm not concerned about clearance on the front of the engine because the latch panel and headlight equipment has gone. I'm using the enclosed lockable style hood pins and TPC's headlight buckets.
In addition, my Griffin radiator is in front of the old radiator mounting point and completely under the header panel.

Yes I'm concerned about the hood clearance but as yet have not cut away the center beam for a trial fit. I think I am going to have to grind away a portion of the throttle body also. I'm using Sloan's 1/2" x-member spacers.

I am very concerned about the head to firewall clearance, I'm using a Sloan stainless firewall plate, the big one, I believe its 1/8" thick. I went through this same problem with my V6 MGB and solved it by using a big hammer on the firewall, this is not possible on the 944.

You should not be concerned with 1/2" clearance....I have only 1/4" clearance AND rubber engine mounts and it does not hit no matter how hard I rev it or drop the clutch or lock up the brakes....

To answer the $$$ question. I was going to mod the X-members and make the billet spacers for $300 plus shipping but realized the steering shaft will need an extra 1" extension (like what I did in my gallery)....$400 plus shipping with the shaft extension mod. I need to build a lockdown plate soon...