Well, this has me a little concerned.

No VIN stamp on the body. I've got one more spot to check...the one that was used from 1960-62. I've got the sale documents for this car...WTF. I've got the vin tag, but there is NO body stamp so far. I'm sure I'll get put in jail if I just whip out the punches and knock a number into a panel...it's a $600 bill to get the province to do it - pretty pissed about this. I know I should have the government do this, but other than the fact that I just publicly announced this problem, who would know?

I checked the final location for a VIN and not a mark on this car. Dammit.

Time to get the trans tunnel sorted out.

The 240 tunnel will work almost perfectly. I was amazed when I knocked out the lip where I lopped this off the donor car that was just about perfect.



Both sides.



I toyed with the idea of reusing the base of the old tunnel, but it just didn't make any sense to do that when I still had to build the flange to attach this tunnel to the firewall. It really isn't the right shape to match at the base, so better do it right.

Didn't take any picture of how I did this...watch the video when it's out.

Here's the top joining part.





Getting it all levelled off was tricky - but worked.



Took two stabs to get the shifter dead centre.



Then the skirting got done. This will get tidied up and finished this week. Then the tunnel is a little closer - next up will be the drive shaft fitting.

That tunnel fits like Binky's driveshaft. Looks great!

Still working on the side flanges...but each day, a little more gets done. First, a little sheet metal welding.

Front.


Now that's welded. Tacks are clearly visible and the weld is fully penetrated.



Wrapped corners (just for the welders...sort of an inside joke).



These have very low distortion and can be effectively hammered. Not a gas or TIG weld, but it's a tunnel.

We're going to be needing a bunch of shape to get this to close up nicely.



I hand hammered these (no E-Wheel yet) - just using a shot bag and hammers.

Getting there.



That's more like it - a lot of shape actually.



The shape added is a bit more evident from this angle. It's also clear that I need to shrink that top edge to get the flange to sit flat again. No big deal.



Moving along - should have it all installed this weekend. Woo hoo.

Anyone reading this thread know anything about drivelines? Specifically, driveline angles for 2-piece shafts. The differential sits at 0º and the engine is at 3.4º.




The Spicer calculator says that I've got to run the operating angles of the ends of the shaft at +- 1º with no operating angles greater than 3º for vibration free performance. This means the angle of the first shaft has to be 6º and the second shaft should be 3º to yield operating angles of 2.6º, 3º and 3º.

Has to come up a bit.


Floor tunnel section needs to be cut - this is on the floor (it's really 2º).



So before I cut things...does this make sense. I know the front shaft will need to be lengthened...I'd like to know have to do this over.

What Spicer says is probably correct - I'd defer to the experts here. My feeling, as you know, is to keep two of the in-phase joints at equal angles and keep the third one as straight as possible. But if Spicer says that you won't feel a vibration with one joint at less than 3 degrees, run with what you've come up with.

As you also know, each u-joint will change constant rotation speed into a variable rotation speed when it's deflected. The maximum speed is 45 degrees off the axis of the yokes. Putting another yoke in phase and at equal (or opposite) angles to the first one changes that variable rotation speed back into a linear one, so the output is back to a constant speed.

The deflection at the third joint will put some variable rotation speed back into the system. This is why I dislike splitting the angles evenly. I think it's better to keep two in phase at equal (or opposite) angles and one at a minimal angle (to keep lubrication active and to keep the joint from seizing up). If possible, try to keep the heaviest section of shaft at a constant rotational speed, to keep the acceleration vibration of the shaft to a minimum.

With a live axle this means keeping the front joint at a minimum angle to maintain lubrication, and having the rear two joints in phase and at opposite angles, because the rear axle articulates and trying to keep the rear shaft in line with the pinion is impossible. With an IRS car you could keep either shaft straight relative to the transmission or differential pinion - it doesn't matter as much.

If you run the shaft out of the transmission at 1 degree deflection (2.3 or 4.3 degrees), what are the break angles at the middle and rear joints? They should be less than 3 degrees each, right? How long is the shaft in total - would it make sense to run a single piece shaft? What would be the critical speed of such a thing, relative to road speed?

I'm not too sure how much further we need to go down the rabbit hole - the good books on the subject are locked up behind a pay wall and I can't get at them (for less than $100 USD - I hate that. So the next best thing is to call the guys at Tech Support at Spicer and lay it all out for them. Aside from the horrific elevator muzak, the tech was nice and knew what he was talking about.

They have a selection of calculators: https://spicerparts.com/calculators

First up - The Operating Angle calculator - https://spicerparts.com/calculators/driveline-operating-angle-calculator

Feed this thing with my angles (drive = 3.4 down, shaft 1 = 6 down, shaft 2 = 3 down and driven =0) so this leaves the following operating angles, first joint = 2.6, middle = 3, differential = 3. The details says that if I run the first joint and the last joint in the series no more than 1 degree different and nothing over 3 degrees...so all good. On the edge, but not against the rules. It's just operating angles - nothing fancy.

If it's outside of these parameters, the calculator tells you that death will ensue.

Next up - The Torsional Analysis calculator- https://spicerparts.com/calculators/torsional-analysis-calculator This tool will give an estimate of various predicted torsional and inertial effects that can damage many of the driveline components in a vehicle. You need more data - length of the shafts and distance the diff is off the centre line.

So to the above data we add, shaft 1 will be 26" long and shaft 2 is 22" long. The diff is 1.875" off the centre line. Bung this in putting all the off set to shaft 2. Then set the shaft RPM to 3000 for the first run.

Inertial Effects-Drive Degrees 6.39 Rad/Sec 1229.2
Inertial Effects-Driven Degrees 9.45 Rad/Sec 2684.3
Torsional Degrees 7 .69 Rad/Sec 1776.0

* Max Allowable Inertias - 1000 Rad/Sec/Sec
Inertia Effects (Drive) - usually caused by a large operating angle at drive end of driveshaft.
Inertia Effects (Driven) - usually caused by a large operating angle at driven end of driveshaft.
* Max. Allowable Torsional - 300 Rad/Sec/Sec Torsional - usually caused by large, unequal operating angles or out of phase driveshafts.

So at 3000 RPM, it's above the max allowable at the transmission and over twice allowable at the differential...let's not talk about torsional limits. Yikes.

I ask the tech - he says "If the calculator runs, it's going to be OK - it won't fail" - I reply that it may be like driving in a paint shaker...he doesn't respond to my witty retort. Hey, it was Monday morning...I understand.

So then I change a few things. Basically, I ran a quick and dirty sensitivity analysis - without changing the drive or driven angles. First, I varied the speed. 3000 RPM is around cruise on the highway - so not really smooth (hard to know what all this means, but most things in my car are not well isolated for NVH and I'm not all that sensitive to it, but let's be realistic). So I up the RPM to 5K...calculator still works.

Inertial Effects-Drive Degrees 6.39 Rad/Sec 3414.6
Inertial Effects-Driven Degrees 9.45 Rad/Sec 7456.5
Torsional Degrees 7 .69 Rad/Sec 4933

How about 6K

Inertial Effects-Drive Degrees 6.39 Rad/Sec 4917
Inertial Effects-Driven Degrees 9.45 Rad/Sec 10737
Torsional Degrees 7 .69 Rad/Sec 7103

7K - BANG - it gives the warning about death.

OK - let's play a little with the offset. If I split the distance between the shaft at 3K (well, 1" to the front and 7/8" to the rear) things look great at 3k

Inertial Effects-Drive Degrees 4.89 Rad/Sec 719.7
Inertial Effects-Driven Degrees 5.27 Rad/Sec 835.9
Torsional Degrees 5.08 Rad/Sec 774.9

Wonderful - let's do this. No idea what it all means, but inertial effects are below tolerance and the torsional thing is only double what it should be...plus a little.

REV it up - 5K BANG

6K Well, if it wasn't going to do 5...I tried it anyway. WTF. I tried every which way to move angles and offsets and it all blows up. Nice. I found the optimal solution by looking at it. It still won't work well, but it will work. Just don't drive it fast. Ya, right.

So what about a one piece. I did this and the shaft angle is 4.6º (3.4 and 0º for drive and driven) - so I can't make it past the first calculator.

The angle results from the engine being higher than the diff...and I can't tilt the diff up 3º without having to cut apart the rear subframe for the 4th time.

Now looking at CV joints instead of U-joints.

Edit - jesus, Matt - understand the damn post you're replying to. I had a LONG winded post about splitting offsets, thinking that you'd doubled the offset. Crap.

First: you can't use this calculator at 6001 RPM or above. Try it even with a straight shaft. Kaboom.

Second: I modeled up the offsets in CAD: with your first try, no lateral offset to the front shaft and all of it in the rear, you've got deflections of 5.727 degrees at both center and rear u-joints, which is a compound from the 3 degree vertical and 5 degree horizontal deflections. With 1" offset at shaft 1 and 0.875" offset at the rear, the actual break at the center diff is back down to 3 degrees while the rear drops to 3.771. The front joint is up to 3.407 degrees in this case.

I got similar results to yours - at 4000 everything's fine, but at 4100 the system with offset steady bearing blows up while the other one is fine to 6k, WTF? At 4000 RPM with the offset steady bearing the inertial values drop from 2185 Rad/Sec at the drive end down to 1279, from 4772 Rad/Sec at the driven end down to 1486, and the torsional effect drops from 3157 Rad/Sec down to 1378. A huge improvement everywhere.

One last hail-mary: Build your car exactly as in the first example, but split the lateral offsets .001" at the steady bearing and 1.874" at the rear. It lives at 3000 RPM but can't even take 3100 RPM in this case, saying that the angle at the 2nd and 3rd joints is 5.73 degrees. No warnings at all if you don't move the steady bearing sideways, makes me think there's a bug in the program.

I modeled it out again using the most direct line I could come up with using two shafts, and the best break angles I could get are 3.619 degrees at the front joint, 3.546 degrees at the middle joint, and 3.510 degrees at the rear joint. The middle joint is offset 1.0141" laterally, with the diff offset the rest. From the side the first shaft is 6.250 degrees down and the second shaft is 2.702 degrees down. I could probably get them all identical with a little more effort, but they're all within 0.1 degrees so that's pretty close. Let's see what happens:

The inertial effects are now 5.13 degrees drive, 5.05 degrees driven, and 5.09 degrees torsional. At 4000 RPM the Rad/Sec values are 1406, 1365, and 1385 respectively.

It still crashes at 4100 RPM, but it's saying that the angle between the first and second shaft is 4.197 degrees, which doesn't match my data.

I guess it's time to look at CV joints. A single piece shaft would have net angles of around 2.5 and 5.2 degrees front and rear, FYI, but the overall length might be a problem unless you run a 3" diameter shaft and have the tunnel to house it.

It's been an interesting adventure getting this sorted out. DL guy was an annoying episode in itself - I just wanted confirmation that this is all going to be OK, you know, sometimes I need to be rocked gently and have someone sing me a song...well, all I get is an email in reply to my call (guy on the phone says...email your question to xyz@differential-dudes.com) - seriously...I was just about foaming as I dashed off an email and get a bunch of one line replies, starting with "I'm not seeing it - it will be fine" - are these guys engineers or what? I explain that I'm on the edge of driveline failure at every turn (as Matt has ID'ed) - like vary things a little and I'm having my fillings knocked out.

This continues from 9 am this morning until now (6:30 pm) - all I want is a price quote and a spec validation (shaft size so I can build the damn tunnel). Can he fit the rear end etc. Drove me nuts. At one point he thinks my car is AWD? Only those reading this thread who know me will get this and be ROFL. I'm basically, trying be remain civil and not go all sarcastic and scuttle the deal with one of the only guys that can solve the problem.

One piece will be no problem - the diff flange to the end of the tailhousing is 49.75" with 4.6º down...so even in steel if you take away a couple of weld/bolt flanges and a slip yoke the shaft won't be more than 46". Well within any spec I'm aware of.

So a carbon one piece shaft is $1450 USD with all the adapters/slip yokes/u-joints balanced and done out the door. I'll order it when I need it. Aluminum would be $900. So Im saving like crazy for the next 6 months. Case closed.

Jesus.

Are you still using U-joints on this new shaft, or are they CV joints front and rear? Rear for sure, but your front break is still almost 3 degrees if I've read your situation correctly.

I was really impressed with the transmission mount you fabricated. This is just getting out of hand Seriously, unbelievable amount of work and attention to detail.

I didn't take a lot of pictures this time. There may be a post, but don't hold your breath.

I like the stop motion, but this one showed more content and is good too. Mix 'em up!

A thought before you box the bottom of that crossmember - weld in a couple of sturdy plates with some captive nuts so you can add a driveshaft loop slash crossmember beneath. I don't think too many track day cars "require" a driveshaft loop but you never know - may as well future proof it.