Determining Driveline Angles

[smhigh]

Inland Empire Driveline Service

"This booklet concerns the placement of power train components in the chassis. The engine/transmission, the third member and the drive shaft must be installed to work in harmony if driveability is your goal."

OPEN PRINTABLE DOCUMENT

[The WidowMaker]

It really does matter.

you are correct. its a HUGE point. but, if the ds is zero there is nothing to add or subtract and therefore nothing to confuse. its the main reason i do it that way. you do have to rezero the level every time an adjustment is made, but that is quicker than doing the math and rechecking your measurements.

They said to subtract the angles. The were wrong then and still are today.

its funny how that works.

[Vegas69]

Originally Posted by smhigh

Inland Empire Driveline Service

"This booklet concerns the placement of power train components in the chassis. The engine/transmission, the third member and the drive shaft must be installed to work in harmony if driveability is your goal."

OPEN PRINTABLE DOCUMENT

Yep, great document.....

[67ragtp]

I pretty much had the same scenario about a month ago with my trans pointing down over 4 degrees. As said earlier if you dont want to chop the tunnel you will have to live with it. In order to get my drive shaft level at 0 degrees I had to put a 5/8 thick plate of 304 stainless under my trans mount to lift it, then slice the tunnel from the firewall hump back about a foot and lift it 1 inch or so, make filler plates or a new hat and reweld(it sucked) but Im glad I did it now that its done. By getting the front drive angle minimum gives you more options/ wiggle room to steer your pionion angle where you want and still maintain very reasonable working angles. On these lowered cars be careful how high you go with the pinion, tunnel to yoke starts to get close.

I have to admit it was Todd who gave me the harsh reality of how much work I was in for, and I thank him for that(did I mention how it sucked).

Rich

[ScotI]

I did start to read that IEDS 'document' but missed the portion where it tells when to subtract for the WA & when to add. It also mentions the uphill d.shaft should be avoided & that it's a common issue with 'hot-rods'.

But, that's w/a standard single shaft & single u-joint @ each end arrangement. I'm waiting on feedback now about the feasibility of using a single shaft w/a double CV joint set-up on the trans output end of the shaft. I have confirmation from one trusted source that it will work but I'm waiting to hear from the driveshaft place for confirmation (since they're building the shaft, I want their 'buy-in').

Using the CV joint would require setting the pinion @ zero (or near).

[Vegas69]

I know that is done, my understanding is it won't hold much power. Let us know..

[ScotI]

Originally Posted by Vegas69

I know that is done, my understanding is it won't hold much power. Let us know..

Could you elaborate? My understanding is these dbl CV joints are for larger, heavy trucks so I thought they'd be decent from a strength stand-point.

[XcYZ]

I got an e-mail from Greg Frick from Inland Empire Drive Line Service, he read this thread and asked that I'd post this on his behalf:

The assumption made in the piece is that the builder wants to actually drive the car on the street. Everything in it is aimed at making a trip from Bangor, Maine to San Diego, CA. smoothly and free of vibrations.

A real Sherlock Holmes will eventually find that Spicer thinks you can live with 1.5 degrees of uncanceled u-joint working angle. We have found that Enthusiasts are not average people and that they will feel any uncanceled angle greater than 1/2 degree.

If it is an eighth or quarter mile car you, the driver, could put up with anything for the 6 to 14 seconds you are running down the track. The sad part is that your axles, rear end and transmission won't like it and will break sooner or later if there is a lot of uncanceled angle.

The CV that is being considered is not a great solution. Typically these are cast parts which wear out fast; in about 50,000 miles usually. Also, they will not run at zero degrees because of the spring inside them. In a drag race car they are hand grenades waiting to go off.

Finally, any time there is a conflict between mother nature's Physics and a desired set up, the Physics will prevail, sometimes at considerable cost to the owner. It is better to get it right regardless of what part of the project has to be modified or abandoned.

Hope this helps,

Greg

[Vegas69]

To do what Greg recommends, cutting the tunnel is the only option.

The compromise point in this thread is which each evil is worse. LARGE canceling angles or small unconventional angles. I found the small unconventional angles to be the smoothest alternative. When you lower these cars beyond what they were engineered to do 40 years ago, you find yourself in a less than an ideal engineering position.

[ScotI]

Thanks for forwarding the message/info.

The truck is being built as a driver. That was the main reason behind raising the suspension mounting/pivot points (to keep them from hitting the ground). So while I won't be making any trips from Bangor, Maine to San Diego, CA, I will likely do the TX to Columbus OH or head the opposite direction out to Scottsdale AZ for some Good Guys shows.

I'm going to re-measure things & see what I get @ a 3° down trans angle. My next option is the 2pc shaft. I'll need to see if they suffer the same fate if that 2nd shaft slopes 'the wrong direction'.