3 Link Pinion Angle Question: Do we run this at ZERO Degrees at ride height?

[GoDadGo]

Hey All Of You Three Link Guys,

> I haven't located the pinion angle specs for the 3-Link set up in my manual yet.
> Can I assume we run it at ZERO Degrees, compared to the transmission shaft angle since we've got a HEIM Joint upper arm and Poly Bushings on the lowers?
> It doesn't look like we've got a lot of flex back there so I don't see how we can have very much pinion rotational changes, other than what was designed to occur within the suspension geometry.
> I'm trying to get my angle right so that I can get my drive shaft measured and made since the stock piece is a bit short because of my SBC & ZF drive train combo.

Thanks-N-Advance!

Steve

[boat737]

I'm no expert, but my transmission expert friends say to run a 1 degree angle to avoid harmonic vibration in the drive shaft. (1 degree? How in the heck do you measure 1 degree?)

There are some more links in this thread on the other forum. http://www.ffcars.com/forums/17-factory-five-roadsters/560297-pinion-angle.html

I just dropped the engine in yesterday, so I'm at the point of getting my drive shaft dialed in too. Time to start studying up on the subject again.

[ryanmac]

Manual says to run it at 2 degrees at final ride height, making the panhard bar nearly level with the ground. Remember: in go-cart form your ride height (rolling chassis) will become lower once car is at final weight.

You can measure pinion angle using dial angle finder on rearend input flange (driveshaft not installed). A good angle finder (manual) will accurately show increments of one degree, and a professional one (digital) will show tenths of a degree. You can also use it to do your rough alignment (camber).

[CraigS]

As ryanmac says the common FFR spec is 2 deg. That is the pinion is pointed down compared to the engine/trans. I usually compare the crank pulley to a couple of the bolts holding the diff cover on. I 'think' you don't have the drive shaft installed yet so you could measure at the pinion flange.

[Jeff Kleiner]

2 degrees down in relation to the trans output shaft. I have described it a number of times. Search "pinion" with my user name and you should turn up a few threads.

Cheers,
Jeff

[NAZ]

If you have a smart phone Tremec has an app for measuring driveline angles.

[GoDadGo]

Thanks Gang!

I really appreciate the quick response from all of you.