Does anyone know the specs on the taper for the rear tie rod ends for an 85 GT?

I'm trying to confirm the taper angle on the stock tie rod that threads through the tapered hole on the knuckle. I have found that GM makes two tapers: the common 1.5 inch per foot or a 7/8 degree taper. GM also makes a 2 inch per foot or a 9.5/10 degree tie rod taper.

I'm modifying the rear toe link mounts on an altered (Northstar engine) 85 cradle and plan to re-taper the mounting hole on the knuckle from the underside.

Anyone know this angle?

This doesn't answer your question about what taper it is but; I would setup the tapered part in my equipment and use an indicator to match my machine setup to the actual taper on the part? You could also measure the existing taper so you know exactly what you have.

I have matched a few tapers on my lathe setting up my taper attachment this way.

Not sure how you plan on cutting the taper though?

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"There is no more formidable adversary than one who perceives he has nothing to lose." - Gen. George S. Patton
http://www.flowbenchtech.com

My son figured out the taper or angle on the tie rod end surface...I think. We think its a 9.5 degree. We want to find a way to confirm or double check it.

I think we will have to buy a ball joint taper reamer. They range from $80-$140...ouch! Just want to be correct before we buy one and ream the knuckle.

I guess we could avoid the whole thing by cutting the mount off, turn it upside down, and carefully weld it back on.

I have a tapered ball joint reamer, though I forget what angle it is at the moment... I bought it for repairs to an ATV. I can double check the angle tomorrow and try fitting it in a spare '85 knuckle to see if it is a match or not. Worst case scenario you'll know what it isn't... best case is that it's a match and you'll know for sure. It'll be 14:00 atlantic time before I can check it out though.

Got that from a NAPA catalog

http://ecatalograck.genpt.c...p?BookCode=chv10flx#

Here's a link to the main catalog list. TONS of great information:

http://ecatalograck.genpt.c..._linecode_partnumber

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1986 SE Aero coupe.

3.4 DOHC swap is complete and running, now just have to finish the rest of the car...

I dont think there is enough precision in those measurements to determine the taper angle. I got 4.61 degrees or .967 in per foot.
Also, 1.5in per foot is 7 and 1/8 degrees of taper, and 2 in per foor is 9.46 degrees.

Looks close enough to 9.5 degrees

quote Originally posted by FieroWannaBe: I dont think there is enough precision in those measurements to determine the taper angle. I got 4.61 degrees or .967 in per foot. Also, 1.5in per foot is 7 and 1/8 degrees of taper, and 2 in per foor is 9.46 degrees.

You only solved for the angle on one side, you have to double 4.61* to get 9.22*. It must be a 9.5* taper

[This message has been edited by TONY_C (edited 08-30-2012).]

Yes, my son calculated it as a 9.5 degree taper or 2 inch per foot using both the knuckle mount and the tie rod mounting surface part of the stud. I'm amazed that this information was not found with GM or any of the tie rod brands and specs. At any rate, I will post the final result to document for anyone in the future that may need the info.

Thanks for the help everyone.

[This message has been edited by IXSLR8 (edited 08-31-2012).]