[slyhog22056]

Hello all, I am building a 347 stroker for my datsun 280 z and i have been desperately trying to locate a front steer power rack and pinion. All that i can find are rear steer power racks. If anyone can help it would be appreciated, fabricating tie rod ends and mounting isnt any problem at all. I think i have about 30 to 36 " of room for the rack.

Thanks in advance

[powerrodsmike]

I am assuming that you are referring to the position of the rack on the crossmember, and not the position of the input shaft.
Mustang II's were front steer. So were T birds.

Check Flaming River and Maval for sources of various types of racks.

You need to read these articles.

http://www.crankshaftcoalition.com/w...inion_steering

http://www.longacreracing.com/articles/art.asp?ARTID=13

Later, mikey

[slyhog22056]

Thanks for the info, was totally unaware that mustang II's were frone steer and T Birds, have to look around, wasnt looking at them at the junk yard because i thought they were manual steer. It is just so hard to autocross a Datsun even with the 17" big honking steering wheel.

[Dave5605]

My 86 vette is a front steer. Rack is 'relatively' inexpensive too. $222 at Advance Auto including the core charge. If you have a core its $75 less.

[Holdon]

I had the same problem as you recently and did a fair bit of searching. I found the cheapest, strongest and most readily available front mounted power racks where out of Toyota Vans like the Hiace. They are commercial so are very strong, parts are plentyfull, and like most Toyota parts they dont cost an arm and a leg! I have some pictures in my gallery of my conversion.

[ScoTFrenzel]

Originally Posted by slyhog22056

Thanks for the info,

It is just so hard to autocross a Datsun even with the 17" big honking steering wheel.

There is more to steering geometry than bolting in a rack and making tie rods reach.
Bumpsteer and roll steer are a major consideration, especially since you are "turning corners" with lots of body roll involved.

You could spend a lot of time creating the "undriveable Datsun from Hell"

BillyShope, member here, is chassis engineer extraordinaire, and has a personal web site.
http://home.earthlink.net/~whshope/ page 27

[Holdon]

Originally Posted by ScoTFrenzel

There is more to steering geometry than bolting in a rack and making tie rods reach.
Bumpsteer and roll steer are a major consideration, especially since you are "turning corners" with lots of body roll involved.

You could spend a lot of time creating the "undriveable Datsun from Hell"

BillyShope, member here, is chassis engineer extraordinaire, and has a personal web site.
http://home.earthlink.net/~whshope/ page 27

Yep you are right about that! Main thing is to have your rack ends in the same plane as the line from your top and bottom swing arm pivots (assuming you have double wishbone) and also make sure your tierod ends are in the plane of the akerman angle. (a line from centre of diff through balljoint axis)

[powerrodsmike]

Originally Posted by Holdon

Yep you are right about that! Main thing is to have your rack ends in the same plane as the line from your top and bottom swing arm pivots (assuming you have double wishbone) and also make sure your tierod ends are in the plane of the akerman angle. (a line from centre of diff through balljoint axis)

Maybe you already said this, but I'll say it a little differently.
If you want to avoid bumpsteer, your tie rod ends must fall within a set of imaginary lines drawn between the upper and lower ball joints and the inner pivots of the upper and lower a arms, and shifted inward to compensate for the difference in position of the steering arm. As a Datsun Z car has struts in the front, (IIRC), you probably only need to consider the length of the lower a arm.


Rack extenders are available to make a rack longer at the inner tie rod end, if you need to adjust the length. There are center steer racks as well, and some of those have bars that you can mount your inner tie rod ends wherever you need to, then fab your tie rod link and outer to the length you need.


I think I'd mock up your steering, then check it with the instructions to check bumpsteer that are found in that Longacre racing article I posted a link to above.


BillyShope is a very smart guy, and was an engineer at Chrysler, (he was one of the original Ramchargers), ... most of his website emphasis is on modifications of the rear suspension for drag racing.


Later, mikey

[slyhog22056]

If i install the power rack with the same mounting locations (front to rear and side to side) as the manual rack there wont be any change in bump steer or ackerman angle.

[ScoTFrenzel]

Originally Posted by slyhog22056

If i install the power rack with the same mounting locations (front to rear and side to side) as the manual rack there wont be any change in bump steer or ackerman angle.

IF the tie rod ends (inner and outer pivots) are in the same locations as the factory car....... you will get factory geometry. Which is not guaranteed to be correct for a race car which uses altered suspension settings.