MR2 rack and pinion Set-Up how to's and test results

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jackedaw11
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MR2 rack and pinion Set-Up how to's and test results

Postby jackedaw11 » 05 Sep 2006 12:10

After looking for a rhd 240z rack for my 510 and coming up with no results; posting on forums and only drawing sellers from nigeria who swore they had the rack and would send it quickly if I would just wire them the money, I decided I needed to find a different rack and pinion set up for my car.

Enter the ghetto-est mr2 ever. It was $100 on craigslist, all sorts of smashed up and 200 miles away. The car had a rough life, when I picked it up it only had 3rd, 4th and reverse gears. 200 miles later, after I limped it home, it had no gears, but it still had a good rack and pinion.

I took the rack off and measured it, with the tie rods it was a couple of inches too wide for the 510's anorexic track. I thought about cutting a section out of the tie rod, sleeving and welding it back together, but that made me a little nervous. I tried to go to machine shops to get the tie rod turned and threaded further down, no one wanted to touch it. Oh well, time for a day in the pull a part.

Armed with a tape measure, I wandered around the import section of the lot until I found a car that had tie rods that looked like they might be winners. The car I found was a 1985 Cressida (any earlier years have the same wonky arm steering as the 510). The tie rod looked about the right lenght and diameter. As it turns out I would need to find another one as well, as the best tie rods are on the drivers side. The ones on the passenger side have big brackets for luxury car style steering dampers.

The cressida tie rods will thread right into the mr2 rack, and the 510's tie rod ends will thread right on to the cressida tie rods, beautiful ain't it? Though you will need passenger side tie rod ends to thread onto the drivers side tie rods, which is a little odd...

Anyways, I re-assembled the rack, with the cannibalized tie rods, and new tie rod ends (new tie rods run about $70 a piece!). After I had it assembled I made some top brackets out of flat steel that I bent around a 2" pipe and then welded onto my swapped crossmember.

Now the rack puts the inner pivots a couple inches further out than the stock 510 steering did, which I understand can run you into problems with bumpsteer. Now, my car is dropped to the earth, so I figured this might create some problems for me.

I have been driving my car around for a month or so now. I didn't want to post up my first impressions prematurely only to have it fail on me, but now I think I have a good impression of the way it works.

I am running paul's coilovers, 275lb springs, camber/caster plates, and 280zx struts, no swaybar at this time; I am using the stock steering column, slightly modified with a newer u joint and custom linkage to the rack.

At its very worst, I would say that bumpsteer is negligible. I have riven this car over some seattle roads that look like the surface of the moon, and bumpsteer is not giving me a problem at all.

I went to the bremerton autocross yesterday, and I had a blast, I did not notice any bumpsteer at all.

I highly reccommend this swap, after having street tested it and having auto crossed I can say only good things about it. The steering is smooth and responsive, and it gives the car ample angle. I'm not sure how it compares to stock, but I would like to check it out at the meet in vancouver this weekend if anyone is willing to let me take some measurements.

If you have any questions post em up, I will try to get pictures up if there is a demand for them.

ben
Last edited by jackedaw11 on 06 Sep 2006 13:09, edited 1 time in total.

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bueiz
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RE: MR2 rack and pinion Set-Up how to

Postby bueiz » 05 Sep 2006 13:39

RHD 240Z Rack:

http://www.zspares.com/catalog/product_ ... cts_id=321

I like your write up. It's sounds worth doing.

freekwonder
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RE: MR2 rack and pinion Set-Up how to

Postby freekwonder » 06 Sep 2006 11:06

sweet nice write up I think I am sold on the mr2 rack. What are all the parts that are needed. You confused me alittle when you mentioned the two drivers side then the passagner side being needed also?

jackedaw11
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Postby jackedaw11 » 06 Sep 2006 11:37

You need the drivers side tie rods from the 85 cressida, and you need passenger side tie rod ends from the 510.

So you need a rack out of a 1985-89 toyota MR2
2 Drivers side tie rods off a 1985 or newer cressida
2 passenger side outer tie rod ends from your 510

freekwonder
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Postby freekwonder » 06 Sep 2006 12:05

oh ok. sorry its been one of those days at work. sometimes I hate working for the Government. Thanks for the help.

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S15DET
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Postby S15DET » 11 Oct 2006 09:23

OK, here I go. Yesterday I bought two '85 Cressida drivers side tie rods, and won an ebay auction for a pair of passenger side tie rod ends for the 510. My only concern is that I cannot get the rack rearward enough before it hits the under-side of the engine block. The height is about right. I've got the rack on a jig that allows me to move it up/down, and forward/backwards in a controlled mannor. Once the outer tie rods arrive, I'll bolt everything up and start taking measurements. The fact that the rack will be a little too far forward will effect the ackerman a little, but that I might be able to fix by using the shorter 280ZX steering arms. Well see. I'm mainly concerned about bump steer. I'll be sure to give some numbers after I've got everything measured. My biggest worry, however, is the angle of the U-joints on the steering shaft. Do you have any pictures of the steering shaft going to your MR2 rack?

Great find on the cressida tie rods, they appear to be just the right length.

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S15DET
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Postby S15DET » 15 Oct 2006 11:24

One problem with the Cressida tie rods is that the ball housing is much longer than the ball housing of the MR2 tie rod. It puts the pivot point about 1/2" further out, which effectively lengthens the steering rack by about an inch, and it was already a little too long. Did you look at any other tie rods? I'd like to find one with the smaller ball housing, and the shorter length and M14 1.5 thread. I will have a look through my local pull-a-part yard, but plan B is to cut these two toe rods and make a hybrid Cressida/MR2 piece. I'll have to measure the hardness at work to determine if this is possible.

datzenmike
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Postby datzenmike » 15 Oct 2006 13:52

There is nothing, I mean NOTHING, like filling a need, and finding and making something like this work! The research, time, fabrication, field testing and the final satisfaction with the results. Congrats, I wish I had more time for it myself.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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icehouse
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Postby icehouse » 15 Oct 2006 22:15

Hell yeah, my rack rides the bumpy seattle roads on a daily basis. I never want to go back to the steering box and idler arm, what a rip off....
"People don't like it when shit doesn't match their rule of thumb." Sam

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S15DET
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Postby S15DET » 17 Oct 2006 10:48

Here’s something very interesting…
http://forums.club4ag.com/topic.asp?TOPIC_ID=147150
It’s a quick ratio rack and pinion set for the MR2 steering rack.

My used MR2 rack has a bad dead spot right on-center. I have been planning on sending it in as a core for a rebuilt unit. However, for $200 I can get this Quaife quick ratio set.

My question is, do I need it? Since I’ve never driven a 510 with a MR2 steering rack, I don’t know what the steering ratio is going to feel like. It may be that the stock MR2 steering ratio is quick enough. So jackedaw11, you may be the only person who can give a subjective opinion on this matter. Having driven your car, would you prefer for the steering to be quicker? With your stock MR2 rack, is the steering faster or slower (I’m talking about steering wheel angle change v/s toe change) than the stock 510 steering? How is the steering effort when parked, or when backing out of a parking spot? If the parking lot effort is already high, then I don’t want a quicker ratio, because this will make it worse. Let me know your opinion please.

And how about you with other racks? Give me your opinion on the steering quickness, and I can research the rack ratios to see how the MR2 unit will compare.

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S15DET
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Postby S15DET » 17 Oct 2006 12:24

Here's my lunch project this afternoon; hybrid tie rods using the MR2 inner ball housings and the threaded end from the Cressida.

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icehouse
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Postby icehouse » 17 Oct 2006 12:35

I like all kinds of racks :)
"People don't like it when shit doesn't match their rule of thumb." Sam

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constellation
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Postby constellation » 19 Oct 2006 20:27

Do you happen to know if this swap will work with an sr20det? It sounds like a good, available swap - but I would probably have to do this swap before the engine went in. Any ideas?

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duke
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Postby duke » 20 Oct 2006 09:28

It actually works best with a front sump sr or ka swap because of the reversed crossmember. This allows you to mount the rack directly to the x-member.
Duke Schimmer

'72 2-Door 510
"Simplify and add lightness."

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S15DET
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Postby S15DET » 21 Oct 2006 19:26

Mine is a SR, and duke is correct that this will be much easier because of the reversed crossmember.


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