EOI: Quick ratio steering pinion

Re:EOI: Quick ratio steering pinion (Admin)

Sat, 30 Apr 2022 12:35:48 GMT

FYI - How to improve an MR2 Turbo’s steering | Project Toyota MR2 Turbo | Toyota MR2 Turbo | Project Car Updates | Grassroots Motorsports

Re:EOI: Quick ratio steering pinion (G_Man)

Tue, 10 Mar 2015 15:21:32 GMT

Marty J

I am wondering if the power steering ECU is somehow malfunctioning due to the new ratio ?

That's funny this has just come up, I was reading this thread the other day about issues the US guys were having with the VMAX quick ration pinion on the earlier model EHPS equipped cars...

http://www.mr2oc.com/showthread.php?t=436121

Re:EOI: Quick ratio steering pinion (MC)

Tue, 10 Mar 2015 13:02:29 GMT

Not so worried about the PS, happy to believe it's a damaged seal at the moment. I don't think it's a smart system, the ecu just turns the pump on and off to save power when you're driving straight? No sensors at all on the rack.

If the pinion ran smooth I'd be ok with loosing the power assist.

Knightrous is right. For normal involute gearing (constant velocity ratio, no sliding contact at the tweth) Pinion diameter = Modulus (tooth size) x Number of teeth. I can still imagine there is a tooth profile that allows extra teeth on the same diameter without introducing slop but would introduce sliding contact and oscillating velocity ratio, but what I have isn't that.

It could easily be bad machining work - they stuffed enough easy things that I'd honestly be surprised if they could correctly machine a helical gear profile. Aside from missing the bearing sleeve entirely, the dowel hole in the end of the shaft was not even aligned through the centre, meaning I had to cut the dowel short.

It could also still be that reducing the OD by 0.65mm was *part* of the problem. Doesn't sound like much but it's probably a 10% reduction in tooth height, which could easily create slack points, depending on how much spare tooth there was in the original profile.

To clarify, my rack is not just loose on centre, it goes loose-tight-loose-tight... The centring problem was PS related.

So at the moment I'm inclined to think there's some combination of:
- 'improper' gear profile because PCD ≠ M x N
- unbelievably **** manufacturing quality - it's not like this is even the first one they made
- my reduction of the OD, which was required to use the pinion at all

I would also like to know the answer to Marty's question - why was there so much good feedback from the US?

Re:EOI: Quick ratio steering pinion (Knightrous)

Tue, 10 Mar 2015 12:08:28 GMT

I'm not studied up on the SW20 PS system. But if it has some kind of position sensor that is on the column side that then references against the rack side, the shift in ratio will definitely cause issues.

Re:EOI: Quick ratio steering pinion (Marty J)

Tue, 10 Mar 2015 10:59:36 GMT

While I am as mystified by this just as much as the rest of you. I must add that this pinion is a rhd version of the lhd US quick pinion that I had purchased from the US group by. I had the UK manufacturer make the helical thread in the opposite direction so it would work for us rhd owners.

So I ask myself, why are there no complaints about the US lhd version ?

If we forget for a moment about the power steering (electohydraulic) for a moment; the pinion fits the rack mechanically correct and also reduces the number of turns it takes lock to lock just like it is supposed to. So why does the power steering behave oddly when activated ?

I am wondering if the power steering ECU is somehow malfunctioning due to the new ratio ?

Anybody want to throw in some thoughts or ideas to get this working ?

Re:EOI: Quick ratio steering pinion (Knightrous)

Tue, 10 Mar 2015 10:30:13 GMT

MC
I still don't understand how you can add a tooth without changing the pinion diameter or rack...

Simply, you cannot do this properly. To introduce another tooth into the pinion while maintaining the pinion diameter and center distances means your changing the tooth shape/pitch to one that does not match the rack, hence why your getting all the slop now.

If your looking at adjusting the steering ratio, I would look at a steering quickener box that is fitted into the non-collapsible section of the steering column.

These are regularly used in rally and speedway where they need quick steering movements and good feedback.

Re:EOI: Quick ratio steering pinion (Falcon)

Tue, 10 Mar 2015 09:11:29 GMT

I also can not understand how this could possibly work correctly. Thanks for posting your findings MC. Most informative. I feel very sorry for Marty who organized this whole damned thing and Im sure acted in good faith.
I doubt your machining of the pinion has created any of those symptoms you describe . (Loose on centre. Notchy and binding elsewhere.) It is pretty much as I would have expected unfortunately.
If anyone else has fitted this quick ratio pinion I would be most interested in an in depth appraisal of your experience. Something along the lines of MCs would be great. Thanks.

Re:EOI: Quick ratio steering pinion (MC)

Tue, 10 Mar 2015 00:19:48 GMT

So I finally installed this pinion today. Not many people seem to have given feed back so I will.

I was in pretty much the same boat as WIDEMR i.e. I had a 'rev A' rack and my QR pinion was missing a bearing sleeve. The pinion bearing in the rev A rack is only slightly bigger than the pinion teeth outer diameter - not enough fit a strong sleeve. So I tracked down a rack assembly from after September 1993 ('rev B') which runs a larger bearing, then got a bearing sleeve from BSC (p/n: PI121608), then had the pinion machined down from 19.7 to 19.06mm and pressed the sleeve on. That bearing sleeve fit perfectly into the rack so I was finally ready to test it out.

First problem I had was the power steering acting up. Same sort of symptoms as Marty and others had with a damaged seal - i.e. steering pulls to one side and tends to steer away from centre. Even though the PS was odd, the steering ratio definitely felt like it should have been that way from factory - much livelier.

Then I disconnected the power steering pump, having read that it doesn't do much over 30kph. That's BS - the steering was still heavy at 90kph but had no extra road feel. I wouldn't recommend disconnecting the PS but iyou could live with it. Manual racks might work better, not having to pump steering fluid around.

The main issue I had was that the steering had a really wide dead band of about 4 degrees - it was great mid corner but sucked when changing direction. I did adjust the rack preload but there really was no happy place - either the rack was very loose, or it was tight, notchy and still with loose spots. It's possible that this issue is due to me machining the pinion down from 19.7 to 19.06. If any else has had these pinions fitted without introducing slack into the system I'd be interested to know. I still don't understand how you can add a tooth without changing the pinion diameter or rack...

On a side note, Marty was very helpful in getting dimensions and other info to get the pinion in the car. Glad to have at least tried it but will refit the old rack tomorrow : /

Re:EOI: Quick ratio steering pinion (Marty J)

Thu, 21 Aug 2014 21:52:50 GMT

Please don't throw the pinion away as it may be able to be resolved.

Re:EOI: Quick ratio steering pinion (WIDEMR)

Thu, 21 Aug 2014 21:48:56 GMT

I ordered a Pinion A, but i have received a Pinion B that still has not been made right? After i already had to send it back to Ireland at my cost as soon as i got it?

I dont think im interested in send it back again and seeing if they will fix it.

If anyone has a Pinion A or B that has been made correctly, that is interested in selling, please let me know.

Re:EOI: Quick ratio steering pinion (Marty J)

Thu, 21 Aug 2014 20:10:59 GMT

I just measured type A and B. The part missing is the main but not only difference between type A and B.

Theoretically if a collar was able to be pressed on depending on the size of the collar, you could make a type A or B pinion.

Re:EOI: Quick ratio steering pinion (Marty J)

Thu, 21 Aug 2014 19:57:30 GMT

dwyer125
I still have to check mine.

Is it possible the ones with only 2 steps could have a sleeve machined and pressed on?

Pm returned.

I'm not a engineer so I don't know if it is possible to press one on. If it is able to be pressed on, so long as the pressed on part rotates with the rest of the pinion body, then I cannot see there being a problem.

Re:EOI: Quick ratio steering pinion (dwyer125)

Thu, 21 Aug 2014 10:54:52 GMT

I still have to check mine.

Is it possible the ones with only 2 steps could have a sleeve machined and pressed on?

Re:EOI: Quick ratio steering pinion (Marty J)

Thu, 21 Aug 2014 06:18:17 GMT

Both types of pinion have three steps just above the helical thread.
MC and WIDEMR pinions only have two of these steps.

I can either have them returned again (I know, it's a pain in the arse and a long wait) or return them to me and I will offer a refund as soon as funds permit. Either way this won't be resolved quickly I am afraid, sorry. I can imagine your patience has run out by now.

One other option would be to see if a local manufacturer could make the missing part, but at your own expense as I'm skint at the moment. I'm not sure if it can be done, but if you would rather not wait any longer it's up to you guys.

Re:EOI: Quick ratio steering pinion (Marty J)

Thu, 21 Aug 2014 05:55:52 GMT

These two pinions have been tested and work correctly.
The type B steering rack rev3 works on my rev2 with no mods needed.

The first two photos are type A pinion.

The photos below are type B.