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Datto 1600 Steering Upgrade? Go To Option?? http://www.ozdat.com.au/forum/viewtopic.php?t=33070 |
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Author: | REI600 [ Sat Jan 17, 2015 9:23 pm ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
for the gains it would Give, 5000 is a pretty reasonable amount i think. And the fact that it would last and last... pays for itself down the road. Very interesting! |
Author: | AlanDatsomefun [ Mon Feb 16, 2015 12:16 pm ] | |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? | |
There was a write up on here before about doing a rack and pinion conversion, but most of us were less than impressed as the guy didn't put up any pictures and claimed it was for "safety reasons" or something as he was a "qualified engineer" but couldn't back up what he was saying. Even before I had an opportunity to post photos, I just got lots of criticism: "Ha Ha Ha ... grow some balls, ... and etc. and no photos - then it didn't happen..." Consider this: You build an engine and a rod bolt lets go, you end up with a rod through the side of the block ... who is affected? You! It hurts your wallet, but you go buy a new engine. You build a rack and pinion conversion for your race car and it seizes up as you go through a corner and you crash into a wall. ... who is affected? You! It hurts your wallet, but you go build a new car. You build a rack and pinion conversion for your road car in your back yard. It is based on selected ideas and potentially incomplete information placed on the Ozdat forum. Your steering seizes up as you go through a corner and you crash into an oncoming car and kill three people. ... well, you get the idea. |
Author: | RJB510 [ Mon Feb 16, 2015 12:45 pm ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
Same thing can happen whilst using your mobile phone when driving, drink driving, speeding, falling asleep at the wheel, getting a sudden flat tire and getting pushed into incoming traffic. Mate, This forum is an information sharing resource. You said you wouldn't post photos! prior to everyone giving you stick about it. Even if people didn't copy you, we just wanted too see your workmanship and how it fitted up with the motor, clearance, neatness and to admire. You also refused to detail the parts you used etc. I was actually very interested in what you had done and I believe I have the necessary skills and knowledge to make a power rack and pinion steering setup on my own car. Which a qualified engineer would then sign off on for compliance before it was ever used on the road. But to be quite frankly honest, after hearing your replies to it I'm now more inclined to go to the wreckers and find parts that I can play around with too see if I can make something work... how much safer is that do you think! As you said, it's been done before, therefore others will also find a way. But your post seemed to serve no purpose other than bragging that you have done something, but then gave no more detail on how you did it, or what parts were used or to advise other willing and capable members to engineer their own systems for their own cars. You assumed it your responsibility should something go wrong if anyone else attempt the same thing and it didn't work. I admit that is a noble view to take, it is also very arrogant given the circumstances. |
Author: | hailest [ Mon Feb 16, 2015 3:39 pm ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
I would of happily paid the 5k when doing my build baz. |
Author: | AlanDatsomefun [ Tue Feb 17, 2015 9:59 am ] | |||||||
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? | |||||||
If you are prepared to build it yourself, this is what a R-n-P conversion could look like. Photos show checks being done before final paint and install. Most important: Several jigs had to be made and accurate measurements taken to ensure correct steering geometry and precise locating of the rack - it's NOT a matter of stick it in and "she'll do, mate": if this isn't right then you will have bump-steer and other steering geometry issues. Here the collapsible steering column with height adjustable steering wheel has its primary attachment at the firewall, meaning that a plate / mounting bracket has to be welded into the firewall. Hence, this is not a bolt-up conversion which could be offered as a kit. The lower intermediate shaft shown here is a temporary installation. It has a splined joint which can be pulled apart and indexed around (one spline at a time) to find the sweet spot for the relative positioning of the universal joints. If you don't find the sweet spot, the steering response will be irregular, and depending on where the steering wheel is turned you could turn a lot with little response or turn some with some response: this is essential to getting it right. In the end I believe that the effort was worth it. Steering is precise, smooth, steering involves less effort than the old gearbox - even without power steering, and no bump steer. Almost certainly (not tested) much safer in the event of a head on crash than the old "spear you in the chest solid steering column". I'm guessing that if you had to pay somebody to develop something like this completely from scratch and do all the fabrication work needed, and have it work properly, there would not be much change from $5k ...
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Author: | Pista_510 [ Tue Feb 17, 2015 1:20 pm ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
This is amazing work and a real treat to look at - sincerely, thank you for sharing these pictures. I said it before when you outlined your detailed post in 2014 that you have an excellent engineering approach to this conversion; just reading your notes and reviewing your CAD / geometry calculations prove that - certainly more than just a cut and shut conversion with sighting in by eye. It would be great to see the rest of your 1600 - the other work must be as remarkable as well. In the late '80's / early 90's I did a similar conversion, along with one or two others I have come across, using a Bluebird Series II rack & pinion gear and the SII crossmember. Had to modify the crossmember to put it into the 1600 and I used the original 510 steering box and idler arm chassis locations to mount anti-roll bars. I did not shorten the rack at all and, of course, it necessitated widening the track by ~30 mm per side to keep the geometry similar to donor car with the consequence that I needed to run NISMO style flared front guards to accommodate the wider track (not something I would do again). I still have the car and will endeavour to get some pictures listed but it is not comparable to your conversion which is definitely an elegant solution! |
Author: | AlanDatsomefun [ Tue Feb 17, 2015 2:45 pm ] | ||
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? | ||
Thanks for the supportive comments. In the case of this conversion, the resulting track is not as wide as a straight transplant of the 910 crossmember and lower control arms, but it is still more than the original 1270mm by some 40mm with the 6.5"x16 +40 offset wheels and standard length 510 LCAs I am using. Overall, the wheels just fit within the front guards. The rack had to be shortened by 25mm (no change in number of teeth, but 25mm removed from the passenger side end of the rack shaft). Caution: If a rack is to be shortened this can only be done at the passenger's side end (because it can be done here without getting too close to the gear teeth), and it must be done following the way it was done by the original manufacturer. This will involve precision drilling from the end of the rack and cutting a new internal thread (some older racks had external threads and rack rod ends with internal threads: recommend avoid this type and go for a rack with an internal thread for the rack rod end) . Cutting a bit off the rack, drilling from the end and cutting a new thread is precision work, which must be done in a lathe by a competent machinist: NEVER ATTEMPT TO DO THIS BY HAND. The tricky bit is that the distance between LCA pivot points (even after these have been moved outboard by 17.5mm each side, and up a little by an amount which depends on strut length, suspension travel, ride height, and etc.) is still 40mm less than the effective length of the shortened rack: the rack is still a bit too long for ideal steering geometry. Despite this, bump steer can be overcome in large part (practically eliminated) by precisely locating the rack, in terms of height relative to LCA pivot points and distance back from the arc through which the LCA travels, as constrained by the tension rod, and the bottom end of the McPherson strut. To avoid bump steer the basic strategy is to have the rack rod end ball joint and LCA pivot points in alignment, so that the [centre of the] LCA ball joint and the [centre of the ball joint at the] tie rod end follow concentric arcs (that is, because their centres align), noting that the condition described only exists and can be measured when the wheels are pointed straight ahead. This explanation is somewhat simplistic because as the car is driven, the steering turned and bumps are hit, camber (and less so caster) change as do relative positions of the LCAs and tie rods. Overall, (worst case as measured - suspension on one side at upper limit of effective travel, and other side at lower limit of effective travel), bump steer is still less than two degrees. The car would have to be pushed extremely hard for this to occur, but the bump steer angles are still small. Under the conditions described, as a driver you would be more concerned about slip angles between road and tyre. I need to add a caveat: the diagram shows the results of measurements with road wheels in the straight ahead position, and these were static. I cannot claim to have taken dynamic measurements with the road wheels turned whilst hitting a large pot hole, and at speed (where slip angles are significant). These are the conditions under which bump steer would occur.
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Author: | nick [ Sat Feb 21, 2015 6:03 pm ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
Awesome thread. Am enjoying reading this. Thanks! |
Author: | SR20Datsun [ Fri Apr 10, 2015 2:53 pm ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
AlanDatsomefun, glad you shared some detail on how you did it. I think most people would understand it's a fair bit of thought/engineering and fabrication that goes into something like this. I agree on your comments of liability. As an engineer we are responsible for things we design, and liable if it doesn't work. Fortunately in this instance, a fair bit of work would have to go into selection/fabrication and testing for even the average punter at home to complete something like this on their own. This is one of the good things about OzDat. There is a lot of knowledge on this site that people have shared with. Regardless, interesting topic and thanks for sharing. |
Author: | wagonjunkie [ Thu Apr 16, 2015 8:02 pm ] | |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? | |
We now find that sourcing 200B front ends for our current conversion kit has become so difficult that we are considering ceasing production.
Nooooooooo!!!!!!!!!!
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Author: | AlanDatsomefun [ Wed Apr 22, 2015 1:55 pm ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
Unfortunately, its only a matter of time before there will be no option but to completely replace the steering. I am convinced that the only way to do this is to have a custom bolt-in sub-frame kit with everything, which I believe originally is Baz’s idea. My design approach, a variation, would involve a sub-frame with integrated cross-member; rack attached directly to the cross-member; boxed in mounts for tension rods; and sway bar mounts. Items which complete the kit would include: lower control arms, steering arms, sway bar, tensions rods, engine mounts for a variety of engine types, steering column, firewall bearing/mount, intermediate shaft(s), bolts, crush tubes, and etc., and hydraulic power steering pump with hoses and such. Optional fitting an EPAS (electrical power assisted steering) column – Barina (Vauxhaul Corsa), Toyota Prius, or similar, is workable but requires the pedal box to be modified and extra mountings provided to carry the torque produced by the servo motor and necessarily transmitted through the steering column. I have already prepared a pedal box in anticipation of upgrading to a Barina / Corsa EPAS steering column: so, I know this is workable. A variation on the arrangement for mounting the steering column would require a custom bracket and a custom, floor mounted clutch and brake pedal arrangement: on the down side - this takes up much of the available foot well space. An EPAS rack (as in Mercedes A and B class cars, and others?) would simplify the steering column mounting issue, but it is unlikely that this is workable because in a Datsun 1600 the rack would have to be fitted beneath the engine and I doubt there would be sufficient room to accommodate the servo motor. A bigger issue would be that the servo, and perhaps the ECU would be exposed to dirt and moisture – NOT good. Mercedes, for example, locate their EPAS rack (with integral ECU and servo) quite high up in the engine bay where it is well away from dirt and water: unfortunately, not possible in a Datsun. Further, any EPAS installation would require digital signals for vehicle speed and that the engine is running (or an interface/ module which simulates the electrical signals carried by the CAN bus, found in modern cars), and +12v 50A power. To install the custom sub-frame would be a matter of cutting off the OEM mountings for the tension rods and attaching to, say, original steering box and idler arm attachment points at the rear and crush tubes with bolts installed at the sides (through the chassis rails) and at front not far behind the radiator support panel. The whole sub-frame assembly would have to be carefully located with respect to centreline of the car and the strut towers. The custom sub-frame approach would have the clear advantage that once correctly installed (and there is no reason why this could not be achieved every time), the ideal or close to ideal steering geometry would be exactly replicated - no mistakes. To avoid the possibility that somebody might make well intentioned but inappropriate changes that cause bump steer, shifts the roll centre, or invokes understeer /(scary) oversteer, the kit could be well designed so nobody would ever need to modify it. Tuning of the suspension would still be possible though spring/shock choice, adjusting sway bar stiffness, and strut top position, producing desired camber, caster, stiffness and damping – as enthusiasts have always done. Personally, I would NOT make LCAs or tension rods adjustable because there is very likely to be some extreme combination of settings that would cause steering geometry problems. Rather, I would aim to accommodate differences arising between chassis (and that chassis rails may be slightly bent, or were never perfect) by providing some adjustment in the positioning of the whole sub-frame. The aim would be to precisely locate the sub-frame and, hence, the cross-member with respect to the centreline of the vehicle and tops of the strut towers, noting that the position of the tension rod pivots would have been precisely set with respect to the cross-member at the time the sub-frame was fabricated. |
Author: | Stoney [ Tue Jun 02, 2015 10:04 pm ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
I was reading on 510realm the other day about a build where the guy had planned on using a complete Toyota AE86 front crossmember with rack and steering setup, not sure what happened but he left that and then redesigned the rear trailing arms with DOM tubing and 5stud hubs. He had comparison photos between the stock Datsun gear and the AE86 stuff, and it all looked very interchangeable. If I was going to retrofit a steering rack, something like this way would be how I would approach it, already designed by a manufacturer and if you don't change anything apart from adding coilovers/strut height change and can maintain a similar control arm angle to stock, then I feel its an easy way to go about it. Factoring in what changes it makes to roll centre F/R etc would be something else to consider as well. |
Author: | Anth510 [ Wed Jun 03, 2015 9:40 am ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
Got a link, Stoney? A mate of mine runs an AE86 front end in his KE25 rolla, I think it's a common upgrade for those guys, but it does increase the track a fair bit. |
Author: | Stoney [ Wed Jun 03, 2015 10:17 am ] |
Post subject: | Re: Datto 1600 Steering Upgrade? Go To Option?? |
You'll like his build too Anth, was about 60 pages IIRC, one minute http://www.the510realm.com/viewtopic.ph ... &start=420 A few pages earlier he describes in detail the AE86 setup |
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