Steering Rack Questions

PostPost by: ppnelan » Wed Jan 28, 2009 1:31 pm

Having checked a few road test reports, it seems that the +2 typically used the same rack as the Elan with 2.6-2.75 turns lock-to-lock. One report has 3.1 turns which would correspond to a change in pinion from 7 to 6 teeth. So does 3.5 turns only come from a standard Herald rack without spacers...? :?
(Just read your last post Andy - you have the solution :D )

:arrow: Matthew
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PostPost by: elj221c » Wed Jan 28, 2009 2:02 pm

Gerry,

The contemporary road tests I have state 2.7 lock to lock.

Roy
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PostPost by: elj221c » Wed Jan 28, 2009 2:12 pm

Gerry,

The contemporary road tests I have state 2.7 lock to lock.

Roy
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PostPost by: gerrym » Fri Jan 30, 2009 8:22 am

Andy, Matthew, Gary, Brian, Mike et al:-
thanks for the various contributions, debate and photographs.
Gary your photographs and explanation of why the limiting spacer needs to fastenened to the pinion side locknut was particularly helpful. I'll carry on with my checks re tyre clearance incorporating some of the comments from this theme. Designed in side-to-side offset of the rack body from the centre-line of the car is not something that has previously been discussed much so it's good to get that aired here.
A couple more thoughts are emerging:- for the Plus 2 with it's tie-rod extensions adding on to the Elan length tie-rods. If using a Spitfire rack with the longer tie-rods, is it possible to shorten the extensions, without compromising the thread engagement and providing enough toe-in adjustment. Do we know what other applications used the the 6 or 7 pinion tooth? Does anyone have a source for the shims and bushes within the steering rack (Moss and others are listing these as No Longer Available)

Regards

Gerry
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PostPost by: garyeanderson » Fri Jan 30, 2009 11:06 am

I think the Spitfire inner tie rod ends are almost useless (spares in the box for the last 20 years?) to either an Elan or Plus2 owner. The Plus2 extensions have jam nuts so if you shorten the inner tie rods, they will be ineffective. At one time the Elan length inner tie rods were not to be had anywhere. When Ray (RDent.com) said he had some 5 or more years back, I orders 2 sets. I believe that they are still around so ask around before you look into the Spitfire ends. I guess extentions would be locked at the outboard end, but it cost Lotus 2 extra half inch jam nuts and Lotus would not have used them if they didn't thinks it was nessessary.

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PostPost by: gerrym » Fri Jan 30, 2009 11:33 am

Gary, thanks for confirming what I had suspected re shortening either the Spitfire tie-rods or the Elan Plus2 Tie-rod extensions.

Another option for Plus2s would be to have some custom (ie shorter) tie-rod extensions manufactured. Material spec is fairly important so will not be cheap!!

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Gerry
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PostPost by: gerrym » Tue Feb 10, 2009 8:33 am

To convert from standard length Spitfire Steering rack tie-rods, to the overall Plus 2 length (10.75"), one option would be to use a suitable 1/2" threaded stud, joined to the tie-rod proper via a deep threaded joiner. A tie-rod end with the ball joint machined off would provide the threaded female joiner: a CrMo wheel stud the additional 2-3/4" roughly of extra thread.

The advantages of the above is that Plus 2 owners would no longer be "tied" into using the special short Elan tie-rod.

Of course assembly issues need to be considered so that only the outer thread to the tie-rod end is ever adjusted in service. Presumably Loctite would have an answer to that. Otherwise, it might be possible to just rely on the 1/2" UNF locknuts.

Anyone been down this road befors?
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PostPost by: garyeanderson » Tue Feb 10, 2009 12:47 pm

Gerry
Why not find the correct inner tie rods and use the stock plus2 extensions. Is this a cost savings measure or are the inner tie rod ends no longer available again? I don't know its been a while since I have looked. I have heard rumors that the inner tie rods are nothing more that AH Sprite inners but I have never done the homework to verify.

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PostPost by: ncm » Wed Feb 11, 2009 12:03 pm

This is a photo of the rack bar that I removed from my +2 a few years ago. If you compare the heat treatment of the teeth on this to the one in Gary's post on the previous page you will notice that somebody has decided to save money by only hardening the 6 teeth either side of the centre one instead of treating them all :( . I have no idea who supplied this rack, but it would be worth checking any recon. before fitting it.

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PostPost by: elj221c » Wed Feb 11, 2009 4:21 pm

Brian,
Just a thought. Most of the wear would be around that centre bit so maybe that is normal procedure?
Just how much time do you spend on oposite lock anyway?! :)
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PostPost by: gerrym » Thu Feb 12, 2009 9:15 am

Gary, to answer your question. No it's not a cost saving measure I'm suggesting. Rather a case of working with commonly available components (ie std Spitfire etc tie-rods) to come up with a good working solution, whilst being aware of any possible downsides. Of course if the Midget tie-rods are in fact the same as the special "short" Elan tie-rods, then that is something that a lot of forum posters would be interested in. In terms of the most elegant engineering solution, then surely this would have been to use bespoke Elan Plus 2 length tie-rods and no tie-rod extensions. However Lotus obviously didn't see it in those terms and went for the cheaper solution of basically using the baby Elan steering rack with the add-on extensions. From a small manufacturer's point of view, that was obviously a good move. Presumably it considerably reduced inventory and parts ordering. But then again the parts list has a type 50 part number against the Plus 2 steering rack?. Do we know for sure if the steering lock limiters are the same for the baby Elan and Plus 2? (I only have the workshop manual for the Plus 2). From my measurements of tyre clearance against the bodywork and the ARB, it would appear that the steering lock limiters in the Plus 2 overly constrain the achievable steering lock.

Regards

Gerry
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PostPost by: garyeanderson » Thu Feb 12, 2009 11:28 am

Hi Gerry

Have you asked for a quote from Susan Miller (or Paul Matty) to see if the inner tie rods are available? I haven't been looking so I don't know if they are available or not. I just knew that 10 years ago that they weren?t so I bought 2 pair when RD Enterprises got some in, one for immediate use and the other set was installed last year (the recent rack photos).

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PostPost by: gerrym » Thu Feb 12, 2009 12:05 pm

Gary, to follow up on your suggestion.

Susan Miller- no stocks

Paul Maty - no stock just now but list them as part number HZZZ027E ?37.50 each. Speaking to Clive, PM are getting these made and are available on a week's leadtime. (Seems a very short leadtime for a special)

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Gerry
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PostPost by: gerrym » Tue Mar 03, 2009 3:27 pm

Back to earlier themes, for the non-driver side lock limiting spacer (shown as 44mm long in Plus 2 workshop manual), can this be made out of any material, say 6082 aluminium, anodised? For the sake of adding lightness of course!

Regards

Gerry
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PostPost by: BillGavin » Tue Mar 03, 2009 7:35 pm

I've been messing with Sprites and Midgets for a very long time, and have a pretty large amount of spares to fall back on when needed. A few years ago, I had my Elan rack apart and suspected that I had the wrong tie rods; Gary was good enough to measure a set for me, and it turned out my tie rods were the correct ones. While all this was going on, I pulled apart a (Triumph based) late MG Midget steering rack to see if any parts were usable in the Elan - it turned out that just about everything except the pinion was usable with some tweaking. The tie rods are an exact match to the Elan.

The rack used in all Sprites and early Midgets is Morris Minor based, and no parts are usable. The Triumph based rack was fitted to Midgets from Feb 1972, chassis GAN5-114588 (LHD) GAN5-114643 (RHD). It seems that some cars from 114352 were also fitted with this rack. The easy way to identify this unit is that it uses steel mounting brackets, split diagonally, rather than the early aluminum brackets that were split horizontally. The tie rods of the early rack are also much thicker than those of the later rack.

- Bill
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