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Post by redsunbeam on May 2, 2010 14:02:24 GMT
I want to do something to lose the steering vagueness at speed as it will get get worse after the engine swap. Have done a search and seen a thread using a 3 series bmw rack. Doea anyone have anymore info on this please. Cheers
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Post by Phil Nottingham on May 2, 2010 21:19:56 GMT
Not heard about this conversion but the steering should not be vague at speed - something is wrong
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Post by Warwick on May 3, 2010 0:33:23 GMT
A couple of members in the RCCA (Melbourne, Aust.) have almost finished a rack & pinion conversion for a P5B. I have no idea what rack they are using, but I can put you in touch if you like.
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Post by redsunbeam on May 3, 2010 8:37:26 GMT
Yes please Warwick that would be great.
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Post by Warwick on May 4, 2010 5:27:13 GMT
PM sent Neil.
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Post by enigmas on May 4, 2010 7:12:53 GMT
The vagueness at speed (mainly the P5Bs ... lightweight V8 up front) is due to the lack of castor in the steering setup. Apparently there is a castor kit which adds a degree or so of castor to the standard setup or you can section and reweld the top wishbones to induce more castor (need to be a competent welder with a MIG or TIG setup). My car runs about 3 - 3.5 degrees of castor (second method) because I didn't like the original straight line instability of 1950's steering technology.
If you've ever driven an MBG you'll find that self-centring is very strong as they have about 6 degrees of castor (very heavy steering). With power steering castor can be increased quite a lot (Mercedes) as strong arms aren't required at slow speed and straight line stability improves markedly (even with the straight ahead vaguenes of the original Rover power steering box).
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Post by johnwp5bcoupe on May 4, 2010 9:00:30 GMT
The vagueness at speed (mainly the P5Bs ... lightweight V8 up front) is due to the lack of castor in the steering setup. Apparently there is a castor kit which adds a degree or so of castor to the standard setup or you can section and reweld the top wishbones to induce more castor (need to be a competent welder with a MIG or TIG setup). My car runs about 3 - 3.5 degrees of castor (second method) because I didn't like the original straight line instability of 1950's steering technology. If you've ever driven an MBG you'll find that self-centring is very strong as they have about 6 degrees of castor (very heavy steering). With power steering castor can be increased quite a lot (Mercedes) as strong arms aren't required at slow speed and straight line stability improves markedly (even with the straight ahead vaguenes of the original Rover power steering box). Increasing the Castor would give more straight line stability I agree and having built Endurance Karts with fully adjustable camber and castor you can gain a lot under different conditions but if you get the setup wrong you can be in the Poo and it doesn't take a lot in degrees For the guy who wants to increase performance or race a P5 I can see the need maybe? or if you are going to the trouble of fitting a rack, but for the normal use as a standard road car I find the standard steering not too bad for a 40 year old vehicle if you drive within it's limits! not to mention the cost of fuel at the moment I have a CRX and it's the other way around it goes where you point it But it's an interesting project if there was a simple bolt on kit that would be great to try, but I certainly wouldn't want to cut and weld the steering components.
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Post by Colin McA on May 4, 2010 9:38:27 GMT
Is it not possible to reduce the amount of assistance from the steering by restricting the output from the pump by changing the pump pulley size or a restrictor in the fluid line??
Colin
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Post by enigmas on May 4, 2010 10:16:41 GMT
Yes it is and it has been done Colin, but it won't cure vagueness at centre. When driving in a straight line there is really no power assistance. Even if a rack and pinion system is fitted the caster remains unchanged. A good power R&P system will have virtually no play at centre so there will be a 'feeling' of greater stability due to the absence of centre free play. Only an increase in caster will improve straight line stability. Add the R&P and increase the caster and you've really got an improvement but then its a lot easier to fit a volvo steering box (as has been done to Warwicks car). The R&P system would require modified steering arms to get the Ackermann right. en.wikipedia.org/wiki/Ackermann_steering_geometryI've not driven Warwick's P5 (nor has Warwick I believe in quite some time) but I have 'handled' the steering in its resting place in his garage and there is no free play when the steering wheel is at its central position. It's a vast improvement with the benefit of attaching straight up to the P5s original pitman arm and steering linkages.
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Post by redsunbeam on May 4, 2010 15:29:57 GMT
Thanks Warwick, will drop them a line in the next few days. The other reason for going the R&P route is that i think the new engine (which i picked up today) may foul the steering box. Enigma, how much did you change the top wisbone by?
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Post by enigmas on May 5, 2010 10:10:06 GMT
I removed both wishbones and placed them on my bench. I cut them through with a slitting disc and moved the front cut sections rewards along the cut line. I then tacked them and V grooved the weld area on the cut line. The result was 3 - 3.5 degrees castor. (check you P5B manual for caster specs and you'll find it almost negligible.) I think I moved them back about 3/8". It was 15 or more years ago. Anyway just get a spare set from the wreckers and try it. You can always swap back the originals.
Many years ago I drove a friends standard P5B and it was scary at speed compared to my car. I hadn't driven a P5B up until this time and only changed mine because I didn't like the vagueness as it felt dangerous to me. It makes a big difference in stability. My car is a daily driver and covers a minimum 300 kms per week for the last 11 years.
The parts are steel and are easily modified by a competent engineer/welder who knows what he is doing. The wishbones are interesting (take a look at their orientation next time you remove a front wheel) in that the they incorporate anti-dive. ~ Vince
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Post by Deleted on Jul 29, 2011 20:10:28 GMT
Hi,
A little more self centering and also negative camber on-lock seems like a good idea. Could you post a photo or diagram to show the details of your wishbone modifications? Having never stripped the suspension on a P5 before I wondered; is it not possible to shim and grind the upper wishbone in order to move it rearwards and obtain increased kingpin inclination?
Thanks.
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Post by baconsdozen on Aug 1, 2011 7:03:15 GMT
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Post by Warwick on Aug 2, 2011 3:56:01 GMT
Someone on here was putting a diesel in a P5B a few years. Can't remember who.
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Post by Deleted on Sept 9, 2011 9:27:34 GMT
Good info as mine is wandering, makes 60mph + very interesting. Ive seen a rack transpant from a Granada years ago, see what the plan is for the winter in the garage.. J.
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Post by p5tgc on Sept 9, 2011 9:57:13 GMT
Going back to the original theme of this thread, I have a vague memory of a Rover factory update on the P5 /P5B which increased the castor angle to improve the self centering action, but I cannot find a record of this.
As I recall, the update used shims and revised bolts to modify the relative position of the top ball joint, it was a fix which dealers could use at their discretion if a customer complained of steering wander and was not intended to be incorporated in production vehicles.
Can anyone with a better memory (or library) dig out details of this? It would seem to be lot less work to fabricate and fit some shims compared to replacing the steering box with a rack, and anyway the use of an alternative box or rack would still not cure the basic problem of inadequate castor.
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Post by Warwick on Sept 11, 2011 2:26:22 GMT
My club in Australia (RCCA) produced a castor kit for the P5 awhile ago. I should have one soon. We're very lucky down here. The RCCA has a parts remanufacturing group consisting of several dedicated and highly skilled people. Over the years they have taken on the challenge of remanufacturing batches of scarce Rover parts, or redesigning and manufacturing improved replacements.
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Post by Steve P5b on Jul 12, 2014 8:05:49 GMT
My club in Australia (RCCA) produced a castor kit for the P5 awhile ago. I should have one soon. We're very lucky down here. The RCCA has a parts remanufacturing group consisting of several dedicated and highly skilled people. Over the years they have taken on the challenge of remanufacturing batches of scarce Rover parts, or redesigning and manufacturing improved replacements. I know this post is from a while ago, I'm wondering did your caster kit ever materialise ?
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Post by Warwick on Jul 12, 2014 12:30:41 GMT
Good question Steve. I'd forgotten all about it. I'll follow it up again. Not long after that I had a few distractions and the car has been on the back burner ever since.
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Post by Steve P5b on Jul 12, 2014 13:33:07 GMT
OK Warwick, look forward to anything you find, thanks.
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Post by enigmas on Jul 12, 2014 14:36:55 GMT
The kit, which is a copy of the original Rover kit produces a negligible difference.
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Post by Steve P5b on Aug 4, 2014 7:41:51 GMT
I want to do something to lose the steering vagueness at speed as it will get get worse after the engine swap. Have done a search and seen a thread using a 3 series bmw rack. Doea anyone have anymore info on this please. Cheers I can confirm that caster angle changes do improve the driving experience and straight line stability even at low speed things are more relaxed with self centering. 2.5 degrees is sufficient, that relates moving the top wishbone 19mm.
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