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1922
United Kingdom
549 Posts |
 Posted - 27 Feb 2010 : 23:12:14
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Thanks Jim!
I've spent a couple of hours under the car this morning. Here is what I discovered:
- It looks like the steering arms can be reversed. This puts the ball joints very close to the brake calipers but there appears to be just enough room, if not then a bit of adjustment with an oxy-acetalene torch and a big hammer will do it.
- There looks to be just enough room for the track rods below the brake reaction rods, so it will be possible to connect the wheels to the steering rack.
- There is a clear path from the rack input shaft to the steering column between engine and engine mount, so it will be possile to connect the rack to the column.
- There is enough room for the steering rack's gearbox next to the engine.
- The rack will need to be narrow but it's only about 3 inches narrower than the Avenger rack I'm experimenting with, should be able to get a custom rack made by Titan Motorsport http://www.titan.uk.net/steering.php
Sounds good so far... but here's the bad news, the sump.
To mount the rack in the right place will foul the sump by at least 2 inches.
To modify the sump means shortening the oil pump pick up - I don't think there will be room.
To put the rack in front of the sump is tricky as the brake reaction rod mounts are in the way but, worse than that, moving the rack so far in front of the steering arms will screw up the steering geometry. The Rapier has almost no Ackermann to start with, if I put the rack that far forward it will get negative Ackermann, and that means toe-in on turns with lots of tyre scrub and unpleasant handling.
As for the other plan, I partly dismantled my spare steering box, and it looks pretty good inside. So this might be off to the engineers in Birmingham along with the box from my '46 Minx.
If only they'd put rack and pinion on in the first place  |
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TurboZed
United Kingdom
94 Posts |
Posted - 28 Feb 2010 : 23:56:47
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Hi Derek,
I've been thinking in the shower LOL!
What about using a Mk2 Vauxhall Cavalier rack mounted where the rod that joins the steering box and idler box together? My idea is that the cav rack is a center takeoff so the rod that joins the steering and idler boxes on the rapier could be mounted to it and use the original track rods (suiltably modified) and steering arms. My only issue is that I dont have a car to look at to see if there is room or not to mount it.
As for your idea, could the sump not be modified and a new oil pickup pipe be made to go to the section of the sump that at the lowest point? Is it possiable to engineer more or less Ackermann into the steering geometry? I've never been able to get my brain round how steering keeps the angles of the wheels right!
Could an entire Avenger front end not be used, or are they very different under the bonnet? (again not having cars to look at is a mahoosive dissadvantage here!)
Regards,
Jim Gough
Looking for a fastback Rapier.... |
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1922
United Kingdom
549 Posts |
Posted - 01 Mar 2010 : 13:56:02
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One of the problems with the "rack behind the wheels" is that that footwell is too close to the crossmember. The steering column would need to go through the floor between the clutch & brake pedals to get to the rack.
I think the "rack in front of the wheels" is possible but it would need major surgery to front of the sump. The sump is high at the back (to clear the crossmember) and low at the front. The front part would have to be moved forward, and the oil pump pickup would have to be extended to reach. It could be done, I think. I can't experiment further with the engine in.
I had an Avenger about twenty years ago and the general layout is very similar (apart from the rack & pinion) but none of the parts are interchangeable.
I have an Avenger cross-member and steering rack which I purchased to experiment with the rack and pinion idea. The crossmember is very similar to the Rapier one. The main differences are that is has the brackets for the steering rack at the back and the mount points for the lower suspension arms are several inches further apart. It might be possible to use the Avenger crossmember, suspension arms, struts and rack but I haven't got enough Avenger bits to try it. The Avenger rack is mounted directly to the back of the crossmember, so it must have much shorter steering arms (the ones the go backwards from the strut) than a Rapier.
The Chrysler/Talbot Sunbeam Lotus used an Avenger floor pan and running gear, which means competition parts are available.
My only worry with the Avenger was that the suspension all looked less substantial - but perhaps the Rapier is over-engineered.
I think the Ackermann will about the same provided that the rack is directly between the track-rod ends. If the steering rack in front of the crossmember then Ackermann decreases if the you move the rack forward of the track rod ends increases as you move the rack back behind the track rod ends (I've got a couple of good books that explain it all!). |
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1922
United Kingdom
549 Posts |
Posted - 03 Mar 2010 : 13:20:36
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Jim you have inspired another thought.
Part of the reason that there is not enough room for the steering rack behind the wheels is that I am using the standard steering arms as a start point. If they are shorter then the rack can be further forward, I wonder...
Anyone know how long the steering arms (the ones that connect the strut to the track rod ends) are on an Avenger?
p.s. Is anyone else reading this - or is it just me and Jim? |
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TurboZed
United Kingdom
94 Posts |
Posted - 03 Mar 2010 : 22:29:03
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Think its just us LOL!
Regards,
Jim Gough
Looking for a fastback Rapier.... |
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1922
United Kingdom
549 Posts |
Posted - 13 Mar 2010 : 17:57:19
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I've been in the garage again - here's what I've discovered:
- Even with the rack close to the crossmember the rack gearbox still fouls the clutch housing - it's too close to the engine.
- The Avenger crossmember is only a tiny bit wider than the Rapier one and it looks like it will bolt right on with just a little widening of the bolt holes in the crossmember.
- The suspension arm pivots on the Avenger crossmember are about 2.5" further out than Rapier ones; this means the rack gearbox is 2.5" further away from the engine; and that means it does not foul the clutch housing.
- The suspension arm pivots on the Avenger crossmember are about 1" higher - but this is not a problem as the suspension is lowered 1" and this just gets the suspension arm back to the normal angle.
- It looks like the Rapier lower suspension arms will bolt onto the Avenger crossmember (but they would have to be shortened by 2.5").
- The track rod end will have to be very close to the strut - like an Avenger one.
Without access to Avenger lower suspension arms and struts I can't get any further but looks like I might be able to do the following:
- Bolt on the Avenger crossmember.
- Use and standard Avenger rack and track rods
- Make new engine mounts, possibly by cutting the Rapier ones off the crossmember and welding them to the Avenger one.
- Use shortened Rapier suspension arms and custom made steering arms or perhaps use Avenger suspension arms and struts.
If Avenger rack and struts fit then Sunbeam Lotus ones should also fit as the Sunbeam Lotus uses a shortened Avenger floorpan.
The camber and castor angles aren't that different so it might be possible.
If I'm very lucky to only fabrication work would be making the new engine mounts and mounting the steering column.
So I need to get my hands on some more Avenger bits.
As a backup plan it seems that my spare steering box is in very good condition so this will get treated to some new bearings and seals at Kiley Clinton.
Here's some pictures of the crossmembers (the Rapier one is a scrap yard find) http://www.photobox.co.uk/1x9C7007/album/335602981?cid=tashare001 |
Edited by - 1922 on 13 Mar 2010 17:58:40 |
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TurboZed
United Kingdom
94 Posts |
Posted - 14 Mar 2010 : 00:21:13
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Interesting stuff Derek. Would any talbot sunbeam frontend do? Might just be able to find one in a scrappy. Unfortunately for us, everything roots is rare nowerdays.
Regards,
Jim Gough
Looking for a fastback Rapier.... |
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1922
United Kingdom
549 Posts |
Posted - 15 Mar 2010 : 14:14:44
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I think that any Avenger, Chrysler Sunbeam or Talbot Sunbeam will do to prove (or not) the concept. Unfortunately my favourite breakers yard closed down a few years ago, they had stuff back to the 1940s!
For the real thing I would want Sunbeam Lotus struts and brakes.
I would not want try to stop a Rapier with brakes from a base model 1 litre Chrysler Sunbeam!
The Talbot Sunbeam Lotus club is very active and it used to be easy to buy race, rally and 'boy racer' bits for the Sunbeam Lotus.
Big brakes, quick racks and various shocks and springs should still be available. Wheel stud spacing is the same too - so the wheels will go on. |
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Holbay120
United Kingdom
177 Posts |
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TurboZed
United Kingdom
94 Posts |
Posted - 22 Mar 2010 : 02:47:58
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Not really......they are off the windscreen wipers!
Regards,
Jim Gough
Looking for a fastback Rapier.... |
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johnc
United Kingdom
212 Posts |
Posted - 22 Mar 2010 : 18:27:08
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| With the motor connected you have power steering and self parking,a boon in todays traffic. |
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1922
United Kingdom
549 Posts |
Posted - 01 Apr 2010 : 14:15:36
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Nice one johnc
Have made a bit of progress with the Avenger strut plan.
Got some information from the Avenger and Sunbeam Owners Club. They tell me that the Avenger struts and Sunbeam struts are interchangeable and have put me in touch with Mal Stuart Motorsport who, hopefully, can find me some secondhand struts.
Interestingly the guy that replied, Steve, said that he had sold a complete set of front end suspension to a guy in Scotland who was, he thinks, working on the same project. |
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1922
United Kingdom
549 Posts |
Posted - 14 Apr 2010 : 20:02:00
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Got a complete Avenger strut from Talbot Spares.
It's very similar to the Rapier strut but, unfortunately, about two inches shorter.
So the next step is the remove the driver's side strut from the Rapier and compare the two.
Possibilities are:
- Use the complete Avenger assembly with the Rapier spring and with a custom made 2 inch extension at the top of the strut.
- Use the Rapier strut and find a way to connect it to the Avenger lower suspension arm and steering arm.
- Use the Rapier strut with shortened Rapier suspension arm (carefully cut and welded) and custom made steering arm.
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Edited by - 1922 on 14 Apr 2010 20:02:35 |
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TurboZed
United Kingdom
94 Posts |
Posted - 15 Apr 2010 : 19:01:19
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Sounds quite a complex job......
Regards,
Jim Gough
Looking for a fastback Rapier.... |
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1922
United Kingdom
549 Posts |
Posted - 15 Apr 2010 : 19:20:53
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Not going to be as easy as I'd hoped; if the Avenger strut was 2 inches taller I think it would just bolt on, then I'd just need to fabricate the engine mounts and various brackets for the steering column.
Need some weekend time to unbolt a few bits and see what will fit what. |
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Steering box
