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MG MGB GT V8 Factory Originals Technical - Steering Mods

Hi folks,
I have just got to the engine fitting/firewall modifying/steering part of my MGB chrome bumper conversion. I have read the archives and want to do a combination of things. I intend to do the following....please can someone tell me if I am about to shoot myself in the foot.

1. Retain original CB crossmember but removing the steering rack mounts.
2. Modify the firewall but in doing so moving the steering cone down half an inch and also back in towards the driver by one inch.
3. Make new rack mounts for the RB steering rack moving it forward enough to fit the pinion through the engine mount at the right angle.
4. Shorten the CB steering column (inner and outer) sufficiently once the rack mounts are permanently positioned. (I have access to a great hot rod shop who will do it for US $50)

Also, as my car is completely stripped and I can't remember how much column there was between the dash and the indicator cowl, could someone with a CB car tell me? The problem is that not only do I have the conversion to contend with but my wife is quite a bit shorter than me and while I'm doing the conversion it would be a good chance to help her feet reach the pedals. This would help me too as I don't like sitting too close to the wheel.

Thanks in advance,
Stainzy
David Staines

Stainzy,
As I'm doing a cb conversion, and just fitted my engine, I can commment on a couple of points.
1. If you keep the cb crossmember, I think that you'll need to open up the transmission tunnel quite a bit. That's because this crossmember will force the engine to sit higher.
2. A good move. Going down and back with the cone will help immensely with clearance between the rear exhaust outlet and the steering. No need to stress the importance of structural soundness here.
As I used a custom steering hybrid setup and motormounts, my methods varied. I have close clearances but am satisfied with how everything fits.

Cheers,
Joe
Joe Ullman

Thanks Joe,
I'm using a Toyota Supra 5 speed box so am hoping I won't have to cut up the transmission tunnel too much. I think it is quite a bit smaller than a Rover 5 speed and is made of alloy....I also have a RB crossmember ready to go just in case.
Good luck with your setup and thanks again

stainzy
David Staines

Stainzy
Be very carefull how you mount the rack.

I have a factory GTV8 and changed the R/B crossmember for a C/B one. To do this with the original Rack I had to move the mounts forward, but in doing so it also moved the rack down by nearly 1". This had an effect on the steering geometry causing bump steer. ie. when the suspension was fully compressed the front wheels would toe in slightly but when the suspension was at full rebound they would toe out.

I am in the process of curing this problem by keeping the rack in the same plane as original C/B but twisting it back slightly and fitting a second UJ with modified shaft.

Waiting for the splines to be re-cut on the shafts at the moment.

Hope this helps.

Mark
Mark Rawlins

Stainzy,first alter the firewall as per "Give your MGB V8 power" or Dave Vale's instructions in "V8 conversions" The workshop that shortens your upper steering column should be able to lengthen the lower part by splicing a section about 2 1/4" long into it.This way you can keep the CB Xmember & steering column & maintain the original steering geometry.All you do is effectively move the uni.joint up past the #8 exhaust port & into the new cone area.You'll need a smaller uni.joint that's all. It helps to keep the cone/hole in the firewall as low as possible to aid steering column/header clearance. If you go this way, you'll have to alter the upper steering column mounting bracket near the firewall.Which is quite straight foreward.BTW the upper steering column is chopped & rejoined below the steering lock, so the in cabin part stays the same.HTHs Barrie E
Barrie Egerton


Mark,
V.interesting i too have a factory V8 and often considered converting to a CB cross member to get a lower ride height...But was not realy sure of the best approach.

I heard of people doing this before but having to resort to an extra uj, and it all sounded a bit hit and miss..How is the steering routed on CB V8 converted cars??

Don't forget to fit the shorter rear shackles to complement the front:)

Ta J...
John

David,

Shortening the collapsible steering column was something I considered when converting my ’71 until I saw a ’75 in a wreaking yard. My thought was, so that’s how it was done. The column in the rubber bumper MGBs is two inches shorter than the column in the chrome bumper MGBs between the mounts under the dash and the mount at the cone which is backed up of course. A smaller U-joint as mentioned connects it to a longer pinion shaft that not only is lengthened to reach the column, but also the lower and more forward position in the rubber bumper cars.

If you have access to a rubber bumper’s rack and pinion then get the column also. It will probably be cheaper than having the old one modified. Next use Glenn Towery’s method of rack mounting. Briefly, that is to leave the rack mounting brackets as they are and modify the mounting lugs on the bottom of the rack housing to get the pinion shaft to point to the new location of the U-joint. Alternately, you could alter the rack mount brackets, but keep them in the same place. The bump steer mentioned earlier renders the car uncontrollable and is utterly terrifying at the end of a towrope! After making the mistake of relocating my rack mount brackets, I got them back to the original location just at the new required different angle. Before that it was undrivable above 20 mph.
George Champion

John

Everything down to the first UJ stays the same.

I managed to fing a C/B crossmember and made a jig by cutting a piece of angle to the same length as the tube on the rack. With the rack bolted to the crossmember I clamped the angle to the rack and welded the angle to the crossmember with some small pieces of flat bar. Next step is to remove rack and cut off the mounts from the crossmember. Now the rack can be positioned back in place resting on the angle, still in the same place but now can be twisted.
Have the steering shaft shortened so that it protrudes from the rack housing by about 30mm and new splines cut.
Bolt crossmember into place with rack resting in the angle. Fit new R/B UJ. The rack can now be twisted to the right position for the steering shaft to pass through the engine mount and up to the column UJ. Measure length for new shaft to connect between the two UJ's. With the rack, UJ's and shaft assembled clearance can be checked before re-welding the rack mounts and cutting off the jig.

Thats the theory anyhow. I am waiting for the shafts to be made before I can go further.
Looks pretty tight between rack and sump!


Cheers

Mark
Mark Rawlins


Cheers Mark,

My car is off the road for the winter and in need of a good mechanical overhall.The original box went south for the winter, and the engine is a bit tired.So i think i will add the rack/cross member mods to my list whilst it's all in bits...Do you have a camera??

Ps.Does anyone know of any power steering kit's/conversions??

Thanks John..
John

John

Yes Ive got a digital camera if you want some pics.

The MG owners club is selling a power steering kit.
Don't know if it will fit the V8.

Cheers

Mark
Mark Rawlins

John,
It seems like there was an article on a power steering setup/kit in MG World magazine recently.
Joe Ullman

Here’s the address for the power steering article…

http://www.mgcars.org.uk/cgi-bin/gen5?runprog=mgoc&a=&p=emg/emg100104.htm

You’ll need to copy and past due to the question mark.
George Champion

I did this a couple months ago, as I'd always had an interference problem with the u-joint, but not like everyone else recommends. ('71 roadster) First though, my engine (BOP) is positioned so that the crank damper and a small diameter oil filter fit between the steering rack and the swaybar. There's about 1/4" clearance between the pan and the steering rack. The only firewall cutting that was necessary was just a very small corner on the right side. I did have to move the radiator forwards though. Here's what I did: Using a RB steering rack and universal joint, I shortened the pinion to the point that it was about 1-1/8" longer than the CB pinion. That makes up the difference in the U-joints but moves that end of the steering column up and out about 3/16-1/4". To accommodate that I elongated the mounting holes, and everything bolted up just fine. I now have about 1/4" clearance between the rear header bolt and the steering shaft, which is plenty. This approach requires no fiddling with the rack mounts which I think is a very bad idea, and no welding of the firewall to replace the cone with the later deeper one which I feel is overly complicated. All in all I'm very pleased with the outcome.
Jim


Thanks all,

John.
John

I too fitted a crome bumper cross member to my '76 B.
here is what i did. using Glen Towery A/C engine mounts the steering rack sits between the harmonic balancer and the oil pan with plenty of air around it, the rack mounts were cut from the bottom up stopping about 1/8" away from being completly separated from the cross member then i bolted the rack hosing w/o the pinion and litlle by little bent the mounts notching the cross member to allow for rotation of the pinion housing i then inserted a wooden dowell of the right diameter and lenght until mated perfectly with the u-joint in the steering column i new then i had it perfectly align i coul rotate the whole assembly with my index and thumb no binding at all i then reinforced the rack mounts with a flat piece of 3/16" iron and welded the mounts back to the cross member. The rubber bumper pinion shaft was shorten about 1- 1/8" and new splines cut and reistalled it works fine. However i do have steering kick back but this can be attributed to the use of wide wheels and tyres (205/60/14) i will try in the future to install a vibration reducer from Flaming river or Borgeson, see what happens.
Romney
Romney

Using a CB cross member in a RB car has no bearing on the engine height. What is important, regardless of the cross member used, is the engine set back. The best location is obtained using Glenn Towerys A/C mounts.

It is easiest to use the RB steering rack with the CB cross member in a RB car. The shaft needs to be shortened- safer than welding onto the end of a shaft that is too short-& the base modified per Glenn, so it bolts in the same place, just at a slightly different angle. I too, have slotted the mounting holes in the fire wall to lower the interior shaft by about 1/2". No additional U-joints are required.
Jim

Jim,
If using a cb or rb crossmember has no bearing on engine height, why does a rb B ride higher? While personally never having used a rb crossmember, it's been my understanding that the factory added some height to the rb unit's mounting pads in order to gain more room for the V8 engine, ie, set it lower between the frame rails, and to gain clearance between engine and steering rack. At the same time, moving the cone lower in the firewall to accomodate the changes to the steering. Having just set my V8 engine in place in my 68 GT was the culmination of several years of reading and research on the best way for me, personally, to go about it. It's definitely possible for me to miss details, as everyone who's read my postings know, but your statement of there being no difference surprised me. Thanks, Joe
Joe Ullman

Joe,

You’re correct in saying the cross member was spaced lower to provide additional space to set the V8 motor lower between the frame rails. Jim’s point is that the motor is mounted on the frame rails so that actually determines engine height whereas the cross member determines clearance below the motor.

I found plenty of space between the sump and cross member even on the chrome bumper MGB with the Buick motor. Paul Hunt’s factory V8 wore a hole through the sump where it rubbed against the cross member when the factor motor mounts were mounted to the wrong sides. That makes me think there is a difference between the two versions in sump design.
George Champion


Your right Joe, the rb cross member has raised mounting points, spacers if you like which made the car ride higher.ie the chassis was higher off the ground.All factory rbV8's, chrome bumber V8 models included had this set up.The steering shaft from the firewall(bulkhead to us liymies) to the rack passed through the right hand chassis engine mounting bracket and all was well.Now, if you use a cb cross member the relative position of the rack to the chassis is now higher.Meaning the steering shaft want's to sit right in the same place as the engine mount.Costello got round this problem by fitting a second steering uj and a few other steering mods.
If a cb cross member is used on a rb car with standard V8 mounts (positions etc)and the rack mountings and rack position is altered to fit, then i think there will always be bump steer as the position of the rack relaltive to the track rod ends/chassis etc will now be wrong....about 35-40mm too low
The rb cars and factory V8 ride approx 35-40mm higher than cb cars.


ps. don't take this for read , but i think it's fairly on track..Until someone comes along and p....s on my bonfire!!

Phew John.
John

Thanks George and John for your input; I was really starting to question my memory and all that. To fit my engine in the cb car, I didn't do anything to the rack or crossmember, but opened up the tranny tunnel so that the engine would sit higher. I'm not worried about that, it's not that high. I have about 3/8 inch between the lip of the pan and the rack. My sump is well above the crossmember. I dropped the steering column as far as it would go in the existing holes, and used two ujoints, the lower one a vibration dampener, and a telescoping intermediate steering shaft for eas(ier) removal. Put the engine in place at the proper angle, and built my mounts from the Buick rubber pieces down to the rear sloping sections of the crossmember. Came out very well, if I do say so myself! Added two 18 gauge shims behind each mount on the xmbr for final fine-tuning of position, similar to the way the factory did theirs. This served to move the engine up and slightly rearwards, and clearances came out just like I'd planned it that way.
Now I can see why, if engine mounts are are the rails, how engine position isn't affected by what type of crossmember. I guess we were talking apples and oranges in that respect.

Cheers,
Joe
Joe Ullman

Thanks guys for all the input. I am about to start in earnest and will keep you posted on progress. As a matter of interest, the sills on the car looked ok....before it went to the paintshop for stripping. It appears that I now I have some holes big enough to use as hand holds...or to inspect the inner sills at least. Man, have I got some work to do. Take care all,

Stainzy
David Staines

Joe Ullman.
How is that vibration dampener works? have you notice a reduction in the steering kick back? which one did you use, Flaming River or Borgeson?
Romney
Romney

Romney,
I used the Borgeson. The steering is very smooth, lock to lock, with the wheels up in the air! I'll let you know how the dampener works when I get the car running...exhaust, wiring, brake lines, etc, come first. Wish I could tell you more right now.

Joe
Joe Ullman

This thread was discussed between 03/12/2001 and 08/12/2001

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