BOOTLEG Gary Rosema Wisconsin (47 posts) Registered: 11/18/2013 07:26PM Main British Car: 1978 MGB Rover 3.5L |
CB Cross member help
I too must lower my 78 B. Currently ~17" wheel center to chrome. Got a donor CB Xmember and cut the steering rack brackets off and bolted them to a steering rack. Installed and leveled the Xmember and car on jacks laterally. Positioned the rack w/steering rod through the motor mount and in the U-joint. Squared them using the distance from the center tube on the steering rack to the front edge of the Xmember. Made paper templates and cut 3" wide 1/8" thick flat steel into 4 bracket connectors and welded the rack mount brackets to the Xmember in the "new" position. Had fun making it and the steering rotates nicely but not sure I want it on my car because the brackets are not centered.
Comments please. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: CB Cross member help
Gary, have you considered bump steer? As you move the rack forward the steering arms should normally be lengthened by an equal amount. That's not practical for most so the rack pinion is usually shortened instead. If you have done that please disregard the above.
Jim |
ex-tyke Graham Creswick Chatham, Ontario, Canada (1165 posts) Registered: 10/25/2007 11:17AM Main British Car: 1976 MGB Ford 302 |
Re: CB Cross member help
Quote: You'll find that if you look at the steering rack alignment on an original RB xmbr, the body is not parallel to the xmbr - the right hand mount bracket is longer than the left, leaving the rack askew - all done to allow correct shaft routing through the engine mount and up to the U-joint. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: CB Cross member help
The RB has a deeper firewall cone and shorter u-joint, but still I don't think it works with the CB rack (if he has one). I think you have to lengthen it.
The RB rack has to be shortened 1-7/16", we just did this with the Chump car: [forum.britishv8.org] The CB rack does have a quicker steering ratio though. Jim |
MGBV8 Carl Floyd Kingsport, TN (4512 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: CB Cross member help
Mike Moor said he didn't shorten his. I haven't tried it yet. If the rack moves forward, though, it will be into my harmonic balancer.
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: CB Cross member help
Might want to ask him how he did his, I've see it done a bunch of different ways. It's pretty easy to change the length, especially if you have access to a lathe. But it can be done using a snug fitting piece of tubing and a welder too. Plus it's a good opportunity to assess the condition of the rack and service it.
Jim |
ex-tyke Graham Creswick Chatham, Ontario, Canada (1165 posts) Registered: 10/25/2007 11:17AM Main British Car: 1976 MGB Ford 302 |
Re: CB Cross member help
I have another original, unmodified rack in my garage with the CB ratio (2.92:1). I ran it for a couple of years before switching back to my RB rack (3.57:1) - both racks have identical length steering shafts, so no modification required to switch racks.
I can't tell you what year it is from, but clearly the quick ratio rack is available as a direct replacement for the RB rack. |
MGBV8 Carl Floyd Kingsport, TN (4512 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: CB Cross member help
That's interesting Graham. Wonder if it was just another transition piece?
Jim, Mike slightly relocated the rack mounts, then it all bolted up. I may have to give it try this winter. Problem is my harmonic balance is only thousandths away from the rack now. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: CB Cross member help
Any time you have to mess with the rack mounts, the split coupler/exhaust clamp mount really is the way to go. Simple and easy to make, easy to position, adjustable side to side and in rotation. Makes aligning the rack a snap, just hook it up and clamp it down.
Jim |
MGBV8 Carl Floyd Kingsport, TN (4512 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: CB Cross member help
Yes, I agree. That was a very slick method on the Roadmaster. In my case, though, the mount has already been modded cause I have Mike's old CB crossmember.
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Capt'n Moorgone Mike Moor Angola,IN (116 posts) Registered: 11/20/2008 07:05PM Main British Car: 1973 MGB 300 Buick |
Re: CB Cross member help
Gary,
There are many ways to skin a cat. As Carl said, I didn't shorten the shaft. The easy way is to leave the RB rack hooked to the steering shaft and cut the mounts off the cross member. Leave the rack hang on the car. Remove the cross member. Cut the mounts off the CB cross member leaving about half the bracket in place. Now bolt the CB cross member up. Where ever the rack and brackets land against the CB brackets, weld it together. I'm not sure, but I may have heated the steering arms on the spindle and bent them down to correct bump steer measurement. This set-up worked very well for several years before converting to Fastcars' cross member. I remember Bob Senecar, ASA champ, driving my car and saying how well it handled before I switched to Fastcars' unit. I almost backed out of the purchase. Don't regret the change. Fastcars' unit took #80 off the front end. Take your time, and you'll be happy with the results. |