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MG MGB GT V8 Factory Originals Technical - Steering Arms

The V8 engine swap requires for the rack and pinion to be moved forward on the chrome bumper cars.
The question I have is; Does the Rubber Bumper cars steering arms are longer than the CB cars? If they are then the arms would have to be swap onto the CB car in order to maintain the right geometry of the steering.
Has anyone encounter a problem with in this area?
Thanks. Bill

Bill Guzman

Not true that it *has* to be moved Bill. Very likely with all the conversion parts available it would be easy to do that way, but my '71 has the rack in the stock location. Oil pan is ~1/4" above the rack, sway bar rides between the balancer and the pulley, oil filter tucks nicely in between the sway bar and steering rack, and the Olds aluminum nose starter (rotated) can be removed without jacking up the engine.

OTOH, the pinion shaft for the rack had to be lengthened a bit and the small universal fitted, and it'd be a challenge to keep the hood stock. Personally, I think I like it this way.
Jim Blackwood

Bill.
I have just changed my rubber bumper crossmember for a chrome bumper one and had to alter the rack mounts as you say.
I am now having problems with the handling. The car is twitchy over uneven surfaces. To complicate matters I am using Ron Hopkinsons front telescopic setup. I am going to check for bump steer at the weekend Ill let you know what I find. I have swapped the steering arms over so that the track rod end fits from underneath the steering arm, perhaps this is the cause.

Cheers

Mark
Mark Rawlins

Bill, Jim,
I too had to move my steering rack to get the engine to the recommend (from Roger William's book) height of 50mm below the bonnet line at the front of the rocker covers (exact measurements are listed in the book). How low does your engines sit as I would love to not have to move the steering rack.


Spriggsie
Clem Spriggs

Hi Bill,
No the CB and RB arms are the same - the factory moved the rack forward on the RB X member and there are no bump steer problems. I use the CB X member and fit a RB rack, moving the mounts down abot 1/4 inch and forward by 1/2 inch. I have absolutely no problems with bump steer.

Mark,
Have you stiffened up the rear suspension? In my experience it is the rear that makes the car twitchy - not the front!

Clem,
The 50 mm dimension is not at the front of the rocker covers but on a line acroos the bay which is 665 mm forward of the rear corner of the bonnet or in line with the front of the low rider casing. As the engine is angled down to the rear this means that the front of the rocker covers can be slightly higher than the 50mm.
chris

Definitely not close to 50mm. Measuring 28-1/2" down the hoodline from the fender/cowl seam and placing a small diameter tube (the only thing that would fit) across the inner fender lips I measure about 3-16" between it and the valve covers. The upper rear header bolt centerline on the passenger side is 4-1/16" from the firewall.
*If* the engine were the same distance from the firewall, which I very much doubt, that would put me about 1-3/4" above the "recommended" height. Which isn't far from the diameter of the steering rack, but there isn't that much room between the pulley and swaybar(GT). The distributor did not hit the hood, but the wires did unless 90° boots were used. A standard 14" chrome air cleaner on a Holley 4bbl stuck out maybe 2" above the hood, which is about what you would expect. Although I believe it would be possible to get a very low profile filter under the hood, I think it would have to be custom made and would seriously restrict airflow.
I also moved the radiator forwards and angled it rearwards at the top. I ran a crank driven fan with a pretty long extension, so I'm pretty sure it wouldn't have to be moved as far forwards as I did it. My current arrangement has the hood latch panel (whatever you call it) moved about as far forwards as it will go, but I had to have some room for the blower drive. I could actually move the radiator forwards almost another inch if I wanted to, but I now have a nice thin high volume electric fan on the back and still have room to put a Mercedes fan on the front if I need it. Easy as it will be for hot air to get out, that may be overkill though.
Jim Blackwood

Thanks for your inputs. Working on the V8 kit I have become aware of some problem areas, one is the rack.
My calculations tell me that if the rack is moved more than 1 inch and lower than 1/4 inch can result in problems in the geometry of the steering. If the rack is moved forward it should maintain the same plain as the original. In the motor mount area I have found that the Alpine Tiger motor mount would work best. This motor mount is the same as the stock Ford but about 50% stiffer though helping to control yaw on the engine bay.
Again thanks for your inputs.

R/Bill G.
Bill Guzman

Ah yes, motor mounts... I like the stock Buick 215 motor mounts. Attachment points are easily fabricated and welded to the front crossmember, and the mounts themselves can be drilled for through-bolts which will limit travel while still providing the stock cushion for isolation of noise and vibration.
Jim Blackwood

Bill, I was wondering why you think it has to be moved. I have a CB Rover V8 conversion with what I believe to be a stock CB x-member, stock bonnet, etc. ... steering rack is the CB rack with the longer RB pinion substituted so as to get the U-joint aft of the header bolts. Not as though I'm an expert by any means; that's pretty much how it was when I got the car, which had already been converted. A picture of the setup is at

http://home.earthlink.net/~davidd_dt/images/blue_mg/DSCF0026.JPG

; I could be wrong but see if that doesn't look pretty normal to you. (Don't go by the bottom of the rad ... it's one of those V8 rads that has been extended vertically by ~3" so it hangs down lower). FWIW: the motor is in the normal, "non-A/C" position; the 2" dropped air cleaner clears the bonnet but only by about 5mm; the bonnet x-brace is in the stock location as well.

David

Very similar to what I have, except mine is a bit farther forwards so the oil filter will tuck in between the rack and the swaybar. It was easier to move the radiator than to find a remote filter plate 15 years ago. I use a lengthened pinion (shorter than the RB model but longer than the CB) small U-joint, and no other mods to the steering except the larger tires. No bump steer. (unless driving one handed, from the weight of my arm pulling the wheel to one side! :)
Jim Blackwood

I installed a cb crossmember and used the rb rack. I welded 5/8" o.d. box tube on top of the cb rack mounts and extended them forward. The mounts slope downward towards the front of the car. The 5/8" box tube raises the rack back almost exactly to stock height and doesn't exhibit bump steer. My Nissan v6 is about two inches behind the rack.
Barry
Barry Parkinson

David, I am trying to figure out what looks wierd about that setup. But it doesn't look wierd. It doesn't even look cramped. Save that picture because it demonstrates plainly that what is thought to be well nigh impossible, isn't. I mean it basically says, w/r/t using the CB x-member, "don't even try it" in _How to Give Your MGB V-8 Power_. Yet I am convinced that the CB x-member has to be the way to go to get the car lower; you can lower the RB setup but you have to use those short, stiff coil springs which for my money really hurt the ride. And the asymmetric RB steering rack mounts have always seemed kind of theoretically impure (not that I can tell the difference from the driver's seat).

I have the forward extension on my rack sort of as per barry. That's definitely a CB x-member and rack you have there; can't see any obvious deviations from stock. Whoever did it did a fine job. Seems to me you must use an intermediate steering shaft? Do you have a picture of the steering column/pinion junction up near the steering cone? You say you have the stock bonnet; I really don't get how you or whoever did this unless I am missing something.
Bob

Bob, there is no intermediate steering shaft. Here is a picture of the u-joint/steering cone area:

http://home.earthlink.net/~davidd_dt/images/blue_mg/blueGT-steercone.JPG

The u-joint clears the rearmost header bolt by 3/8" or so. FYI, the angle of the steering column is a little steeper than on a standard B; that is, it comes through the firewall a bit lower than it would have on the 4-cyl.

David

Guys

please see my posting on the stability at speed thread lower down the list.( I'm not going to tap that lot out again!)

Basically it is possible to use the CB xmember with the V8 mounted with factory style mounts-this is important as the various mounts availble may mount the motor lower-most that I have seen in the UK mount the motor higher. The front sump edge ends up about 1/4" oof the rack body tube with factory mounts which is ok esp if you have a steady bar.
You MUST mount the rack as per the C/B position if you want all the benefits of the CB handling(see stability at speed posting.) The only modification should be to reweld the mounts to correct the elevation of the upper end of the pinion shaft,ie to rotate the rack about the body axis. Reinforcement is a good idea as well.
You must also shorten the shaft some how as the joint will end up too close to the rear exhaust flange if the CB rack is retained-or will end up inside the car if the unaltered RB rack is used. Having the joint too close to the flange is one of the criticisms levelled at the original conversion that Costello did for BL and could lead to steering problems should a mount break and a steady bar is not fitted.
To my knowledge the steering arms are the same for both CB/RB .When you get into the design you realise that the factory basically did a very good job within the limitations of the kingpin design and you have try not to harm these good points when modifying the car.

Regards

john Bourke
John Bourke

I have simply got to get my photo uploading capability taken care of. You fellas would appreciate this. The U-joint is about 1-1/2" back from the rearmost header bolt. Clearance between that bolt and the pinion shaft is in excess of 1/4", and yes, the oilpan sits about 1/4" (or less) above the steering rack. The car is a '71 with the original front crossmember and the rack mounts are unmodified. The original steering column was retained, but the hole through the firewall was enlarged upwards something less than 1/4". The original nuts were not moved, but the bolt holes in the column were offset by a similar amount. The small universal joint was used, and the pinion was lengthened something like 1-1/8" by drilling a hole in one piece and turning a pilot on the other and then pressing, truing, welding, checking straightness and turning down the welds. After paint the seam is barely perceptible if you know where to look. It took two pinions to make one, and the weld joint is in all liklihood at least as strong as the rest of the shaft.

I feel it is a real shame to do anything that could mess up the excellent handling of this car, and one of my original design goals was to avoid that completely, therefore I worked out the swap with that in mind. Just wish you could see it.
Jim Blackwood

Great thread! Seems like licking the steering issue roundly is the lynchpin to creating a fine V8 conversion. How the heck do you guys know all this stuff? Seriously, this kind of info makes "How to Give Your MGB ..." seem like a book for toddlers.
Ted

Mostly just picked it up here and there, but formal education didn't hurt any. Growing up on a farm was a tremendous benefit for thinking "outside the box". Since mine was done back when they were uncommon I had many problems to solve, and some solutions were unconventional but worked. Main thing, don't rush it. It's a good feeling to wake up knowing exactly how you are going to do something difficult and know that it will work. As opposed to waking up knowing how you should have done it.
Jim Blackwood

Jim
this thread isn't about, and you haven't mentioned the firewall. I assume you did have to modify the fire wall?
Barry
Barry Parkinson

Bill, are you working on the 215 V8 or the 302 V8 kit? I know I have heard you mention both.

I am deep into my 302, and haas found a way to get it in without moving the rack. After I (try) to get the mounts fully done this weekend so the engine is supported by the chassis rather than a milk crate I will check hood clearance. Without the rack installed I had it in with clearance, but we will see now as the rack has bumped it up just a touch.. On the 302 another issue is the distributor, mine is right under the hood brace.
Larry Embrey

Larry, FWIW it's pretty easy to move the hood brace. I don't know how to weld but I took it over to a body shop and they did it in a matter of seconds -- I moved it 1" forward. Or you can yank it altogether; it's not really necessary. But surely the 302 will require some sort of bulge/scoop/etc. (at least if you want a reasonable air cleaner on there), no?
Harry

Larry I am working on the Ford V8 302. The engine swap is totally different than the Buick/Olds V8.

Many factors are involved in the swapping of an engine; and they have to be looked at. Also I am going to make a kit, what that means is that I have to make it simple and be able to duplicated. Also very important is the satisfaction of a well-completed swap.

Do not ignore Mr. John Bourke advice. He is an old pro at the Buick/Rover engine swap and other mods to the B. also don’t forget Mr. Roger Parker.

R/Bill
Bill Guzman

<<<But surely the 302 will require some sort of bulge/scoop/etc. (at least if you want a reasonable air cleaner on there), no? >>>

No. Take a look at Dale Spooner's car. Stock hood ('cept for louvers).

http://members.aol.com/danmas4/mgv8conv.htm#eng#5

http://www.larryembrey.com/mgb/PhotoAlbum/Various%20V8's/Dalesmgb50.htm


Note to Larry: That is not an 8.8 under Dale's car. It is an 8" Ford/MBG hybrid that Dale built himself.
Carl

Hey Guys,
As mentioned above I have removed my steering rack to allow the engine to be positioned in accordance with diagram in Roger Williams book,

"50 mm down at 665 mm forward of the rear corner of the bonnet or in line with the front of the low rider casing"

I also removed the steering rack as lowering the engine also meant that I could get the U/J angles to be what they should to avoid prop shaft vibrations. As an added advantage my Federal Type Fuel Injection unit now fits under the bonnet without modification (according to other sources this should have to be lowered some).

My question to all is at what height is your engines at and how has this effected your prop shafts and steering racks???

Thanks

Spriggsie
Clem Spriggs

Clem, when you say you've removed the steering rack, I assume you'll be re-attaching it before taking the car out! ... greatly enhances the handling!

I would not worry so much about the UJ angle ... the key thing is to get that steering rack exactly where it should be ... everything else is secondary in importance! While driveshaft/U-joint angle is also important, you can just stick shims into the rear spring perches to orient the rear end as you would wish (speed shops sell these shims; they're cheap) ... as you know, the line of the pinion must be parallel to the line of the crankshaft. However, for the sake of the U-joints, they should not be co-linear. It is thought optimal to get a 3 degree offset between the line of the driveshaft vs. that of the pinion/crankshaft. This is so that you keep the U-joints slightly moving as they rotate, which greatly increases their life by smushing the lubrication around, and having the bearings move slightly. This foots with my experience. When I first built my V8, I had the motor a little high in front, and the crankshaft was directly on axis with the driveshaft. Guess what, the front U-joint bit the dust in no time flat; it lost all ability to move and was essentially stuck in position. Under hard acceleration, this resulted in MAJOR vibrations in the driveline. Had the driveshaft rebuilt, re-oriented the motor very slightly (by fiddling with the front motor mounts and the tranny mounts, and finagling the exhaust) for approximately a 3/3 offset (this is very hard to measure accurately; there may be some special tools to do it) and things are massively smoother.

I just have a RB crossmember and I am pleased to see it is apparently possible to get everything in place with a CB crossmember. That is worth investigating, because I can confirm that the shorter, harder RB springs that you use to lower the car when using the RB unit give rise to a pretty lousy ride, though the handling is sharp.
Dwayne Smith

Dwyane,
Thanks for the input, I have not got my car back on the road yet I'm still playing around with where to mount the engine. I also have not cut anything from where the steering rack mounts as I was just playing with the idea of moving and have to consult a specialist before cutting anything. How high is your engine in the bay?

Spriggsie
Clem Spriggs

This thread was discussed between 04/04/2001 and 21/04/2001

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