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MG MGB GT V8 Factory Originals Technical - Steering UJ Advice

Second post of the day!

Have a look at :

http://www.occpsy.demon.co.uk/uj.bmp

This is the lower UJ for a CB conversion. I need to fix the shaft in the UJ. The PO has ground down the shaft ends, I will be replacing the shaft so I can start from scratch. The UJ is drilled and tapped either side.

Clearly it needs to be safe and strong above all, welding is not an option because it needs to come apart to go in and out. In any event the heat might ruin the UJ.

The way I see it have 3 options:

1. Use grub screws, one either side and flatten either side of the shaft for them to butt up against.

2. Use grub screws, one either side and drill and tap out the shaft so they screw right in and meet in the middle. (Or dethread the bottom of the grub screws and have them fit into a drilled but not tapped hole.)

3. Drill and tap the shaft and fix a bolt right through the whole lot.

The same issue is faced on the other side with the lower pinion shaft.

Any thoughts appreciated.

Liam

Liam H

Liam, is this shaft an intermediate shaft between the steering column and the rack? If so, I'd recommend using a splined or double D shaft and the matching U-joints. Don't know of UK sources, but here's a site that has a lot of useful information http://www.borgeson.com/
You can download their catalog and tech guide which has a lot of good information about shaft strengths etc:. They state that crossdrilling a shaft even for a shear pin reduces the strength by 30%. By the way, the spline size for the B is 3/4" diameter with 48 splines.
Bill Young

Hi Bill,

It's the one just above the steering rack, right at the bottom and is obscured by the engine mount.

Space is a real issue, even the small UJ I took off my 78 B is too large.

I think the UJ is strong enough, it was used on another car with no issues. The other problem is that I have a ton of sterring componenets so finding a splined shaft to come down from the column is not an issue, but the actual pinion shaft which goes down into the rack is not splined and I wouldn't know how to get that done.

Liam
Liam

In that case I'd have it machined to a double D configuration and use the proper u-joint and grub screws.
Bill Young

Liam, one other thing. If using grub screws make sure you use locktite and if possible get screws which have drilled holes for safety wire. I have seen an instance where the grub screws fell out and left the driver with no connection in the steering.
Bill Young

Liam,
One of the problems you are faced with is the play or clearance between the shaft and jount. Even the closest fit will have clearance and taking the play out can be very difficult with space limitations. Using grub screws won't make a reliable connection. Having a shaft with flats on both sides and a joint to match would be very helpful but then you still need a reliable means of retention. The practice of using an offset pinch bolt is very widely accepted when used with a tightening band and a split collar but it would mean machining down your u-joint to accept the band and then cutting the 1 or 2 slits and the relief for the pinch bolt, and there would be some concern about the strength of the remaining material as well as the need to make certain of a generous radius where the body necks back up, and then the pinch bolt would have to clear the car as well. How about welding a splined section to the pinion? Seems a much cleaner solution to me. Another option would be a tapered offset pinch bolt. These are sometimes made as a straight pin with a taper cut on the side and a thread and nut to pull it tight into a flat on the shaft. Sometimes used on motorcycle kick starters.

HTH

Jim
Jim Blackwood

Helpful thoughts Jim. The inside of the UJ is smooth with no splines, otherwise I could go down one of the routes you describe. The shaft is actually a very snug fit, there is no play that I can detect.

I'm hampered by the fact that anything much bigger in UJ terms interferes with the engine mount, I have ground away a little to clear this one and dont want to grind any more. I doubt there would be enough clearance for a pinch bolt.

I could get a custom UJ and upper pinion shaft from the states as Bill suggests, but very pricey, plus import tax we're talking 100 quid plus? and I'm still left with the lack of splines on the short bottom pinion shaft.

Would welding a splined section on not be a bit dodgy?

Liam
Liam

Not at all. There are several proceedures that are quite satisfactory, for instance using a lathe to drill a pilot hole in each piece and joining them with a dowell pin, followed by welding the two (chamfered) stubs together. About a 1/4" pin should locate the pieces well enough and give a minimal effect on overall strength. As long as the weld is above the seal area of the steering box and done in a manner to keep warpage down the results should be quite good.

Jim
Jim Blackwood

Possibly
http://mgv8.homestead.com/steering.html

or the mgb hive were selling V8 conversion bits and peices, so worth a call.
Peter

Thanks Peter. I spoke to them a couple of months ago but they no longer supply the double UJ shaft for CB conversions. Their advice was use a RB front end and lower it.

No further forward!
Liam

Are you using through the guards extractors?. I've often thought that the back pipe could be made to go wide around the universal joint. Up and over, or back and under. There would be a little cheating on the back out let, but not too much. I saw a car (a supercharged V8)where they had set the motor very low, low enough so that the pipe was under the joint. I could not see clearly, but they might have put the mounts down on the front crossmember, that would be my aproach.

or Here's a thought, since Clive is no longer supplying the racks he might tell you where he got the work done.
Peter

Liam,
Maybe I'm a bigger risk taker than most, but I don't see a huge problem with cross drilling your shaft and bolting through it. I prefer to use a hardened roll pin with progressively smaller roll pins pounded through the center of the fist one. Makes a very tight fit and the spring tension of the roll pins does a better job of preventing movement between the u joint and the steering shaft.
There's no question that cross drilling the shaft will weaken it compared to a proper splined setup. But then again, how much strength do you need? How much torque does it require to turn the steering pinion on an MGB? Maybe if you're one of those people that who always slams the wheel hard at the end of it's stop to make a u turn etc...

FWIW

Scott
Scott Wooley

Engine mounts on the crossmember work well and clear the area of the steering shaft. I've had crossmember mounts on my car for 20+ years now and never a problem. However for high horsepower applications it is advisable to through-bolt the mount cushion for torque limiting, a simple operation easily and cheaply performed. And, the crossmsmber mounting bolt holes in the frame need to be checked for cracking first. If any cracks are found or the engine is expected to make lots of power it wouldn't hurt to reinforce that area a bit, but all I ever did was weld up the original cracks during the first conversion and they've not come back, probably becauses I swapped the delrin suspension bushings for V8 ones. Personally the only reason I would even consider frame mounts would be for consistency with the original cars or because they are readily available complete and ready to bolt in.

Now granted, a 1/4" pin in double shear should be more than you can take on with arm strength alone. But I *have* seen a curb strike take the wheel out of a driver's hands and slam it forcibly against the stop and I do feel this would damage the roll pin. The splines are there for a reason, and if an advantage could be had from a simpler, cheaper, or lighter construction you'd be seeing that on some of the new cars, at least on the top end ones.

Liam, why was it again that you need a u-joint above the rack? Something about your engine position and exhaust was it? I just took another look and my block mount supports clear the steering shaft by less than 1/8", but then my engine is positioned very far forward and with the engine moved back there would be plenty of room.

Jim
Jim Blackwood

Jim, It's a CB conversion. The pinion point too high and I dont want to shim the rack.

I suppose that now the engine mounts are in I could try it again and see where it ends up.

A UJ, a UJ, my kindgom for a small UJ.

Liam
Liam

I'm using a tubular exhaust.

Jim, or anyone, do you have a photos of what engine mounts on the crossmember look like?

As I had to grind mine off anyway that might have been an easier route.

Liam
Liam

Liam, mine also is a CB, 1971. There was no vantage point from which I could get good or even usable photos but I'll do my best to describe it for you. I used 1/4" pipe for the bolt tubes that the motor mounts sit on and attach to. Below that I cut a short piece of 1" pipe (I think) sized to hold the engine the right distance above the steering rack (about 2-1/2" long as best I can recall). The top end of this pipe I flattened enough to match the 1/4" pipe and welded them together, welded the bottoms to the crossmember (tacked it with the engine in position) and then cut two triangular gussets from ~7ga steel for each side and braced them fore/aft and sideways. After that I found I needed to make a vertical adjustment of the driver's side mount so I simply cut away the top tube and welded in a new one. Actually the first time I adjusted it I left the bottom of the top tube and welded another above it, but later I moved the mount downwards again and cut both the new tube and the remains of the old one out. I drilled the tube slightly over 3/8" for a loose fit and that works well.

Your car is RHD and maybe the starter is an issue with the space needed for headers and the steering shaft as well, depending on what you are using and how the engine is positioned. I was able to originally get by without modifying the steering at all. I did have a header bolt that was uncomfortably close to the steering u-joint and later changed to a later U-joint and lengthened the pinion shaft and moved the lower steering column mount about 1/4". However, the cylinder bank on the right sits further back and jockeying engine position alone cannot really be expected to solve all the clearance issues confronting you. It appears you have taken on the challenge of the most difficult configuration possible with these cars and this engine but don't get discouraged. There is a solution it's just a matter of finding it. I'll give you a blue-sky example: Let's say you had the means to machine whatever configuration of mating parts you wanted, it would be possible to cut a tapered spline which would eliminate all play when driven together and basically lock up solid with maximum torque transfer in a very small package size. Then a strategically placed roll pin, preferably offset from centerline to get maximum bearing area across the shear plane of the pin, could be used to lock it into position. This should satisfy your needs just fine, or an even better locking means might occur to you.

So let's simplify the manufacture. Let's say instead of a spline you use a close fitting set of flats on the shaft and retain the taper on the round part. Now your shaft is easily constructed by milling two opposed parallel flats on the sides and turning a taper on the end. The socket is a bit more difficult however, as it must have the matching flats and taper but it is still possible to manufacture by EDM, as a powdered metal part, or perhaps by welding inserts into a tapered bore. Depends on how good your machinist and welder are. BUT, looking at existing technologies there are examples of four sided tapers and matching sockets that could possibly be made to work. What springs to mind are valve stems and handles (not intake and exhaust valves, the other kind for water and such) and the shafts of some auger bits. The four sided taper could be cut on the shaft rather easily and the socket could be cut from a forged valve handle and welded to the u-joint. Then it could be locked with a roll pin or grub screw and be reasonably secure.

So there's some more food for thought, hopefully it will lead you somewhere productive. hth

Jim
Jim Blackwood

If you abandon the traditional engine mounting point then you are pretty much free to use any rubber mounts you want. Subaru rubber mounts have a neat back plate overlocking arrangement so you don't need a steady bar.
The next MG I do will use the front crossmember, but I'd check with your engineer first about legality.
The thing seems to be all positives to me. Lower centre of gravity so the car handles better, no steering alterations, better bonnet clearance which is always an issue etc . I wish I had thought of it before I did mine.
Mind you I don't know how block huggers go for clearance.
A thought- Why not try costello? I heard that he has been known to put V8's in MGB's ;)
Peter

Another thought, if you know a blacksmith he can easily fashion a tapered socket for you from any suitable chunk of steel with a hole drilled through it if you provide him with a tapered pin to drive into it. (Don't use the pinion for this, have a separate tool made up.) Then a lathe would make short work of preparing it for welding to the u-joint, using the same tool as an arbor for the turning operation. A slow taper of 2-3 degrees would be in the "self holding" class and should be suitable for your application but would need to be at least 1-1/2 inches long if possible. Any taper in the neighborhood of 5/8" per foot should be suitable, however be mindful that the slower the taper the more variability in the seated position so you will want to drive it in hard as is practical and have some means of unseating it as well. And you should still provide a lock. Also too much seated pressure can crack the seat so don't overdo it. One firm smack with about a 12 oz hammer should be sufficient. A faster taper will seat in a more positive location and can be made shorter but will come loose more easily and will therefore need a more positive lock.

Jim
Jim Blackwood

Some great advice all round. Thanks everyone.

I looked at borgesons and flaming river's web sites and realised I have only been thinking in terms of splines.

Getting a splined UJ from those people wold not be an issue, bit tighter round the engine mount but solvable.

Getting the rack side short emerging pinion and upper pinion shaft splined at the bottom end was the problem.

I can now see there is no reason why my local engineering shop cannot take these two shafts and machine them to a DD configuration. Plus the 3/4 DD UJ, using a grub screw instead of a bolt to secure, from either of these suppliers ($110 to the UK) solves the bottom UJ issue.

At the top end all I then need to do is use the smaller rubber bumper UJ and the longer rubber bumper pinion shaft to go down to the new UJ at the bottom, the shaft is too long but I could cut to size before having it machined to DD.

The rubber bumper upper UJ fits onto the splines emerging from my chrome bumper steering column I just need to cut 10 mm or so off it as it sticks right into the UJ.

That took some working out.

Liam
Liam

Hi Liam,
Sorry to throw a spanner in the works, but I went down this path without success. Note, my car is left hand drive, chrome bumper. When I tried to fit a Borgesen/Flaming River joint at the botttom (attached to the steering rack) it fouled the engine mounts. I ended up tapering the feet of the steering rack to lower the top and and then using one of Flaming River's low profile UJ's ( http://www.flamingriver.com/index.cfm/page/ptype=product/product_id=207/category_id=112/home_id=82/mode=prod/prd207.htm ).
From your earlier photo's, it looks like the joint you are planning on using is one of their "racing" joints ( http://www.flamingriver.com/index.cfm/page/ptype=product/product_id=209/category_id=113/home_id=82/mode=prod/prd209.htm ).
Be aware, these are not joints with bearings and they are not sealed, they are not designed for road use and will need constatnt lubrication.
Regards
Tony
Tony Bates

Also note, if your local shop can mill the flats they should also be able to mill splines as all that takes is a suitable cutter and an indexing head, things that most shops should have. At worst you might have to buy a cutter but one for a bridgeport type mill is about $25. See: http://www.use-enco.com/cgi/INSRIT?PMAKA=367-7100&PMPXNO=948041&PARTPG=INLMK3

They are available with different angles and you can be off a bit without any real trouble. Just need the spline count or a matching part (better).

Jim
Jim Blackwood

Good tip, Tony.

I knew the clearances would be tight - I had to grind away some of the mount just so I could steer the car around with the engine out using the UJ's you see in the photo, but I had not seen the low profile version at all.

Do you know the dimensions? They don't list them on the web site - could be a life saver.

Thanks, Liam
Liam

What dimesions do you need, I have one in the garage
Regards
Tony
Tony Bates

Hi Tony,

Length and diameter at the ends really.

Cheers,

Liam
Liam

Give me 24 hours, I'm at work at the moment.
BTW, I was able to order one with splines (48x3/4) at both ends, or any other configuration needed.
Regards
Tony
Tony Bates

Hi Liam
3 3/4 inches long and 1 1/8 inches diameter at the end. Sorry about it not being metric, when I left the UK (I'm a Brit) we still used UK measurements instead of EU ones. Thank god a "pint" is still a "pint" and not a "semi litre" :-)
Regards
Tony
Tony Bates

That would fit comfortably, thanks for the help Tony.

I would add, thanks for pints in general.

Liam.
Liam

This thread was discussed between 12/05/2006 and 17/05/2006

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