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MG MGA - 5-Speed Gearbox Speedometer Right Angle Drive

I Have just received the right angle drive assembly for my Sierra 5-speed box (picture attached). I will probably be fitting it tomorrow, so will post some photos in due course.

For those that missed the discussion a couple of weeks ago, this item costs between 80 - 100 depending on the supplier. It enables the original MGA speedo cable to be used and is said to cut out some of the instrument swing us 5-speed users suffer with a compromise speedo cable.

The only other comment I will make at the moment is to quote the following instruction that came with the unit: "Due to the thinness of the lip it is essential that the angle drive is supported. We recommend a cable tie round the flex drive and a chassis member as close to the angle drive as possible."

Steve

Steve Gyles

Steve,
Thanks for the info....

For the price, I would think they would include the 60 cents worth of tie straps. I am still interested in purchasing this unit. Let us know how the install goes.

Ray
Ray Ammeter

I am not sure how that tie would be fitted. I understand the idea of supporting the weight of the flex drive cable, but the gearbox moves independently of the chassis. Not much, but a small amount.




Mick
M F Anderson

Just had a quick look at what's involved in the fitting. The right angle drive fits neatly inside the tunnelling with half an inch to spare to the tunnel wall, with the cable then running up inside the tunnel. So anyone fitting a 5-speed box does not now need to drill a cable access hole through the tunnel.

Steve

Steve Gyles

Bearing in mind what the instructions say about support for the drive and also what Mick says in his post, I would be interested in any comments about using a rubber buffer between the unit and the tunnel. See attached Schematic.

Steve

Steve Gyles

Steve,
What if you were to put silicone sealant around the right angle drive where it attaches to the tranny to give support. It would be much easier if the tranny was out of the car to make a neat job. Then again, it might be bumped when installing.
My thought would be to use industrial strength silicone sealant from the surface of the tranny to the corresponding surface of the right angle drive unit.Flexible, yet supportive enough for this installation. A person probably would need a extension on the tube nozzle to put the silicone in the right spot. If not it would be one heck of a messs.

If you were to use tie straps, wouldn't you need to encirle the tranny, so the cable,right angle drive and tranny would all move in unison. If this is done, then I would think you would need to block the cable near the right angle drive to so the cable itself wouldn't pull the right angle drive out of the tranny.
Maybe a combination of both silicone, blocking and tie straps.
Try the tie straps first then see how it supports.

Ray
Ray Ammeter

Ray

Thanks for your thoughts. I am not ruling anything in or out at the moment.

For anyone not familiar with the Ford box, the 'thin lip' referred to in the instructions and visble in my first image is retained in a gear box housing by a circlip. There would seem to be concern that the weight of the drive assembly could cause fatigue failure to the lip or perhaps cause the circlip to be levered out, hence my thoughts along the lines of the rubber supporting block in my schematic.

Steve
Steve Gyles

Steve:

The arrangement that you show in your diagram would not work. One side (tunnel side) of the block rests on a stationary surface and the other side (drive/transmission side) is moving relative to the tunnel as the engine and transmission assemblies flex on their mounts during acceleration (torque) or braking (linear displacement). In order to relieve strain, the cable strain relief would need to be mounted relatively near the drive on the transmission so that the cable and drive move in concert with the transmission movement. Maybe loosening one of the transmission casing bolts and mounting a "P" clip with a rubber bushing betweeen the clip and cable (i.e., as was done on the original at the firewall) would be possible.

The point of attachment of the cable to the frame should only be done at the original attachment point on the firewall to allow the length of the cable to move and evenly distribute the motion of the transmission.

Steve
Steve Brandt

Wow. All done. Not a swing on the speedo at all. Totally rock steady. Unbelievable. Brilliant.

Fitting was quite fiddly. For those fitting a 5-speed box for the first time I recommend fitting the geabox without the tunneling, then fit the right angle drive, then fit the tunnel. I found it all such a tight fit that the right angle drive protuded through the existing cable hole during the fitting process. Because the speedo drive is angle down, the top of the unit just about touches the tunnel wall and a half inch gap at the bottom. Fitting the circlip was quite a game - lying on my back under the car - oh for a ramp or pit. The original gearbox bracket provided an excellent speedo cable attachment point using a cable tie. I glued some rubber bewteen the unit and the tunnelling. The original speedo cable from a RHD car (is it a different length to LHD?) was only just long enough.

Attached schematic and photo give you an idea. Photo is looking almost vertical upwards, with tunneling (plus square cable access hole) just visble on right hand side. Front of the car is at the bottom of the photo.

In the original configuration I made a large rectangular cable access hole plus a cover plate with a grommetted cable hole. Once the cable had taken up its natural lie I trimmed the plate to suit and fixed to the tunnelling. The large hole, as it turned out was very useful when manouvring the unit into the drive, otherwise I think the tunnel would have had to come off.

Steve

Steve Gyles

Steve

Many thanks for your thoughts. I think our posts crossed.

The rubber strip I eventually fitted will serve more as an anti rubbing buffer against the tunnel than for anything else. The natural geometry of the right angle drive also appears to generate its own support against the tunnel, so that should sort out concerns about the weakness of the lip. The cable tie to the chassis (original gearbox mounting bracket) is more of a stabiliser for the unit, the tie is about 4" infront. There is sufficient movement in the system to take care of the engine/gearbox twist. The tie simply holds the weight of the cable in its run along the gearbox to the engine compartment.

First run out in the car was totally staggering. I have never, ever, ever seen the speedometer so stabilised. I have routinely followed Barney's notes for cleaning the instrument innards. Now combined with this very smooth drive mechanism the speedo stability is every bit as good as my 2008 Merc!! Sorry to use so many superlatives, but I was genuinely impressed.

Steve
Steve Gyles

Steve,

I have a 5 speed kit on order along with the right angle drive and plan on installing it in the next month or so.

Do you think it is possible to place the angle drive on the gearbox after initial placement of the engine/gearbox but before final positioning of the rear support crossmember or connection of the drive shaft? In other words would sufficient space be afforded by slightly shifting the gearbox to the left before final allignment, etc.

Did you use any type of sealant on the adapter to help prevent oil leaks as mentioned in the previous thread on this subject?

Jim
Jim Ferguson

Jim

I would think so, especially if the tunnelling is not in place. There are no other obstructions within the odd inch. just take it easy.

No, I did not put any sealant in place. I did not have any leaks with the previous cable attachment.

Best of luck.

Steve
Steve Gyles

All seems very complicated to me! I have a five speed box in a Twin Cam with normal speedo drive cable (no special right-angle drive) and the speedo runs steady and true without the need for any outside assistance! Maybe I'm just lucky.
Bruce Mayo

Hi Bruce

Not all that complicated. Several of the guys wanted information once I got the drive unit so I went into a little more detail than is the norm.

You are lucky if you have no instrument swing. The cable from the the Ford box to the speedo has different area square cross sections at either end, resulting in a smaller diameter inner cable than is ideal for the outer cable. Consequently, the inner cable usually winds up/catches then releases, causing the swing.

Not sure how you have your cable routed. Mine was right across the right hand cockpit infront of the crossmember, up the right hand side, then doubling back through the steering column brackets(RHD) to the instrument. I am glad to have got all that cable out of the way.

Steve
Steve Gyles

Thanks for posting this info Steve. I have my speedo cable running in an arc accross the right hand floor and up through the toe board near the transmission tunnel. I do get a bit of waivering of the needle, maybe by 1-2 mph. It seems a bit more pronounced as the speed increases. I had assumed the problem was in the speedo itself, but from what you're saying, maybe the cable is the cause. I'd be interested to hear an update in a month or two to know if you're still pleased with the right angle adapter. If it really does solve the problem once and for all, I might be interested in one myself...except that they are quite expensive. Did you order it directly from Speedograph and if so, which specific model did you get?
Andy Bounsall

Andy

Sure, I will update in a month or so. I keep looking at it expecting it to start wandering again! But so far so good. I must add that I have never had it so stable, even when I had the original gearbox fitted. The cable and speedo are the same now as they were then. The only differences in that department are that I have twice had it calibrated (once for the gearbox change and once for going 3.9) and I have also done Barney's innards clean-up about 3 times trying to correct the swing.

I actually ordered the right angle drive through Mike Gamble (Hi-Gear) before I had seen the maker's (Speedograph) website. I dare say you may be able to save a few dollars by going direct. I will get the item model description off my invoice tonight and let you know. Failing that you may be able to see the numbers in my original photo in the first post.

cheers

Steve
Steve Gyles

Andy

My invoice show the Speedograph unit as part number RGB1030/03A.

They list the cost plus postage to the USA as $157 approx.

http://www.speedograph-richfield.com/html/rgb1030.html

Steve
Steve Gyles

Thanks Steve. Can I be so bold as to ask what Hi-Gear charges for the part?
Andy Bounsall

Andy

I paid 114 ($198) including 17.5% UK tax and postage.

Steve
Steve Gyles

Wow that is quite expensive Steve. But it looks a worthwhile option - so yet another cost to add to my piggy bank saving so I can buy the complete kit.
Cam Cunningham

Cam

Yes, it is expensive, although buying the unit from the maker would appear to save several pounds. Also, you can continue to use the original speedo drive cable, so the adapter cable normally supplied with Hi-Gear's kit is not required - that should also save a few quid. Maybe Peter Gamble will provide a good discount on the complete kit?!

I wound the car up to 85mph this morning on the way to work. Still not a flicker on the needle, totally rock steady. Brilliant.

In summary, an expensive mod if you already have the 5-speed box installed, but close to an essential add-on if you are in the process of converting to the 5-speed. One of the better mods I have incorporated, in that the benefit is immediately visible.

Steve
Steve Gyles

This thread was discussed between 23/08/2008 and 27/08/2008

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