5 Speed gearbox

[jddevel]

I realize that there are tose among you who will throw their arms in the air and say "Why" but having enjoyed the conversion of my TF1500 to a 5 speed box I`m asking those among you who have converted their TC to a 5 speed "Do they regret it" My car currentlt sitting as a bare chassis it would make life so much easier to complete the task now.

[Steve Simmons]

On one hand, I think a 5-speed is probably the most practical modifications one could do to make a TC better suited to modern American roads. BUT, having driven one I can say that the feel of the gearbox completely ruins the vintage experience for me. This is of course a personal viewpoint and others will certainly disagree, but while lowering the RPMs at speed as well as attaining a slightly higher cruising speed would be nice, I just HATE the feel of the 5-speed. If I could somehow put a 5th gear into the original box, or an overdrive unit bolted to its rear, I would do that. But driving a 5-speed conversion completely cured me of the desire to go this route. For those who like their old cars to feel like old cars, I feel that a better route is to increase the rear end gearing. And if that isn't enough, add oversized tires. Of course the taller gearing/tires you go with, the more you may need to build up the engine to handle it.

[Ray White]

I have fitted a 5 speed box to my TC as part of a comprehensive rebuild. I am not trying to emulate a "vintage" feel...I have a 1930 Austin Seven Swallow for that!.

It was the broken bell housing and the fact that my original gearbox had been driven dry that tipped the balance with my "basket case" TC.

No, I am attempting to build a TC which will be capable of long distance touring and to that end it is important that I keep the engine revs down to a more acceptable level at 70MPH. I might add that I have also opted for a modified (higher) first gear and a TA CWP. In order that acceleration is not compromised I have a supercharger.

If what you have is an essentially original car then, as Steve has pointed out, a 5 speed gearbox will completely alter it's 'feel'. That is not a problem for me and I have also opted for a VW steering box with it's lower gearing (one complete turn lock to lock as opposed to 3/4 turn) and a 15 1/2" Brooklands Steering wheel. I have also fitted a Panhard rod to the front suspension and uprated the brakes with Alfin style drums.

I am living in hope that the finished car ( when I eventually get the body delivered) will drive well but I am not under any illusions that it will be anything other than a modified old car.

[i.thomson]

I can't help but think that asking people if they regret paying a lot of money for something which is no doubt satisfactory is asking a lot. After all to regret it is to question the reasons for doing it which we would all be loath to do under the circumstances. As Steve says the alternative is to upgrade the CWP and having fitted a foreign gearbox people are not in a position to compare the two, except by driving another's car. A better question is to ask yourself why you should buy an old car to make changes which take away some, or all, of the reason for buying it in the first place.

Ian

[Steve Simmons]

Ray, I've made some of the changes you mention, plus more... TA CWP, panhard rod, Datsun steering (similar to VW), polyurethane bushings, Alfin drums, etc. No supercharger but a slightly warmed up engine running 9.1:1. The steering alters the feel of the car for certain, but none of the others do. They improve the performance, but not in a way that makes it feel modern or non-M.G.

The steering bothers me a little, being so "truck-like" in steering compared to the very sporty original ratio. But in my opinion the gearbox made a bigger difference and it was just not acceptable to me. I drive old cars because they are old cars, so I like them to feel at least period correct. To be totally honest, my TC came with the Datsun already installed, so the comparisons to original I make are based on other TCs I've driven. And had mine come with original steering then I may not have changed it. But the stability at any speed is addictive so I don't know if I will ever change it back.

Just FYI, the original TC steering is 1.5 turns lock to lock, and VW is 3.125. Datsun is 2.75.

[John Cockrem]

Living is Australia I decided to fit a 5sp Ford 9 conversion after a lot of soul searching. Frankly I have no regrets. My TC is a fairly low milage car at 92,000 thousand. I think perhaps that the "old car feel" of some TC gearboxes may be due to age and mileage, because the newish Ford box in my car feels pretty much the same as my old TC box, except that it is quieter. I currently run 16s with radial tyres (5.125) and even with a 4.875 diff at 55mph, it was pulling over 4 thou rpm on the highway, a bit nerve racking! At least with the kit from Hi Gear there's no butchering except for a few snips on the tunnel, so easy to revert back. If I was Jan having a clapped out TC box, I would definitely go for the 5 sp.
Incidentally, after 2 failures with the Bishop steering box, a Datsun box was fitted about 30 or 40 years ago, can't really remember the exact year but although not as direct, a great and safe move. A steering failure is pretty scary! I seriously know! However I believe that if the pitman arm on the Datsun box is lengthened by an inch it really sharpens them up. I think a completely new recast longer arm would be the shot rather than a risky weld.........food for thought?
John Cockrem TC 2268

[jddevel]

All the comments give me food for thought and now some soul searching. My previously owned TC owned around 15 odd years ago I only changed the steering to a VW. But the car had limited use locally until needs meant it had to go. This car on the other hand I`ve never actually driven due to having been in storage for many many years and whilst only showing surface rust bodily the interier was completely shot with totally unusable seating, hood, sidescreens and wiring without repair. Although an excellant chassis as seen after shot blasting the timber tub whilst it could be repaired and reading the problems some have encountered to make good, bought a new paneled tub. The engine and diff oil was more like tar than oil and although the engine ran for a few seconds without horrible noises it will need internal inspection really.. The original steering is tight with a mileage reading of just over 36000 miles which may well be true. Gearbox unknown condition. Brake shoes only partially worn. Due to lack of my experience diff and shafts going to Roger Furneaux who lives locally for an opinion on condition. Due to the work involved to just get it roadworthy just doing the brakes, engine and getting seats in would take a great deal of work so after 18 months of staring at it I decided as I coudn`t afford to leave it as a time capsle I`d start by doing the body etc. which to me was the hardest part before working on the mechanics. So in anticipation of the mechanics being the next step, I`ve asked the question. How will the car be used? Well hopefully everything from in the local Cornish lanes to trips to Europe and general touring in the UK. I`ve still time to make a decision whilst I get the spraying sorted . How easy will it be to convert back to the original box if I decide to make the change may sway my opinion I suppose.

[Duncan M]

Just a note, most suggest the 5 spd be used with stock 5.125:1 rear end. I run a stock 5.125 and TC stock transmission, but use slightly larger 30" OD Model A tires, which in effect gives about equivalent of a 4.8:1 rear end. Only thing to add about Model A tires is the ones I got (Universal brand made in Vietnam) is they do much better with around 30-32psi.

[Ray White]

If I may make what I think could be a useful observation for anyone thinking of fitting a type 9 Ford box; first gear is too low for normal driving; especially if you have a more powerful engine. The original MG TC gearing is already low in 1st at 3.38:1. The Ford (Sierra) box is even lower at 3.65:1 . I chose a modified (higher) 1st gear at 2.98:1.

It costs a bit more... but unless you intend to go competition hill climbing, the ultra low 1st gear might soon become tiresome.


Ray.

[lindi]

So, why not install a longer dufferential?
Will cure the too short first, help lower turns at high speeds and keep the wonderful feeling of the original gearbox. Plus costs a lot less.

Best regards
Lindi

[Ray White]

So, why not install a longer dufferential?
Will cure the too short first, help lower turns at high speeds and keep the wonderful feeling of the original gearbox. Plus costs a lot less.

Best regards
Lindi

My original pinion was broken so having taken advice from Steve Baker, Roger Furneaux and others I opted for a TA CWP which is 39/8 (4.875 : 1) as opposed to the original TC 41/8 ( 5.125 : 1). I am hoping the supercharger will handle the higher gearing. I have also replaced the hubs and half shafts with new.

As far as the original gearbox is concerned, mine - as I have said - had been run 'dry' and was so worn it would needed to have been replaced anyway. The bell housing was also scrap so when I read about Peter Gamble's 5 speed conversions (he is just down the road from me) and how delighted people were with them, the answer seemed obvious.

[lindi]

Ray,
no problem with your gearing, having a supercharger.
Also in our TC there is one plus an exctractor manifold and the ratio I chose is 4,22. Works very well. I calculated all before I went therefore as I am living in the mountains and it should be an improvement against the former 4,875. So it came. Using one gear lower, I can benefit from better rpms in relation to our everyday-hills.
So, your 5-speed will do the same and it will be a pleasure for sure.

Regards Lindi

[Ray White]

Thank you Lindi. I have also fitted an extractor manifold. It required a lot of fettling to get the supercharger and the exhaust manifold ports to line up.! The entire exhaust system is now stainless steel so I am aware that I could have heat and noise issues but I will cross that bridge when I come to it. I have numerous other refinements such as a shaped and ported cylinder head with TF valves and hardened seats.

One little extra item that I have fitted is an exhaust vacuum crankcase ventilation system. There is a scavenger unit fitted to the exhaust just ahead of the silencer. Any blow by exacerbated by the supercharger will be extracted via a pipe attached to the rocker cover vent. There is a catch can to collect and separate any oil from the fumes as they are drawn down to the exhaust via a non return valve. This system is hopefully an improvement on the original road draft tube - which has been removed. These modifications may add a little extra power...we shall see!

(This idea is similar to the modern pcv valve which does not work well with forced induction.)

[lindi]

Stainless steel exhaust makes no problems. Is that, what I have. The idea of ventilaton sounds good, indeed !
Best regards
Lindi

[jddevel]

Ray, Your setup sounds intriguing. I for one would appreciate some pictures if that is possible without to much of a problem.
Jan

[Ray White]

[Ray White]

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[Ray White]

[Ray White]

Photo 1 was taken at the experimental stage.

I had to considerably alter the scavenger unit to achieve the correct angle and make it secure. I just hope the theory works in practice. I believe it should pull about 4HG but until I am further on with the build I won't know for sure. I got the idea from another T type owner who fitted a similar set up to stop oil leaks from the crank case. In his case it worked and he has had no leaks since.

The catch can has a dip stick to keep an eye on any oil deposited. I have added an additional baffle to make it more efficient. There is a stainless steel one way valve in the line which is made from reinforced rubber tubing and the original draft tube has been replaced with a vent which can be gradually blocked off as required. The only other entry point is the filler cap and I have been assured that this will not be a problem - but if it is then I shall have to replace it with a cap containing a one way vent.

[jddevel]

Thanks for that Ray.