Help needed: Type 9 gearbox in Lotus 7 S4. How to fit?

[Kghaas]

Sooo

My little Duratc project has hit a major speedbump: I cant fit the T9 gearbox into the chassis. The main chassis cross member is situated 2 inches too far forward to clear the gearbox. This means that I cant get the right angle for the prop shaft.

I have looked at several ways to solve this:

1. Cut the cross member in the middle and weld the center 2 inches further back. Could also do some strengthening to it. This looks like the most viable option at the moment.

2. Place the engine 2 inches to the front. This will require me to cut the front plate, and weld in a strengthening rail in front. Might give some problems with the gear lever...

I have also looked at the possibility to lift the engine to get the right angle, but it will need a heavily modifyed bonnet.

SO. If YOU have some tips or pics I would love to hear and see them

This is the problem. The gearbox is resting on the crossmember. I cant move the engine further rearward.


Here are the two options I have thought up so far..

[Steffan]

I an no expert on Loti but I do modify and complete a lot of unfinished Kit Cars. I strongly advise you to find a way to site the engine so that the box clears this member, Do not under ant circumstances cut through it. It is clearly a serious structural piece,

[Kghaas]

Thanks Steffan,
I totally agree with you that cutting the cross member is not the best idea. I do hovever think that I can get the same strength with welding in a second crossmeber. BUT, and it is a big but: I have to take the bodyshell off the chassis to get it properly welded! That is just too much at the moment, so I have thought about a couple of other options:

-Install the duratc with the 4 speed gearbox. The bellhousing should fit. In the long run the gearbox will not survive..

-Get a short version of the T9. The one I currently have is the long input version, and I have a 30mm spacer on it. By using the short version, I will gain 30mm at the gearbox end, and I can get maybe 10mmm at the front by repositioning the engine. It might be enough. Gearlever will be some custom job.

I have searched the net, and there are quite some S4 advertised with a 5 speed, so someone probably have a better idea

If I could get help with the bodyshell from this girl I might do it, though...

Edited by Kghaas on Friday 27th September 08:38

Edited by Kghaas on Friday 27th September 08:40

[Kghaas]

OK
Problem solved.
Took off the bellhousing spacer, and cut the input shaft about 25mm.
Then I took my floor mounted drill, and converted it to a lathe. Took an agle grinder an took off some of the splines.

Then I converted my lathe to a belt drive motor and machined rest of the splines with grinding stone. Looks good and everything fit in the car!
Haven't measured the driveshaft angles yet, but it looks way better, and I will be able to get this to work

Lesson learned: All Caterhams use the long input shaft T9 except for the Lotus S4!

Edited by Kghaas on Friday 27th September 22:28

[Steffan]

Kghaas said:

OK
Problem solved.
Took off the bellhousing spacer, and cut the input shaft about 25mm.
Then I took my floor mounted drill, and converted it to a lathe. Took an agle grinder an took off most of the splines.

Then I converted my lathe to a belt drive motor and machined rest of the splines with grinding stone. Looks good and everything fit in the car!
Haven't measured the driveshaft angles yet, but it looks way better, and I will be able to get this to work

I do admire your efforts. I also believe that cutting the main structural members on such a car is never a good idea. I do hope your solution works and I wish you well on the project. I bought a Dutton with a Rover V8 shoehorned into a car designed for a 1.3 Escort engine years ago. I knew it would be undrivable and very unsafe and by gum it was. I had that car for some years and completely rebuilt the front and rear suspension but I never solved the chassis flexing because the chassis was totally inadequate for the torque and power. I sold the car (I own fifteen currently and just enjoy different kit cars and projects) to an acquaintance who fully understood the problems but still wanted the car and eventually the car was scrapped.

Having had that experience and many others sorting badly constructed kit cars I avoid cars with major chassis alteration because putting it right really can mean totally uneconomic work to the car. I do think your car with the unaltered chassis will be absolutely fine. I would also avoid a four speed box. I always change to the Sierra 5 speed when I have any Midgets/Sprites which I do currently. Motorways are so much more accessible and cruising is so much more refined.

[Kghaas]

If you have a look in the MG section, I just started a thread about my Midget. Since its an historic racer I am not allowed to change the gearbox. Stillgood fun :