Paul, my comment about possible weakness was because the S2 tunnel isn't welded to the floor all around, just at a few discrete spots.
At some point I may be motivated enough to complete the welding job and then remove the section of floor that's underneath the S2 tunnel. Or maybe it would be better to remove the section first, then weld from underneath.
RIght now, though, there's no pressing need to do anything ... but at least I understand what's there!
Peter
S2 5 speed in an S1 body?
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William
S2 5 speed in an S1 body?
I have done the 5-speed mod in my 4-speed 66 car and can tell everybody that it is a pain.
First if you do not want to modify your first series engine you have to modify the 5 speed box. For this you need to replace the 5-speed bell house which is to large for the engine with a four speed bell house. It does not fit the box because the flange on the box is to large. You have to machine the bell house which can be very expensive since the required accuracy makes it a very specialist job. If you are willing to change the engine rear cover (were the engine number is stamped on) for a 2nd series cover you save this trouble, but then you have to replace the flywheel and starter motor for 2nd series items as well. This gives the advantage of using the modern series 2 clutch. I choose to keep my (1200HF) engine original so had to go the hard way.
The rear subframe cross member has to be changed for a 2nd series item.
With the 5-speed-box you need the rear side bracket as well since it is different from the series 1.
I have kept my four speed transmission tunnel (for obvious reasons) and have the 5 speed linkage visible inside the car. The tunnel however is shorter and narrower so the box makes contact with the transmission hump. Some could be cured with trimming the protruding fins on the box castings but I had to modify the rubber where the box sits on as well. Shaving this rubber about 4mm gave me just enough clearance (you have to shim the 'Eifel tower' as well to keep the load divided.) The box now sits so tight it can only be removed by dropping the subframe as the shift linkage can only be tightened when the subframe is not fully home.
Then there is the problem with the drive shafts. Most 5 speed boxes come with the 'modern' cone shaped drive shaft flanges. You need to use 2nd series drive shafts or open the box and change the differential gears for series 1 gears. These flanges are fully interchangeable between both 4 and 5-speed boxes but require a complete dismantling of the box. Guess which option I choose...
Replacing all plastic bushings in the shift linkage for bronze removes the play in the lever but makes the shift more sticky and heavy. To be honest I do not like the shift of the 5 speed much compared to the four speed of the coupe'. And anyone who has ever sampled the delightful shift action of a well maintained berlina column shift knows it can be even better!
So after months of modifying I have a 5-speed 1600 (close ratio) box with 10:41 final drive in my series 1 coupe' which gives super useable ratios on the track but is downright frustrating on the public roads for the noise (not only the high revs but also the 'open' shift linkage which transmits all engine and gearbox noises ). The shift action is poor compared to the long lever.
On top of all they claim it is consuming more power. My advise is to leave your series 1 car alone. In the end it is hardly worth the trouble...
First if you do not want to modify your first series engine you have to modify the 5 speed box. For this you need to replace the 5-speed bell house which is to large for the engine with a four speed bell house. It does not fit the box because the flange on the box is to large. You have to machine the bell house which can be very expensive since the required accuracy makes it a very specialist job. If you are willing to change the engine rear cover (were the engine number is stamped on) for a 2nd series cover you save this trouble, but then you have to replace the flywheel and starter motor for 2nd series items as well. This gives the advantage of using the modern series 2 clutch. I choose to keep my (1200HF) engine original so had to go the hard way.
The rear subframe cross member has to be changed for a 2nd series item.
With the 5-speed-box you need the rear side bracket as well since it is different from the series 1.
I have kept my four speed transmission tunnel (for obvious reasons) and have the 5 speed linkage visible inside the car. The tunnel however is shorter and narrower so the box makes contact with the transmission hump. Some could be cured with trimming the protruding fins on the box castings but I had to modify the rubber where the box sits on as well. Shaving this rubber about 4mm gave me just enough clearance (you have to shim the 'Eifel tower' as well to keep the load divided.) The box now sits so tight it can only be removed by dropping the subframe as the shift linkage can only be tightened when the subframe is not fully home.
Then there is the problem with the drive shafts. Most 5 speed boxes come with the 'modern' cone shaped drive shaft flanges. You need to use 2nd series drive shafts or open the box and change the differential gears for series 1 gears. These flanges are fully interchangeable between both 4 and 5-speed boxes but require a complete dismantling of the box. Guess which option I choose...
Replacing all plastic bushings in the shift linkage for bronze removes the play in the lever but makes the shift more sticky and heavy. To be honest I do not like the shift of the 5 speed much compared to the four speed of the coupe'. And anyone who has ever sampled the delightful shift action of a well maintained berlina column shift knows it can be even better!
So after months of modifying I have a 5-speed 1600 (close ratio) box with 10:41 final drive in my series 1 coupe' which gives super useable ratios on the track but is downright frustrating on the public roads for the noise (not only the high revs but also the 'open' shift linkage which transmits all engine and gearbox noises ). The shift action is poor compared to the long lever.
On top of all they claim it is consuming more power. My advise is to leave your series 1 car alone. In the end it is hardly worth the trouble...
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Peter Cripps
Re: S2 5 speed in an S1 body?
William, thanks for your very detailed description. I’m sure you will have persuaded anyone thinking of fitting a 5-speed to a 4-speed car that they shouldn’t do it!
In my case someone has already ‘done it’ and I’m beginning to wish that they hadn’t! However, I think they bypassed many of the problems you described by transplanting a complete subframe, engine, transmission, suspension, brakes, everything.
You mention removing the transmission by dropping the subframe. I’m wondering how this would work out, since the 5-speed extension projects inside the car. Does this mean you have to edge the subframe forwards as you are lifting the car body upwards?
Peter
In my case someone has already ‘done it’ and I’m beginning to wish that they hadn’t! However, I think they bypassed many of the problems you described by transplanting a complete subframe, engine, transmission, suspension, brakes, everything.
You mention removing the transmission by dropping the subframe. I’m wondering how this would work out, since the 5-speed extension projects inside the car. Does this mean you have to edge the subframe forwards as you are lifting the car body upwards?
Peter
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P. de R. Leclercq
Re: S2 5 speed in an S1 body?
Yes as someone has left the original "tunnel" in place, you will have to do this, unless you can get underneath during the process and remove the extension.
Obviously no problem with only the five-speed tunnel as I have.
Paul
Obviously no problem with only the five-speed tunnel as I have.
Paul