Racing 4 Speed

G

Guy Engelsman

New Member
G'Day all

I am currently in the process of sorting out the tech requirements for me to race my 74 V8 S "Pooh" here in Australia. One of the requirements under the local rules is that the original gearbox must be used (the ratios and internals are free) and it must have the same number of gears as standard. This brings me to the crux of my question.

The ability of the rover V8, even in lowly 3.5L form, to produce great chunks of power is well documented, but how do I get a Rover 4 speed manual to handle 280hp reliably? Has anyone else had experience in this area? Am I just barmy and ready for a padded cell?????

The easiest method is of course to just bash a 5 speed Toyota (yuk, ugly word in my household :wink: ) into the car and thats it, but the rules wont let me.

Always receptive to the voice of experience...........most of the time.... :oops:

Cheers

GUY :p
 
The four speed police spec boxes were stronger but I don't think they would handle 280bhp reliably. :(

I there no way you fit a 4 speed LT77, or is that against the rules?
 
G'day Guy,

I would be inclinded to think that the Rover 4 speed gearbox would break just thinking about 280 hp! Even keeping engine power to standard, say 150hp, the gearbox is still fragile and all too easily broken.

If the rules won't allow you to fit a much stronger 4 or 5 speed gearbox.....

Ron.
 
It seems to me that the 2200 4 cyl box is a more promising start than the V8. The V8 is notorious for having that extra layshaft.... Perhaps you could get someone to knock up a set of inernals with straight cut gears (as per police spec) but in more modern materials with suitable heat treatment, shot peening etc, then whack a really good oil pump on the outside to make sure its properly spray bathed and a proper oil cooling system?

Chris
 
P6B Police spec 3500S boxes never had straight cut gears, (other than for reverse), and the lyshaft set-up is the same as on the 2000/2200 only a bit bigger, in that it doesn't have a separate shaft, it's all part of the laygear cluster.. (But not big enough, obviously...... :LOL: )
 
chrisyork said:
It seems to me that the 2200 4 cyl box is a more promising start than the V8. The V8 is notorious for having that extra layshaft....
Click to expand...

I have had a few 3500S boxes apart but have never seen an extra layshaft?
 
Thanks for all the rapid responses!

I have copied the relevant section of the CAMS tech regs and as you can see, I cannot fit a 5 speed or a later type of box (damn... :cry: )

(k) Transmission: The flywheel must be of the original diameter, as determined by the ring gear, but is otherwise
free.
The clutch is free.
The original type of gearbox as supplied by the manufacturer for the make and model concerned,
assembled and operating as originally supplied by the manufacturer, shall be retained. The number of forward
and reverse gear ratios may not be changed, however the use of alternate gear ratios is permitted. The gear
lever may be modified but the original shift pattern must be retained.

I have had a chat with a few specialists and they have no problem making a complete new set of internals (which is allowed under the rules) in a straight cut setup, with stronger modern materials and modern tolerances, for "only" a few thousand dollars. The main cost is in the setup and design time on the computer. The actual materials are quite cheap (compared to gold perhaps?) but the actual machining time is a huge factor. The only real advantage is that once the computer setup is complete it becomes easy to modify and produce more sets for a lot less.

For the moment I will be concentrating on the rest of the car, such as seam welding the whole thing (Oh joy) and fitting roll cages, race seats, making a fuel cell, removing weight (the original seats come to mind) and other similar jobs. I will just have to start saving for the gearbox in the mean time.

Cheers

GUY :p
 
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