The transmission tunnel that is.

I am at the latter stages of the chassis build and am undecided whther or not to add the transmission tunnel yet. Mr McSorley advises (on his site) that it is better to wait until the axle and engine/gearbox are in place so as to be 100% sure of the dimensions.

I had the chassis out in the fresh air yesterday and placed the engine/gearbox in the frame to get an idea of where it sits and am fairly happy with it. I marked up the tubes where diff, gearbox etc sat.

What are the opinions on what to do next....

Do I go ahead and build the tunnel so I can finish welding and paint, or do I wait until the engine/gearbox, and axle are in place???

Cheers.

hi mate
i dry fitted all mine before i made the tunnel just so i knew all would fit and also to be able to make floorpan area as big as poss with the prop and axle in you will be able to gauge this better
hth
cheers
colin

Better to dry fit, then make it as tight as possible, any extra room you can win is worth it.

Thanks for the input guys.

I haven't got my prop done yet because I'm going to get it made to fit. I am working on the premise that the prop will be no wider than the diff output flange so will use a tube of card or similar to give me the run to the gearbox output shaft.

Do you recommend leaving the chassis on the board to do the tunnel or will it be OK off once fully welded?

Cheers.

JB

Be careful where you put the tunnel uprights, do not have one coinciding with the end of the box as this is wider at the end
Rescued attachment TunnelClearances.JPG

This shot may also help
Rescued attachment Gearbox Spacing.jpg

Thanks Mark. I had made a note of that, I wondered how much 'out-of-line' the geqarbox output shaft and input to the diff is acceptable, I assume that some is OK as the prop has UJs at each end and I don't want to offset the engine too far to one side in the bay.

Good job I am building a +442 really as the diff forces the tunnel over to the right of the car. Still gonna have around 18" floor space though so should be fine

JB

You have to have some angular displacement (!) in the prop so the roller bearing to revolve around the race, if dead inline they will just chatter against the same place on the race surface - they call it brinelling.

Look at the angle of my prop (home made) it has just finished it 4th year on the road with no problems
Rescued attachment Underneath.jpg

Thanks mate. Makes me feel a little better about having the diff invading my (driver's) space!

Looks like your engine is slightly twisted in the frame, or is that my old eyes playing up again ?

Just the angle of the camera

Or my eyes

I tried a dry fit today and to keep the gear stick well back in the cockpit, I placed the gearbox so the rear of the starter housing is just inline with the rear of the cross member 'C', so probably around 1" further back than yours. Do you think this is going to make the front of the tunnel too wide, and would I be better to move it to the same position as yours to give me extra foot room?