Chassis vs. gearbox

[Pete Gossett]

OK, so I haven't actually started on my Europa(s) yet, but I dusted off the workshop manual and have been giving it a good read in preparation of starting!

Anyway, I happened upon the page that shows the different braces on the rear of the frame for each gearbox to mount to and became a bit concerned. You see, I have two cars - partly disassembled, but presumably mostly complete - one, with a rusted front box, the other seemingly good, plus I have a spare  frame that's been stitch-welded and just needs prepped and painted before use. Both cars are 4-speed cars, but if I read the manual correctly the spare frame I have is a 5-speed model.

So I peeked in the garage tonight and took a couple pictures. I was surprised to find that each car has a different frame type, despite them both being 4-speeds(I presume, based off the tag anyway). The pictures are below. The yellow '72 is the "good" car with the rusted frame & gearbox still installed. The black '73 is the "parts" car, and the gearbox supposedly came from the '73.

Will I have troubles if I use the good frame to build the car up around and keep the 4-speed? Is this a good excuse to upgrade to a 5-speed???









Thanks!
Pete

[BDA]

The second frame is indeed for a 5-speed. I have only heard of one person who said you could put a 5-speed in a frame for a 4-speed:

I have personally replaced a 4-sp Type 352(rear shift - NOT the 336 side shift) in Europa Special to a Type 365 5 speed! YES, the rear mounting brackets are different, but you DO NOT have to modify the frame. After I did the swap, I was told that the shift linkage should be lengthened shightly(adjusting center u-joint), but unknowingly I did it without that change and it worked fine -- for many years!

As far as a comparison between the two, the 5-sp is much "friendlier" on the highway -- 5th gear OD makes for much lower highway RPM, lower noise, better mileage(who cares!). The 5-speed also accelerates quicker because of lower gear ratios(1st-4th), but the 4-sp actually produces quicker 0-60 times because only one gear change is necessary(2nd gear will go 60 on the 4-sp, not on the 5-sp).

Cost is also a factor -- last time I checked(a while ago), a 4sp could be had for about $500, 5sp cost at least $1500. So, consider your driving purposes and the depth of your pockets - "There is no substitute for cubic DOLLARS!".

Another consideration is if you decide to use a Renault 5-speed NG series tranny. The one I have works with a different rear hoop (I got my tranny and rear hoop from Richard at Europa Engineering (http://www.banks-europa.co.uk/index.php).

I've had both 4 and 5 speed trannies but it's been so long ago that I couldn't compare them by memory. I've read that there actually isn't much difference performance-wise, but I can't disagree with the guy I quoted from experience. In any case, it is a lot cooler. 

[Pete Gossett]

Thanks for that info!

Considering this will primarily be a street-driven autocross car, it sounds like the 4-speed may be the better choice anyway. I wonder if anyone has used a 4-speed in a 5-speed frame?

I'm not really fond of cutting up my good frame to swap in the hoop from the rusty one.

[pboedker]

Don't worry, you already have the necessary chassis. But the Workshop Manual is somewhat misleading in showing that only the 365-type gearbox fits on the chassis of which you have two. This is not the case.

Instead, have look at the parts manual (http://lotus-europa.com/manuals/tcparts/a/index.htm) where the three chassis types used on the TC/Special are shown. 

Item 1 is the one you have on photo 1, it will only take the 4 speed 336 box (like on an S1/S2).
Item 2 is made for the 4 speed 352-box, but only for this as I believe the hoop and brackets will interfere with the 5 speed 365 rear casing. But you don't have one of these, so just forget it... 
Item 3 is the one you have on photo 2 or 3, and it was in fact used with either a 352 or a 365 box. The difference is in the mounting plate that goes between the gearbox and the hoop. For the Special, the 5 speed was optional but the chassis always of type 3. 

So, you have a lot of options:
A. Stick with the chassis and 336 type gearbox from photo1.
B. Use your 352-box with one of the two other chassis. The 352-box has the same gear ratios and strength inside the differential as the 336-box has. But it takes another gear linkage. Which you probably have.
C. Find a 365 gearbox because you want 5 speeds. The quoted comment above is in sync with my experiences, although I did lengthen the rear part of the linkage about half an inch.
D. Find another gearbox (NG, 385, 395, other) and modify the rear hoop or the mounting plate to fit.

[Pete Gossett]

Thank you Peter! Now I understand. 

I wonder though why my yellow '72 TC has the 336-type frame. I thought the Twinks in the US were only offered with the 352 or optional 356?