Lotus Elan

Lotus 5 speed gearbox mount

PostPost by: gjz30075 » Mon Jul 11, 2016 3:19 pm

I'm working on getting a Lotus 5 speed into my Elan with a homemade bellhousing. I understand the Lotus
5 speed bellhousing is 196 mm, face to face. My homemade bellhousing with two adapter plates measures
almost exactly the same; 7 13/16 inches, face to face, which translates to 196.8 mm. Problem is, it puts the
gearbox too far rearward to fit properly. I cannot get the gearbox rubber mount on and the gearstick hole looks out of place (see pics) (ignore 'left to right' relationship).

Without the aluminum adapter plate, all lines up fine, but there's no room for the clutch mechanisms, so I'm
sure the face to face dimensions with the adapter plate are correct.

The other variable is the frame I'm using. It's simply a spare one, not the one for my car. Shouldn't be a
problem but .......never know.

So, any ideas what could be the issue? Can someone provide an under chassis picture (Elan, not +2)
showing the relationship between the mount and frame? And maybe the gearstick hole in relationship
to the frame?
Attachments
dsc08291.jpg and
dsc08290.jpg and
dsc08289.jpg and
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PostPost by: RichardHawkins » Mon Jul 11, 2016 6:57 pm

Greg,

Measuring my original chassis and replacement, the centre of the circle that is cut into the chassis to the point of the V in the chassis is about 125 to 130mm. Difficult measurement to make as the centre of the circle is an estimate. Hope this helps.

I could measure from the front of the 4 speed gearbox flange to the centre line of the 4 speed gear stick where it comes out of the gear box if that is of any use.

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PostPost by: gjz30075 » Mon Jul 11, 2016 9:05 pm

Thanks Richard. That is a hard measurement to take and I come up with 123mm. I don't think the 4 speed
measurement will do me any good, ie, apples vs oranges here, but I appreciate it.
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PostPost by: rgh0 » Tue Jul 12, 2016 10:18 am

The 5 speed gear box cars used a different support bracket and different bolt holes in the chassis to line up with the gearbox mount. My replacement Elan chassis I got in the late 70's came with holes / captive nuts for mounting both the 4 speed and 5 speed gear box bracket.

The 196mm depth of the bell housing is correct for the 5 speed so if the gear lever is out of place then I would question the engine location in the chassis or the gear lever cut out location.

cheers
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PostPost by: gjz30075 » Tue Jul 12, 2016 10:35 am

Thanks Rohan, engine placement in the chassis could very well not be correct. I can't even get the rubber
gearbox mount on the gearbox; it's just too close to the tunnel (as seen in the pic, taken from below).

Thanks for confirming the bellhousing depth, too.

I'll try to get other points of reference to determine if the chassis is correct.
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PostPost by: gjz30075 » Tue Jul 12, 2016 2:55 pm

Well, I'm able to get the rubber gearbox mount on by turning 180 degrees. One side is apparently
slanted differently than the other. I remember discussion about this somewhere on the forum. So that
means I'm able to mount the crossmember mount to the rubber mount, however, based on many other
threads on this, I should be able to use both frame holes and simply drill new holes in the crossmember
mount. Can't be done here. I'm still too far rearward, I think.

If anyone has a bodyless frame, can you measure from the front shock tower to the motor mount? I measure
exactly 12 inches from the corner of the shock tower to the 'far' corner of the motor mount. Still like to
find the root cause here.

I would still like to see similar pictures from an Elan 5 speed; I don't know if a +2 would be the same but
I'd like to see them, too.
Attachments
dsc08293.jpg and
dsc08294.jpg and
dsc08295.jpg and
dsc08296.jpg and
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PostPost by: nmauduit » Tue Jul 12, 2016 5:25 pm

In case it may be of any help, the use of a 4 speed bracket with a 5 speed gearbox is discussed in this previous thread (which also refers to the Hollnagel paper)

lotus-gearbox-f37/plus-speed-box-t20698.html
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PostPost by: RichardHawkins » Tue Jul 12, 2016 6:28 pm

Greg,

What I was trying to say is that the 5 speed gearstick needs to pass through the centre of the chassis circular cut out. Therefore the distance from the front flange of the 4 speed to the gearstick, and the distance from front flange of the 5 speed to the gearstick need to be pretty much the same if the 5 speed is to fit without some other alterations.

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PostPost by: RichardHawkins » Tue Jul 12, 2016 6:42 pm

Greg,

I have a frame without the body, but do not quite understand where you are measuring from to. Do you have the rubber engine mountings bolted to the frame or are you measuring a bare frame? Are you measuring a diagonal, or a line parallel to the centre line of the frame.

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PostPost by: gjz30075 » Tue Jul 12, 2016 8:15 pm

Richard, shown is a pic of the measurement needed.

Nmauduit, also shown is a pic of my gearstick, per the Hollnagel Papers. Richard, that thread also mentions
the stick location will be about 1 inch further rearward, hence the stick modification needed. I think I'm
ok there.

Also shown in my previous pics is the 4 speed mount being used. It is right up against the tunnel. If all
other measurements are Ok, then the mount against the tunnel must be ok, right? I'd sure like to see
the underside of an Elan 5 speed mount. Cleggy, Brian Clarke, and whoever owns Alex Black's car, are
you out there :-)??

Thanks much guys, so far.
Attachments
dsc08298.jpg and
dsc08299.jpg and
dsc08300.jpg and
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PostPost by: john.p.clegg » Tue Jul 12, 2016 8:38 pm

Greg
Have been silent on this so far as you stipulated elan not Plus2,have gearbox out of the car,spare mounting plate and gerabox in car...pit is open...what exactly do you want piccies of ?

John :wink:

P.S. also try the photo gallery,filter by name. john.p.clegg, 52 per page, page 8....
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PostPost by: RichardHawkins » Tue Jul 12, 2016 10:00 pm

Greg,

Thanks for the photographs. My frame also measures 12".

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PostPost by: gjz30075 » Tue Jul 12, 2016 11:12 pm

Thanks Richard!

And John,,, BIngo! One of your shots showed the mount right up against the tunnel. I don't think the +2
frame would be any different at this point, as I believe its longer length (over an Elan) is in the middle.

Thanks guys! My worries are much less now (concerning this project, anyway :-))
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PostPost by: RichardHawkins » Wed Jul 13, 2016 7:05 pm

Greg,

Glad to be of help.

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