Tachometer drive from Ford timing cover

[Charles Helps]

A couple of us want to drive chronometric tachometers from the
camshaft of our Ford Consul Mk1 engines in Mk VI Lotuses. I have seen
an engine with this arrangement and also seen pictures of the
Aquaplane aluminium timing cover for the Ford sidevalve engines (100E/
E93A).

My question is what happens to the Ford arrangement for taking the
camshaft end thrust when you modify the timing cover to take the drive
through it and onto an adaptor plate which bolts to the front of the
camshaft drive gear? Before modification the following parts appear
to take the end thrust on the E93A:
6058 Plug (cylinder front cover thrust)
6275 Plunger (camshaft thrust)
and
6276 Spring (camshaft thrust plunger)

There's a diagram here (courtesy of the Small Ford Spares people)
http://www.smallfordspares.co.uk/en/plate.phtml?PlateID=32

Has anyone got one of these tachometer drives and remembers how it
goes together?

[Stewart Smith]

Hello Charles,

With my old Aquaplane cover I had to make my own drive. I made the
adjustment in the cover itself with a rifle drilled bolt and set end float
with a lock nut. I guess I could send a hand drawn picture. Worked fine.

Stewart

--------------------------------------------------
From: "Charles Helps" <charle...@btopenworld.com>
Sent: Tuesday, June 09, 2009 9:23 AM
To: "Lotus History" <Lotus-...@googlegroups.com>
Subject: Tachometer drive from Ford timing cover

[alba...@comcast.net]

Is it possible to drive the chronometric tach from the back end of a dynamo as in T-series MGs, early AH sprites, etc.?  If so, no liberties would need be taken with the engine.  Just a thought.

George in Maryland

----- Original Message -----
From: "Charles Helps" <charle...@btopenworld.com>
To: "Lotus History" <Lotus-...@googlegroups.com>
Sent: Tuesday, June 9, 2009 12:23:51 PM GMT -05:00 US/Canada Eastern
Subject: Tachometer drive from Ford timing cover

[John W. Watson.]

Dear George,

 

We are aware of this. I have three Lotus cars, all with chronometric tachos, all driven off the back of the dynamo. Fan belt slippage means that the rev readings are not as accurate as they might be if driven directly off the end of the camshaft.

 

Thanks for your thoughts anyway.

 

All the best,

 

JWW

[John W. Watson.]

Hi Stewart,

I would like a picture please.

Sounds good!

Thanks.

All the best,

JWW

-----Original Message-----
From: Lotus-...@googlegroups.com [mailto:Lotus-...@googlegroups.com]

[Charles Helps]

Thanks Stewart

I am guessing that this is something more than just replacing the
parts listed with a 7/16" tapped hole in the timing chain cover and a
7/16" bolt with rounded end and locknut on the outside (as shown and
described on page 44 of Philip Smith's book The Ford Competition
Engine). I still can't see how the cable and associated gearbox are
compatible with either method of controlling camshaft end float as the
cable wants to go through the point where the bolt is controlling end
float.

My dynamo with crudely (not by me!) welded on flange to take a
miniature gearbox to drive the tachometer has just suffered rear end
bearing wear to the extent that it has stopped working as the carbon
brushes no longer touch the commutator so I rather fancied the
camshaft drive solution.

Charles