Zenith 35/40 INAT question

[tc20]

Hi all,
the ongoing saga continues....
im in the process of getting the twin zeniths rebuilt on my 230.
Im ready to order the parts, but i've been asked to confirm if the
carbs have an M3 or an M4 thread.
This sounds greek to me, and its possible that this is a euro
measurement rather than US.
If anyone can shed some light on this for me, i'll be eternally
grateful, and provide with with Guinness by the gallon should
you ever make it to these shores

Cheers

[Mike D]

Are they asking if it has M3/M4 THREADS or SCREWS? Usually the designation for threads are in "pitch". For example, a M3 1.0 pitch. Translation, 3 millimeter shaft size with a 1.0 pitch of the threads.

Our translation of S.A.E. bolts coumes out as size and number of threads per inch. 7/16" by 20 T.P.I. We always did prefer to do things in our own fashion no matter what anyone else does.

[tc20]

MikeD - sorry for my lack of knowledge on this
I've asked the guy who is sourcing the parts to
clarify, so i'll get back when i have the relevant info

hers his site if you want a peek -

http://lichtenberg-classics.ie

Cheers,
tony

[Blue 72 250]

what parts for the INAT are you looking for?

[tc20]

Well pretty much all Blue72. The guy im sourcing from can provide the needles, jets, gasket kits, membranes.
M3 thread refers to M for metric, 3 being 3mm

Pardon my stupidity, but what does INAT stand for, or is it the carb model designation or something?

[Mike D]

I Need A Towtruck!

[Blue 72 250]

sounds like you would be better off finding a set of parts carbs for about $50 us. The repair kits run about 25 each and the only other thing you will be missing, assuming that the parts carbs are in good condition and have all parts, is a new accel. Pump. But you may be able to use the old ones.

Don't let anyone tell you the INAT is a bad carb. Often the person working on it is just lazy, or the body was warped by the exhaust heat. After a lot of work (in most cases) they will run flawlessly.

[tc20]

Blue72 - im gonna get the new parts and get the car upto my mech. He wants to perform a leakdown test & compression test, (to see what condition the head is in) as well as repairing the carbs. I've also got a set of OE door seals and a front windshield rubber to go in, but sure thats another days work

Cheers

[tc20]

Ok guys, so the latest is this -
my fuel tank is silted and will have to come off. I was up with my mech last night and he has asked me to find out a couple of things. He wants to know if the choke housing cover has an integral bi-metallic spring? We were looking at a Haynes workshop manual, at the exploded carb pics, but he couldnt see the aforementioned spring in the diagram. Can anyone confirm this for me please?

Cheers

[JMela]

Check this BMW CS Coupe manual. It helped me with my Zeniths.

http://www.cscoupe.org/tech/zeniths/bmw2/bmw2.html

[Blue 72 250]

Yes on the spring. On mb it is heated by elec. Current. On BMW it has coolant bypas pipes.

Make sure when you have the choke apart you tighten the cam return spring for the high idle cam. The little brass slot that it keys into rotates. Also- the jamiekoop maunual is a great resource.

[230/8]

tc20:

This is the link for the jaimekop manual that Blue refered to. It is a copy of the factory Zenith manual.

http://www.jaimekop.com/

Grab the link on the left for Carb Manual.

230/8

[tc20]

Guys i want to say a big thanks to all for your (as ever) prompt
and helpful replies. The links provided are a great help.
The Guinness is on me!

[Blue 72 250]

I bet this is the drawing that you have, but I figured that I would post it for further questions.


Blue

[tc20]

thats one of 'em Blue, but good idea to post it for others.
I'll keep ye updated on progress

tony