Thread: How do I overhaul my CD175's?

Also, will add that I'd rather DIY it as I like the learning experience

Cheers
Will

I believe the technical term you need is "workshop manual".

Written on the carburetor is "175 CD - British Made By The Zenith Carburetter
Co LTD", so am I correct in assuming these are SU's as opposed to strombergs?

No they are not SUs , they are Strombergs.
The losing oil thing is a bit of a bugger as every one ever made does it, BUT the car should run well when warm anyway without oil. Are you sure you do not have a holed diaphragm?
To fix the losing oil thing my understanding is that there is an O ring in the base of the tube the little piston goes up and down in, and it is held in place by a spring clip "over centre" type thing with barbs going out instead of in. The trick is to remove the holder without marking the tube which is difficult.
Now I have rebuilt about 6 sets of Strombergs but never tackled the losing oil thing .
I suggest you take it to a rebuilder. If you live around Sydney I saw a couple advertised in the latest Classic car magazine, and one was in Parramatta.
Regards Philip A

Thanks fellas.

It runs fine when it's warm however it is annoying having to have the choke slightly up while it's cold.

I thought the Strombergs were from a different manufacturer or something...?

There are CD175 carby overhaul kits on eBay, however I'm unsure on quality.

I'll ring the Carburettor service company (Parramatta road) and see what they say.

Cheers
Will

Will - take the tops off the carbs and put in a new diaphragm - 5 minutes work - this is the main cause of issues.

What oil are you putting in the dash pots - I use sewing machine oil from woolies in my 101 and use standard ATF in my Jag - (it has four of the CD 175s).

I have found that my 3.5 does not like cold weather when the oil in the dash pots is low but runs better when full - I fill mine right to the top and slowly put the plunger in and any excess just flows out the top so you get max oil in. After replacing the diaphragms and you are still loosing the oil quickly go to a slightly thicker oil but not too thick as it can have a slight impact on mixture.

Once stommies are set up they tend to stay set up and run well forever. I have had my Jag for 30 years and its carbs have never been touched, likewise the 101 strommies have only been touched to replace the diaphragms and mixture adjustment.

If after changing the diaphragms, topping up the dashpots and doing idle and mixture adjustments you still have issues, it is only then I would be looking at more detail work.

Oh - if it has been running on LPG for any length of time you could have worn needles as there is no lubrication with the gas where petrol does provide some lube.

Garry

If you're looking for a supplier:


Home Page - Zenith Caburetters


Never used them, but I soon will be.

I get them from MR automotive,