DDK - Die Deutschen Klassiker

Matched pair of Zenith 40TIN carbs for Porsche 911T 1970-73, part numbers 911.108.123.00 / 911.108.124.00

These were overhauled and fitted to my car for one shake down run of around 50 miles whilst i waited for my Webers.

Also included but not on the photos are the 6 * ram pipes and the auxiliary enrichment devices that were removed during overhaul.

These will obviously need setting up for your vehicle.

Overhaul report, more photos and a video of them running on my car are available if needed

Any questions please ask

*** Price reduced £1000 ***

Overhaul report:
Brief report through of what he found during the strip down, clean and inspection. There were quite a few things which would have compromised how the carbs worked/behaved. There hasn't been anything that he wasn't able to repair/rectify so they should be absolutely good to refit, start and use without any issues.

Float Height

Key primary factors such as float heights have been set exactly to the Porsche book values, and physically checked via an external sight tube which he fabricated as a second method of verification.

Recommended Fuel Pressure

The other key thing which he mentioned is that he had pressure tested the needle valves and at approx 3.75psi they do start to weep ever so slightly. One the road the rate of fuel consumption and reservoir replenishment would pretty much negate the extra fuel volume entering the reservoir. However, his base advice is to regulate incoming fuel pressure down to a maximum of 3 to 3.5psi.

Jetting

As fitted
Manual Spec
Idle Jets
55
47.5
Venturi
27.5
28.5
Main Jet
115
120
Needle Valve
1.5
1.5
Idle Mix Screw
2.5 Turns
2.5 Turns

Note - The existing jets as fitted on arrival have been cleaned and re-fitted!

Inspection, and rebuild notes

Visual inspection. OSR. Reasonably clean exterior.
Hose condition poor, varying materials some hoses loosely fitted.
OSR, internally poor, lots of debris in all areas, jets fuel galleries float bowls etc.
Float heights not to manual spec and uneven. Throttle discs’s contaminated with rust and grime. Some screws seized and O rings and seal perished. One injector damaged.
NSR. Reasonably clean exterior, hose condition poor, varying materials and some loosely fitted.
NSR. Internally cleaner , although tainted possibly through being stood for a period of
Time. Ie evaporated fuel stains. Some seals hardened to perishing point,
Float heights too high but equal.
Throttle discs stained.
Cleaned both carbs and fitted new O rings and seals. Repaired damaged injector.
Removed all auxiliary enrichment items for over run conditions and blanked off associated ports and outlets.

Many thanks & best regards,

Andrew
AG Classic Car Tuning
www.classic-car-tuning.com