Carburation advice?

PostPost by: sepans » Tue Jul 25, 2017 8:43 pm

Purchased 1966 S3 Coupe Project, which had some accident damage to o/s/rear wing and serious bodywork issues. The car came with no service history, and no seats. Plan is to get the car back to as close to original as possible. The Chassis has been stripped and overhauled (body-off) but before I take it to be resprayed I thought it would be wise to get the engine running smoothly. To be frank the engine runs like a pig fouling plugs 3,4. It seems that no 2 cylinder is doing most of the work. Compression is excellent all cylinders over 170lb. One inlet tappet requires attention 14 thou.(no 4) Timing chain looks new, oil pressure good.Ignition timing is checked.
Need some advice and or help, pretty sure carburation is the problem, as the has stood for years probably. I live in Kingston, Surrey.
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PostPost by: jono » Wed Jul 26, 2017 11:36 am

I think the first thing I would do is strip the carbs, run them through an ultrasonic cleaner and rebuild them using a rebuild kit.

Refit with new Misab plates and go from there.

I recently invested in a 4 column balancer which is great if you have Dellortos (I don't think Webers have vaccuum take off ports)

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PostPost by: The Veg » Wed Jul 26, 2017 1:14 pm

Welcome Sepans!

One more thing about rebuilding carbs: do them one at a time so if you get lost or forget how something went together, you can refer to the other one.

Sounds like another great project; looking forward to hearing about your progress getting the car back on the road!
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PostPost by: ericbushby » Wed Jul 26, 2017 1:46 pm

Just a small point.
Weber carburettors do have a vacuum gauge take off point. It is under the small brass plug next to the idle mixture screw and downstream of the transition jets brass cover and therefore also downstream of the butterfly.
The four gauge rig which I borrowed from the local Lotus specialist came with tubes which screwed in there.
I have since found the airflow meter easier to use although the airbox cover has to come off for that.
These comments refer to the 151 version of the 40 DCOE carb. I have no experience of the older types.
Eric in Burnley
1967 S3SE DHC
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PostPost by: richardcox_lotus » Wed Jul 26, 2017 1:51 pm

Eric is correct for Weber 151s having vacuum takeoffs

Weber 0018's and 31's do not.

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Richard
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PostPost by: ericbushby » Wed Jul 26, 2017 1:54 pm

Thanks Richard.
That clears up some recent confusion.
Eric
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PostPost by: William2 » Wed Jul 26, 2017 4:37 pm

I would also suggest fitting a new set of plugs probably NGK BP6ES as they don't foul up as easily.
Sounds like a great project car but seats can be hard to come by. Have you got some photos you could add?
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PostPost by: Stevie-Heathie » Wed Jul 26, 2017 4:53 pm

Hi Sepans
I'm just down the road in Thames Ditton. I can recommend a couple of local mechanics I used to set up my Webers if you like.
Best
Steve
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PostPost by: MarkDa » Wed Jul 26, 2017 8:40 pm

Flow meter to adjust balance and colourtune to set idle running is the quick accurate way forward after cleaning and rebuilding the carbs.
It's always worth checking that the jets are correct of course.
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PostPost by: jk952 » Sat Jul 29, 2017 12:16 am

Are the valve guides good, could it be sucking too much oil down a few of the guides?
The "reputable" outfit that did a head of mine once botched the guides, had to have it redone properly.
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PostPost by: sepans » Wed Aug 09, 2017 11:05 am

Thanks everyone for your advice. I have moved on, and removed the carburettors, only to find a inlet trumpet lug had broken and had been repaired with epoxy resin on no.2 cylinder (which strangely was the piston with best compression 175) and doing most of the work. Have removed the head and the broken trumpet has been tig welded. I intend to check the valves and lap them in, then adjust tappets and overhaul carbs. Hopefully that should solve my problem. This car was bought as a project with no history it has a Big Valve Cam cover which is not relevant to the engine(the valves are standard size)The car is a `66 coupe standard. However it does have markings of a single groove on the camshafts denoting S/E. I don`t think the engine has done much mileage since it had a rebuild the head has a thickness of 4.625 which would denote a light skim, and a 20+ rebore.
Questions:- How can I confirm the camshafts are S/E configaration? Measurements?
What alterations to carb jetting is needed to be compatible to S/E camshafts?
Tappets are set at present Inlet 5-7 Exhaust 6-8 any changes?
Need early history of car from Factory?
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