Tuneup, and Solex 34 PICT/3 Carburettor Adjustment

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This method will also work for the 30PICT/3 30PICT/4, 31PICT/4, 31PICT and H30/31 carburettors with the two adjusting screws in the side.

Before we begin to adjust the carburetor, the valves, points, and timing should be set. This is important, and they should be done in the right order, as you start with a cold engine, and end with it warm. These topics are addressed in the following -

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Setting the Valves

Valve adjustment is always done with the engine stone cold.

0.004 inches (0.1 mm)is the factory setting for pre-71 engines. Some folks find that this is too tight after the engine warms and use 0.006 inches (0.15 mm). Thats engines with a number starting B..., D..., E..., F..., H..., L..., or a plain number. (I've always used the factory setting on my H... engine without any problems.)

0.006 inches (.15 mm) is used on 71 and up engines. Thats engines with a number starting AB..., AC..., AD..., AE..., AF..., AH..., AJ..., AK..., AR..., AS....

The aim of the tappet setting is to provide virtually NO gap when the engine is at operating temperature.

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Setting the Points

The points are adjusted to .016 inches (0.4 mm). Replace them if the contacts are pitted or the cam rubbing block is badly worn. Add a touch of grease to the cam lobs at the same time. Also pull off the rotor arm and take a look in the centre of the spindle it rides on. If your distributor has a felt pad in there, put a few drops of oil (engine oil is fine) on it to lubricate the distributor drive - don't overdo it though - a few drops only. Some distributors don't have this felt pad - in that case skip this procedure.

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Setting the Timing

The usual timing settings are:

  • 1200 engines with single vacuum distributor - 10BTDC. This is set static - engine off (or at idle with a timing light and the vacuum line disconnected).

  • 1300/1500/1600 engines with single vacuum distributor - 7.5BTDC. This is set static - engine off (or at idle with a timing light and the vacuum line disconnected).

  • 1300/1500/1600 engines using the double vacuum distributor - 5ATDC. This must be set using a timing light, with the engine idling and the vacuum lines connected so the retard line can pull in the 5ADTC (After TDC).

Note: Any VW engine using the Bosch 009 (or other centrifugal distributor) must be set at the maximum advance with the engine at 3000+rpm, and let the idle advance fall where it may. The reason for this is that the 009s vary in the total amount of advance they make, and the maximum advance is more important than idle advance. The normal setting is a max advance of 28-30BTDC. If you have high quality non-oxygenated fuels, you may be able to use 30-32 degrees advance. The idle advance will then usually fall in at about 5-8BTDC. Please note that VW never used the 009 for any of it's beetle models, and so, although it will work, you may get flat spots and poor pick-up when using this distributor.

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Checking the Choke

Now start the engine and warm it up. Take the air cleaner off the top of the carby (if it's the oil filled type be careful, you don't want a shoe full of oil) and check that the choke butterfly is standing vertical. If it isn't, run the engine some more to make sure it's throughly warm, and check the choke butterfly again. If it is not standing vertical, the butterfly needs adjusting or fixing (another topic).

It's important to set the valves, points, timing and check the choke (in this order) before setting the carburettor, they all work together for a smooth running engine.

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Setting the 34PICT/3 Carburettor

  1. Engine warmed up, but switched off. The screw on the throttle arm, which faces to the rear of the car is called the Fast Idle Adjuster. This works with the choke to give a smooth idle on a cold engine. Unscrew the Fast Idle Adjuster (sits on the stepped cam), until it is clear of the stepped cam. Now screw it in until it JUST touches the very bottom of the stepped cam - NOT on any of the steps themselves. Now screw it in another 1/4 turn - no more. This sets the throttle butterfly open the required .004 inch, so you can use the Bypass screw (read on) to set the idle speed correctly. Now leave the Fast Idle Adjuster screw alone.

  2. Turn the Volume Control Screw (smaller screw in the side of the carby) in until it bottoms. GENTLY please - you don't want to open up the hole. Now unscrew it 2.5 turns. This is the starting setting.

  3. Start the engine and use the Bypass Screw (larger screw in the side of the carby) to set the idle at 850rpm (fast idle if you don't have a tacho). For a semi-auto car, use 900rpm.

  4. 4. Go back to the Volume Screw and adjust it slowly for the fastest idle. It should not be much outside the range of 2-3 turns (½ turn in/out from the 2.5 basic setting). Then turn it very slowly IN until the revs drop by about 30rpm. If you don't have a tacho, listen until you can just hear the revs start to drop, maybe as little as 1/8th turn.

  5. Now use the Bypass screw again to reset the idle speed to 850 rpm (900 for the semi-autos).

That's it - you're done.

You should now have an engine which purrs like a kitten.

Rob Boardman
Adelaide Australia

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Disclaimer stuff: Rob and Dave have written these procedures from their own experiences. We have not assumed any specialised mechanical knowledge, but we DO assume that anyone using these procedures has at least some basic mechanical ability.

We hope you find the procedures useful, but we don't take any responsibility for anything which happens to you, other people, your VW or any other property or goods resulting from your use of these procedures.

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Have fun fixing your VW - just keep them fweeming, OK?

Last revised 3 May 2004.