240 General: The continuing story....

[c_lee]

Originally Posted by Beetledrive

...........
I have a timing light and can do the timing on my Beetle as an aircooled engine is set while the engine is idling. I have checked the 240 tickover at idle with the light and it is a steady 900rpm. I was under the impression that only a garage with the correct equipment would be able to tune a water cooled car as I thought it was done when the engine was under load. Any info would be much appreciated

I have nothing fancy to set the ignition timing - just a stroboscopic timing light - an old Gunsons one I've had for donkeys years.

There is a timing mark on the crankshaft pulley and a marked scale on the lower part of the plastic timing belt cover, just above the crank pulley.
The engine is not likely to stop at TDC so you would have to turn the engine over by hand until it was at TDC, then put a dot of quick drying white paint in the grove of the timing mark to make it easily visible under the strobe.
Make sure the engine is ticking over at the right speed so that the distributor weights don't influence the setting. Disconnect the vacuum advance hose on the distributor and plug the end of the pipe that goes to the inlet manifold.

Connect up your strobe to monitor cylinder 1's HT lead.
Start the engine and point your strobe at the crank pulley, be careful of the rotating fan and belts.
Your strobe will now illuminate the white dot against the timing scale and this indicates your timing.
If the timing is as it should be rev the engine a little and watch for movement of the dot with respect to its previous position - it should advance further ie: move leftwards.
If it doesn't the weights in the distributor have a problem.
If it does, reconnect the vacuum hose to the distributor and rev the engine again to about the same RPM as before - the timing should advance even further that it did on the weights test.
If it doesn't there is a problem with the vacuum advance system and that could be either in the distributor or in the vacuum advance hose.

If the basic timing is out then what I do is stop the engine and loosen slightly the distributor bolt that allows the distributor to rotate. Then I do the basic setting again whilst rotating the distributor slowly until the timing is correct. I would then do the weights and vacuum advance test after re-tightening the distributor bolt.

Just thought - what I describe here is OK for cars that don't use contact breaker points in the distributor - ie: the Hall sensor type as in a B200E.

If you have points then they should be set first either with a feeler gauge as per specified gap or ( preferably ) a dwell angle meter if the dwell angle spec is known.

There is nothing particularly difficult in any of these settings, just watch out for rotating parts whilst in there.
If you've used a timing light on your Beetle I don't really think I will have told you much you don't already know - the water cooling makes no difference.

HTH - Colin

BTW I used to have a 1974 Beetle myself in my younger days.
A proper running flat 4 VW aircooled engine is music to the ears and rare to see ( hear ) these days.

[loki_the_glt]

Originally Posted by c_lee

EDIT: Loki - I think one of the main reasons for the double head gasket was to reduce the compression ratio to take unleaded as I understand it.
It might have altered the timing slightly due to the very slight increase in the distance to the camshaft pulley but I think it would have only been the valve timing, the crank to intermediate shaft distance would have remained the same.

Colin, you're correct about Volvo's reasoning as the B21 was meant to run on 4-star (98 RON) and unleaded was roughly equivalent to 2-star so the compression ratio had to be reduced and a second gasket was their solution. Because the heads are alloy there was no need to fit hardened valve seats as was done on many contemporaneous iron-head engines. Now leaded petrol is little more than a fond memory, though I think it can still be purchased.

[Beetledrive]

Originally Posted by c_lee

I have nothing fancy to set the ignition timing - just a stroboscopic timing light - an old Gunsons one I've had for donkeys years.

There is a timing mark on the crankshaft pulley and a marked scale on the lower part of the plastic timing belt cover, just above the crank pulley.
The engine is not likely to stop at TDC so you would have to turn the engine over by hand until it was at TDC, then put a dot of quick drying white paint in the grove of the timing mark to make it easily visible under the strobe.
Make sure the engine is ticking over at the right speed so that the distributor weights don't influence the setting. Disconnect the vacuum advance hose on the distributor and plug the end of the pipe that goes to the inlet manifold.

Connect up your strobe to monitor cylinder 1's HT lead.
Start the engine and point your strobe at the crank pulley, be careful of the rotating fan and belts.
Your strobe will now illuminate the white dot against the timing scale and this indicates your timing.
If the timing is as it should be rev the engine a little and watch for movement of the dot with respect to its previous position - it should advance further ie: move leftwards.
If it doesn't the weights in the distributor have a problem.
If it does, reconnect the vacuum hose to the distributor and rev the engine again to about the same RPM as before - the timing should advance even further that it did on the weights test.
If it doesn't there is a problem with the vacuum advance system and that could be either in the distributor or in the vacuum advance hose.

If the basic timing is out then what I do is stop the engine and loosen slightly the distributor bolt that allows the distributor to rotate. Then I do the basic setting again whilst rotating the distributor slowly until the timing is correct. I would then do the weights and vacuum advance test after re-tightening the distributor bolt.

Just thought - what I describe here is OK for cars that don't use contact breaker points in the distributor - ie: the Hall sensor type as in a B200E.

If you have points then they should be set first either with a feeler gauge as per specified gap or ( preferably ) a dwell angle meter if the dwell angle spec is known.

There is nothing particularly difficult in any of these settings, just watch out for rotating parts whilst in there.
If you've used a timing light on your Beetle I don't really think I will have told you much you don't already know - the water cooling makes no difference.

HTH - Colin

BTW I used to have a 1974 Beetle myself in my younger days.
A proper running flat 4 VW aircooled engine is music to the ears and rare to see ( hear ) these days.

This is great advice, and you are right it's not a million miles away from what I am used to. I will have to give it a go. I am glad our 240 doesn't have points to fiddle about with as the large engine bay must make it difficult to reach, and I can't imagine you can turn the engine by pulling on the belt with your hands! The Beetle is an un-modified '73 model which I have owned for the last 10 years and I completely agree about the noise of a healthy, stock engine. Having said that, the roar of a 240 is a pretty great sound, and the click of the gearbox when put into reverse is something else I like.

Thanks again

[345DL]

And just because I know he's too modest to do it himself, here's a picture of Beetledrive's Beetle:

[Beetledrive]

Some time has passed since I last did anything about this little annoyance as I have been pretty busy and the car just soldiers on regardless. I have used the timing light to set the idle speed but have had repeated difficulty getting the cambelt cover off due to all three very rusty bolts. When they were eventually free the top cover does not want to come off as it seems to be sticking at the bottom. I have tested the thermostat in the air box firstly using the methods in the Haynes manual and thinking it was broken, but then sticking it over a boiling kettle which did the trick and the flap did open. I looked at the Warm up box thingy and undid the connectors to find that they were corroded and green (see pics part way through cleaning).





After a good clean I started the car for the first time that day and it started perfectly with no hesitation. Unforunately the next morning I started it again and the problem was back

I am still at a loss. It is possible it could be a head gasket problem as there is a lot of white smoke in cold weather. However, there is no cream sludge in the oil which looks fine, and the coolant looks fine too.

I have cleaned the connecter for the thermal timer but this hasn't made any difference

The vacuum advance unit looks like it has seen better days and does seem to have a white powder residue over it. When I pull the vacuum hose off at idle there is no apparent change in engine note at all (unlike I would get with the Beetle). Is this normal and where would you get a replacement?

I have also cleaned the earth connections for the cold start valve. I didn't touch this when I replaced the seals for the injectors. Could this be the cause of the problem if it is leaking?

[Beetledrive]

I have since realised that according to the Haynes manual I will not be able to take the cambelt cover off (for timing purposes) without firstly removing the belts and pulleys (relates to B200/B230 engines). I have to say that I am rather reluctant to start doing this as all the belts (incl cambelt) could really do with changing in one go. As it appears this engine is an interference type I am not happy about doing this myself due to the potential damage that could be caused through incorrectly refitting the cambelt. I think it makes sense to leave this to a garage (although I don't want to), as and when I have the funds. The car actually first-started perfectly again yesterday but both times have been in very warm afternoon temperatures.

[rogerb]

The unit that you show with the poor conections is the headlight dip/main beam realy.

I used to work ona fare few of these old kjet cars and had the right prasser test kit for them.
Things I would look at for poor start up idle would be:
1 dry joints cracks on the pcb of the injection realy it is a seperat pin for the air valve and fuel regulator
and the conections to both the idle air valve and the fuel control regulator (towards the front under the inlet manifold.)
2 leaky inlet mafold gaskit, often around no four cylinder.
3 dirt around the edge of the airflap or the air flap ring having gone off centre so that it sticks very slightley
4 poor or uneven flow from the injectors at low speed, causing bad atomision of the fuel.
5 is the CO when hot ok or is it too lean?
6 is the in tank pump working ok?
7 on the red block engines, as had been said already,they can seep a very small amount of coolent
in to one of the cylinders casuing poor running on start up.This would meen a new head gaskit and getting the head skimeed cleen (unless real clean and flat).
8 you can alter the flow through an idle valve if needed to acount fot engine ware, if you look down the valve when stone cold with a torch and the top pipe off, you will see a moon shape gap.There is a nut on the side (normaly with a dob of paint on it) that can be undone a littie bit and slides side to side.
If you open up the moon gap a small amount it will increase the cold idle speed.
Dont over do it, and check the other things first.
To see if the valve is working the moon gap should be closed after a few mins of running if you switsh off and look quickley.Also when running there should be around 12volts across the conector terminels.
9 have you changed the main fuel filter?
Note the thermal start only works the 5th injector when cranking from cold and then only for a few seconds or so depending on temp(on red blocks, the v6 is difrent).
There is a load more things that can go wrong with kjet caused by old age, crousion, dirt, or other problems.

Regeards Rogerb

[Beetledrive]

Oh crap, that's rather embarrasing. I had been looking for 'a silver metal box about the size of 2 large matchboxes stacked up' and that was the only thing that seemed to match that description. Thanks for all the other suggestions. I have since been told that the vacuum advance does not kick in until around 2500rpm so will discount that for now. We recently had an electrical problem with the tailgate wiring, despite a new loom being fitted. The tailgate number plate light, wiper and rear brake light had started to continually operate with each one taking turns to work for several seconds each!! The problem turned out to be a corroded earth hence why I have started looking at all the other electrical connectors which might be causing the same problem. Incidently I would be very grateful if someone could explain where the warm-up regulator is in a way that a five-year old might understand as I couldn't work it out the first time. I attach a picture of Vincent's engine to help:



And another one I have found from a different angle:

[Beetledrive]

Well, hopefully I have got it right this time. I have been searching the web and worked out that the 'Warm up regulator' that I was looking for is also known as the Control Pressure regulator, which is what it is called in the Haynes manual. So it's actually this thing here that sits next to the bellows, behind the distributer:



(I think this picture also shows the location of the thermal timer which is just above it and plugged into the side of the engine block)

Unfortunately it seems there is very little I can do about the control pressure regulator myself. I have however ordered a new inlet manifold gasket which on inspection I suspect has a leak, so that will be my next task.