Variomatic 4-way vac valve pipe connection to manifold

[Bjorn Belter]

I at last got a chance to look around the engine compartment of my newly saved 1985 340 Variomatic, the other day.

I've driven it a bit since the new clutch and belts were fitted, and things seemed OK, but I did think that the transmission was perhaps not in its very "top gear" when doing 70/80.

Anyway, looking around the engine, I noticed that the pipe that goes from the front of the 4-way vac valve (I think it's number 2, looking at your excellent manuals on here). The end of the pipe is just tucked under the inner wing by the battery.

I assume that this should really be connected to the manifold?

Could this be a reason for the symptom I mentioned?

When i get a chance to go back to the lock-up, I hope to try to reconnect it. Trouble is, I'm always reluctant to start taking bits out of engines to gain access etc., because invariably, I can't get them to go back properly, and finish up with more problems that originally!

Does this all sound feasible, and I wonder why the pipe appears to have been disconnected.

Will keep you posted.

[foggyjames]

Sadly Richard, CVT experts are a bit thin on the ground here, so you may have to wait a while. I wish my knowledge of the CVT was better.

Have you seen Mac's excellent guide to the 300's CVT setup? I know you're well familiar with it in DAFs...

cheers

James

[volvodspec]

Trouble is, I'm always reluctant to start taking bits out of engines to gain access etc., because invariably, I can't get them to go back properly, and finish up with more problems that originally!

Does this all sound feasible, and I wonder why the pipe appears to have been disconnected.

you probably have taken of your air filter housing, cause that's where thoe hose came of , it doesn't matter thogh this hose is the exit to ditch the unused vacuum.


so the rpm rate is a bit high when driving at about 70/80kmh, and you have replaced the belts, in that case a very good possibility the belt tension hasn't been set properly, there should be about 1,5 mm of clearence inbetween the pullies of the secondairy gearbox. when the clearence is lower the transmission can't get into it's highest gear. clearence needs to be in the range of 0,5mm to about 1,5mm for optimum.

and a easy way to test if the vacuum system is ok, pull of the exit hoses at the emvk (the ones that go into the chassis, towards the gearbox.) blow in one of the hoses (not with an air compressor, with you mouth is fine!) and hold the air a bit under pressure, when the air doesn't get back from the other hose or the pressure you build up doesn't fade the membrames and rotary seals in the primairy unit are ok.

next, start the engine and manually raise the rpm's to about 1800. the gear up side on the emvk should now give vacuum, this vacuum has been limited so you'll have to put your finger on the connection to feel it's sucking.