340 CVT Reference RPMs

Jan 20th, 2003, 23:06

I just bought a 1991 340CVT 2 weeks ago and find the gearbox a little unpredictable. Can anyone give me reference figures for what RPM I should be seeing at 20, 30,50 mph under acceleration, cruising, deceleration? 3300 at 30mph cruise seems a little fast to me but the last time I drove a 340CVT was 1985!

foggyjames · Feb 9th, 2003, 04:56

Yeah - those RPM speeds are wrong. There's a whole load of info in the archive about this topic (if you can find it!). Not an expert myself, but its something to do with a 4-way valve from memory?!

cheers

James

Bob · Feb 9th, 2003, 11:38

Try using the search facility for our web site also. I have recently uploaded new documents in pdf format, and several have CVT info.

Peter Milnes · Feb 9th, 2003, 22:20

Sounds as if the drive belts need their tension adjusting or may be due for replacement. German, Swedish and French have them at £72 per pair. It is alos possible that the clutch release mechanism (vacuum servo) may need investigation.

All the best, Peter

Feb 10th, 2003, 13:40

Well I've been doing a bit of testing since I posted the original message.

The four way vacuum valve is working correctly from the electrical side and can be heard to click when energising. However if I pull off the change up vacuum hose there is less suck than a baby sucking your finger! Does anyone know how much vacuum I should expect?

I have sucked and blown down said hose and it sucks and blows back at me so I hope that means I haven't got blown diaphragms.

I have not yet been able to test the vacuum supply to the 4-way valve, although the vacuum servo on the clutch does work.

I have also not had a chance to get underneath and check the belt tension. The belts do not skid on the pulleys, though.

Also the car behaved much better in the recent warmer weather - Hmm I think I will go for the air intake thermostat next.

Any more help would be appeciated.

Feb 12th, 2003, 17:03

It's the 4-way valve alright.
If I swap the hoses and operate the low ratio hold switch it changes up no problem. It's just manually controlled.

Off to find a replacement valve, then.

Feb 21st, 2003, 22:56

OK
The secondhand vacuum valve arrived and I bunged it on the car but it was dead as a dodo!
So I got it off again and stripped down both valves on the kitchen table.
The rubber mushrooms on the armatures are stuck to the valve face, not to the armature. I put the old valve back on the car (I have just the one car) and head for Sainsburys for a tube of superglue.
Get the old valve back off the car again. Glue the rubber musrooms back together.
After time for the glue to dry I reassemble both valves and fit the best one on the car.

It works! 2000rpm at 30mph cruise and 3100rpm under acceleration. How long will it last?

Now I must get underneath and adjust my drive belt tension before the pulleys chew them up.

Jan 20th, 2003, 23:06	#1
jwool 340 auto Guest Location:	340 CVT Reference RPMs I just bought a 1991 340CVT 2 weeks ago and find the gearbox a little unpredictable. Can anyone give me reference figures for what RPM I should be seeing at 20, 30,50 mph under acceleration, cruising, deceleration? 3300 at 30mph cruise seems a little fast to me but the last time I drove a 340CVT was 1985!

Feb 9th, 2003, 04:56	#2
foggyjames 300 Register Keeper Last Online: Apr 24th, 2024 09:13 Join Date: Dec 2001 Location: Nottingham	RE: 340 CVT Reference RPMs Yeah - those RPM speeds are wrong. There's a whole load of info in the archive about this topic (if you can find it!). Not an expert myself, but its something to do with a 4-way valve from memory?! cheers James __________________ VOC 300-series Register Keeper '13 V70 D4 SE Lux '89 740 Turbo Intercooler '88 360 Turbo Intercooler '84 360 GLT '81 343 GLS R-Sport '79 343 DL '70 164

Feb 9th, 2003, 11:38	#3
Bob Club Director Last Online: Apr 22nd, 2024 17:25 Join Date: Nov 1999 Location: From Neath, now London View Photos By: Bob	RE: 340 CVT Reference RPMs Try using the search facility for our web site also. I have recently uploaded new documents in pdf format, and several have CVT info. __________________ Robert Isaac VOC Director 1995 850 T5 auto estate. 280hp 289K miles and purrrs 2009 Jap import V70 2.5T 200hp 51K miles

Feb 9th, 2003, 22:20	#4
Peter Milnes Premier Member Last Online: Apr 10th, 2014 00:01 Join Date: Feb 2002 Location: Tonyrefail	RE: 340 CVT Reference RPMs Sounds as if the drive belts need their tension adjusting or may be due for replacement. German, Swedish and French have them at £72 per pair. It is alos possible that the clutch release mechanism (vacuum servo) may need investigation. All the best, Peter

Feb 10th, 2003, 13:40	#5
johnw Guest Location:	RE: 340 CVT Reference RPMs Well I've been doing a bit of testing since I posted the original message. The four way vacuum valve is working correctly from the electrical side and can be heard to click when energising. However if I pull off the change up vacuum hose there is less suck than a baby sucking your finger! Does anyone know how much vacuum I should expect? I have sucked and blown down said hose and it sucks and blows back at me so I hope that means I haven't got blown diaphragms. I have not yet been able to test the vacuum supply to the 4-way valve, although the vacuum servo on the clutch does work. I have also not had a chance to get underneath and check the belt tension. The belts do not skid on the pulleys, though. Also the car behaved much better in the recent warmer weather - Hmm I think I will go for the air intake thermostat next. Any more help would be appeciated.

Feb 12th, 2003, 17:03	#6
johnw Guest Location:	RE: 340 CVT Reference RPMs It's the 4-way valve alright. If I swap the hoses and operate the low ratio hold switch it changes up no problem. It's just manually controlled. Off to find a replacement valve, then.

Feb 21st, 2003, 22:56	#7
johnw Guest Location:	RE: 340 CVT Reference RPMs OK The secondhand vacuum valve arrived and I bunged it on the car but it was dead as a dodo! So I got it off again and stripped down both valves on the kitchen table. The rubber mushrooms on the armatures are stuck to the valve face, not to the armature. I put the old valve back on the car (I have just the one car) and head for Sainsburys for a tube of superglue. Get the old valve back off the car again. Glue the rubber musrooms back together. After time for the glue to dry I reassemble both valves and fit the best one on the car. It works! 2000rpm at 30mph cruise and 3100rpm under acceleration. How long will it last? Now I must get underneath and adjust my drive belt tension before the pulleys chew them up.

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