Mixture adjustment on a 175 CDUS

paul4be · May 20th, 2006, 15:20

Sorry for yet another (probably stupid!!) question.

Which direction weakens/ richens the mixture when turning the small recessed nut on the bottom of a Pierburg CDUS 175 (on a 1984 B21A)?

From the plugs, things seem to be a bit lean and it's going to be a week or two until I can get it onto a gas analyser and do the job properly. As such, don't want to lean things off even further by going the wrong way.

Do I screw the nut up the protruding shaft to weaken or richen??

Many thanks.
Paul

Mike_Brace · May 20th, 2006, 19:55

This raises and lowers the jet on the needle - screwing out will richen up as it will increases the gap between jet and needle letting more fuel through.

Mike

paul4be · May 20th, 2006, 21:03

Thanks Mike!

classicswede · May 22nd, 2006, 21:49

Hi Paul how is project twin carbs going?

paul4be · May 22nd, 2006, 22:54

SU's and manifolds are still at the engineering shop. They've cut a manifold up for a look/see and recon it would be do-able to adapt an original, but a new manifold would be better. As such I am going to leave the car with them once I can do without it for a while (it's my daily driver).
Getting there slowly!!

There's always one more job to do.
Killed the engine mounts on Sunday. Guessing they were the originals and they didn't seem to like the fact that the car doesn't just potter around any more but gets driven harder than the old guy who had it previously.

Pick up new mounts tomorrow.

Also waiting for a V cam to arrive.

Still need to start on swapping bushes as well.

classicswede · May 23rd, 2006, 20:37

Be warned with the engine mounts. We are finding more and more problems with the repro items lesting only weeks!! We are now fitting poly mounts at the cost of a vibration at idle.

paul4be · May 23rd, 2006, 20:44

Dai,
Spent a fun hour after work this evening swapping the mounts, so mobile again.
Didn't realise you did poly engine mounts. Could you let me have a price for them please as it may reduce the engine rocking. Think I may knock up a steady bar as well.
Also, do your poly rear trailing arm bushes fit into the existing metal sleeve without having to press it out?

Thanks.

classicswede · May 25th, 2006, 20:21

The poly engine mounts are £15 each.
The rear axle bushes fit into the existing shells so do not need pressing out.

paul4be · May 25th, 2006, 20:44

B*gg*r!!!!!!!!!!

If i'd known they were only £15 each, I'd have had them instead, still might!!

I have a rear end clunk that I suspect is trailing arm bushes, so polys will be the easiest way to go.

Really need to go through all of the bushes anyway and see exactly what's what.

Thanks for the info Dai, I'll be in touch when I know what I actually need, rather than just guessing.

May 20th, 2006, 15:20	#1
paul4be Junior Member Last Online: Apr 16th, 2008 21:24 Join Date: Dec 2005 Location: North Yorkshire	Mixture adjustment on a 175 CDUS Sorry for yet another (probably stupid!!) question. Which direction weakens/ richens the mixture when turning the small recessed nut on the bottom of a Pierburg CDUS 175 (on a 1984 B21A)? From the plugs, things seem to be a bit lean and it's going to be a week or two until I can get it onto a gas analyser and do the job properly. As such, don't want to lean things off even further by going the wrong way. Do I screw the nut up the protruding shaft to weaken or richen?? Many thanks. Paul

May 20th, 2006, 19:55	#2
Mike_Brace Former contributor Last Online: Jul 2nd, 2022 07:54 Join Date: Dec 2004 Location: Rhosgoch, Anglesey	This raises and lowers the jet on the needle - screwing out will richen up as it will increases the gap between jet and needle letting more fuel through. Mike __________________ A Volvo is for life not just for Christmas!

May 22nd, 2006, 21:49	#4
classicswede Trader Volvo in my veins Last Online: Today 20:52 Join Date: Dec 2004 Location: Anglesey	Hi Paul how is project twin carbs going? __________________ http://www.classicswede.org www.classicswede.co.uk

May 22nd, 2006, 22:54	#5
paul4be Junior Member Last Online: Apr 16th, 2008 21:24 Join Date: Dec 2005 Location: North Yorkshire	SU's and manifolds are still at the engineering shop. They've cut a manifold up for a look/see and recon it would be do-able to adapt an original, but a new manifold would be better. As such I am going to leave the car with them once I can do without it for a while (it's my daily driver). Getting there slowly!! There's always one more job to do. Killed the engine mounts on Sunday. Guessing they were the originals and they didn't seem to like the fact that the car doesn't just potter around any more but gets driven harder than the old guy who had it previously. Pick up new mounts tomorrow. Also waiting for a V cam to arrive. Still need to start on swapping bushes as well. Last edited by paul4be; May 22nd, 2006 at 22:56.

May 23rd, 2006, 20:37	#6
classicswede Trader Volvo in my veins Last Online: Today 20:52 Join Date: Dec 2004 Location: Anglesey	Be warned with the engine mounts. We are finding more and more problems with the repro items lesting only weeks!! We are now fitting poly mounts at the cost of a vibration at idle. __________________ http://www.classicswede.org www.classicswede.co.uk

May 20th, 2006, 21:03	#3
paul4be Junior Member Last Online: Apr 16th, 2008 21:24 Join Date: Dec 2005 Location: North Yorkshire	Thanks Mike!

May 23rd, 2006, 20:44	#7
paul4be Junior Member Last Online: Apr 16th, 2008 21:24 Join Date: Dec 2005 Location: North Yorkshire	Dai, Spent a fun hour after work this evening swapping the mounts, so mobile again. Didn't realise you did poly engine mounts. Could you let me have a price for them please as it may reduce the engine rocking. Think I may knock up a steady bar as well. Also, do your poly rear trailing arm bushes fit into the existing metal sleeve without having to press it out? Thanks.

May 25th, 2006, 20:21	#8
classicswede Trader Volvo in my veins Last Online: Today 20:52 Join Date: Dec 2004 Location: Anglesey	The poly engine mounts are £15 each. The rear axle bushes fit into the existing shells so do not need pressing out. __________________ http://www.classicswede.org www.classicswede.co.uk

May 25th, 2006, 20:44	#9
paul4be Junior Member Last Online: Apr 16th, 2008 21:24 Join Date: Dec 2005 Location: North Yorkshire	Bggr!!!!!!!!!! If i'd known they were only £15 each, I'd have had them instead, still might!! I have a rear end clunk that I suspect is trailing arm bushes, so polys will be the easiest way to go. Really need to go through all of the bushes anyway and see exactly what's what. Thanks for the info Dai, I'll be in touch when I know what I actually need, rather than just guessing.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)