Volvo Community Forum. The Forums of the Volvo Owners Club

Forum Rules Volvo Owners Club About VOC Volvo Gallery Links Volvo History Volvo Press
Go Back   Volvo Owners Club Forum > "Technical Topics" > PV, 120 (Amazon), 1800 General

Notices

PV, 120 (Amazon), 1800 General Forum for the Volvo PV, 120 and 1800 cars

Information
  • VOC Members: There is no login facility using your VOC membership number or the details from page 3 of the club magazine. You need to register in the normal way
  • AOL Customers: Make sure you check the 'Remember me' check box otherwise the AOL system may log you out during the session. This is a known issue with AOL.
  • AOL, Yahoo and Plus.net users. Forum owners such as us are finding that AOL, Yahoo and Plus.net are blocking a lot of email generated from forums. This may mean your registration activation and other emails will not get to you, or they may appear in your spam mailbox

Thread Informations

Need carburation advice double SUs SH6

Views : 2058

Replies : 39

Users Viewing This Thread :  

Reply
 
Thread Tools Display Modes
Old Jan 10th, 2019, 04:32   #31
adarvasi
Member
 
adarvasi's Avatar
 

Last Online: Mar 1st, 2022 01:17
Join Date: Sep 2018
Location: Mexico City
Default

Quote:
Originally Posted by blueosprey90 View Post
I think Ron will say yes.

See this link, first 3 or 4 pictures. They may help you visualize the situation.

https://sites.google.com/site/fifers...wPrintDialog=1
In addition to everything else that has been mentioned about what might cause the carburetor to overflow, It also may be possible for the fuel pump to have too much pressure. The SU carbs only require about 3 psi of fuel line pressure. If you have an aftermarket fuel pump it might be rated at too high a pressure.

My money (of course, I never bet more than $1) is riding on a leaking float as your cause of overflow. Initially you did not seem to have this overflow problem. My guess is that it took a few days of gasoline sitting in the float chamber for the float to slowly fill with fuel and sink to the bottom - or at least to the point where the float wouldn't rise high enough to shut the needle valve.
Very interesting points, will check both
adarvasi is offline   Reply With Quote
Old Jan 11th, 2019, 00:50   #32
adarvasi
Member
 
adarvasi's Avatar
 

Last Online: Mar 1st, 2022 01:17
Join Date: Sep 2018
Location: Mexico City
Default

Took both carns out today, they were in a filthy state, and had a surprise, in the manifold connection for the rear carb, there was a piece of folded metal, see picture.
Also the interior of the manifold is quite black, except where I imagine that the fuel flow has kept it cleaner, is this normal?
The piston on the rear carb has some rough edges, is this a problem?
I do not cease to be amazed as the poor maintenance and aberrant things that some people so to their cars, like painting all the carb linckage with aluminum paint.
As usual, grateful for your kind advice.
Andres
adarvasi is offline   Reply With Quote
Old Jan 11th, 2019, 06:00   #33
blueosprey90
Master Member
 

Last Online: Today 16:06
Join Date: May 2017
Location: New Milford, Connecticut
Default

I think you were very lucky not to have that piece of metal ingested into the engine. Is it a piece that was part of the air filter canister assembly?

Use carburetor cleaner to clean the carburetors as best that you can.

You can try smoothing the piston with 0000 steel wool of maybe 1500 wet/dry sandpaper, but don't mess with the top lip interface between the piston and the dashpot dome. The piston interface is supposed to be machined to match to the dashpot.

https://youtu.be/IfU47Oqq9wA

It almost looks like the black are oil deposits. Does your car have an crankcase ventilation system where there is a hose running from the block to the carburetors.

Last edited by blueosprey90; Jan 11th, 2019 at 06:06.
blueosprey90 is offline   Reply With Quote
Old Jan 11th, 2019, 12:31   #34
Ron Kwas
Premier Member
 
Ron Kwas's Avatar
 

Last Online: Today 16:40
Join Date: Jul 2007
Location: Connecticut, USA
Default

adarvasi;

Remove Foreign Object Debris from intake track (obviously, and check for secondary damage), and clean using carb cleaner and rags, and don't let a little remaining soot bother you too much...you can clean up what looks like a poor casting edge (possibly FOD) at the guide groove in the Dashpot with a file as it is not part of the many other precision machined and matched surfaces of an SU carb**...otherwise observe the rule to remove no metal and USE NO ABRASIVES on any part of the Dashpot or Dome or their Centering Guidetubes...ever!

Notes and recommendations here: http://www.sw-em.com/SU%20Carb%20Service.htm ...take particular note of Contact/Non-Contact area Graphic located there.

** While they are apart, perform 5-7 sec test to check matching. See: http://www.sw-em.com/su_carbs.htm#Da...20of%20Dashpot

Cheers
Ron Kwas is offline   Reply With Quote
Old Jan 11th, 2019, 13:45   #35
adarvasi
Member
 
adarvasi's Avatar
 

Last Online: Mar 1st, 2022 01:17
Join Date: Sep 2018
Location: Mexico City
Default

Great advice and info Ron, most grateful for your help.
There is no secondary damage to the intake manifold, the FO was lodged at the entrance, and I remove it as soon as ai discovered it.
The car has a cranckcase ventilation hose from the oil filler cap to the carb
Have a great weekend
adarvasi is offline   Reply With Quote
Old Jan 11th, 2019, 14:15   #36
Derek UK
VOC Member
 
Derek UK's Avatar
 

Last Online: Today 17:01
Join Date: Jul 2006
Location: Chatham
Default

The guide groove is there to stop the piston rotating but if damaged can cause the piston not to rise and fall smoothly. File with care. The piece of folded metal may well have been causing the fuel flow to be biased into one of that pair of intakes so there may be an improvement in running with it out of the way. Carbs look as if they need a rebuild but the essential thing to look at is how worn the throttle shaft bushes are. If there is any wear at all they really need replacing along with the shafts if you are to get good idle and low speed running, as the air leaks make tuning impossible.
If your engine is a B20 and the breather pipework is all correct the hose from the filter to the cap will be flowing air from the filter into the engine so there should be no problem with oil coming into the engine via the filters. Carb cleaner or cellulose thinners plus an old toothbrush should make the carbs look a lot better. A basic gasket service kit isn't expensive.
Derek UK is offline   Reply With Quote
Old Jan 11th, 2019, 14:46   #37
arcturus
arcturus
 
arcturus's Avatar
 

Last Online: Today 09:21
Join Date: Mar 2006
Location: Sagres Portugal
Default

What is the object indicated in Picture 4?
Attached Images
File Type: jpg carb3.jpg (153.5 KB, 19 views)
__________________
life's too short to drink bad wine
arcturus is offline   Reply With Quote
Old Jan 11th, 2019, 15:23   #38
Ron Kwas
Premier Member
 
Ron Kwas's Avatar
 

Last Online: Today 16:40
Join Date: Jul 2007
Location: Connecticut, USA
Default

Arcturus;

...it's the bottom end of screw(4) which holds the anti-rotation pawl(3)...(which incidentally rides in that slot of Damper Piston(12)).

Last edited by Ron Kwas; Jan 11th, 2019 at 15:29. Reason: Edit: Added Graphic
Ron Kwas is offline   Reply With Quote
Old Jan 11th, 2019, 16:20   #39
adarvasi
Member
 
adarvasi's Avatar
 

Last Online: Mar 1st, 2022 01:17
Join Date: Sep 2018
Location: Mexico City
Default

Thank you Derek, Monday I am receiving a rebuild kit and new needles (HF) that wre recommended by Joe Curto for higher altitude.
I will carefully clean as best as possible the carbs, change the bushingsand shafts and replace all gaskets.
The metal piece definitely was causing a flow disturbance.
My engine is a B18D.
adarvasi is offline   Reply With Quote
Old Jan 25th, 2019, 01:16   #40
adarvasi
Member
 
adarvasi's Avatar
 

Last Online: Mar 1st, 2022 01:17
Join Date: Sep 2018
Location: Mexico City
Default Finally running well

Installed the carbs today and started iinmediately, adjusted the patameters and is runnng great.
Learned quite a bit about SU carbs!
Thanks for all of your help and patience.
Attached Images
File Type: jpg JPEG image.jpg (130.7 KB, 11 views)
adarvasi is offline   Reply With Quote
Reply


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

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 18:31.


Powered by vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.