1968 280 S smog pump removal - PROBLEM - Mercedes-Benz Forum

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 22 (permalink) Old 10-15-2012, 09:16 AM Thread Starter
Lifetime Premium Member
 
Scoot's Avatar
 
Date registered: Oct 2002
Vehicle: 1967 250 SL, 1963 220Sb
Location: Los Angeles / Altadena
Posts: 2,591
Mentioned: 3 Post(s)
Quoted: 103 Post(s)
Lifetime Premium Member
(Thread Starter)
1968 280 S smog pump removal - PROBLEM

I am putting the engine from a 1968 280 S M130 into a 1967 250 S body. I would like to remove the smog pump and cap everything off. I was in the process of doing just that yesterday (engine is out of the car at present) and made an unpleasant discovery. The smog pump pivots and serves to act as one of the belt tensioners. I do not find a corresponding idler pulley and since this was running when I removed it from the 1968 280 S (I have since cut and removed the belts) I'm in a bit of a pickle.

It seems very much like I need to keep the smog pump to act as a belt tension adjustment.

When I have read the posts on smog pumps before, the concensus seems to be "just remove the belt". Well I can't see how that is going to work either given that the smog pump is the tensioner for the belt that also operates the PS pump.

Thoughts?

Currently: 1967 250 SL, 1963 220Sb, 1965 300SE Lang, 1971 280SE parts car, 1972 Alfa GTV, 1965 Alfa Duetto, 1993 BMW R100R
Past: 1971 250 C, 1985 300 TD, 1967 250 S, 1968 280 S,1981 300 D, 1982 280CE, 3 Facel Vegas, Borgward Isabella Coupe, Alfa 2600 Sprint, Volvo P1900 (yes), numerous less interesting Volvos, ...
Scoot is offline  
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old 10-15-2012, 10:11 AM
BenzWorld Elite
 
Grubeguy's Avatar
 
Date registered: Jan 2006
Vehicle: 73 280SE 4.5, 71 300SEL, 03 BMW Z4, 72 Fiat 850, 80 Triumph TR7, 85 Porsche 911
Location: DC Area
Posts: 2,110
Mentioned: 1 Post(s)
Quoted: 97 Post(s)
Send a message via MSN to Grubeguy Send a message via Yahoo to Grubeguy
Does the PS pump pivot as well? Perhaps use a smaller belt and the PS pump as a tensioner?
Grubeguy is offline  
post #3 of 22 (permalink) Old 10-15-2012, 10:38 AM Thread Starter
Lifetime Premium Member
 
Scoot's Avatar
 
Date registered: Oct 2002
Vehicle: 1967 250 SL, 1963 220Sb
Location: Los Angeles / Altadena
Posts: 2,591
Mentioned: 3 Post(s)
Quoted: 103 Post(s)
Lifetime Premium Member
(Thread Starter)
Quote:
Originally Posted by Grubeguy View Post
Does the PS pump pivot as well? Perhaps use a smaller belt and the PS pump as a tensioner?
I wish. The only things that pivot seem to be the alternator (which is a bitch to get to under the AC compressor) and the smog pump.

Currently: 1967 250 SL, 1963 220Sb, 1965 300SE Lang, 1971 280SE parts car, 1972 Alfa GTV, 1965 Alfa Duetto, 1993 BMW R100R
Past: 1971 250 C, 1985 300 TD, 1967 250 S, 1968 280 S,1981 300 D, 1982 280CE, 3 Facel Vegas, Borgward Isabella Coupe, Alfa 2600 Sprint, Volvo P1900 (yes), numerous less interesting Volvos, ...
Scoot is offline  
post #4 of 22 (permalink) Old 10-16-2012, 01:56 PM
BenzWorld Senior Member
 
drew56cus's Avatar
 
Date registered: Oct 2006
Vehicle: 1965 220SE sedan (finnie) with 450SE conversion, 1964 220SE coupe project, 1966 300SE coupe
Location: Brisbane Australia
Posts: 418
Mentioned: 1 Post(s)
Quoted: 32 Post(s)
Hi Scoot,
These engines in Australia did not have any smog pumps on them - the power steering pump adjusts to tension the belt - check the bottom left hand side and there may be a little bolt and two nuts poking out that adjust it.
You can just see the bolt and nuts in this pic. Also note that there are dual belts that go around the crank and power steer pump pulleys - nothing else.
1968 280 S smog pump removal - PROBLEM-dsc00036.jpg

If yours is not the same and you can't get one, then I have heard of people pulling all the insides out of the smog pump so it is essentially an idler pulley.
Cheers,
Drew
drew56cus is offline  
post #5 of 22 (permalink) Old 10-16-2012, 02:00 PM Thread Starter
Lifetime Premium Member
 
Scoot's Avatar
 
Date registered: Oct 2002
Vehicle: 1967 250 SL, 1963 220Sb
Location: Los Angeles / Altadena
Posts: 2,591
Mentioned: 3 Post(s)
Quoted: 103 Post(s)
Lifetime Premium Member
(Thread Starter)
Drew - thanks for the post and the pictures. My PS pump is mounted rigidly above the smog pump. It looks very much like your PS pump is mounted where my smog pump is, and pivots in the same manner as my smog pump.

I would be interested in removing the guts from the smog pump but don't know if I am opening a can of worms. I assume all I want in there is whatever bearings exist for the shaft and pulley.

Should I be brave and take apart the smog pump? If anyone has done this I would appreciate a comment on the ease/difficulty of the task....

thanks
Scott

Currently: 1967 250 SL, 1963 220Sb, 1965 300SE Lang, 1971 280SE parts car, 1972 Alfa GTV, 1965 Alfa Duetto, 1993 BMW R100R
Past: 1971 250 C, 1985 300 TD, 1967 250 S, 1968 280 S,1981 300 D, 1982 280CE, 3 Facel Vegas, Borgward Isabella Coupe, Alfa 2600 Sprint, Volvo P1900 (yes), numerous less interesting Volvos, ...
Scoot is offline  
post #6 of 22 (permalink) Old 02-24-2013, 08:56 PM
BenzWorld Junior Member
 
Date registered: Feb 2013
Posts: 5
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
1968 280 S smog pump removal - PROBLEM

Hi Scoot,
I am near done restoring my 1968 250S from full frame off. Couple years ago I rebuilt all the engine and accessories. Got a bit bold and removed all the Smog stuff, tossed it, then capped at all six exhaust ports and welded closed the fitting on the carburetor. As for the smog pump, you are correct, it is the belt tension pulley... So, I had to keep it. Removed all the insides, fins, and such, then cleaned it all up and reinstalled it. There is no functionality as a pump and it keeps the belt tight.
==> now I have another concern: Maybe I need the smog apparatus...
Just two weeks ago, I began to tune the engine. It doesn't start well. Once running, I am having trouble with acceleration. It idles ok, and will run if I manually choke it during the initial movement of throttle. All is pointing to vacuum type issues.
In other words, the engine might have been designed to run with this
additional piping into the manifold...
Still learning and debugging this...
-Charlie.

Last edited by charliehook; 02-24-2013 at 09:00 PM. Reason: typo
charliehook is offline  
post #7 of 22 (permalink) Old 02-24-2013, 10:01 PM Thread Starter
Lifetime Premium Member
 
Scoot's Avatar
 
Date registered: Oct 2002
Vehicle: 1967 250 SL, 1963 220Sb
Location: Los Angeles / Altadena
Posts: 2,591
Mentioned: 3 Post(s)
Quoted: 103 Post(s)
Lifetime Premium Member
(Thread Starter)
Quote:
Originally Posted by charliehook View Post
As for the smog pump, you are correct, it is the belt tension pulley... So, I had to keep it.
I took a different path. The smog pump is mounted where the power steering pump would be mounted on a car without a smog pump. So I found a junker without a smog pump and got the PS bracket that replaces the smog pump bracket. The PS pump and bracket move in and out to take up the slack same as the smog pump.

Quote:
Originally Posted by charliehook View Post
...In other words, the engine might have been designed to run with this additional piping into the manifold...
Still learning and debugging this...
No, there are lots of other reasons that it would run like crap. Carburation, timing, spark. Or you could have a big vacuum problem but it isn't because of the smog pump. Cap everything off related to smog pump and it should be fine.
Scott

Currently: 1967 250 SL, 1963 220Sb, 1965 300SE Lang, 1971 280SE parts car, 1972 Alfa GTV, 1965 Alfa Duetto, 1993 BMW R100R
Past: 1971 250 C, 1985 300 TD, 1967 250 S, 1968 280 S,1981 300 D, 1982 280CE, 3 Facel Vegas, Borgward Isabella Coupe, Alfa 2600 Sprint, Volvo P1900 (yes), numerous less interesting Volvos, ...
Scoot is offline  
post #8 of 22 (permalink) Old 02-24-2013, 10:05 PM Thread Starter
Lifetime Premium Member
 
Scoot's Avatar
 
Date registered: Oct 2002
Vehicle: 1967 250 SL, 1963 220Sb
Location: Los Angeles / Altadena
Posts: 2,591
Mentioned: 3 Post(s)
Quoted: 103 Post(s)
Lifetime Premium Member
(Thread Starter)
Quote:
Originally Posted by charliehook View Post
then capped at all six exhaust ports
What did you use to cap them? I used the existing fittings with the tubes cut short and brazed shut. Looks like crap. If there is a "good" capping solution I would like to know about it...

Currently: 1967 250 SL, 1963 220Sb, 1965 300SE Lang, 1971 280SE parts car, 1972 Alfa GTV, 1965 Alfa Duetto, 1993 BMW R100R
Past: 1971 250 C, 1985 300 TD, 1967 250 S, 1968 280 S,1981 300 D, 1982 280CE, 3 Facel Vegas, Borgward Isabella Coupe, Alfa 2600 Sprint, Volvo P1900 (yes), numerous less interesting Volvos, ...
Scoot is offline  
post #9 of 22 (permalink) Old 02-25-2013, 07:23 AM
BenzWorld Junior Member
 
Date registered: Feb 2013
Posts: 5
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Hi Scott,
Thank you for the reply. I was hoping it wasn't due to this vacuum h/w... Yes, there must other things creating this stall. As for the capping, I removed the short fittings into the block and used six bolts into the head. Had to trim each one down and slightly rounded the heads of the bolts, since there was one that comes close to the water fitting. It is still not awesome looking... After this discussion, I will now try to find some Allen-type bolts to be more flush and look a little better.
charliehook is offline  
post #10 of 22 (permalink) Old 02-25-2013, 07:26 AM
BenzWorld Junior Member
 
Date registered: Feb 2013
Posts: 5
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Hi Scott,
On the intake side, I couldn't find a fitting to cover that...
So cut the existing 1/2" pipe, crimped shut with a press, and gas-weld the end. It looks ok.
-Charlie.
charliehook is offline  
Sponsored Links
Advertisement
 
Reply

  Mercedes-Benz Forum > General Mercedes-Benz Forums > Vintage Mercedes-Benz

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











  • Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
     
    Thread Tools
    Show Printable Version Show Printable Version
    Email this Page Email this Page
    Display Modes
    Linear Mode Linear Mode



    Posting Rules  
    You may post new threads
    You may 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
    Trackbacks are On
    Pingbacks are On
    Refbacks are On

     

    Title goes here

    close
    video goes here
    description goes here. Read Full Story
    For the best viewing experience please update your browser to Google Chrome