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bvd
Samba Member
Joined: September 17, 2010
Posts: 207
Location: Long Island, New York
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 Posted: Sat Jun 23, 2012 4:57 pm Post subject: Help with timing a 205K on a 1600cc dual port |
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So I have a 1600cc dual port engine in my '74 beetle, with a Solex H30/31 and a 205K signal vacuum advance distributor. The only reason I'm not posting in the late model section, is because of the fact that most of the people who frequent this forum know more about the 205K.
I just finished adjusting my valves (all to .006") and proceeded to reset my idle timing with a strobe light at 7.5 degrees BTDBC. When doing this, I pulled the vacuum line off of the distributor vacuum can and plugged it with a pencil, then I timed it without a problem.
As soon as I reattach the vacuum line to the vacuum can though, my idle speed increases slightly, and with the strobe I can see that I now have about 15 degrees BTDC of advance at idle.
If I unplug the vaccum line from the can, the idle drops back down to where I set it, at 7 degrees BTDC, but as soon as I reattach it, the advance spikes back up to 15 degrees BTDC!!!
I sucked on the vacuum line to test the advance, and the plate is advancing and returning fine.
Anyone know what's going on here?!?!
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61SNRF
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Joined: March 29, 2009
Posts: 4656
Location: Whittier 90602
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| Posted: Sat Jun 23, 2012 5:19 pm Post subject: |
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I have no experience with that carb, but it sounds like you have the vacuum hose connected to a manifold vac port on the carb. Manifold vacuum is normally used with dual vacuum distributors for ignition retard at idle. Either that or the idle has been adjustd too high by using the throttle stop screw, thus exposing the ported vacuum passage source in the carb to manifold vacuum.
You need to hook it to a ported vacuum source. It should have no vacuum at idle, but comes in just off idle, and is what that distributor was designed to use.
Here is a discussion on that carb and the best place to connect the vac hose...
http://www.thesamba.com/vw/forum/viewtopic.php?t=185095
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-Bruce
An ounce of prevention is worth a pound of cure. |
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Culito
11010101
Joined: December 07, 2006
Posts: 5879
Location: Columbia Missourah
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| Posted: Sat Jun 23, 2012 7:54 pm Post subject: |
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I'm not sure that the H30/31 works with that distributor. You are using the port on the left side of the carb, right?
The timing should not advance at idle.
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'64 standard w/2.0L type 4
'62 bug
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glutamodo 
The Android
Joined: July 13, 2004
Posts: 26533
Location: Douglas, WY
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| Posted: Sat Jun 23, 2012 8:02 pm Post subject: |
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YES, the H30/31 should work OK with the 205K distributor.
However the H30/31, like the 30PICT-3 and 31PICT-3s it was derived from, need to be adjusted so that the throttle is totally SHUT at idle. Just like the 34PICT-3. (steps 4-5 in the image below) With it adjusted as such, there should be NO vacuum signal when the throttle is closed, and thus, no advance.
(on previous carbs that were not set up for idle like that, it was not unusual for to get a bit of advance even at idle, which was why the books always said to have the vacuum line unhooked and capped when setting the idle timing)
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Aussiebug
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Joined: June 03, 2002
Posts: 2162
Location: Adelaide Australia
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| Posted: Sun Jun 24, 2012 12:03 am Post subject: |
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| glutamodo wrote: |
However the H30/31, like the 30PICT-3 and 31PICT-3s it was derived from, need to be adjusted so that the throttle is totally SHUT at idle. |
Errr - not quite.
The H30/31, the 30PICT/3 and the 34PICT/3 are set to idle with the throttle plate about .004" open - that's what turning the fast idle screw (on the bottom of the stepped cam) 1/4 turn does.
The important thing though is that these carbs use the large Bypass screw on the left side of the carb to alter the idle speed - NOT the fast idle screw on the stepped cam.
The earlier 30PICT/1, /2 and the 28 series carbs do use the fast idle screw (on the stepped cam) to set the idle speed - they don't have a Bypass screw in the left side.
Mixing up the tune-up sequence between carb types doesn't work very well.
So to recap, there is a complete tuneup guide for both carb types on my web site at
www.vw-resource.com/30pict2.html for the carbs with only one screw in the left side, and
www.vw-resource.com/34pict3.html for the H30/31, 30PICT/3 and 34PICT/3 carbs which have the two adjusting screws in the left side.
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Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
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BDSBSS23
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Location: Colorado
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bvd
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Joined: September 17, 2010
Posts: 207
Location: Long Island, New York
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| Posted: Sun Jun 24, 2012 10:57 am Post subject: |
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Hey guys, thanks for all of the advice. Is this small spike in advance when the hose is re-attached normal? I that why the procedure is to time it with the vacuum hose plugged in the first place???
And also, I have two 205K vacuum cans...but in looking at them now, I am worried that they might not be the proper ones as they look slightly different from each other. Can anyone help me identify them (Andy, I saw a thread awhile back where you had posted extensively about different types of vacuum cans and how easy it can be to mix up the 205k, m, and l).
Both cans have GERMANY stamped into the front (upside down). But the one on the left (in this photo) has a small ridge around the outside circumference of the can which the one on the right does not.
Also, the one on the left (with the ridge) has a smooth back, and the one on the right has a star cast into the back.
Finally, the one on the left, with the ridge on the front, has a shorter rod of 1 5/8", and stamped into the rod is the number 069.
The one on the right has a considerably longer rod, about 1 7/8", with nothing stamped into the rod.
Anyone know if either of these is for a 205K??
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"I paid 2000 for my MR2 with the back quarters rusted out, 900 for the bug. So rice is more costly than kraut."--doc1369 |
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26533
Location: Douglas, WY
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| Posted: Sun Jun 24, 2012 12:27 pm Post subject: |
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Measure the amount of movement of the operating arm - it's 4.5mm for the "K" distributor and other such 64-67 era vacuum canisters, and 5.5mm for the 68-70 113-M and 113-T vacuum canisters. (That extra millimeter of travel translates to about 7 degrees more advance)
The one with the "star" pattern in the back is probably the one you want to put on the K distributor.
That thread you mentioned, I only contributed to it, Tasb is the one who started it rolling.
http://www.thesamba.com/vw/forum/viewtopic.php?t=307450
-Andy |
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garagebandking41
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Joined: June 15, 2011
Posts: 302
Location: Gulf Coast Florida
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| Posted: Sun Jun 24, 2012 12:34 pm Post subject: |
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| You can (sometimes, I'm told) tell the advance p/n as the last 3 digits of the Bosch # are stamped on the arm. 279 is correct for the TDC timing of the '68 205M dist and 210 (from memory) is correct for the stock applications of the 205K dist. |
From one of my old threads about the 205K |
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