TheSamba.com :: View topic - 1961 Ragtop parked since around 2017 need help with carb tuning.

Fri Jul 05, 2024 2:58 pm

Jeff Geisen wrote: Worn camshaft

The car has under 40K miles on it. Would the camshaft wear out that soon?

Fri Jul 05, 2024 3:01 pm

VW_Jimbo wrote: What happens if……

With the car not running. Remove the air cleaner. Hold back the choke plate. You should be looking straight down the carb throat and be able to see the throttle plate. As you are looking into the throat, pull the throttle arm. Is there an instant stream of fuel squirting down the throat, the entire pull of the arm?

Thanks. I am going to where the car is located tomorrow and will check this and let you know. I know the fuel squirts but do not know if it is happening for the entire throw of the throttle arm.

Fri Jul 05, 2024 3:04 pm

USWR wrote:

The nozzle is clear because when rebuilding the carb, I could squirt cleaner through it and it came out the little hole with a nice stream.

I did look in the bottom of the distributor and the grease is still soft and slippery. Do I need to take it apart to fully inspect?

Thanks for taking time to respond.

You might have cleaned the nozzle and carb, but now have gunk that broke loose from not cleaning it thoroughly. Had once a problem with that nozzle plugged just a bit, but still sprayed and that caused problems starting.

Grease out in the open might be soft to your touch due to having been slapped on there by the DPO, but still be a drag on the advance inside the moving parts. The only way to find out is to either take it apart for a good cleaning and lubrication up, or apply a suction to the vacuum tube and see if the advance moves easily/quickly both ways fully.

Fri Jul 05, 2024 3:14 pm

rcooled wrote:
How are you able to see the points plate move while the motor's running?

If you look it the photos at the top of this thread, you can see I don't have the right grommet for the wire that goes to the coil from the points. I can see the plate moving by looking in the big hole where the wire comes out.

Quote: Check to see that the distributor's vacuum advance is working

I forgot to mention above that I have a vacuum leak-down tester with a hand pump that I connected to the vacuum hose that goes to the carb. It seemed to move the plate with the application of the vacuum and it held position for 2 minutes.

Quote: Check to make sure that the points are clean and that the gap is set to .016".

This was suggested above and I checked it. Points were set to 0.20" when I first checked, and I adjusted down to 0.16".

Quote: Replace the condenser.
What exactly does the condenser do, by the way?
I have a replacement with the tune up parts that came with the car, but the condenser in the distributor doesn't come out. It's riveted to the advance plate. How would I attach the new one?

Thanks for all the comments.

Fri Jul 05, 2024 4:19 pm

USWR wrote: What exactly does the condenser do, by the way?
It absorbs excess current and keeps the points from sparking each time they open & close. Too much spark will quickly degrade the contact surface of the points.

Quote: ...but the condenser in the distributor doesn't come out. It's riveted to the advance plate. How would I attach the new one?
Condensers can occasionally fail and need to be replaced...there's gotta be a way to do it. This photo of a similar 'Big Cap' distributor shows a screw holding the condenser in place.

I'm not familiar with the ZV/ PAU 4 R 1 distributor...maybe someone who knows more about them will chime in.

If your distributor still has an original/old condenser, that could very well be your problem.

Fri Jul 05, 2024 5:27 pm

rcooled wrote:
It absorbs excess current and keeps the points from sparking each time they open & close. Too much spark will quickly degrade the contact surface of the points.
Interesting. I did notice the points visibly sparking while static timing.

Quote: Condensers can occasionally fail and need to be replaced...there's gotta be a way to do it. This photo of a similar 'Big Cap' distributor shows a screw holding the condenser in place.

I read somewhere that this distributor came from the factory with the condenser riveted in. I was hoping to keep it factory as much as possible. I included a photo of the rivet I took last year.

Quote: If your distributor still has an original/old condenser, that could very well be your problem.
I have all the service records and no mention of the condenser being changed.

HOW ABOUT: I have an idea. I can disconnect the factory one and leave it in place, and connect the replacement on the exterior of the distributor and run the wire in through the side hole. If the new one fixes the issue, then the original one id bad and I will figure out how to remove the rivet and move the new one inside the cap.

That should rule out the condenser if the problem persists with the new one, correct?

Sat Jul 06, 2024 12:17 pm

USWR wrote: I read somewhere that this distributor came from the factory with the condenser riveted in.
If that's the case, I guess Bosch figured that you'd need to replace the entire plate assy if the condenser failed.

Quote: I can disconnect the factory one and leave it in place, and connect the replacement on the exterior of the distributor and run the wire in through the side hole. That should rule out the condenser if the problem persists with the new one, correct?
Yes, just make sure that the condenser's outer shell is grounded

Sun Jul 07, 2024 10:24 am

Your dist. looks WAY to far retarded. It is sitting at the 8 O' clock position. Typically if it is in the correct range the vacuum canister should be in the 6/7 O'clock position.
Double check.

Sun Jul 07, 2024 8:20 pm

swharris wrote: Your dist. looks WAY to far retarded. It is sitting at the 8 O' clock position. Typically if it is in the correct range the vacuum canister should be in the 6/7 O'clock position.
Double check.

This distributor from what I can tell is an oddball. It's not very common. Most of the pictures of VW engines from this year have a similar looking distributor, but the coil wire comes out of a hole but it is in the back of the distributor. This particular distributor has the positions of the vacuum can and the hole for the wire swapped around. I thought it was weird that it didn't match most of the engines you see, but old pictures of this car when it was young have the same orientation.

The #1 spark plug lines up with the groove on the rim of the distributor, so I think this is right, but thanks for taking the time to give your opinion. I wish you were right. :-)

Sun Jul 07, 2024 8:28 pm

UPDATE:
I put in the NOS points and ran into an issue. The new points must be defective because they are shorted to ground even when opened. The phenolic washer in the pivot point seems to be shorting. I have ordered a new set and another new condenser.

To kind of do a cheap test of the condenser, I tried shorting the coil wire with the old condenser and a very old NOS one connected to ground. With the NOS condenser, the spark on the wire to the coil is very noticeably smaller. With the original condenser in the circuit, the spark is blue, and large, and throws off little orange mini sparks like a firework. With the NOS condenser in place, there's a small blue spark and no little sparks shooting off.

I'm hopeful that this is the cause of my issues.

Mon Jul 08, 2024 8:05 pm

USWR wrote: This particular distributor has the positions of the vacuum can and the hole for the wire swapped around. The #1 spark plug lines up with the groove on the rim of the distributor, so I think this is right...
It's possible that the distributor drive shaft was removed at some point and not returned to the correct position when re-installed. This would account for the distributor being rotated around from its usual position. This won't affect the ignition timing...just looks a little wonky.

Sun Aug 04, 2024 9:53 pm

I am back with another update!

I took out the distributor so that I could replace the consenser since it is riveted in on my ZV/ PAU 4 R 1 distributor. While in there I decided to clean everything up and check all the shims and washers.

When I removed the breaker plate from the distributor, the bushing was covered with rust colored grease and oil. I cleaned all of that and looked closely and the inside of the bushing on the breaker plate was totally pitted and rusty.

Inside the bushing there is a 5mm (or so) hole drilled from the inside that does not come out the exterior. It was packed with dirt and rust. Does anyone know what this hole is for? I don't know for sure but is this supposed to be a reservoir for lubrication? Is there supposed to be something in it like a felt pad or something to hold oil?

I washed the plate with solvent and dried it. Replaced the condenser and points and put it all back together with fresh oil and grease, then set points gap. Back in the car and set the timing and tried starting it up. Would not run except on starting fluid.

Checked spark and spark is now very weak. It was hot blue when I removed the distributor, so I'm very sure the coil is okay. I backed up and rechecked the timing and points gap. When I looked at the timing I noticed that the points would do this "double" flash on my static timing light. When I checked the points gap I noticed what I think is the problem. It looks like removing the rust and dirt from the bushing was bad for the tolerance of the bushing. The breaker plate can wobble on the bushing a couple of thousandths. I can see the spring tension of the points as the lobe on the shaft opens the points will cause the plate to wobble and close the points and then open them again as the lobe reaches the maximum. It looks like the "double tap" of the points is the cause of the weak spark.

I'm wondering if that wobble has been present all along and was causing all my timing issues, and I just made it worse.

At any rate, it looks like that breaker plate bushing is my problem, and I was wondering if anyone knew of a replacement for this? I looked in all of the usual places and cannot find a replacement plate for the ZV/ PAU 4 R 1. I did find one for the ZV/ PAU 4 R 2 that appears identical but when I received it, it has a larger diameter bushing, so it won't fit.

Anyone have any suggestions or experience to share? Thanks!

Sun Aug 04, 2024 9:59 pm

rcooled wrote: USWR wrote: This particular distributor has the positions of the vacuum can and the hole for the wire swapped around. The #1 spark plug lines up with the groove on the rim of the distributor, so I think this is right...
It's possible that the distributor drive shaft was removed at some point and not returned to the correct position when re-installed. This would account for the distributor being rotated around from its usual position. This won't affect the ignition timing...just looks a little wonky.

Is it possible to rotate the position of the distributor drive shaft without disassembling the engine? Like lifting it up the distributor hole with a magnet and re-clocking it, then dropping it back down?

Mon Aug 05, 2024 7:48 am

USWR wrote:
Anyone have any suggestions or experience to share? Thanks!

Find a local machine shop and have them them make a bushing for it and have the original bored to fit. Good to have a spare bushing made.

Wed Aug 07, 2024 8:37 am

USWR wrote: Is it possible to rotate the position of the distributor driveshaft without disassembling the engine?
Yes, no need to do anything more than remove the distributor to re-index the drive. There’s a special tool for pulling the shaft out but it’s not always needed.

Remove the spring in the center, screw a proper-sized tap into the hole until it bites, then lift up. It sometimes helps to rotate the crank pulley counterclockwise just a bit as the drive starts to come up.

There are two thrust washers on the drive’s lower end where it fits into a bore in the case…don’t let them drop down in there, or you WILL be disassembling the engine to get them out.

And don’t forget to replace that spring before reinstalling the distributor.

This photo from the gallery shows the correct orientation of the drive when it’s fully seated and #1 piston is at the top of its compression stroke (TDC notch on pulley lined up with split in case). It’ll rotate as it starts to engage with the crank gear, so it might take a few tries to get it right. The slot is offset toward the front of the case and should be as parallel to that front edge as possible.

Sun Aug 11, 2024 6:54 pm

I have a new update with some forward progress. I wanted to thank Eric@Barb and rcooled for the suggestions before I dive in.

I wasn't getting confidence from the shops I talked to that they could replace the bushing or that they wanted to bother with a job this small, so my fallback idea was to bit the bullet and get a rebuilt distributor. I was having a hard time finding the ZV/PAU 4 R 1 distributor for a 1961 Type 1. Even the Bosch Tune Up Specs (https://www.thesamba.com/vw/archives/manuals/Bosch_Tune_Up_Parts/Bosch_Tune_Up_Parts.pdf) say that this distributor is for a 1960 Ghia. The correct distributor for the 1961 type 1 is listed as a ZV/PAU 4 R 2, and I was lucky enough to find a rebuilt one for a reasonable price.

I was going to index the drive gear, but when I looked down the hole, it looks like the photo rcooled posted, so I didn't mess with it. When I put in the replacement distributor, the canister is clocked more like what I see in photos of the 1961 engines, so I think the ZV/PAU 4 R 1 looks funny because the vacuum canister and the grommet where the coil wire comes out are swapped around on the case.

Anyhow, I got everything together, and static timed and got it fired up. It seemed to make a big improvement. It was much more willing to rev and wasn't backfiring like it was. I adjusted the carb by starting are 2-1/2 turns out and slowly turned the mix screw in until the RPM started to drop, then backed off 1/2 turn.

I had let it warm up completely to adjust the carb, and I noticed that it was stumbling a bit when revving from idle again, but it was way better than before. I let it cool off and tried again, and it essentially runs perfect until the choke is mostly open, then I get a slight stumble.

I was pondering what was going on and I did the "spray can" test for intake leaks once again, and did not find any change.

I was frustrated and kept thinking over the weekend that it could be an intake leak and so I checked the nuts holding the intake manifold on, and the passenger side rear nut was looser than the others. I could not find a torque spec for these nuts. They are M6 and I was terrified of snapping one off, so I snugged them all a bit with a short handled ratchet and one hand. All of the nuts were able to turn a bit so I snugged them as much as I dared.

Tightening the intake made another positive effect and the problem was reduced even more. It just hesitates a slight bit when revving up when fully warmed up.

I took it for a drive and it drove well and wasn't bucking or backfiring, but it's noticeably down on power. I'm not sure why.

I'm happy to have found a problem with the distributor and I believe I fixed an intake leak. Maybe I just improved the leak and it's still there but reduced. I'm just terrified of snapping a stud off the head.

The only other symptom I can report is that the idle screw on the carb to me seems like I have to screw it all the way down until it bottoms out in order to get the idle to where it needs to be.

I'm happy to have made what feels like real progress. I hope someone has some clue what I should look at next. Any help would be appreciated.

Thanks everyone!

Mon Aug 12, 2024 11:42 am

USWR wrote: I hope someone has some clue what I should look at next.
You may want to adjust the jetting in the carb. What sizes are in there now?

Mon Aug 12, 2024 12:09 pm

rcooled wrote: USWR wrote: I hope someone has some clue what I should look at next.
You may want to adjust the jetting in the carb. What sizes are in there now?

The main jet is marked SOLEX 0122,5 so I think it's the stock 122.5 that came in the carb. I don't recall if there were numbers on the pilot jet. I suspect that it's stock as well. Where is that marked?