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Thu Feb 11, 2010 3:28 pm

1973, dual carb, 1700 bus

After cleaning off the timing scale, I can see some etching from the PO.
So the timing mark on the crankshaft pulley should be aligned with the correct mark on the degree scale. In my case 10* ATDC.
The little notch on the back part of the pulley is the timing mark & TDC, right? So I'm aligning the TDC mark(timing mark)
with 10 degrees on the scale. My problem is that I'm not sure what the scale is supposed to look like. There's a "0" (zero) and climbing degrees...but that zero starts several inches to the left of the crack in the crank case.

If it is After TDC I'm looking for, then why would the scale be to the left
of the crack in the crank case?
If it is rotating around it is going to spark before it reaches TDC.
Am I missing something here?

-p.s. I would appreciate it if Vdubtec does not reply to any more of my posts.
thanks.

Thu Feb 11, 2010 3:33 pm

Could you please just post normally and not in tiny little paragraphs? Makes it difficult to read, I won't even bother.

Thu Feb 11, 2010 3:38 pm

Here is the timing scale installed in the ex-Road Warrior.
The fact that the "0" happens to be to the left of the crankcase is utterly immaterial. You can see two white dots to the right of the "0" on the scale. Those are factory highlights for the 5º and the 10º marks AFTER Top Dead Center.

The scale and the notch on the pulley have nothing to do with crankcase seams because they never mentioned anything about crankcase seams. We Type 4 engine folks get a scale that was placed to the left of the seam because it is easier to read there. If your notch is lined up with the "0" on the scale, your #1/3 pistons will be at TDC.

While we are here, do NOT adjust the timing to 10º ATDC until you know that the vacuum retard unit on your distributor is working. If the vacuum can is leaking, your idle timing will be around 5 to 7 degrees BEFORE Top Dead Center.
Colin

Thu Feb 11, 2010 3:41 pm

After cleaning off the timing scale, I can see some etching from the PO. So the timing mark on the crankshaft pulley should be aligned with the correct mark
on the degree scale. In my case 10* ATDC. The little notch on the back part of the pulley is the timing mark & TDC, right? So I'm aligning the TDC mark(timing mark) with 10 degrees on the scale. My problem is that I'm not sure what the scale is supposed to look like. There's a "0" (zero)
and climbing degrees...but that zero starts several inches to the left of the crack in the crank case. If it is After TDC I'm looking for, then why would the scale be to the left of the crack in the crank case? If it is rotating around it is going to spark before it reaches TDC. Am I missing something here?

is that better professor?

Thu Feb 11, 2010 3:47 pm

silverside61 wrote: After cleaning off the timing scale, I can see some etching from the PO. My problem is that I'm not sure what the scale is supposed to look like. There's a "0" (zero)
and climbing degrees...but that zero starts several inches to the left of the crack in the crank case. If it is After TDC I'm looking for, then why would the scale be to the left of the crack in the crank case? If it is rotating around it is going to spark before it reaches TDC. Am I missing something here?

You are missing something here.
Use your head, erase prior assumptions.

As the pulley turns (with the notch cut into it) all numbers to the LEFT of the "0" are BEFORE Top Dead Center. As the pulley continues rotating clockwise, all numbers to the RIGHT of the "0" are AFTER Top Dead Center. You have the photograph right there. I do not know what is going on with your engine regarding the absence or presence of scales.
Colin

Thu Feb 11, 2010 3:49 pm

What Colin says, it is the scale that counts not the case split, this is not a Type 1. Besides you can't even see the case split as the fan shroud is in the way. Your retard can must work correctly to be able to set your timing by the book and many retard cans no longer do work correctly. Best to set your timing at 28° BTDC at 3500+/- rpm's, hoses off.

Thu Feb 11, 2010 3:52 pm

Quote: If your notch is lined up with the "0" on the scale, your #1/3 pistons will be at TDC.

Wow, I feel like I've been searching around for information on timing
and adjusting the valves on this bus for days...
and no where did I find someone who said that. It was always,
"crack in the crankcase" But seeing that "0" on my scale kept making me
think what you said. Thanks for clearing that up!

As well... when I suck/blow on the green hose... the vacuum retard I'm pretty sure, nothing happens in the distributor. When I suck on the black (the vacuum advance I'm pretty sure), it moves the thing in the distributor.

Thu Feb 11, 2010 3:56 pm

RyanPatrick wrote: Quote: If your notch is lined up with the "0" on the scale, your #1/3 pistons will be at TDC.

Wow, I feel like I've been searching around for information on timing
and adjusting the valves on this bus for days...
and no where did I find someone who said that.

It was always, "crack in the crankcase"
But seeing that "0" on my scale kept making me think what you said. Thanks for clearing that up!

Quote: erase prior assumptions

The people giving you advice may be suffering from assumptions too.
If you have a 1972 and later bus, there is no crack in the crankcase! It is a different engine than the countless earlier bugs and buses.
Be careful and accurate with the information you provide and vet the information you receive.
Colin

Thu Feb 11, 2010 3:58 pm

I may be wrong here, but if the distributor is not advanced at all (engine not running) it's not gonna retard v/ vacuum because it is already fully retarded.

Thu Feb 11, 2010 4:20 pm

ScottK wrote: I may be wrong here, but if the distributor is not advanced at all (engine not running) it's not gonna retard v/ vacuum because it is already fully retarded.
Vacuum retard is an active movement of the breaker plate in the direction of rotation. When the engine is off, or the hose/diaphragm is leaking, the breaker plate reverts to its static position. That is why you cannot static time to factory spec after 1971. But here in 2010, we know to time to 28* @ 3,200-3,400 rpm, where you will find that the idle timing of a retard distributor that doesn't retard, is somewhere around 3-7* BTDC. No screwing around here. If you time to spec with a non-functional retard, the entire timing map is on average, 12º too retarded all the way up.
Colin

Thu Feb 11, 2010 4:25 pm

So I am mistaken in my perception.

Learn something every day,

still.

Thanks.

Wed Mar 31, 2010 6:34 pm

Wildthings wrote: What Colin says, it is the scale that counts not the case split, this is not a Type 1. Besides you can't even see the case split as the fan shroud is in the way. Your retard can must work correctly to be able to set your timing by the book and many retard cans no longer do work correctly. Best to set your timing at 28° BTDC at 3500+/- rpm's, hoses off.

i know this is an old post but it was exactly what i was looking for. i timed my bus for the first time to 28* at 3200rpm with the hoses ON. Then i started thinking about the hose, searched and found this. so i know i need to go back and re-time it with the hoses off but how far off will the timing be right now?

Wed Mar 31, 2010 6:53 pm

How retarded it is is really hard to say. Somewhere between 5-10º would be my guess.

Time it correctly and see how it drives.

Wed Mar 31, 2010 8:23 pm

i keep reading this: http://www.vw-resource.com/tune-up.html
and keep getting myself more confused... i have a 76 that was converted to a single carb. the distributor only has one vacuum hose that runs to the carb. so do i have a Dual-advance distributor or a 009/SVDA distributor???

also i'm really confused on BTDC and ATDC. BTDC are the numbers left of the zero and ATDC are the numbers right of the zero?

Wed Mar 31, 2010 9:03 pm

benw82 wrote: i keep reading this: http://www.vw-resource.com/tune-up.html
and keep getting myself more confused... i have a 76 that was converted to a single carb. the distributor only has one vacuum hose that runs to the carb. so do i have a Dual-advance distributor or a 009/SVDA distributor???

also i'm really confused on BTDC and ATDC. BTDC are the numbers left of the zero and ATDC are the numbers right of the zero?

If you have a single vacuum can/hose you have a SVDA, Single Vacuum Dual Advance distributor.

Looking at the back of the engine, the engine rotates clockwise. The timing mark will reach the Before Top Dead Center markings before it reaches TDC and will reach the After Top Dead Center markings after it has passed TDC. You are correct, BTDC is to the left and ATDC is to the right.

Wed Mar 31, 2010 9:09 pm

good explanation Wildthing. :wink:
Kind of like learning how to read the time. With old clocks that had hands. Not with digital clocks. Maybe that is why 10 before the hour or 5 after is more difficult these days.

Wed Mar 31, 2010 9:50 pm

thanks fellas! one last question: whats the best way to plug both the distributor and the carb vacuum ports?

Thu Apr 01, 2010 4:48 am

benw82 wrote: thanks fellas! one last question: whats the best way to plug both the distributor and the carb vacuum ports?

Don't need to plug the ones on the dizzy. Lots of things will work to plug the hoses coming off the carb. Nails, small screws, golf tees, etc. I like to keep a few of the nozzle tips that come with squeeze tubes of silicone around. With their stepped conical shape they will plug a large variety of hoses.