sigh.. this may sound like a stooopid question, but here goes!

When it comes to ignition timing, they always say to set the idle first, and then check the timing. Okay fine... but your timing also affects the idle speed, so how do you "de-couple" them?

In other words, on my fuel injected 1975 VW bus (with an upgraded 2.0L engine, which uses the original 1.8L distributor), the timing at idle is 5 ATDC. And I always check not to exceed 32 degrees at 3500RPM... okay fine. But I have noticed that if my idle speed is low, and my timing is slightly retarded, I can do two things that give identical results, but different performance:

1) I can advance the timing to its correct 5 ATDC, and the idle speed will now read correctly also .... or

2) I can simply increase the idle by adjusting my idle screw, and this will automatically advance my timing to its correct value.

Both methods above give the same answer, but with totally different results in performance?!?!?!

"MOMMY!!!!"

How do you know which is correct? How can idle speed, and ignition timing, be de-coupled?!?!?!

If you can answer this... I have a swell piece of cheese you can have.

Thanks.

- Tony
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vwsurfbum

my thoughts on it would be get the idle speed right then adjust the timing to 5btdc then check idle speed and keep doing this until both match?

does that make sense?

 

do i get the peice of cheese?

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sorry dude... that doesn't quite cut the cheese.

there is no reason to assume the idle is wrong, if the timing in reality (lets assume "actuality") is too retarded. advancing the timing will increase the idle. so how do i know which is right?

i am still left with my conondrum.

in your scenario, if i increased the idle speed, and it happen to make my timing look right at idle, then i never would have adjusted the timing only because the idle compensated for it... how do i know my timing wasn't too retarted to begin with?

i need some more fries with my ketchup.

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Wayne

Here's a page on how to set the timing on a Beetle.

http://www.superbeetles.com/Tech_talk/apr.htm

 

Maybe there's some information there that might help you. You could always email Rick Higgins from Bug Me Video to see if he has any advice.

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Thanks Wayne... I read your article. sigh.

If you read it, you would find that the article doesn't even get into the idle specifics, let alone the idle coupling, when you set the iginition timing. The article was basically the same old "yadda yadda yadda" about basic timing instructions, that we all know about. (In fact, more info should have been supplied about centrifugal and vaccum timing... but i digress).

But hey... thanks for trying.

Now come on guys... I am a newbie here! I need some real help!

Somebody step up to the plate, and bat me to at least 3rd base!

I thought my question would be so "stooooopid" to some of you (i mean yoose, or yooses) experts, that I would get tar and feathered for asking!

But so far... sigh... i am waiting for the tar!

You guys who have tuned up your engine do know what i am talking about...right? My question does make sense... right? Can i at least get some sympathy here?

By the way... my name is Tony... a "newbie". I like Volkswagens. I like their sound, feel, simplicity, ... and hanging my leg out the back of my bus on a sunny morning, and having the sea breeze blow up thigh, tickle my senses, as the smell of black coffee and burnt toast cooks on my stove.... but hey.. i am just a bastard that way!

now puhleeeaze... put a little thought into my conundrum!





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Tony, I understand your question, I think?! I agree with Surfbum's answer, but I see where it leads your thinking again.
You say both affect each other, idle speed and timing, true. They do go hand in hand. My question is this: Are you having trouble getting your timing set or are you thinking too hard?
Sounds like you know what your talking about but... Which of the 2 methods gives you the best performance? Idle speed or timing adjustment? Go with what works. I'm sure that was little to no help!

Steve
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Well obviously when i advance my timing, I get the best performance... I just feel guilty doing this knowing that I might BBQ my pistons at the higher RPM's.

I appear to be slightly pushing the 32 degree boundary at 3500 RPM, but it runs and idles better, and reads 5 ATDC at idle.

Also, my distributor has a dual vaccum line connection. The vaccum lines both retard (at idle) and advance. I thought I read somewhere that these latter day VW distributors should be allowed a bigger advance at full throttle (relative to the standard 009 centrifigul advance), but I have not been able to confirm this.

To make matters more confusing, my whole engine set-up is somewhat "bastardized" (non-stock). I am running a 1975 distributor (I think), computer, and flow meter, with a 1978 2.0L engine. The original 2.0L engine had 7.5 BTDC timing at idle. I have a modified transmission with higher 3rd and 4th gears. So I can easily cruise down the freeway at 70 MPH with my foot barely on the pedal, and pulling less than 3500 RPM's, so it seems i should be able to advance it a tad more than normal.

But that could all be the family of clowns talking. The family of clowns that live within my head, and sleep under my bed, and bicker and snicker all night long... but I digress.
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vwsurfbum

after consulting the clowns on my head i still think i'm right and i want the damm cheese!

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Mike

tonyo wrote:

When it comes to ignition timing, they always say to set the idle first, and then check the timing. Okay fine... but your timing also affects the idle speed, so how do you "de-couple" them?

In other words, on my fuel injected 1975 VW bus (with an upgraded 2.0L engine, which uses the original 1.8L distributor), the timing at idle is 5 ATDC. And I always check not to exceed 32 degrees at 3500RPM... okay fine. But I have noticed that if my idle speed is low, and my timing is slightly retarded, I can do two things that give identical results, but different performance:

- Tony


First off .. you have some facts confooooosed.... 32 Deg at WOT is for typeI engines with 009 distributors.. not T4 engines with factory distributors

sooo.. start off....
always set your timing first,, fuel last.. i.e.  replace tune up parts,, set valves, dwell,, timing, then idle....

set you Dwell at 50 .... then set your timing with no advance at spec.  to be 7.5deg BTDC

then adjust your idle . so you have the correct idle. 850-950 rpm Man. Trans

Then check your WOT full advance.. and I bet you will see it goes to about 43 deg .... perfectly to specs.
You may not have the correct distributor.. you can check the specs of the distributor you have using this page
http://www.oldvolkshome.com/ovhignbo.htm

then you can see what the full advance will be for the dist your using..

tonyo wrote:

Also, my distributor has a dual vaccum line connection. The vaccum lines both retard (at idle) and advance. I thought I read somewhere that these latter day VW distributors should be allowed a bigger advance at full throttle (relative to the standard 009 centrifigul advance), but I have not been able to confirm this.

To make matters more confusing, my whole engine set-up is somewhat "bastardized" (non-stock). I am running a 1975 distributor (I think), computer, and flow meter, with a 1978 2.0L engine. The original 2.0L engine had 7.5 BTDC timing at idle. I have a modified transmission with higher 3rd and 4th gears. So I can easily cruise down the freeway at 70 MPH with my foot barely on the pedal, and pulling less than 3500 RPM's, so it seems i should be able to advance it a tad more than normal.- Tony


Most likely you have a different 4th,, and R&P ,, sounds like the 4.57 R&P and the ).82 4th...but a stock 3rd, unless you know what gear set was installed....
Do NOT advance the distributor ,, unless you have a CHT gauge .... as it will run tooo hot unless you richen the mixture significantly..  
the only diff between a early 2liter and a late 2liter is hydraulic lifters... which makes no difference to the dist or the idle bypass settings

The retard part of the dist will alter the WOT setting as you drive.. 
if you want more info.. subscribe to type2.com list.. and ask ... the experts there , who will set your mind at ease.
Hope that helps

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olspeed

Damn Mike you know your stuff on type 4's  I bow to you brother VW'er

66 Ghia 76 std Beetle
It's not a car it's a VolksWagon
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