Timing marks mk1 golf gti cabriolet

I'm about to put my timing belt back on my mk1 golf gti cabriolet… I've a 6* btdc mark on my flywheel and a tdc mark and I don't know which one to choose to set my car to before I put my belt on?? I have an arrow on my plastic lower cover etc too what do I do? 

Setting it to 0 mark is the way to go.

Crank to 0.
The Dimple on the back of the cam even with the valve cover tin (Not the rebar on top of the tin.).
Dizzy in the middle of the hash mark stamped on the case. (loosen the pinch bolt at the bottom)

Do not try to align the pulleys for the intermediate shaft, as it could of been off, it is best to rotate the shaft so the dizzy aligns.  Cap off, Rotor off, plastic shield off and reattach the rotor.  If your dizzy is in the proper position (usually 12:00-1:30) then the notch is on the block side.

See www.cabby-info.com as Kammy has pictures of the timing mark.

Digifant can be set timing to 950, and CIS to 750 RPM with a timing light at 6btdc.

There is a thread on how to time Digifant cars to 6TDC with nothing more than a DVOM.  CIS is a different story.

I've never used that mark for changing the cambelt.

Depending on what year your car is as the timing marks on the cam shaft did change on later car.
From my 1988 gti cabriolet.
I've painted the marks to make it easier to see when I change the belt.

You should not need to adjust the timing (move/rotate the dissy) if it was all ok before changing the belt, if the timing is out (engine running lumpy) when you put it all back together the you are 1 tooth out somewhere, it's usally the intermidiate shaft which goes out as that turns very easily when the belt is not on.

Without lower plastic cover on, when you remove the lower pulley from the crank (to remove the old belt) you must make sure you put it back on in the same position.



Cam shaft.


Lower plastic cover back on

 

There are pro's and Cons with the Intermediate Shaft and if the cover is on or off.  The issue is that with the cover on, you have to rely on Pulleys, and their marks.

The most simplest way is to align the Crank to 0TDC on the Crank.  Your rod Trick on the Head to Cam is Brilliant, I think it eliminates the "parallax" error, but I have used the Valve cover tin for years to no ill effect, albeit that the Bentley shows it as with the tin installed so with the Width of the Gasket and Tin, you have less than the desired setting.

The other issue is that you or the Mechanic who doesn't take the Lower cover off, to see where the marks are, can't rely on them for "being" correct.  

It is way better to error on the side of caution, than to assume.  I mean that even if you align the marks, you had better Validate that the Dizzy's rotor is in the correct position.  This is why over here we just "do" it.

Now I have a Digi, and the upper cover has a 0TDC on it, I normally set the rear dimple, then cross check the cover.  I still can see a "parallax" difference, in a Visual or a Camera, photo.  So I suspect it is subjective, not like  lining up a timing chain and holding a straight edge between the dots.  

Also the Crank can be 180 out from the Cam, and the Dizzy.  So it is best to error on the side of caution, than to make an assumption on a visual inspection.  

Everyone has a method of setting time that suits them.
Everyone doesn't do it my way or for the reasons that I have stated…. I try to use the K.I.S.S. methods for everything.  Keep It Stupidly Simple.

I also have been ingrained to work smarter not harder, and that sometimes, you have to inch things apart as that is the fastest way to do things.  I can recall wasting
a couple of hours to find a better way to remove a nut, than the one face turn at a time for a nut or bolt….

main thing if using the crank pulley is make sure the outer part hasn't slipped if its the damper type, I worked on a 2.0 8v mk3 and it was near 90 degrees out from where it should be. flywheel mark will always be spot on (unless a chimp has worked on it!) so I always use that if possible.

I never bother to check the intermediate shaft sprocket marks either, they can be way off if previous mechanics haven't bothered using it. I just take the cap off and line the rotor arm up to the notch on the dizzy, if the int shaft hasn't been messed with it'll be lined up, if not it wont be but who cares it'll run still

other thing to be aware of with the int shaft is it will spin freely once the belt is off, so easy to knock the dizzy out of time if you're not paying attention so keep an eye on that while you're trying to get the cam and crank to tdc

it can be a bit of a fiddle getting the cam and crank lined up, then fit belt, then tighten the tensioner as it can move about. my method is fit the belt as tight as i can between cam and cranjk, then slowly rotate the cam anti-clockwise till i can get a 90 degree twist on the belt. note the position of the marks, if out move it a tooth either way as necessary then try again. when its right then set the tensioner, rotate the engine 360 degrees clockwise and recheck marks and belt tension.

the smallest unit of movement either way is 1 tooth, so if the difference between cam and crank is less than that then its correct. Another thing to note take the spark plugs out, it makes rotating the engine much easier, and try to use the crank bolt to rotate the engine rather than the cam bolt

Oh just for informational purposes, I don't have any cam belt covers on this car…….so just gearbox window and head to go by.

So when I rebuilt my engine I set the the engine up at TDC and aligned the cam. So few months on, I now got my car running but it sounds a bit like chitty chitty bang bang right now! Seems to idle ok but its spitting back thru the carbs so while it was idling I pulled out the timing light just to verify and hit the cam sprocket with it. The timing mark lines up perfectly with the top of the head block where it should be so I then moved to the flywheel through the little window in the gearbox and hit that with the light, but the 6° before TDC and the TDC marks are nowhere to be seen……….so stupid question but what is going on? Seems like my crank……is misaligned to the cam right?

So what next…..? Take the timing belt off, reset the crank to TDC with the flywheel marks and reset the cam mark to top of the head. I'm wondering if it's jumped a couple of teeth or somthing. So what about the dizzy and the intermediate shaft, I assume if I have crank setup correctly (via flywheel marks) and cam set correctly then as long as the dizzy is aligned for cylinder 1 at the 6° before TDC on the flywheel I should be good right?

No you have to remember that the timing is Everything.

for the Chitty-chitty-bang-bang sounds as if you where out of time a tad.  At least that is what I found out over the years on Carbed Cars and either it being Post or Pre-ignition.

If you align the car at the 6 BTDC then the cam would need to be at the same relation to the Crank.  

You have to remember that Static Timing gets you to the ball park, Setting it with a timing light when the engine is up to temp, gets you to your row and seat.

Digifants are easier timed with a DVOM than anything else and the rev above 3 times and loose the CTS, then hold at 2250 for the 6BTDC…

I used to time Beetles with nothing but a 12V light bulb and 2 leads.

thanks for the response Briano1234, but i guess i'm still a little confused or not understanding something related to the 6 degrees before TDC and what i expect to see with the light, related to timing….. perhaps you can add some clarity for me. This is what i think i need to do……..is that correct or am i missing something here? or is there a better way?

1. Remove timing belt
2. align cam notch on inner side with engine head
3. Set up TDC mark on flywheel with the timing mark on gearbox??? ///// OR should this be the 6 degree BF-TDC mark?????   which one is aligned with cam mark?
4. Reinstall timing belt
5. Turn engine over with wrench until i get back around to the 6 degree BF- TDC mark on the Flywheel.
6. Set up Dizzy with No. 1 cylinder mark on the dizzy housing when 6 degree BF-TDC mark on flywheel is aligned with gearbox mark. (at this stage cam mark will not be on the head mark)

7. Turn engine over by hand several times to verify no interference.
8. Run engine and get the timing light out to verify cam mark and flywheel mark (the 6 degree BF-TDC is on the light or TDC mark??) ///// SO at this stage i guess im confused a little based on item 3 above also. , so the cam mark will line up with TDC mark on the flywheel if i used TDC and similarly if i used the 6 degree BF-TDC that will align with cam mark. SO which one do i use?i guess main confusion is when i set cam to the head mark i assume this needs to be aligned with the TDC mark on the flywheel i can then rotate the engine by hand and get back around to the 6 degree BF-TDC and set the dizzy to the 6 degree BF-TDC so which mark with i see when i use the light…… i assume i will see the 6 degree mark or will i see the flywheel TDC mark?

 

Well let me try this.
Rotate the engine to the 0TDC mark on the flywheel.
Loosen the Tensioner, adjust the cam so the Dimple on the back is even with the valve cover tin, not the rebar.
Spin the Intermediate gear so the distributor's rotor is in the middle of the hash mark stamped on the side frame of the Dizzy.

Tighten the timing belt so there is 1/2 twist between the intermediate shaft and the cam shaft.  Tighten the tensioner towards you, not away from you.

On the 90's Cabriolets with the 3 piece upper belt cover you can use the mark and arrow on the rear of the upper cover, to the hash stamp on the cam gear,  if you don't see that then take the Cam Shaft gear off as it may be on backwards.  Because the 90's had the 0 I T on the front of the gear and a dimple on the back that is even with the valve cover tin.

www.cabby-info.com has good pictures on this.
http://cabby-info.com/Files/AdjustingTheTiming.pdf

the rev to 3 times thing is only required to set base idle and co on the digifant, for ignition timing just pull the blue sensor and set to 6 degrees (it wont hurt to put it in setup mode first I dont think? I've never tried it)

rubjonny said

the rev to 3 times thing is only required to set base idle and co on the digifant, for ignition timing just pull the blue sensor and set to 6 degrees (it wont hurt to put it in setup mode first I dont think? I've never tried it)

Since I learned the Static Timing Method with my Digi's I use but a DVOM.  Don't event have to start the engine, just turn the key on and adjust the diz.  Easier, and the running fan doesn't nick my tools or fingers.