Timing 1.6 EZ

I’ve trailed the web for an hour, nothing definitive.

How to set timing with a strobe? Now I know the basics but what I can’t find is where to set it. The talk of being 18 BTDC, how do you know where 18 BTDC is?

Is there a link or a wiki page here for timing because I can’t find it. Thanks.

1990 1.6 EZ (auto)

 

You have to adjust the timing on the ignition. If it's a rotor, adjust the rotor.
If it's fired by the computer, adjust the sensor (or the computer if possible).

 

I don't mean to be rude, but I don't understand your response at all and I've been playing with these Mk2's for 30 years - you'd think I know this by now wouldn't you! So many variants, they all seem to having different set-ups.

You have to adjust the timing on the ignition. What do you mean, can you eloborate?
If it's a rotor, adjust the rotor. Adjust the rotor, what? It's fixed in the dizzy. I assume you mean rotate the dizzy. Yeah, I'm fine with doing that, but to where?
If it's fired by the computer, adjust the sensor (or the computer if possible). Computer, what? It's transistorised, but no port for computer plug in on these old cars?!

So, the crank pulley has a dot, the timing cover has a line, the dizzy has a notch for cylinder 1. I can line all those up for TDC, not a problem. But when I then attach the strobe and run the car up to temp. Where does this 18 BTDC come into it and where is the mark for that? If it's relevant at all? dunno.

 

Well I didn't understand what you meant by "Now I know the basics but what I can’t find is where to set it." so we're even

On my flywheel there are 2 marks, one dot for the 0° and a line for the ignition before TDC, I thought it was about 6°.
Isn't there a second mark on your flywheel as well? I can't see the second mark when the other one is in view either, so maybe that's where it goes wrong.

Also, if you have set up everything to 0°C, does this correspond with cylinder #1 actually being at TDC?
You can test this by removing the spark plug and inserting a thin but long rod. When roting the engine by hand, the rod will go up and down.

(I'm not familiar with the engine itself, just thinking along )

 

17-19 btdc for a carbed car (GTI is 6 btdc)

Big hole at the top of the bell housing and your timing marks will be visible through there, hook up a timing light to number 1 lead so it pulses every time the first cylinder goes bang. Then point it at the hole with the engine warmed up and running at idle speed and see where it's at - the timing mark should line up to the arrow. If it doesn't loosen the dizzy locknut and rotate it gradually until it lines up.

You'll know what it wants by ear because the engine will sound better/ worse depending on what it wants - you can set timing pretty damn close by ear tbh.

The only unknown in this dark art is do you leave the vacuum line connected or not, seems to be some debate on that. I believe haynes says disconnected for 1.6, weirdly, it says connected for 1.8 carbed.

 

Cheers. Yeah, I've been doing it by ear too. The 18 BTDC bit is still a mystery then, unless the V in the flywheel (bellhousing hole) is in fact the 18 BTDC mark. I think it is and the DOT on the flywheel identifies 0 TDC.

There seems to be so many variances on these Mk2 engines, be good to get a accurate guide for all engines in the site wiki, if this site has one?! Must come up all the time.

Vacuum Line - it's a vacuum advance (carb to dizzy - higher revs = more advance it needs). So if it has one, then logic suggests you should disconnect it as you are setting the timing at idle. I'm not 100% on this though. The revs should drop when you disconnect it and you need to plug it too, use a bolt.

 

My understanding is the vac advance is to manifold vacuum on these. Which will pull a vacuum at idle so should be attached?

 

18 BTDC at 900 idle, vac hose connected. Diamond mark on flywheel is at 18btdc. If your timing light has advance dial you can use static timing marks, if it does not, use diamond mark on flywheel.

 

I've had mine set as my previous post, and still going well. Feels good and pulls well.

https://clubgti.com/forums/index.php?threads/1-6l-carb-timing.173845/#post-1574840

 

get a timing light with adjustable advance - set to 18 (or whatever you need) then line it up at the TDC marks