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How to watch timing without removing belt cover

the_hairy_baboon

Active member
Joined
Dec 1, 2021
When I replaced the timing belt I had to take off the radiator shroud, radiator fan, some belts and pulleys, all just to be able to take the timing cover off.

I have a small misfire when cold so I would like to take a look at timing (as well as all the fuel side stuff, but that's irrelevant for this), Is there a good way of watching timing with the cover on, or a way to get it off without having to remove umpteen and a half items first?
 
B21FT.

A timing light requires looking at the white stripe on the belt which is covered by the cover, hence its name. Without removing the cover, where do you point the stroboscopic light to glean useful information? Or is this the reason that my cover is warped at the top, someone pried it partly away so they could peek in without fully removing it?
 
clean and put some tire maker/ white mark in the timing notch of the crank pulley, and point the timing light on it, and see where it flashes, there is a little scale with numbers on it on the lower timing cover. You will need to read and learn where the mark lines up in relation to TDC, and what the number mean, as spark advance changes with RPM, etc

this is what you do with a timing light. the with mark on the belt doesn't line up the cam gear after each revolution.

I suggest you google "how to use timing light" It will make many things more clear.

the top of your cover is loose, check for a missing screw, the covers warp even if it is in place.
 
Ignition timing is not valve timing.

Many people get confused when "timing" is mentioned, and they just assume they're the same thing.

To the OP: You say you replaced the timing belt. Did you verify the valve timing was correct? In other words, did the engine run as it did before the belt was changed? If yes, you're good to go. Timing (any timing) doesn't change by itself. Unless, the cam belt lost tension and skipped a tooth or two

You should be able to identify what has happened
 
Did you pay attention when you put the balancer back on? If you didn’t turn anything after putting on the belt the mark on the balancer should line up with the tic mark on the cover. This is a ez way to determine if the pulley has slipped.
 
I'd like to add that the outer part of the pulley can slip with age and wear, I think you should first verify that the pulley reading is actually accurate before ruling out ignition timing. Valve timing being off would cause a whole lot of issues that would be hard to miss.
 
Aaaannd.... that's what my brain kept jumping over.

Camshaft spins 1:2 with crankshaft, not 1:1 (since 4 stroke), and the crankshaft has that protruding marker to help with alignment judgement. That part is always visible (albeit buried down near my shins)

When I replaced the timing belt I had all the marks aligned (along with belt teeth), so I'm not worried about misalignment there, but I don't know if general timing is correct or not (see cold misfire). I found this old thread from Dave (https://turbobricks.com/index.php?threads/timing-a-b21ft-for-retards.99499/#post-1206848) so i'll follow that to make sure base timing looks good. I have a bunch of the greenbook guides for checking all the rest of the higher level stuff.
 
I'd like to add that the outer part of the pulley can slip with age and wear, I think you should first verify that the pulley reading is actually accurate before ruling out ignition timing. Valve timing being off would cause a whole lot of issues that would be hard to miss.

That's true for B230/B234 crank pulleys but B21/B23 crank pulleys are solid.
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