Flywheel marks

[Greenmachine]

So we have the TDC mark, and we also have a flywheel alignment mark, and there is a raised 'finger' pointer too. They're all within a couple of inches of each other.

Alignment of the cam with any of them does not cause interference on my motor. But it sure affects drivability.

I have not been using the right one I think, but I think I have it now. I set it to the diamond shaped indentation and I'm thinking that the slot indentation is the flywheel alignment mark and I have no idea what the finger thing is, but the diamond indentation is right behind it. I am confused.

[82vdub]

So we have the TDC mark, and we also have a flywheel alignment mark, and there is a raised 'finger' pointer too. They're all within a couple of inches of each other.

Actually, on the flywheel, there is only one TDC mark that's manufactured into the flywheel. The raised points are not marks. The only TDC mark manufactured into the flywheel is the arrow, or diamond shaped mark (can't remember off the top of my head) that's supposed to be alighed to the little arrow that's on the transmission. These are both accessed through the cover plate that is in the top of the transmission.

Unless you've positively identified TDC as something different than the TDC marks on your flywheel (or someone made a paint mark to say that's TDC), use the factory marks on the flywheel to set TDC.

Here's a pic of what you're looking for (thanks Vince!)

[Greenmachine]

Wow mine does not look like that at all. I'm confused because all the pics I've seen look a little different. I have a slot like that and I have a diamond. One book I have shows 2 different marks, one for the TDC and one for aligning the flywheel when disassembled.

When I timed to the slot it smoked like crazy, and bad power, but started good. Too retarded I thought. I should say the pump is timed accurately. When I looked again yesterday I found the diamond (<>) and it was about an inch further advanced. Haven't had time to fire it to know if it is better for smoke and power.

Before I started messing with it it was timed to the finger thing, further advanced and it didn't smoke much and had pretty good power. I might need to post some pics to illustrate this better.

It's an '81 caddy.

[idhoho]

TDC mark on an '81 VW Rabbit Diesel car or pickup is pretty darned easy to differentiate from other marks. Any other marks are likely post factory. The "real" TDC mark is cast into the flywheel and is the diamond pointer that you have seen. There are no other special marks to align the fwheel as it will only go on one way if all the alignment staubs are still in place. Another way to make sure you are at TDC is with a piece of copper (12ga. or so) wire poked down through the No. 1 Injector orifice. Stick the wire in there and rotate the engine. Watch the wire reach it's zenith and you have TDC! Go around and look at your flywheel.... It should be at least showing the little diamond though the view portal in the bell housing. If it isn't you might need to rotate the engine 180 degrees, watch the copper feeler wire and look again at the fwheel.

[82vdub]

There are no other special marks to align the fwheel as it will only go on one way if all the alignment staubs are still in place.

Just for clarification points on this, my flywheel had all the alignment dowels on it and was installed 120 degrees off from where it should be. So, somehow it doesn't always go on only one way. Just a word of caution.

Also anytime you mess with your timing belt and cam timing, make sure you rotate the engine by hand a coupld revolutions before you engage the starter to make sure you don't mash your valves into your pistons.

[Vincent Waldon]

Yup, VW has used a couple of different marks on the diesels over time, and then there's the gasser marks if someone subbed in that flywheel, and then there's the raised lugs that are evidently designed for an electric sensor some shops and/or the factory uses, and then the aftermarket flywheels.... sigh.

If anyone wants to take pictures I'm happy, actually very happy, to add them to the HOW-TO... the idea is to build up the most usable reference possible... and right now all I have is my MK2 flywheel (with whiteout and cute red and yellow nailpolish already applied!).

[vwkook]

I've got a loose flywheel in the garage I could wire wheel up and snap a picture of this evening.

[vwkook]

or this

[Fatmobile]

That last pic is the one I always see.
Haven't seen one like 82vdub posted.

[bscutt]

Just off the top of my head (since I'm at work) I recall that the marks on my '80 were different than the ones on my '82. Once I located each I cleaned them and put a nice dap of white paint on them. I think my 82 also looks a little like what 82vdub shows.

[Greenmachine]

I had a hard time photographing the marks but here you go. Still not sure which one is timing and what the other one is (flywheel alignment?) but they both seem to have a diamond. The mark in the first two seem also to have a small slot that the diamond points to, but then there is the weird horn thing:



another view:



Then there is this, which I painted and looks a little like timing marks some others posted. Both marks in question are actually visible (the previously pictured mark is to the left of the painted mark:




Since they are within an inch or so of each other, I'm really confused.


Chuck I did your test where I turned the motor over with a rod in the injector hole and could not discriminate between the two marks, they're both in the TDC area. Thanks!

[82vdub]

My .02 worth is this. The mark in the top two pictures looks more like a factory style mark, similar to the pic by vwkook. The bottom picture you posted looks like it's some other mark, or casting divot. Did you put the dab of paint on it, or did someone else?

If it were me, I'd use the mark in the top two pics, time to this, and absolutely definately postitively rotate the engine a couple revolutions by hand before you engage the starter to make sure there is no interference.

[Greenmachine]

No I painted the mark in the 3rd pic because I thought I was sure that was the timing mark. I appreciate your interpretation 82vdub...

[82vdub]

The reason why I said the top two pics was that the mark was a nice straight line that looked machined, or factory marked, not some mark that someone made or mistake in a casting. The one with the paint on it looks like a divot, but I can't see how the line looked under the paint. That's why I said what I said.

[Greenmachine]

So you're saying they machine in the timing mark after the flywheel is cast.