Flywheel Timing Mark

I'm replacing the flywheel on my 1987 VW GTI with a brand new one. The Bentley Manual says that new flywheels do not have an ignition timing mark, so it must be measured from the TDC mark on the new flywheel. Problem is, my new flywheel doesn't have a TDC mark either. If there's no TDC mark, what reference do I use to create the timing mark? Also, what do you all recommend for making the timing mark: paint, grind, scribe, or ?.

Thanks in advance.

Reply to
Kent
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Jim B.

Reply to
jimbehning

Thanks, this makes sense. I expected the new flywheel to come pre-marked with TDC, but now I can see why that's not necessary.

Thanks again,

Reply to
Kent

I agree with this method with one enhancement. At TOD the up and vertical movement of the piston is at it's smallest. In other words it's hard to tell the difference between say TDC and 5 degrees off TOD. A more accurate way is to look at the piston travel at 90 degrees of TOD where the piston travel is it's greatest. Using the same technique with the screwdriver or pencil. Mark the pencil against the spark plug hole anywhere around 90 degrees of TOP and mark the flywheel. The actual distance from TDC is not critical. Now turn the engine the other side of TDC until the mark on the pencil is exactly in the same spot against the spark plug hole. This needs to be accurate. Sometime I shine a light across and let the shadow line be my guide. Mark this spot on the flywheel. TDC is exactly half way between the two marks on the flywheel. Check your work by going to TDC and looking at piston travel.

Reply to
Paul Johnson

I understand what you guys are saying, but to identify TDC and mark the flywheel by either method I'd have to first install the flywheel and the transaxle since the timing pointer is part of the transaxle bell housing. Unless I could then get a chisel or whatever through the timing hole to properly mark TDC and then measure and mark the timing mark, I'd then have to remove the transaxle again. Hopefully I don't sound lazy, but due to limited tool availability I benchpress the transaxle in and out.

Since I have the old flywheel, why can't I just use a common reference such as the center of a bolt hole, and then measure the arc length distance to the timing mark on the old flywheel using a flexible scale? This dimension could then be transferred to the new flywheel by measuring from the same bolt hole. Do you see anything wrong with this approach?

Thanks again for your help.

Reply to
Kent

Jim B.

Reply to
jimbehning

Sorry, maybe I wasn't clear; allow me to clarify. The transaxle is already out of the car. I have a new clutch pack and flywheel to install. Now, let's assume that I bolt up the new flywheel right now and go through your recommended process of finding TDC. Okay, the flywheel is now properly positioned for TDC. Unfortunately, I still can't properly mark TDC on the flywheel because the timing pointer (the little pointer that you align with the timing mark on the flywheel when timing the engine) is part of the transaxle (cast near the timing hole on the bell housing), and the transaxle is not in the car. Now, I could go ahead and reinstall the transaxle at this point, after which I can mark TDC through the timing hole (since the timing pointer is now there for reference). Now I have another problem: I think it would be hard to accurately measure the required .472 inch arc length (6 deg. BTDC) from my TDC mark through the timing hole with the transaxle installed. So the transaxle would have to come out again to gain access to the flywheel so I can accurately position the ignition timing mark. Does this make sense or am I totally clueless here?

Reply to
Kent

Wow this is a long discussion! :-)

Install the d#rn clutch kit with the new flywheel and drive your VW again. Mark the flywheel for TDC AFTER you have the engine running. I think I have even found some TDC marks that either did not exist or were off.

I think someone mentioned using the almost TDC method to locate TDC. Something safe stops the #1 piston from reaching TDC and this position is marked at a reference point, then the engine is rotated in the other direction and the flywheel is again marked. Then you can measure for the center of those two marks! This method is commonly used to locate exact TDC on the crankshaft and then you can dial in the camshaft. I personally like/use this method. ;-)

Of course you could install the used flywheel and align the mark with a reference pointer on the engine made from a coat hanger bent and bolted to the engine block. Then take off the old one and install the new one to mark it. You would have to make sure that the crankshaft did not move though. by locking down the sprocket or timing belt. It can be done this way also. Now you will have to assume that the pressure plate is perfectly aligned also! lol

good luck with this and let us know what you do! later, dave Reminder........ Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you are a mile away from them, and you have their shoes. Frieda Norris

Reply to
dave

Jim B.

Reply to
jimbehning

Okay, thanks, I'm going to give it a try.

Reply to
Kent

Jim B.

Reply to
jimbehning

I expect they will be, once they arrive at the end of the week or maybe Monday (I had to order them from the dealer). Fortunately, I do have a tool to compress the springs while the circlip is installed. A funny story regarding that tool: it just so happens that the spare tire/jack hold-down from a 1987 Dodge Omni is nearly identical to the special VW tool used to compress the flange springs. Weird huh? I took it off my girlfriend's car 10 years ago right before it went to the wrecker. At least that old Omni turned out to be good for something...

Reply to
Kent

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