Need Help with TDC - Mark Seems off
 

Hello,
The water pump on my '84 944 was seized so I replaced it with a rebuilt one. While everything was off I decided to change all the belts and pulleys. I had alligned the marks on camshaft gears before I took off the timing belts etc. However I had not marked the flywheel! (I am still kicking my self for this).So when I was removing the crankshaft pulley the engine rotated a bit. Now that the water pump and all the tensioners and pulleys are in, I rotated the crankshaft until the piston in the first cylinder (colse to the back of the engine) on top dead centre (using a thin rod in the piston and finding the highest position). I re-iterated this and marked OT position on the flywheel. All the iteration proved that OT mark is at 4 o'clock position, which I know is wrong. I think the OT mark is supposed to be visible from the flywheel housing window on top left. Am I right? If so why the difference? Is it possoble that the flywheel was changed at some point in the past and not replaced it properly? Also, I do not see any gap on the flywheel which is supposed to be alligned with the gap in the buttom of the housing.

Any help will be appriciated.
( I can post some fotos if it helps)

RE: Need Help with TDC - Mark Seems off
 

Well, the cylinder closest to the back of the engine is #4, not #1. They go in order from front to back, 1, 2, 3,4. Do not get confused by the firing order that is stamped on the cam tower.

RE: Need Help with TDC - Mark Seems off
 

Wow! Thanks Doc. Actually that's what I had tought at first until I saw the stamp .
I will post pictures once I align all just to make sure.

Thanks again.

RE: Need Help with TDC - Mark Seems off
 

Hi Doc,
Attached are few fotos.
I made sure that the mark on the back plate of the flywheel is alligned properly when looking on top through the flywheel housing window. Also the marks on camshaft and the other gear alligned with back cover. piston number one, closest to the front of the engine is at its higest position. However I noticed that there is another TDC mark one the front plate of the flywheel looking from underneath as well which is now almost at 3 o'clock position! Is this right?

Also, Is there another way beside using belt tensioning tool for 944 to adjust the tension on the belts? In my old Mercedes we just had to make sure you can press about one inch on the belt.

Thanks

[IMG]local://upfiles/3882/E30145DA5A6945759CD4DB8DDAD29051.jpg[/IMG]

[IMG]local://upfiles/3882/B33FA639043947DAA4311EC0F14F7D66.jpg[/IMG]

[IMG]local://upfiles/3882/8B4B106EF2904101B2939162B7F3391F.jpg[/IMG]

RE: Need Help with TDC - Mark Seems off
 

I can't make out what the 2nd picture is looking at. If you look through the top of the bellhousing on the back of the engine, the Line that has OT marked underneath it should line up with that metal pointer.

Your cam mark is correct, as is your upper balance shaft. The lower balance shaft gear will have that mark/notch in the gear lining up with the timing belt cover at about the 7 oclock position.

Not understanding what you mean about another mark on the flywheel. The only mark on the flywheel when looking from underneath is a thick line (about 1/4" thick), which should line up with the tiny opening in the bottom of the bellhousing (note, it will more than likely be off to one side or another, and not centered directly in the middle of the notch). Note, pictures are borrowed from Clarks garage since i don't have any handy.

Bottom mark from underneath the car.....
http://www.clarks-garage.com/graphics/tdc-3.jpg


Looking through the top window
http://www.clarks-garage.com/graphics/tdc1-1.jpg

How the mark on the flywheel looks out of the car.
http://www.clarks-garage.com/graphics/tdc-2.jpg

RE: Need Help with TDC - Mark Seems off
 

To tension the belt, I use a 90 degree twist method on the T belt, and about a 150 degree on the balance shaft belt. Unless you have used the tensioning tool to see how the belt should feel, I don't know that I would recommend this. You can get the kricket tensioning tool from Napa for about 30 bucks that will work fine also.

RE: Need Help with TDC - Mark Seems off
 

Thanks Doc.

The OT mark is aligned on top. I made sure of that even though it is not clear in the picture. But in my flywheel, there is also a TDC mark on the other plate of flywheel which is now at aboy 3 o'clock poition. There is no other gap mark like the one in your first photo.
For the tension,the 150 degrees twist for the balance shaft belt will seem very loose. Is this OK?

RE: Need Help with TDC - Mark Seems off
 

Yes the balance shaft belt will be much looser than the timing belt, which is why I recommend using some type of tensioning tool the first time around. There aren't two plates to the flywheel though, so I am not sure what you mean by that. The flywheel is a single mass object.

RE: Need Help with TDC - Mark Seems off
 

OK. Thanks. I will get a tool from Napa as the one from dealer is about $250.
BTW, what I meant was the plate on the left, separated by the grove on flywheel circumference, as shown in your 3rd photo.

RE: Need Help with TDC - Mark Seems off
 

I guess if the OT mark is lined up, and your cam is lined up, toss a belt on there.