I finally started my timing belt project. Is this what I want for TDC? Not sure if it centers on the line or the OT.
Is this what I want for Top Dead Center?
- Tom
- Site Admin
- Posts: 8920
- Joined: Fri Jun 25, 2021 2:04 pm
- Location: Silicon Valley, CA
- Has thanked: 931 times
- Been thanked: 3989 times
- Contact:
Hard to get my bearings on that close up, but I assume that is the top window port in the bellhousing. If so, you're good. In theory, I always shoot to have the line (not the OT letters) right at the pointer. But as a practical matter, when all is done, the cam gear marks and TDC marks are rarely 'that' precise... once the belt is on.
I like using the line at the bottom of the bell housing. Much easier to see if the car is already on stands.
Don’t forget all the other reference points at the balance shaft pulleys and other belt pulleys.
Don’t forget all the other reference points at the balance shaft pulleys and other belt pulleys.
- PSU_Crash
- Posts: 274
- Joined: Sun Apr 06, 2025 4:34 pm
- Location: Decatur, Tennessee
- Has thanked: 185 times
- Been thanked: 108 times
I believe that line should be at the top edge of the "pointer" in your pic for TDC. Like Tom said though, they rarely line up perfectly with the cam timing. Mine was about half way closer between where you have it in the pic.
'86 Zermatt Silver 944 N/A 
'86 Mitsubishi Starion - Purpose built SM class Autocross car
'87 Chrysler Conquest - Mid LS Swap
'86 Mitsubishi Starion - Purpose built SM class Autocross car
'87 Chrysler Conquest - Mid LS Swap
I’m with Tom, PSU and 944m3 .
Once you are lining stuff up again, you may not have the flywheel lock in place for better alignment. Which means Lots of trips back under the car checking the line at the bottom of the fly wheel.
Once I got it perfectly to TDC, I made a mark on the front pulley and the timing cover with a paint pen. This acts as another quick reference to make sure the crank hasn’t moved.
Once you are lining stuff up again, you may not have the flywheel lock in place for better alignment. Which means Lots of trips back under the car checking the line at the bottom of the fly wheel.
Once I got it perfectly to TDC, I made a mark on the front pulley and the timing cover with a paint pen. This acts as another quick reference to make sure the crank hasn’t moved.
Tom wrote: Wed Dec 24, 2025 2:32 pm Hard to get my bearings on that close up, but I assume that is the top window port in the bellhousing. If so, you're good. In theory, I always shoot to have the line (not the OT letters) right at the pointer. But as a practical matter, when all is done, the cam gear marks and TDC marks are rarely 'that' precise... once the belt is on.
[/quote
Yea, the picture is kind of upside down for looking at it from the driver's side of the car. I had to adjust it slightly to get the teeth on the tool and flywheel to engage and bolt in. Once I got it torn down the camshaft gear is on it's timing mark. I didn't care so much about the balance shafts since they are easy enough to get back in time once I put the belts back on.
I did buy all of the seals to reseal everything on the front of the motor but it's going to take some time to clean up. There is a crazy amount of crud everywhere. I guess it's the difference between a mechanic working on your car and you working on your car. It appears that at no time did any mechanic in the past ever suggest resealing everything or did anything to actually clean anything. The previous owner (my wife's aunt and uncle) were the type that if you had told them X service needed to be done they would have done it.
I should have taken more pictures but the entire bottom is like this and all the way back to the transaxle. I think the source is the bottom balance shaft seal. I'm gong to clean what I can get access to for now. Next fall/winter I'm planning to pull the motor and refresh it and at that time I'll have better access to get everything cleaned up.
- Add Pictures/Files
-
- Screenshot 2025-12-27 at 4.29.59 PM.png (5.76 MiB) Viewed 311 times
Once I got it torn down and the covers off I was able to see I am in time. This is my first time doing a timing belt on any car and the biggest project I've done on a car so far.PSU_Crash wrote: Fri Dec 26, 2025 7:53 am I believe that line should be at the top edge of the "pointer" in your pic for TDC. Like Tom said though, they rarely line up perfectly with the cam timing. Mine was about half way closer between where you have it in the pic.
