Another TDC question
 

Doing the belts/wp/roller/front reseal on the 944T and finding my TDC marks not lining up. The camshaft timing looks good, but the lower balance shaft and top balance shaft marks are both off.

I cannot read the bellhousing TDC mark by the reference sensors, too much crap in the way.

So from what you see, should I be okay to install the flywheel lock? Picture below.http://forums.pelicanparts.com/uploa...1413300989.jpg
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I think you should find that flywheel mark - I know it can be hard to see so once you find it mark it with white paint - it's just a line across the top flywheel surface and blends in - either your balance belt is off a tooth or your timing belt is - no way of knowing which unless you make sure the flywheel is spot on

It doesn't matter where the balance shafts are at when setting TDC for the cam belt. Look for the TWO flywheel marks and the cam mark.

Still a no go, I checked the flywheel and found the raised line off by 1inch from the starter/bellhousing notch. What's even stranger is I get significant resistance when trying to rotate the engine over at the crank bolt trying to get TDC.

I must be really messing a something up, I should have been done by now.

On a good note, all cooling hoses and clamps are replaced, differential fluid replaced, oil and filter done, spark plugs, cap and rotor replaced, so still a good day, but I want to be driving!!!!

:eek:/http://forums.pelicanparts.com/uploa...1413320532.jpg

This makes me cringe. Best hope it is just a lot of compression and not a valve hitting a piston

I hope not, I just drove the car right before doing all this, belts didn't jump a tooth...I might grab a beer to think it out. Thinking about pulling the spark plugs out to see if it relieves the compression.

Probably your best approach. You need to get that flywheel mark centered within the window and keep the cam mark lined up.

I'm certainly no expert, but I've never had any great success getting things aligned with the plugs in. It takes a gentle touch to ensure the flywheel mark lines up (it can move by that window without you even noticing), and I just can't pull it off while overcoming the compression.

You've probably tried, but I usually get best results on seeing the flywheel TDC mark with a high-powered flashlight and one knee on the upper strut mount. It helps to have a helper so you can watch for the mark. Some cars have a cover over the inspection hole, so there's that...

Strictly speaking, if you are 100% sure that the alignment is on, you could align the cam pulley mark and stick the flywheel lock in. As long as you put it back together the same way, it should be as fine as it was before you started. I'd probably only do that if I somehow ended up with a flywheel with no mark though.

You can also locate/verify TDC through the #1 spark plug hole. Place a long (make sure that it's long enough that it can't fall in) wooden dowel into the #1 plug hole and allow it to rest on the piston. Then watch it as you rotate the shaft. It will be highest at TDC (i.e. the piston will be all the way up).

...For what little it's worth, I've never been able to see the alignment mark through the window on mine (a 951) and have always used the bell housing.

Right... Totally forgot about this one. Definitely use a wooden dowel. Don't do what I tried and use stiff plastic hose. I don't care how stiff it is, it'll crinkle and get stuck in there. Took me 3 minutes of panic and attempted turning to realize I hadn't had some sort of valve collision. Took me 10 minutes to get the bloody plastic hose (which was super flat by this point) out of the spark plug hole. Bad choice overall.

The only trick with this method is ensuring the cam isn't 180° off when cylinder #1 is at TDC. Not tricky at all, really.

Seconded. That distance you are off on the flywheel notch is less rotation on the cam gear than one might think. Line that mark up and check the cam mark again, you should be very close.

Also, its certainly the compression thats hanging you up, pull the plugs first.

I'll pull the plugs and hope for the best, thanks all.

--phil

Object in the hole is a terrible method. Next time you have an engine apart, look how much time the piston spends NEAR the top of the cylinder as you rock the crank back and forth. You could easily be several degrees off doing it this way.

"Too much crap in the way" is a poor excuse not to use the factory timing mark. We've all made it work, just get it done.

LOL, I just got the disapproving dad talk. I will check it out again tongiht after work. Thanks for the words of encouragement.

I found if you close one eye and hold a flashlight right next to your open eye it is possible to see the mark through the top of the bellhousing.

Awesome. . .just the tone I was going for!

;)

I get it from the wife too, "going to see the mistress?", when I go work on the porsche. I just want to get back into the seat and drive it a bit before the snow flies, otherwise its staying the garage for 6-7 months till spring.

So, ultimate bonehead here. I pulled the plugs tried and still nothing. I stood there staring at the car in disbelief, and while doing that i was looking at the dash and saw the car in gear, enough said. TDC was found easily.http://forums.pelicanparts.com/uploa...1413414150.jpg
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I wish I could say I havent done that before.

Good going, brother! If you havent already, watch Van's video on youtube.

Yea, Van's videos are a great resource, watched them plenty already.

I just finished my belts (cam and balance). It was my first time doing this work. Once you have the engine at TDC, check it at the bell housing, cam gear, balance belts and the bottom of the bell housing. You can also do the check with the position of the number 1 cylinder with the spark plug. Plus, the rotor on the distributor should point to or line up with the number 1 cylinder itself.

Be aware that the balance belts being aligned with their marks while at TDC ensure that the rotation of the balance shafts properly counter and offset the naturally unbalanced 4 cylinder engine.

I would use the flywheel lock. When you try to install the flywheel lock, you might find that you need to tweak the crankshaft to get the holes for the bolts to line up to install the flywheel lock. This slight movement will take the bell housing mark off TDC. This really concerned me at first. However, you will find that the crank will turn one tooth or less without moving the belt. You are taking out the slack in the belt. So, you can realign the TDC mark on the bell housing by tweaking the crankshaft after you remove the flywheel lock. Again, the crank will move slightly but not the belt.