Help all you TDC Guru's

robs944 · robs944's Garage

O.K. I have attached some pics.
I am in the final stages of putting engine back together after having the valve guides and much other stuff done.

I have cranked it by hand and it seems to move freely, valves not hitting.
Tried to turn it over but it sounds like a motor just spinning away, I've got fuel and spark the compression? Which leads me to my Q

Trying to find TDC,
Pic 1 .....I have Camshaft set to TDC?(BTW it was done with the belt off)
Pic 2.....from my understanding the crankshaft (flywheel)can be aligned by viewing the window at the back of the engine looking down. Is the pic that window? If so why is it when I turn the flywheel with socket and breaker bar (5-speed in neutral) nothing in the window moves? I can turn the flywheel while holding a screwdriver in no.1 cylinder and can notice movement inside.

Basically How in the hell do I get this adjusted???

Unfortunately prior to my friend removing the head he did not check for TDC on the flywheel, but did align TDC on the camshaft.

As always appreciate the help and advice...

PIC 1

PIC 2

SoCal Driver · SoCal Driver's Garage

Ah...you rotated the engine with the head on but without the timing belt on????

Did you notice any resistance? Like valves being in the way?

Look under the car. There is a big groove in the flywheel that lines up with a very obvious notch on the bell housing.

If the engine turns over the same with out the spark plugs as it does with the spark plugs -- sounds like a sewing machine -- then the valves are bent.

You don't turn the engine over with the head on and no timing belt.

robs944 · robs944's Garage

No, the T belt was on when the engine was cranked.

Did not notice any resistance.

I will check the groove on the flywheel.

Thanks for your reply.

I will post back about the flywheel.

robs944 · robs944's Garage

So Cal,
BTW

wouldn't the engine sound like a sewing maching if the timing (TDC) is off?

SoCal Driver · SoCal Driver's Garage

You can only go about two or three belt teeth either way or you bend the valves.

The only way an engine sounds like a sewing machine is when there is no compression. For a 944 it's either bent valves or no spark plugs. Take the spark plugs out and spin it with the starter. If it sounds the same as with the plugs in you've bent the valves.

If it sounds different then your problem is else where. You should also be getting 150 psi or more of compression.

overkill · 03-16-2003, 06:44 AM

Ok, let me get this straight,... you set the cam gear to TDC with the belt off. Then you put the belt back on the cam gear and you are now turning the engine over by hand looking for the crank TDC? Ummm,... when you put the belt on the cam gear what was the position of Cyl.#1? Now SoCal is saying someinthg about you having the plugs in and you are able to turn the crank over with ease? So at no point during your turning over of the engine do you feel alot of tension? Dude you got a BIG problem. When your spark plugs are in it is really friggin hard to turn the engine over. When I was working on my car, I had forgot to remove the plugs this one time. When I was craking the engine over by hand I could even get the pistons over the top. Thats how much tension to should be expecting. When you set the timing you make sure that your engine is in perfect TDC first. Then you time your camshaft and then tighten the cam gear with the belt already on in the TDC position. AFJuvat said the some mechanics will actually clamp down the timing belt once it is removed from the cam gear so that the belt doesnt skip the teeth on the crank. They do that so when it is time to put the belt back on the cam gear all they have to do is turn the cam gear back to it's original postion then put it back on. They are experienced and know what they are doing though. But, for everyone else including myself,... once that belt comes off, you start over from scratch and you have to set the timing all over again to be sure that it is correct. Once that belt skips a gear you puts you closer to engine failure. That skipped tooth might be your last to, so you never know. Your car can skip more teeth then mine can so I dont take any chances. But then again who the hell wants to drive a car with the timing slightly off? Not me. Dude, you need to get the factory manual and read it. If you already have it,........ read it and keep reading it until you fully understand it or you can ship the car off to someone who does know how to do it. That is if your valves arent bent

Britwrench · 03-16-2003, 10:47 AM

If Overkill is telling you there's a problem you'd better listen up.

Take the plugs (which you should have done anyway) and crank the engine over until the #1 pistonis on TDC. Stick a long screwdriver down the plug hole and CAREFULLY follow the piston up. Then look at the timing mark for OT (manual trans only) and make sure it's right on the mark. The cam pulley should then line up with the notch. Make sure it's on the #1 firing stroke.

If it's out, remove head and repair damage.

And the reason you were working on this car without proper technical information is why????????