Setting TDC on an M42

[Low Level E30]

How do you set TDC on Piston #1 on an M42?

Is there a marking somewhere on the crank pulley that I can use?

My motor is bone stock --- I have the head on, but the cams are not in place yet. I figured I would set the crank in the correct position first, then set the cams, put the sprockets on, then the chain, etc etc.

Thanks!

[ak96ss]

There is a hole in the flywheel you can use - look near the starter, IIRC it is below the starter, but it's been a while. Get the #1 piston close, then put an 8mm drill bit in the hole and rotate the motor. When you are at top dead center, the drill bit will slide in and lock the flywheel in place.

In theory. YMMV.

:)

[Low Level E30]

There is a hole in the flywheel you can use - look near the starter, IIRC it is below the starter, but it's been a while. Get the #1 piston close, then put an 8mm drill bit in the hole and rotate the motor. When you are at top dead center, the drill bit will slide in and lock the flywheel in place.

In theory. YMMV.

:)

Great, thank you!

I'll do this tomorrow, and then I can send you your cam tool back :D

[bmwpower]

I'm in the middle of doing this now....

Did you lock the camshafts using the special lock tool over the square ends of the camshafts?

Would like to pull the head tonight, but don't want to screw something up.

[e304me]

just use something long and skinny in the spark plug hole. make sure the cams are facing up and inward. turn the engine over several times and verify the timing is set right

[Low Level E30]

just use something long and skinny in the spark plug hole. make sure the cams are facing up and inward. turn the engine over several times and verify the timing is set right

Once everything is bolted up, how do you verify that the timing is set right... ?

Surely if it's wrong, you'll bend something... ?

[bmwpower]

just use something long and skinny in the spark plug hole. make sure the cams are facing up and inward. turn the engine over several times and verify the timing is set right

On, say, my 325ic I can do that since the cam sprocket only goes on one way. On the 318ic, the cam sprokets are adjustable, right? So unless things are lined up just right, your timing will be off.

I guess I could just mark the sprockets where they meet the end of the cams.

I'm guessing I should stop working for the night and borrow the tool from someone....

[Low Level E30]

On, say, my 325ic I can do that since the cam sprocket only goes on one way. On the 318ic, the cam sprokets are adjustable, right? So unless things are lined up just right, your timing will be off.

I guess I could just mark the sprockets where they meet the end of the cams.

I'm guessing I should stop working for the night and borrow the tool from someone....

I marked the sprockets before I took them off the cams.

I used a tiny bit of bright orange acrylic paint --- just a tiny bit --- two marks on each sprocket / cam, so that there can be no confusion as to which sprocket belongs to which cam, and how they should be aligned.

[e304me]

check this out

http://www.esatclear.ie/~bpurcell/318istimingchain.html

really all you need is a ruler or something flat

just put the cams approximatly in the middle of the sprockets. It doesnt really matter if its completly exact. what you really want to avoid is the sprockets being a tooth or more off. Thats trouble.

[KenC]

So my M42 isn't starting, but has spark and fuel. I want to verify that the timing is correct.

So I just need to use the alignment hole in the rear of the block to set cylinder #1 at TDC, and then remove the valve cover and make sure that the squares on the rear of the cams are lined up?

[dude8383]

Yup...

Was the motor opened up before? Maybe the head and bottom end were not set to TDC during install.

So my M42 isn't starting, but has spark and fuel. I want to verify that the timing is correct.

So I just need to use the alignment hole in the rear of the block to set cylinder #1 at TDC, and then remove the valve cover and make sure that the squares on the rear of the cams are lined up?

[KenC]

Was the motor opened up before? Maybe the head and bottom end were not set to TDC during install.

Trying to figure out why it won't run when there is spark and fuel present. Engine hasn't been opened up.