Finding TDC

[canadian]

Is there anyway to from TDC on the comp. stroke with the timing cover on?
I have the camshaft timing sprockets lined up with the mark, and have the crankshaft pulleys mark at 0*. BUT stupidly, I am not sure if my #1 piston is at TDC. Is there a way to test this, or should I pull off the timing cover and re-do it?

In the TSRM for setting TDC they say rotate counterclockwise 120* after the camshaft lobe is in the right position. then rotate it clockwise 10-40* until the timing cover and crankshaft pulley mark are aligned.

What mark on the timing cover do I align it to? The 0, 5, 10 or 15 degree mark?

Thanks

EDIT:
This is on an engine that the timing belt was already removed and the crankshaft/camshafts were moved, now I am putting on a belt and trying to find TDC from scratch...

 

[spoolint78]

pull out the sparkplug in the # 1 cylinder, and check and see if its at the top.


everything should be at 0

 

[canadian]

pull out the sparkplug in the # 1 cylinder, and check and see if its at the top.


everything should be at 0

If it's at the top is it on the compression stroke for sure?

 

[canadian]

Which other piston is at the top of the stroke when the first piston is at the top too?

 

[Mr. Y]

Which other piston is at the top of the stroke when the first piston is at the top too?

6

BTW, it doesn't matter where timing belt now. Just set crank at 0*, then align camshafts with marks up and put timing belt on. After that check your ignition timing... (using timing light)

 

[Blackfin]

6

BTW, it doesn't matter where timing belt now. Just set crank at 0*, then align camshafts with marks up and put timing belt on.

...while making sure that piston #1 (the front one) is all the way up. BTW, a good way of telling where the piston is is to insert a screw driver into the spark plug opening so that it stands on top of the piston; just make sure the screwdriver doesn't slip to the side and bind.

 

[starscream5000]

On one of my other cars, don't know about the supra, but TDC on the piston is actually a tad bit off compared to TDC according to the crank pulley marks.

I'd be curious to see if yo uset it a 0* TDC and move it slightly either way, to see if a screw driver on top of th piston will go up a tad bit more before falling back down....

 

[IJ.]

...while making sure that piston #1 (the front one) is all the way up. BTW, a good way of telling where the piston is is to insert a screw driver into the spark plug opening so that it stands on top of the piston; just make sure the screwdriver doesn't slip to the side and bind.

I use a piece of Vaccum hose just in case so it can't mark the piston.

 

[canadian]

So I don't have to use the TSRM way of setting TDC? I can just align the 2 camshaft marks and 1 crankshaft marks, making sure 1st piston is at TDC?

 

[IJ.]

Yes both cams on the base circle with their marks up and the crank at true TDC.

A lot of times the outer ring has slipped on the stock damper giving a false TDC if you go by the mark so it's a good idea to confirm it using some hose.

If it has slipped NOW is a good time to replace the damper before it seperates and does damage.

 

[figgie]

A twig is my friend.

I would be afraid to stick any metal screwdriver down the spark plug hole. Gouge the hell out of the piston top.

 

[extendor]

I dont think you can beat a dial gauge. I have seen timing marks quite a way off and in that case you need to make a new mark on the pulley that you can trust.

 

[starscream5000]

Like Ian said, a new dampner is most likely what would be needed, especially if your goal is higher HP ratings...

 

[jetjock]

Understanding how engines work on the core level is my friend.

Mr Y: Ti imeet bolshe terpenia chem ya....

 

[canadian]

Understanding how engines work on the core level is my friend.

Mr Y: Ti imeet bolshe terpenia chem ya....

How did you learn?

 

[NeatOman]

On one of my other cars, don't know about the supra, but TDC on the piston is actually a tad bit off compared to TDC according to the crank pulley marks.

I'd be curious to see if yo uset it a 0* TDC and move it slightly either way, to see if a screw driver on top of th piston will go up a tad bit more before falling back down....

Sure the previous owner didn't adjust the belt for brake in? Some cars require that.

 

[jetjock]

How did you learn?

I'm a believer in learning about something before I do it. Theory and fundamentals first. Makes things go a lot smoother.

 

[canadian]

I'm a believer in learning about something before I do it. Theory and fundamentals first. Makes things go a lot smoother.

I agree, I try to learn as much as I can about something before I start...sometimes it doesn't work for me though.
Thanks

 

[tlo86]

A twig is my friend.

I would be afraid to stick any metal screwdriver down the spark plug hole. Gouge the hell out of the piston top.

oops! :biglaugh:

 

[canadian]

Well I guess I got lucky-I measured with a piece of cardboard lol I couldn't find a long enough piece of pipe- the 1st piston was up significantly higher than the other ones! So I guess I did things right for a change :naughty: