Where is Top Dead Center?

cdigerlando · #1 10-30-2001, 07:50 PM

Anyone know how to find top dead center on the crank? I need to install a new pully and crank gear for my Tec II and need to know how to set and mark at TDC.

Thanks
Chuck D.

huck369 · #2 10-31-2001, 04:57 AM

Haven't accually noticed it on the SVX, but on all my other Subie's there is a set of timing marks made onto the timing cover that pertrude out over the side of the crank pully with degrees on them, and the crank pulley has a small notch in the outer and inner edge (just outside of the acc. belts), if you line that mark up to "0" on the timing marks, it should be TDC ( I THINK that the crank pulley keyway is straight up at TDC, but that is from memory, which isn't as sharp as it used to be)

#3 10-31-2001, 05:30 AM

Good job man!

I'll email you scans of the pages for timing belt installation (out of my trusty shop manual).

cdigerlando · #4 10-31-2001, 05:40 PM

I have not noticed the notches that you are talking about, but if there is a notch, do you line up the left side or the right side with the mark?

Thanks for the reply.

Chuck D.

svx_commuter · #5 10-31-2001, 06:22 PM

What is a TEC II"

TDC is when the number one piston is at the top of the cylinder and the valves are closed, ready to fire away! At least that is what I remember and I hope that is right.

Can't you get the marks off your old pulley?

cdigerlando · #6 10-31-2001, 06:31 PM

Thanks for the answer, but I know what top dead center is, I just don't know exactly how to set the pully to TDC. Please read my previous e-mail. I need to know if there is a notch and if so how it should be set respective to its left, right, or center to the zero timing mark.

A Tec II is an engine management package that requires a crank trigger sensor and a toothed wheel be mounted on the pully. Tuning and new injectors may then be done.

cdigerlando · #7 10-31-2001, 08:30 PM

There are not notches on the SVX crank pully. Only two holes. I'm assuming that these holes would mark TDC but I'm not sure. If i'm wrong the whole thing will not work. My chilton's is no good either. Wish I had the SVX Maintenance manual. Anyone out there that can help? How about you SVXtypeR?

#8 11-01-2001, 06:04 AM

Sorry, I could'nt get to my 'puter last night (it's terrible, I have more time to post here at *work* than I do at home!!)

From memory though, basically, after you take the timing belt cover off, look for a mark on the belt itself (more than likely, it's faded). Rotate the crank pully so the belt mark lines up on the *top* of the crank pulley itself. Make a mark over the existing belt mark and onto the pulley with white-out (I'm not making this up, the shop manual *actually says to do this*...

). Now this is where it get foggy, but basically, you're supposed to do the same thing on the left and right cam pullys.

I'll just quit from here on and post the scans...

cdigerlando · #9 11-01-2001, 12:30 PM

Yes I have noticed that there is a mark on the cam gear (from my chilton manual) showing where the cams should be set at TDC. So, in theory, if your cam belts have not streatched too much, your crank should be right at tdc where the belt mark is on top of the crank gear and the left and right belts are aligned with the marks for the cam gear. I have seen this done in my chilton, but I'm still not convinced that this is the best way to set TDC at the crank, due to belt streatching and slight differences in the visual mark. I cannot believe that there is not a mark somewhere on the gear or connector shaft marking TDC. What if this was an engine rebuild. You put the thing back together, and have no idea where TDC is on the crank, without looking into the engine block through one of the piston peep holes. Yuk!

Thanks for the help. If you find anything else in the manuals, please let me know. I was thinking of calling you some time anyway.

Chuck D.