Maybe a more appropriate question would be:

"How many degrees at the cam gears does being off by 1 tooth at the crank equal?"


Here's the situation:

Halfway through removing my timing belt, I notice that with the #1 at tdc and both cam gears straight up, the crank pulley mark is a little ccw of the mark on the timing belt cover... I think, no big deal right? I mean these marks might be off a little... But then I start thinking about my cam gears giving me best tuning results at +15,-5 and everybody thinking that's crazy extreme..... Well it's been like this since the cams went in, and I rotated the crank a few times again to make sure... Yup, the mark on the crank pulley is a little bit ccw of the mark on the cover.

Either I'm crazy, the marks are off a little, or the belt stretched...

Please vote.

 

What ever one tooth is on the cam sprocket (in terms of degrees) multiply that by two on the crank sprocket.

The bottom end spins around twice and the cams spin around once for each set of intake/compression/combustion/exhaust stroke(s).

Sorry, I don't know how much one tooth on the cam gear is equivalent to in degrees.

-kenji

 

I wish I knew what you were talking about. Im mechanicially not-inclined when it comes to cranks, timing, degrees, yadda.

 

um... total # of teeth on a cam gear / 360. shrug, duno how many teeth are on a cam gear off the top of my head.

 

360 degrees / number of teeth on the camgears = degrees per tooth.
As mentionned above multiply by two if you want to know what it comes to at the crank shaft pulley.
If I remember correctly one tooth off equal +- 10 degrees on the camshaft but I don't remember the exact number of teeth on a camgear.

Do you run a thinner head gasket or a milled head ? because that will create the situation you are describing.

 

.....nope, head has not been off the block.

I will resort to counting teeth, but was hoping someone could tell me what their experience has been with this damn crank lining up.

I think I'll take Willard's suggestion and use the old screwdriver in the spark plug hole to make sure I'm at tdc for realzzzzz.....

 

Before I installed my thinner head gasket, everything lined up "perfectly". As a last verification, are you sure both mark on the camgear are lined up with the pointer on the back top plastic cover (behind the camgears). They might seem lined up to each other but are off just a little bit. Just a tought.


[Modified by JPP, 1:51 PM 7/19/2002]

 

nah, cam gears are lined up perfectly with each other and in relation to the plastic cover... Although I suppose they could be off in their markings (since they ARE aftermarket)...

I think I'll just keep playing with it... If I'm really off, then I know all my settings and where to put stuff so that my tuning has not been for naught.

On the other hand, maybe I'll say "**** it" and put the spec c's in as now is as good a time as any with this PE belt.....

Damn retuning!!!!!

 

re-tune, re-tune, re-tune (crowd chants)

Might as well, I'll go with you and we'll do my car with the AEM EMS system on the same day. One sick all motor R, one sick b00sted R. Then we'll compare graphs and street race all the way home!

 

apparently i had mistakenly assumed that you had already done so.

 

nah, me = wetodddid and thought I could eyeball it through the spark plug hole with a flashlight. btw: piston = nice and black. running rich anyone?

 

I ran into the same problem while changing out my timing belt. After doing the procedure, I ended up messing up something (??? :mad and I'm now paying for a rebuild.

You might try setting the crank mark a few degrees CW of TDC and letting the tensioning of the belt move the crank mark to TDC. I think it's the tensioning of the belt that causes the crank mark to move when you turn the crank, but the camgears stay the same b/c the crank gear takes up the slack first.

The best tool to use to stick down the cylinder is the hook tool from your carjack tools. I rotated the engine and marked the tool with TDC and BDC.

 

Are the lines in the middle of the cam gears /directly/ lined up?

Take out spark plug #1, and use your dip stick while you turn the crank to verify piston 1 tdc....

 

Thanks man, that thing worked perfectly. Nothing was off - just those marks on the crank pulley move really easily in relation to the tdc on #1... I checked the actual crank where it pulls on the belt and that mark is dead-on to the block. That, and the method mentioned above by IN VTEC worked perfectly.