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-   -   Issue with base timing. Can't line up the marks on the pulley (https://www.miataturbo.net/engine-performance-56/issue-base-timing-cant-line-up-marks-pulley-65267/)

Rushin 04-19-2012 12:23 AM

Issue with base timing. Can't line up the marks on the pulley
 
Long story short. Just put in a built 1.6 long block. Installed big nose crank with all the proper parts for the conversion. Car started right away and drives pretty well. Today i decided to make sure the base timing is right.

Took a timing light hooked up the spark plug sensor to the first spark plug and got power from the timing light power connector.
Set the fixed angle to 10 degrees in MSPnP.
Made sure i can see the mark on the pulley and cleaned it.
Turn the engine on, set idle at about 900 rpm.
Directed the light at the pulley and the mark is no where in sight
I did notice a little gouge on the pulley that was in one spot.
I turned the engine off and found the above gouge and it was about 90 degrees away from the mark.

What the hell is going on? I tried setting the trigger angle at 50 degrees and the car runs very good, at 60 it runs much worse and 55 is still pretty good.

I did carry over the CAM sensor from the old engine and set it at about the middle point.

When I set the first cylinder at TDC the mark on the pulley is not lining up with the T on the cover.

What am i doing wrong?

Bryce 04-19-2012 12:31 AM

How old is your harmonic damper? When they fail, the outer ring will slip, causing the timing mark to shift. It sounds like yours has failed.

I once set my timing before I knew it had failed, and ended up being like 20 degrees retarded. My exhaust manifold was glowing red hot.

Rushin 04-19-2012 12:33 AM

I have a feeling that's the case:-( I bought all the swap parts used so I have no idea how old they were. I am going to have to get a new pulley I guess.

Bryce 04-19-2012 12:35 AM

You could buy an underdrive pulley on ebay. They lack the rubber part so they'll never fail........ Just kidding.

Joe Perez 04-19-2012 12:38 AM


Originally Posted by Rushin (Post 866702)
I am going to have to get a new pulley I guess.

Before you do, perform a simple test:

Pull the #1 spark plug.

Drop the oil dipstick down the hole such that the tip rests on the piston face.

Rotate the crankshaft by hand in the direction of normal operation while observing both the crank pulley and the dipstick. The stick should reach its peak and start back down again just as the timing mark on the pulley crosses the "T" line.

Bryce 04-19-2012 12:40 AM

He says he already set #1 at TDC. I do this almost every time I set my timing now.

Rushin 04-19-2012 12:44 AM


Originally Posted by Joe Perez (Post 866705)
Before you do, perform a simple test:

Pull the #1 spark plug.

Drop the oil dipstick down the hole such that the tip rests on the piston face.

Rotate the crankshaft by hand in the direction of normal operation while observing both the crank pulley and the dipstick. The stick should reach its peak and start back down again just as the timing mark on the pulley crosses the "T" line.

I actually just tried that right before posting and forgot to add the result. The mark was not even close to the T when the #1 piston was at TDC. The little protruding metal alignment pin on the pulley boss was at the top but the mark the noth on the pulley was probably 90 degrees forward. I have a feeling the pulley is just plain shot.

Bryce 04-19-2012 12:45 AM

Yup. Your harmonic damper has failed.

skidude 04-19-2012 08:02 AM

I think that happened on my old car, but I had already set the timing so I never fixed it. My new car seems to have two timing marks, and with timing set at 10*, one lines up with the T and the other lines up with the 10. I don't understand, but it seems to work.

Rushin 04-24-2012 11:42 AM

Reporting back. Got new pulley and the old one was for sure screwed up big time. New one is perfect.


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