I wanted to run a problem by all of you to see what you think and to get some suggestions.

I've got a '66 Toro that runs fine but when setting the timing, the timing mark is off about 30 degrees. I replaced everything in the ignition system, sprayed the intake and heads with water looking for a vacuum leak and plugged all the vacuum ports but still no change. I also confirmed Top Dead Center using a stop and it lines up nearly exactly with the 0 degree hash on the timing marks.

My last and only remaining idea is that the harmonic balancer slipped, but I'm not sure if it would like up properly with the engine off but be out of place with the engine running.

Any thoughts?

Chris

 

I had the same issue and it was a bad PCV.

 

I'm not completely sure what you mean.

It sounds to me like you have confirmed the alignment of the balancer mark with the TDC mark at TDC and it "lines up nearly exactly."

If that's the case, then "the timing mark is [NOT] off by 30°."

If the timing mark is properly aligned, but shows 30° off when the engine is running, then you are either doing something wrong while checking the timing, or the timing is off.

Possibilities include:

• Not using the correct (#1) spark plug wire
• Not disconnecting the vacuum advance (and plugging the port)
• Having an advance timing light that is set to 30° instead of 0°.

How could a bad PCV put your timing off by 30°?

- Eric

 

It was causing a vacuum leak, could not adjust timing or mixture properly.

 

But a vacuum leak will only affect your timing with the vacuum advance connected, and you set timing with the vacuum advance disconnected.

A vacuum leak (or attempting to compensate for one through carburetor adjustments) may affect the idle, and the wrong idle speed will yield the wrong base timing, but not by 30°.

Not trying to be critical - I'm honestly interested in knowing what happened to create the situation in case I see it somewhere else.

- Eric

 

Can't really explain it clearly, but will try. I had my carburetor rebuilt, when I reinstalled it I couldn't set the mixture, just couldn't get it right, so I drove my car to shop that rebuilt the carb, he said there was had to be a vacuum leak, I changed all the hoses and still a problem. He checked it out, found a bad PCV, when I changed that and set my mixture, I found out my timing was off. I don't remember how much it was off, but reset it and now runs perfect. I hope that helps.

 

Eric and Pgraziani, thanks for your input. I'll double check the timing procedure the next time I'm out with the car to ensure the vacuum advance is plugged off. I do recall checking the PCV and it rattled fairly easily but I'll replace it anyway since it's cheap and simple.

Any thoughts on the harmonic balancer shifting when the engine is running?

Chris

 

Fair enough. Thanks.

No way, José.

If the balancer mark shifts, it stays shifted.

If it was loose enough to go back and forth, you'd notice it flopping around (for the minute or two it had before flying off into your radiator ).

- Eric

 

Not disconnecting the vacuum advance (and plugging the port)

 

x2

 

Sorry this cannot effect your timing if you disconnected the vacuum line from the advance can. What might have effected it would be idle speed or an eratic idle.

To answer the OP's question, I believe he has his vacuum advance connected to manifold vacuum and is reading initial timing plus vacuum advance which would put it somewhere around 30 + or -, at idle.