Initial timing issue

[Lorne G.]

Re: Initial timing issue

Thanks for the information Duke.
The engine is more happier at 700 RPM than 500 RPM so perhaps a cam swap was done in the past. I will download you presentation and start from scratch.
Lorne

[Steve G.]

Re: Initial timing issue

Steve,
I fully agree with you that the car is not actually running at 32 degrees but closer to OE specs but for the life of me I can't figure out what is causing the false initial timing reading. I thought my timing light was the problem but a mechanic using his own light had the same 32 degree reading.


I will go back and recheck the timing marks on the balancer and timing tab.

Lorne

What method are you using to determine the accuracy of the marks? The best way to do this is to remove all the plugs so that you can easily turn it by hand. Using a tool like this
cca-4795.jpg

or one made by knocking out the porcelain centre and welding a 3/8 bolt in, threaded into the #1 cyl, you slowly roll the engine over by hand until the piston comes into contact with the tool and stops. Make a mark on the damper at the 0 mark on the tab. Now roll the engine over by hand in the opposite dirrection to the way you first turned it. When it stops at the piston stop, make another mark at the 0 mark on the tab.

TAKE THE TOOL OUT

TDC is the mid point between the two marks. Using a flexible steel ruler measure out the mid point and mark it.

You'd have to have a spring missing or extremely light springs to have it return to 0 advance for cranking and up to 32* by 750 rpm. You would know if you had 32* at cranking speeds. Likewise trying to drive off idle at that much advance. My money is on mismatched balancer/tab or a slipped ring on the balancer.
Steve

[Lorne G.]

Re: Initial timing issue

Steve,
I didn't use a Piston Stop Tool but I had a friend crank the engine with No.1 plug out until I felt the pressure from the compression stroke. At this point timing marks were almost right on TDC.

[Steve G.]

Re: Initial timing issue

Steve,
I didn't use a Piston Stop Tool but I had a friend crank the engine with No.1 plug out until I felt the pressure from the compression stroke. At this point timing marks were almost right on TDC.

Lorne,
That is not an accurate enough means of confirming the timing marks. Even when the piston is at it's highest point there are several degrees of crankshaft movement without perceivable piston movement as it goes over the top.

Using a method that is just checking for compression you will start to feel compression when the piston is only half way up it's climb. You use the "feel for compression" thing to determine whether you are on the exhaust stroke or the compression stroke. Beyond that it is of no value.

Steve