The Stovebolt Site Forums The Shop Area Engine Shop What cam do I have?

Is there an easy way to know roughly what duration cam I got in my engine? Stock, mild or hot?
I never had another engine and can't compare with another known stock or modified engine.

I have a 1962 235 with a 1955 9-1/4 flywheel (original trans) with BB, 5 and triangle marks.
It seems the triangle indicates max. possible advance at 32-34*
If I time the engine at the recommended 5* mark per shop manual, it never comes close to pinging and the exhaust is rapping like crazy at deceleration - as in too retarded.
It seems to run much better, if I time it around the triangle. Then I get slight pinging at WOT uphill and hardly any rapping in the exhaust when decelerating.
The engine is smoother, quieter and responds better when accelerating.

Could it be that I have a non-stock cam with higher duration that likes more max. advanced timing?
It does feel a little bumpy and uneven at 500 rpm idle and smoothes out only after 800-1000 rpm.
Also I noticed at 2500-3000 rpm the engine is smoother and quieter and runs very nice without overheating.

It doesn't sound or feel like it, but I am worried that I am running too advanced and may damage the pistons.

Set it where it pings & then retard it just enough to stop the pinging. That is the best setting & will not damage pistons. It,s doubtful you have a modified cam in it. They are pretty rare in those engines.

You are right - that's what seems to be the best setting. Been running it that way for many years, every day.
I checked TDC on cyl#1 and the pointer is perfectly above the BB on the flywheel. I also have the correct distributor and vacuum adv. for the year.

I just never knew why this engine prefers base timing at idle to be set so far advanced at the triangle mark, which I understand is the total advance recommended for these engines after max. centrifugal advance.
However I'm already there at idle...

I often wondered about the cam.
This engine was rebuilt at some point. It has a 55 head and the crank is also not original as it only accepts the smaller 55 flywheel.
But I also can't imagine anything but a stock cam.

Just a quick note:

Learned that the triangle is actually used to check cam timing.

Also found other bolters in past threads, who had best results using it as the timing mark, rather than the BB.

I'm no expert, but I doubt that you can identify which cam you would have without taking it out and taking some accurate measurements. Unless there are some numbers stamped on it. That would also require removal, unless its stamped on the end.

John

You can check total cam lift with the cam in the engine using a dial indicator .You could then compare to specs of a stock cam.This would at least give you a starting point.You may have to do some research to find the stock specs?