3 HP Briggs Camshaft Timing

[pete108]

How do I setup the timing of the camshaft?

On the crankshaft I have a small indention. On the camshaft I also have a small indention but at about 90 degrees to it I have a hole in the gear of the camshaft.

Thanks for any help.

pete108

 

[jimh]

One gear should have a mark between two teeth, the other should be on a tooth. If you turn the crank and cam they should come to a spot where they line up. If noone has ever had it apart it should still be in time.

 

[pete108]

No mark on a tooth. The mark on the crankshaft is no the counter weight. On the camshaft it's on the face of the gear.

 

[jimh]

The marks on both gears should be on the face of the gears. One will be even with the point of a tooth. The othergear should have one even with a valley between two teeth. When you turn the shafts, at some point the tooth on one gear should be in the valley of the other.

 

[jimh]

Give me a few minutes and I'll posta picture in a reply.

 

[pete108]

like this. http://www.oldminibikes.com/forum/photopost/data/630/medium/camshaft_alignment.jpg

 

[jimh]

Here's a pic. Mine has a slash and an indentation, but same principle.

 

[jimh]

Maybe you need to mark the tooth on the crank gear and line it up with the one on the cam. That one's got me.

 

[minidragbike]

It looks like it's lined up correctly. (line on crank gear, lined up to the dot on the cam gear)
But why is your picture so tiny?

 

[pete108]

It looks like it's lined up correctly. (line on crank gear, lined up to the dot on the cam gear)
But why is your picture so tiny?

My picture?

 

[minidragbike]

My picture?

Nope, not your picture. Yours might be a little off. You will have to rotate it to look like jimh's picture. Then I can see if it's lined up correctly.

 

[jimh]

Pete, mark the tooth on your crank gear that lines up with the dot on your counterweight. Then turn the crank a little and see if your mark lines up with the dot on you cam gear. I know mine was in time. It's a running engine. I've never seen one without a mark on the crank gear.

 

[pete108]

I aligned the camshaft so that the intake valve has just closed and the exhaust valve just about to open. Then I place the crankshaft to TDC. That's how I got to the picture.

 

[jimh]

Looks like you might be a tooth off. Looks to me like the tooth marked should line up with the dot on your cam.

 

[minidragbike]

I aligned the camshaft so that the intake valve has just closed and the exhaust valve just about to open. Then I place the crankshaft to TDC. That's how I got to the picture.

You have just explained it the worse way you can ever explain it.

Look at jimh's picture, it's that simple.

 

[pete108]

You have just explained it the worse way you can ever explain it.

Look at jimh's picture, it's that simple.

Well I was just explaining how I got to that picture(to that point). At least I'm not far from being properly aligned using theory and not the marks.

 

[jimh]

Try it the way I marked that one picture. It's hart to tell where TDC is without the rod and piston. If you had your rod and piston in, and turn the crank counterclockwise the intake valve should start opening as the piston starts to move down.When the piston comes back up, both valves should be closed at TDC. Turn more and when the piston starts the next up stroke the exhaust valve will start to open.

 

[pete108]

Yep. That's how it's set-up now. Maybe a tooth off but close. Thanks for the help.

 

[minidragbike]

A tooth off is a whole lot, trust me.

Don't worry about the relationship of the piston to deck to intake and exhaust valve "confusing deal". It takes to many special tools to get it perfect that way.

Dot to line, or Dot to dot only takes seconds.

 

[jimh]

You only have two marks. Just tink if you had 6. The old Triumph twins had a crank gear an intermediate gear and two cams. When you lined them up, you had to turn the engine 94 complete revolutions before they lined up again. All the gears had a prime number of teeth. i'm pretty good at math and I never tried to figure that one out. i just used the marks.:thumbsup: