Briggs Cam Problem

[Fish]

Here was a problem on some of the Inteks made @ 2004 or so, one of the lobes would wear down to almost round, and would cause all kind of squirrelly running problems.
Here, I put a black line @ where the lobe tip should be on this old junk cam.

 

[Mower King]

Here was a problem on some of the Inteks made @ 2004 or so, one of the lobes would wear down to almost round, and would cause all kind of squirrelly running problems.
Here, I put a black line @ where the lobe tip should be on this old junk cam.

View attachment 53732View attachment 53733

Too much valve spring pressure? Something in valve train on that valve hanging up and not moving free?

 

[ILENGINE]

Have seen that issue on both the single and V twin engines. Some were caused by the valve guide moving causing valve pressure issue, but not enough to bend the push rod, and on others it was just an improper hardening of the sintered metal lobe.

 

[Fish]

Yeah, they did a cam change and the cams looked different, more of a 1 piece deal, not those pressed on lobes.

 

[Mower King]

How about the cams in the Briggs & Stratton 206 Intek engine.....Steel shaft with PLASTIC pressed on gear and lobes.... and they fit into the Briggs & Stratton Motorsports "Animal" single cyl racing engine....plastic lobes does make it real easy to gain lift & or duration though also makes it real easy to screw it up too!
I've got one on them somewhere around here!

 

[bertsmobile1]

Too much valve spring pressure? Something in valve train on that valve hanging up and not moving free?

Because the lower lobe was designed to be running under the oil level it was assumed that it would require less hardening so that is what it got.
Not a good engineering solution but it did save 5¢ on every cam.

 

[ILENGINE]

How about the cams in the Briggs & Stratton 206 Intek engine.....Steel shaft with PLASTIC pressed on gear and lobes.... and they fit into the Briggs & Stratton Motorsports "Animal" single cyl racing engine....plastic lobes does make it real easy to gain lift & or duration though also makes it real easy to screw it up too!
I've got one on them somewhere around here!

I have a cam from a late 70's early 80's from a 3-3.75 hp Briggs that has the plastic cam lobes and gear molded as one piece with a metal shaft pressed through the center.

 

[Scrubcadet10]

Plastic cams seem to do good durability wise.

 

[Tinkerer200]

Because the lower lobe was designed to be running under the oil level it was assumed that it would require less hardening so that is what it got.
Not a good engineering solution but it did save 5¢ on every cam.

?? Note it is not always the lower cam lobe which rounded off, see pictures. I think there was simply poor hardening on a bunch of Chinese cam lobes. Going cheaper, doing away with the one pc. forged camshaft was the mistake.
Walt Conner

 

[StarTech]

So far this year I had two 793880 cams with the exhaust lobes worn away. Both were from 2011 engines.