Briggs Cam Problem

[Mower King]

Plastic cams seem to do good durability wise.

Yes they do but, they are not just plastic, they are Phenolic Plastic....crazy tough!

 

[Scrubcadet10]

Yes they do but, they are not just plastic, they are Phenolic Plastic....crazy tough!

Of course I should try telling that to a FD590 owner ,lol

 

[Mower King]

Of course I should try telling that to a FD590 owner ,lol

Yeah, no kidding....nobody thinks a plastic cam is a good idea....even people that don't know about engines knows plastic in an engine is no good!....we're not gonna tell them that their governor assy is probably plastic too...are we?

 

[bertsmobile1]

?? 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

Interesting Walt
The only ones I have seen were lowers and because I am curious & still have some friends in the business, took one in, cut sections & did micrographs.
The depth of the hardening on the base circle , which should have not been worn was a lot thinner ( by about 1/3 ) than the other lobes, thus the assumption of deliberate less hardening.
Even more interesting was it is a powder pressing .

 

[StarTech]

Bert, in my case the two I seen on Briggs single cylinder cams have both been the upper lobe (exhaust).

 

[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.

?? I know things are different "down under" but here in the States cam lobes do not actual run under the oil level (grin)
Walt Conner

 

[ILENGINE]

Got a Toro in yesterday with a Kawasaki engine popping through the intake. Exhaust cam lobe on number one cylinder is almost round with very little valve lift.

 

[Scrubcadet10]

It can even happen to the best of them.?