Putting in a new Cam/Crank gear set in my mild performance motor build. Plan on a Aluminum Cam Gear with a Steel Crank Gear, American Made.

Best unit's in the market place?

 

Cloyes 8-1014 Performance Set is said to have an aluminum cam gear and a steel 3 key crankshaft gear (st up / -4* / +4*.

Is this correct? Is it a good unit?

 

I'm no expert, but I would be cautious about "mixing" gear metals. It's likely that the steel and aluminium will wear at different rates and cause problems. (If I had to guess, I would think that the steel gear would eat the heck out of the aluminium one.)

It might be better to match steel with steel, and aluminium with aluminium.

But I'm sure some guys smarter than me will chime in soon and you can get a more definitive answer to this.

 

Not to be argumentative, but many original factory gear sets were "mixed". The cam gear was phenolic. The ones on my 1986 have 206K miles and the ones on my son's 1984 have 240K miles.

 

1986F150six & hansol04 -- thanks for the reply. I think the aluminum cam and steel crank gears are the norm for today, using a phenolic cam gear will run a little quieter. As I am upping the compression ratio and cam lift I think the Aluminum / Steel gear set is the way to go.

 

Cloyes 8 - 1014 Performance Set is the way to go. I have run many of these when I was racing and never had any real problems with them. I took a fender washer and a allen head counter sunk bolt and put in the end of the cam for safety. Had to grind a spot in the timing cover to clear.

 

I put a steel/steel gear set on one of my previous engines and it was a very loud whirr. Almost to the point it sounded like an electric motor. I didn't care for it.

On my performance build that I just finished, I have an aluminum/steel gear set and it is nice and quiet. A slight whirr if you know what to listen for (which I like), but not obtrusive.

I don't recall the make, but I can find out.

 

The point of dissimilar metals for something as over-built as out timing gears is that they lap to each other very quickly (google "gear lapping" to learn more) whereas two hard metals will take damn near forever because the load is so low.

Everything in a complex system of interchangeable parts like an engine has a manufacturing tolerance.

A competent gear manufacturer can make gears for a far more precise fit than the variation among 300s. Cloyes (or whoever) looks at the manufacturing tolerances for everything involved, cam bore position relative to crank bore position, how close to parallel the bores must be, crank dimensional specs, cam dimensional specs, probably a couple others I'm not thinking of selects a point in that range (probably near the middle) and builds their gears +/- their spec.

On any given engine the gears won't be "textbook perfect" aligned but the engineers designing the gears in 1965 knew this and spec'd gears big enough to live a million miles regardless of where the engine it's installed in falls within the range of misalignment possible from the sum of all the manufacturing tolerances involved (I'd bet it's at least a couple thou).

In addition to noise/friction/heat generated by less than perfect gear alignment noise/friction/heat/ is generated by less than perfect surface finish. Matched gears are lapped at the factory to improve fitment with each other and reduce noise/friction/heat generated by variations caused by the manufacturing process and surface finish.


The whine AbandonedBronco described is the same whine you get from any gears, more misalignment gets more noise. We've all heard of poorly installed diff gears whining. (the acoustics of steel on steel and steel on aluminum are different as well but that's separate). He'll just have to listen to it longer than if he had aluminum gears because the timing gears are so massive for the load they carry that the break in period is damn near infinite. An aluminum gear would wear to match the steel gear in very short order.

In any case the aluminum gear is far stronger than the fiber one.

(FYI, when I says "perfect" in all of the above, I mean the kind of textbook perfect "exactly 1" peg in "exactly 1" hole that doesn't exist in the real world)