I was pondering the thought of getting adjustible cam gears made for our cars but have a question about them. Why is the cam gear a two piece unit Does it serve any real purpose? What would the side affects (if any) be if it was a single piece.

Just to clarify things a bit. What I am talking about is the gear itself. If you take the gear off the cam you will notice that the back 1/3 is a different piece and the teeeth are offset about 1mm from the front part. Each of the seperate pieces have a hole and a pin which line up with the other side. There is also a horseshoe "tensioner" between the two that each pin goes in also. You need a team of mules to get the two pieces back together. If this confuses anybody let me know and I will post pics.

So any thoughts on this?

 

The two pieces are to eliminate backlash and noise along with it.

Adjustable gears would be very expensive with that feature. I think doing away with the spring loaded gear would lose some precision and therefore power along with it.

It would be less expensive to do a whole 3 gear (Dog) straight cut system, rather than doing 4 reverse cut helical gears. Or if you want noise kind of like a supercharger just use the two helical cam gears without springloaded teeth.

Dog cut = Noisy whining + not so accurate (even with adjustable feature)
Helical without springs = still a bit noisy but more accurate
Helical spring loaded gears = most accurate and precise + most quiet

IMO there should be some type of adjustment at least on the main chain just so after maybe 150-200,000 miles you can take up some chain stretch. (well not ON the chain but for it)

 

One of the issues with gear drive on modern cars is that the gear noise can often trigger the knock sensor. This is a "bad thing™". Hence the almost complete lack of gear driven cams, despite the improved accuracy and durability over chain and belt units. This is also the reason Honda went with a scissor gear setup.

You can create adjustable gears while retaining the scissor gear setup, but it isn't cheap. Tom at C&T Engineering has already designed a set (all CAD files are completed, materials selected, etc.), but he hasn't set a date for production. This is because:

1) It's going to cost a lot as these have to be hobbed just like helical tranny gears (unlike traditional belt driven cam gears which are much easier to make).

2) The benefit is unknown, as is the level of interest.

Tom estimated that a set of gears would be priced somewhere in the $500-$600 range and he'd have to sell quite a few just to make back the tooling and materials cost, let alone the R&D, as making small quantities overseas (where costs are cheap) isn't as feasible.

If you're really interested, send him an email and tell him you want a set. tps21@earthlink.net

UL

 

Thanks UL,

I will get in contact with Tom since he already has the design made. No need in wasting my time if some one else has done the work already.

Many thanks


-Eric