Big Dog wrote:


Good point (and memory), Jim!

This was approved as a unique allowance based on a specific request. Is there interest/need into making this a general rule out there?

If not, as I think this through, I'd rather not clutter the rules with issues unique to one car or person's situation.

Not meaning to rehash but what would the difference be between an offset key or an adjustable timing gear? Besides the obvious. If you pay to have multiple keys installed and dyno'd each time to see which key gives you the most power or use an adjustable gear to see which key to use you still have the labor of installing and removal of the gear once.
Buy the gear, install it once and make multiple pulls on the dyno.
Wouldn't this be a better way to spend the money?? Not to mention but if you make changes and want to retest it would be much easier with the gear.

The only difference I could see in practice would be being able to adjust you power curve for difference tracks - moving peak power up and down in the rev range a bit. Weight might be slightly different? I'm not sure that either of these issues is significant.

Dialing in timing is a bit tricky. The OEM cam gears vary a bit (I tested 6 a year or so back). The cam tower makes it very hard to use feeler gauges on the cams. So it may be hard to dial in timing without a cam gear on a dyno, or a custom tool.

Finding an adjustable cam gear is also tricky. The Lindsey Racing one reuires some clearancing of the cam tower to work, so we would have to allow that, or find another source. The only other 944 ones I found a year ago were from Europe, but I can look into this again.

Lindsey racing is where I saw it at. They said some cases might have to be clearanced.

OK, did some research on offset keys and cam gears.

Offset keys are available here for $50: [url]http://www.928motorsports.com/parts/offset_camshaft_keyset.php[/url

They come in 2 & 4 degree offsets. According to posts on Rennlist, one tooth in the cam belt is 9 degrees. So. getting a 2 & 4 degree offset key can make for a large number of combinations in advance & retard:

+2°
-2°
+4°
-4°
+5° (+cam tooth, -4°key)
-5° (-cam tooth, +4°key)
+7° (+cam tooth, -2°key)
-7° (-cam tooth, +2°key)

If you are very careful, this may be able to be done with the car on the dyno. Then see what makes the power you are looking for.

So far, it still seems that the $300 Lindsey Racing adjustable gear is the only one out there. It offers more fine adjustability, but a bigger cost, and likely need to clearance parts.

Perhaps talking to a knowledgeable engine builder will help with this question. The purpose of this proposal is to allow low compression cars to adjust their timing when they shave their heads. There seems to be sentiment that the factory timing is very good so I am not thinking that someone will be going to the dyno and spending lots of money to fine tune the timing and, even if they do, they will not get much of anything better that of factory timing.

IF the above is reasonably true, what most are trying to do is restore factory timing on their shaved heads. (Again, with our power cap I don't care if someone does want to monkey around with timing and thinks they get more power anyway.)

My point is perhaps someone could suggest what "offsets" are needed for various amounts of head shaving. That way, most would measure their head and get one key that brings their timing back (or real close) to factory. It would restore some of the power lost due to timing changes and life is good and it does not need to get real complicated for most of us and we don't care if someone wants to play around with it anyway.

Big Dog