cam "blue printing"

[Ed Funk]

What's legal? What's enforceable at the typical regional event? Is anyone ever going to send a suspect cam and a known stock cam to Topeka for verification of legality?

[lateapex911]

It's been done. But, you (the protester or the protestee) don't send the 'stock cam'. For evidence purity reasons, a third party procures that. SCCA has some cams on digital file. They source the rest, then send them back.

I don't know what the Cam Doctor uses as a pass/fail threshold, but I imagine it will catch things like the ITB BMW 2002 cams I read an ad for that called them "IT tech shed legal cheater cams".

As to enforceable at a local event, I'd imagine that if it had excessive lift, it would be dinked right away. Measuring cams is something that (I bet) tech would get a bit bnervous about. If I had reasons to think that I needed to protest somebody over a cam, I would:
-find a tech guy I know and discuss it quietly, then..
-inform the tech staff that would be attending that event to be prepared for such a protest. That part would make me nervous, as it presents a chance for info to leak, but I think things would go smother with that approach.

In any case, I'd be prepared to have the cam impounded and sent to Topeka. Also, out of fairness to the protestee, I might plan on doing such a protest when there wasn't an event the next weekend, so as to not disable his car and preclude him from racing. (See spiteful Spec Miata protest fiascos of years past as examples of such 'strategies')

[Greg Amy]

Measuring cams is not difficult, if you have the specs. In fact, macro checks of the lift can be done with hand tools (not to the level to get bounced - you need specs, v-blocks, and a dial-indicator setup for that - but certainly adequately enough to check for gross cheating). But the only real way to do it per the GCR is to send them to Topeka with the (now, lower) test fee (non-refundable).

Jake, you're mistaken: the GCR actually requires the protester to provide a "known stock example" of the part(s) being protested. In the past, that's generally meant the protester has the part(s) sent directly to the inspector(s) from a trusted third party. Topeka does have camshaft profiles of common cars, but don't count on them having one for a Suzuki Swift <...rubbing hands/evil grin...>

Don't worry about the "word getting out"; once a protest is filed against a competitor, the car is immediately impounded, and their failure to allow inspection (or impound) results in immediate Steward action. - GA

[quadzjr]

Do you have to have a known good cam for simple things like lift and duration or can you use the factory service manual?

[Ed Funk]

Do you have to have a known good cam for simple things like lift and duration or can you use the factory service manual?

The few factory service manuals that I have seen don't list cam specs, tho you can usually extrapolate lift, but duration etc ---fugidabotit!

[Greg Amy]

Addendum, for simplicity: you can do the same thing a Cam Doctor does. All you need are a couple of v-blocks, a degree wheel (I've got one), a dial-indicator (ditto), and a dial-indicator magnetic base (or some kind of fixture - ditto).

Drop the known stock cam into the v-blocks. Attach the degree wheel to the end of the camshaft with the wheel's TDC at the cam's TDC mark (or any suitable "zero" point such as the center of the pin/keyway). Zero the dial indicator on the base circle at TDC. Slowly rotate the cam 1 degree at a time and note the dial indicator's reading. Do this 359 more times and you have the cam's profile; toss it into an Excel spreadsheet and you can even chart the profile graphically. Do the same thing for the camshaft in question and compare the data; it will give you lift (is the total lift different?), duration (has the duration been changed?), profile (is the lift and duration the same, but the cam's been changed in between?), and pin location data comparisons (has the pin been moved to change timing?)

Any technically-competent person should be able to do this, but this is what the Cam Doctor does for you, without having to know how to use the above tools.

Now, would a protested competitor settle for this method? Probably not. And, does the majority of SCCA Regional/Divisional technical staff have these tools and technical abilities? Probably not. Thus, SCCA bought a Cam Doctor and performs the service for you (and retains database info about various cams). - GA

On edit:

I've sometimes wondered if your increased role in the tech dept was in part due to your observance of the proceedings.

Absolutely. Two major things happened to motivate me; that was one of them.

[lateapex911]

Greg, I hear you, but...what I meant was that the protester provides the means to get the "Known stock example". If I showed up with a Honda/Nisaan/Mazda etc cam in a bag and handed to to you and said, "here is the stock version" it would be rejected, as you would have to assume I had some trick up the sleeve....it's an obvious conflict of interest.

But in the protest, I provide the means for others (unbiased third parties , ie, Stewards) to do the legwork, right?

I was told (by Tech) when I did a similar protest, that I should have contacted tech a week or so in advance, so that they would be prepared. As it turned out, they were most certainly NOT prepared (search this site for "A Protest Story" for a detailed rundown of how that played out) for what I had thought was a semi do-able protest. The concern going in was that leaking word that far in advance might yield adverse results. (That and the fact that the group of guys made the final call the morning of the actual protest...and we decided "By the book" was the way to go)

Heck, in that protest, the tech guys called out asking for tools to do the protest. We offered tools, but were rejected on teh conflict of interest basis.

[Greg Amy]

Do you have to have a known good cam for simple things like lift and duration or can you use the factory service manual?

A cam's duration is not a simple matter of measuring the base circle and subtracting that from the lobe measurement (thus my allusion above to "gross" cheating); cams' measurements are typical to and from a certain degree, and/or height between specific valve lift ('lash'). So, to measure lift correctly you need v-blocks (to spin the cam on), dial calipers (to measure the starting/ending point and the total lift), and specs ('cam card'). The Cam Doctor does all this for you. It'll "create" a cam card electronically if you measure a known stock example, then you compare that data to the part in question.

An alternative is to use an optical comparator, which projects the profile of the cam visually over a known shape. From there you actually compare the shape/profile.

To answer your question directly: yes, a known stock example is needed, assuming you don't have the Cam Doctor or optical comparator info already.

...(search this site for "A Protest Story" for a detailed rundown of how that played out)...

Oh, I'm well aware and remember it well. Everything that COULD have been done incorrectly WAS. However, I'd like to think that your experience is not indicative of how the process would work as a matter of course...I know it's not the way I would have handled it.

[lateapex911]

Oh, I'm well aware and remember it well. Everything that COULD have been done incorrectly WAS. However, I'd like to think that your experience is not indicative of how the process would work as a matter of course...I know it's not the way I would have handled it.

I've sometimes wondered if your increased role in the tech dept was in part due to your observance of the proceedings. Certain the release of the questionable parts that hadn't been determined to be legal/not legal was a huge shock to me, and I had a hard time following Dick Patullos first rule of screw ups, to wit: "Assume stupidity before malice"......

[tnord]

What's legal? What's enforceable at the typical regional event? Is anyone ever going to send a suspect cam and a known stock cam to Topeka for verification of legality?

it's been done in this division.