really stupid cam question

turbonola · Post by **turbonola** » Fri Jan 14, 2011 5:59 am

ok i my book the only stupid question is one that isnt asked.

why cant we just use a stock cam gear on aftermarket cam and instead of setting them the stock way turn them to where it should be set at with adjustable cam gears. its a question thats been bouncing around in my head for a while. i just dont understand the need for aftermarket cam gears. i did pick up bc 264 and hear that they need to be degree'd. this is why i'm trying to find out whats so special about cam gears that move the cam from one position to another. can someone clear this up for me please.

**YouTube channel** · Post by **adamky** » Fri Jan 14, 2011 7:34 am

I can only assume you're talking about rotating the cam gear a tooth on the chain? If so, that won't work because it moves it waay too much. There are 19 teeth on the cam gear. Divide 360 (degrees) by 19 and you get 18.9. So, moving the cam gear a tooth moves it approximately 19 degrees. If your cams are that far out of spec, you've installed them wrong.

Honestly, I thought the same thing before I understood exactly how the JWT cam gears worked. It's not as simple as just rotating the entire cam and gear by one tooth. The cam gear actually comes off of the end of the cam. Then you rotate it to the desired setting, and then move the cam a very small amount to make it line up with the corresponding hole in the cam gear.

I found a thread where I went through and explained how the gears work. Hopefully it makes sense: viewtopic.php?p=269550#269550

adamky wrote:Just moving the gear over a tooth on the chain would move the cam timing A LOT. You wouldn't get the same results at all and would accomplish nothing other than moving your cam 20+ degrees. Let me try and explain....

Okay, see how there are both inner and outer numbers? There's a "2" in the center on one of the holes, and a "2" on the outer part near the teeth. Well, if you were to precisely measure the difference between the gear marked with a "2" and the hole for number "2", you would find that measurement would get slightly larger each time you measure the same difference for the inner/outer "3", inner/outer "4", inner/outer "5", etc.

Take, for example, the first picture showing the cams in their stock position. Stock position on these gears is a "1", meaning the chain marked with the //// lines lines up with the "1" on the outer gear. Notice that the original "slot" that the gear goes in is also marked with a "1".

So, say you wanted to advance a cam 2.5 degrees. So, we look at the JWT cam adjustment chart: http://jimwolftechnology.com/wolfpdf/CA ... CTIONS.PDF

According to the JWT chart,, to advance the gear 2.5 degrees, you would use the outer gear tooth marked with the 2 and you would use the hole also marked with a 2. So, you move the gear so that the 2 aligns with the chain link with the //// lines on it. Once that is done, you move the cam ever so slightly to align the cam pin up with the hole marked with a 2. While it may not look much to your naked eye, the difference between the cam/gear aligned with the # 1 hole and gear, and the # 2 hole and gear is precisely 2.5 degrees.

Likewise, to advance the cam another 2.5 degrees (5 degrees total advanced), you would move the gear so that the # 3 gear tooth aligns with the gear marked with the //// lines, and the cam's pin goes in the # 3 hole. Again, even though it may not look like much to the naked eye, you have just advanced the cam another 2.5 degrees.

Does that make sense? It's confusing at first, and admittedly, I didn't understand how they worked at first either. After I understood how they worked, I was pretty impressed how JWT was able to come up with that design. The KA's gears are simply too small to have any type of slots/bolts for adjustment. This is about the only feasible way to have adjustable gears on a KA.

Jus14 · Post by **Jus14** » Fri Jan 14, 2011 11:17 am

I May be wrong but i think he is asking if he can use the stock cam gear? As far as i know you should be able to do this correct? and still get a good degree..

basic · Post by **basic** » Fri Jan 14, 2011 11:35 am

the stock cam gear is set, so unless you are rotating an entire tooth (~20 degrees) you can't use the stock cam gear without drilling a whole for the pin. The thread linked above goes into more detail about that - the JWT cam gears are basically machined so that you can rotate the gears using different holes and change the base timing of the cams with respect to the crankshaft

**YouTube channel** · Post by **adamky** » Fri Jan 14, 2011 1:49 pm

Jus14 wrote:I May be wrong but i think he is asking if he can use the stock cam gear? As far as i know you should be able to do this correct? and still get a good degree..

You may be right. If that is what he is asking, then I would say that it usually depends on which cams you are using. With JWT and Kelford, you can probably just use the stock cam gear. Both of those cams are pretty well- known for being "drop-in" cams. My centerlines with my JWT S1's were very close to the cam card when installed with stock gears. With BC cams, I would recommend cam gears. BC cams have been known to be good cams once degreed properly, but the centerlines are often off when used with stock cam gears. I'm pretty sure I've seen reports on here of them being off as much as 10 degrees.

boker240 · Post by **boker240** » Fri Jan 14, 2011 10:14 pm

u can't use the stock one cuz its set up for stock lift and duration. that changes drasticly with stage 3 cams.like said before the ajustable cam gears allow u to fine tune(degree) the timing with lift and duration. i bet if u throw adj. cam gears on a stock ka it can be degreed tighter than it is with the stock cam gears. significant power comes out of degreeing cams.

**YouTube channel** · Post by **adamky** » Sat Jan 15, 2011 5:46 pm

boker240 wrote:u can't use the stock one cuz its set up for stock lift and duration.

I'm not really sure what you mean. I installed my JWT S1's in the stock positions, and the centerlines were very close to the what the cam card calls for. I only had to adjust one cam 2.5 degrees to match up with the cam card.

Plenty of people have installed JWT and Kelford cams with stock gears and noticed good gains. Last I checked, Orion is still running JWT S1's with stock cam gears, putting down close to 330 whp @ 12 psi. He constantly road races the car and loves the powerband. I'm running mine very close to stock positions and my car runs great right now. You can almost always get gains by fine tuning cams, especially for forced induction apps, but you can't really say that stock gears can't be used.

Like I said, for the BC264 cams the OP has, I would recommend using cam gears because BC cams are well known for being quite a bit off from the cam card when installed with stock gears. You CAN use them with stock gears, but gains will be minimal or non-existent. For example, seanc installed his BC264's with stock gears and noticed almost no gains. He actually lost power in a few places: viewtopic.php?p=180360#180360

seanc wrote:same exact curve. lost like 4 hp and gained like 4 ft lbs. very disappointing. maybe mine and way out of wack.

But then you take someone like Bonomoskat who degreed his BC cams and picked up almost 50 whp and 70wtq: viewtopic.php?p=352532#352532

Bonomoskat wrote:i pretty much picked up 30whp all the way up to the peak power and then gained 52 whp up top even with a boost leak. not to metion the 70 tq gain!

So, the basic rule of thumb goes like this:
JWT or Kelford = cam gears may or may not be needed. Check cam timing regardless to make sure they are close enough to the cam card. Use cam gears if you want to shift the powerband, reduce or increase overlap, etc.

BC cams = Cam gears needed. Start out by trying to match the cam card, and then adjust as necessary.

**In both cases, you always want to set your lash correctly before checking or adjusting cam timing.

Kfred · Post by **Kfred** » Sat Jan 15, 2011 10:18 pm

boker240 wrote:u can't use the stock one cuz its set up for stock lift and duration. that changes drasticly with stage 3 cams.like said before the ajustable cam gears allow u to fine tune(degree) the timing with lift and duration. i bet if u throw adj. cam gears on a stock ka it can be degreed tighter than it is with the stock cam gears. significant power comes out of degreeing cams.

WTF? Are you saying stock centerlines aren't good for aftermarket cams?

I beg to differ.

turbonola · Post by **turbonola** » Sun Jan 16, 2011 3:18 am

ok just to clear things up: i was wondering if you could degree bc cams using stock gears by just putting the teeth in a different position on the chain. that question was answered, thanks for all the awesome info, it anwsered alot of question i had.

Preston · Post by **Preston** » Sun Jan 16, 2011 3:38 pm

Yes, you could do that but every tooth is about 19 degrees timing change...if you find you need a multiple of 19 degree (19, 38, etc) you can do that. Otherwise you will over or under time the cam.

**YouTube channel** · Post by **adamky** » Sun Jan 16, 2011 5:25 pm

Preston wrote:Yes, you could do that but every tooth is about 19 degrees timing change...if you find you need a multiple of 19 degree (19, 38, etc) you can do that. Otherwise you will over or under time the cam.

Really? That hasn't been mentioned in this thread at all yet. What else can you tell us?

TryingToTurbo · Post by **TryingToTurbo** » Sun Jan 16, 2011 5:43 pm

adamky wrote:
Preston wrote:Yes, you could do that but every tooth is about 19 degrees timing change...if you find you need a multiple of 19 degree (19, 38, etc) you can do that. Otherwise you will over or under time the cam.
Really? That hasn't been mentioned in this thread at all yet. What else can you tell us?

LMAO! That's great. Almost as good as people who ask a question answered in the same thread a post above theirs!

**YouTube channel** · Post by **adamky** » Sun Jan 16, 2011 9:16 pm

Sorry. I'm sure Preston just overlooked the other replies or something.

I edited my first reply to include the JWT cam gear pic and explanation of how they work, just for help with future searches on this topic.

Walperstyle · Post by **Walperstyle** » Sat Jan 28, 2012 10:13 am

...word of advice everyone, don't use crower v3's.. Nightmare to degree properly. I gave up for now, need to sleep.

No, really, you have no idea!

I found out with crower v3 cams that I wanted to have a CL of 124' intake, and 118 CL for exhaust.

SO, I retard the intake cam (turn CCW) to the mark 'b' on the JWT Cam gear, and it lines up perfect!!!! yay. Unfortunatly, when I go to adjust the cam on the exhaust, I take the timing chain off, and that lack of tension causes the DUAL SPRINGS, to move the Intake again. ...throwing it off about 10 degrees.

Are any of you other guys with dual springs familiar with this? There has to be a way I can Adjust my exhaust cam and intake cam at the same time.

I guess its a matter of finding the sweet spot in the intake, then do them both at once so the chain can hold the cam in place without snapping shut.

jlpowell84 · Post by **jlpowell84** » Mon Jan 30, 2012 1:26 pm

I bought BC 264 cams and planned on using them in my turbo build. I called BC after I came across this post and they said stock gears are fine, that jwt adjustable will only change your powerband in the rpm range. I think if you lost 4hp and gained 4tq then they must have not been set up right.

**YouTube channel** · Post by **adamky** » Mon Jan 30, 2012 2:22 pm

Walper, I never do cam timing changes without a buddy to help me hold the cams. I put a wrench on each cam and have them hold one of them steady, while helping me while I move the other one. I've never done it by myself.

Walperstyle · Post by **Walperstyle** » Mon Jan 30, 2012 3:01 pm

Those dual springs are something else eh?

I bought BC 264 cams and planned on using them in my turbo build. I called BC after I came across this post and they said stock gears are fine, that jwt adjustable will only change your powerband in the rpm range. I think if you lost 4hp and gained 4tq then they must have not been set up right.

Yeah, I'll take SMracing and Brad D's word on decreeing first. Brad D got 100+HP almost across the board by setting his v3 cams properly. I'm not skipping this step.

jlpowell84 · Post by **jlpowell84** » Mon Jan 30, 2012 6:09 pm

Yeah I got the dual springs as well. Hasn't been put together yet though. Still have the turbo setup to get and am thinking about an aem series 2. So I have a bit to buy still. I am new to this site, I am assuming SMracing and Brad D are members on this site. Are there any threads for proper, right, and effective BC cam installs ?

Walperstyle · Post by **Walperstyle** » Mon Jan 30, 2012 6:42 pm

You can find them by searching. Search 'BC V2 DEGREE' on here, and on google, you will find some information.

Here is a couple I found, bookmarked on my computer

viewtopic.php?t=41520&highlight=crower+cams

viewtopic.php?t=42833&highlight=

Can I send you a bill for finding that?

www.ka-t.org

really stupid cam question

really stupid cam question

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