Important info about the Gilxal A9 cam...

[ratdog]

I have been doing a lot of measuring of cams lately and I thought I’d post a little info that is different from what most people think.  The Gilxal A9 cam.  First, this is NOT a “ racing” cam.  In fact it has LESS duration then the stock cam.  The Gilxal A9 is what we normally call a torque grind.  The valves are open for a shorter time and the “meat” of the lift is later then the stock cam.

This is very important to those of you trying to get stupid high compression!  If you are running at the upper limit of compression ( like close to 200) swamping the Gilxal cam will make you engine run hotter!  We normally think that a “ hotter” cam is going to lower compression slightly.  This cam raises compression slightly!  Unlike most “torque” cams, it does not have more lift.

with all that said, for some reason, many of us have reported a slight increase in preformance.

i mention all this because it is ultra important that if you switch to this came, you must run some plug chops to see where your mixture is running!

[ratdog]

I copied this over from a different thread. I'm thinking you may not have read thru the dribble in that thread, i figured I'd copy it here

OK. long post about cams, hope you can stay awake to the end

Cam #1
stock from a new icebear 50cc falcon
“CX” on the gear. “6002/p6” on the bearings. Two small holes one large hole

Cam #2
Glixal A9
AT-A9 on gear, 16002 and 'XS” on bearings. 9 holes plus the two small timing holes

Cam #3
OCC Performance cam A9
3 hole like stock 6002/p6 on bearings

Cam #4
Fly Pig performance cam A9
oval with “S” thru it on gear 6002/P6 on bearings three hole like stock cam

Cam #5
cam made it Taiwan Sorta a teardrop inside of teardrop graphic on gear three holes like stock

Cam #1 lift, .187” on intake .179 on exhaust
lift at TDC on intake stroke .008 intake .026 on exhaust
duration intake @.001 162.2 @.005 122.7
exhaust @.001 161.2 @.005 152.8

cam #2 lift .187 on intake .179 on exhaust
lift at TDC on intake stroke .004 intake .021 on exhaust
duration intake @.001 156 @.005 135.2
exhaust @.001 150.8 @.005 119.6

cam #3 lift .187 on intake .182 on exhaust
lift at TDC on intake stroke .009 intake .030 exhaust
duration intake @.001 176.8 @.005 171.6
exhaust @.001 145.6 @.005 140.4

cam #4 lift .182 on intake .176 on exhaust
lift at TDC on intake stroke .020 on intake .010 on exhaust
duration intake at .001 156 @.005 119.6
exhaust at .001 145.6 @.005 119.6

cam #5 lift .186 on intake .179 on exhaust
lift at TDC on intake stroke .006 on intake .022 on exhaust
duration intake at .001 159 @.005 139.3
exhaust at .001 153.2 @.005 121.2

Read more: 49ccscoot.proboards.com/thread/23399/new-project-excited-on#ixzz5QKfCEK3i

[ratdog]

This is a graph showing the A9 and Stock cam profiles. As you can see, there is very little difference in the profile. the biggest difference is that the A9 exaust opens a littler sooner then stock, but also closes a little sooner. On the intake side, the A9 opens a little later and closes a little later But the A9 is not "fatter" and it dose not have more duration.

[magoconnor]

Damn man.. Good work and thanks for all the specs.

[ratdog]

Thank you, at least one person was interested!

[scootnewb]

Good to know. I have that cam and heard it might lower compression and keep it cooler (which turned out to be untrue).

[scooterpimp]

So when will we see ratdog made cams?

[ratdog]

I’m working on a couple right now. ( in the cad stage). My first thought is to get more lift. Non of these cams move the valve more then .183 off the seat, and there is a lot more room. It’s fairly easy. All I have to do is grind the cam circle a few thou smaller. Welding up the lobes to allow a different lobe is a lot more hassle. I’m not good enough a welder to do that, but Walt (earsplitinglounerboomer) or black bike, is a fantastic welder. He is distracted right now working on his drag bike ( has it down to the same bracket as my 600 now)

I’m still hoping to get someone to test these cams on other bikes, but first I have to get good results on our bikes. The other issue is we could loose the weather any time now. I very much doubt we will be riding in Nov. so I’m thinking we may only have 4 or 5 weeks

Stupid has red bike now ( and hasn’t blown it up yet) so we mostly will be expermiting on Walt’s bike... when he isn’t working on the 105

[GrumpyUnk]

Intewesting, vewy intewesting. (in Bugs voice) I could try the voice/accent of German WWII soldier of Laugh In but no one would understand....

So, no more area under the graph. Thus no significant change in performance or power. Hokay. Having the I & E both open and close sooner should be an attempt at lower rpm results rather than overall power developed. At least that's what I figure, to be corrected as necessary.
My thoughts on increasing lift go towards grinding more from the 'heel' side of the lobe, shaped of course, so that the valve at rest will have a higher lift from base to the tip of the lobe. That's what I thought was done rather than welding more material. If course, that is in the enclosed/limited diameter of the cam bearing lobes in an OHV car/truck engine. The total, heel to tip, cannot be larger than the cam bearing diameter. In the 139, the measure is not as limited... If I understand.
tom

[jackrides]

Ratdog, this is a fantastic thread!! Thanks!!

[ratdog]

Grumpy,

The A9 intake actually opens ( slightly ) later and exaust slightly earlier. This is why the duration is less for the A9. Another odd thing, the cam circle and lift are less on the exaust cams.

Years ago, we used to make grinds like this to increase tourque. The Big difference is that on those cams he offset the lesser duration with more lift. In fact if you look at the other “A9” cams I tested, most have LESS lift then stock and less duration then stock.

My first project is grinding the cam circle ( or as you call it the heal side). I have access to both a CNC turning center and a 5 axis CNC machining center. My first thought was to do it on the lathe ( turning center) as I was making a holder for a die grinder to mount on the tool carrier. But the more I think about it, I think I will do it in the machining center( mill) as I already have a 10,000 rpm spindle there. Ofcourse the question is how deep the hardening goes. I decided it’s easier to just grind it then to do any fancy testing.

[ratdog]

Didn’t want this to get lost...

[islandscrub]

As a GY6 newb that just got this cam, am I better off with the stock one? Planning on doing a mini stroke 52mm kit. I have the 64? rocker arms too.

[ratdog]

I believe this cam was designed to give more tourque with a std bore engine. I don’t have anything to prove that, but that is the only thing that makes sense based on the design. As I mentioned in Your other thread, put you engine together with the stock cam. Get the jetting right and everything set up right, then try the cam as it’s own upgrade. I will bet that there is no measurable inprovment. I did it the other way around on blue bike recently. I took a bike that was tuned correctly and working very well with an A9 cam in it, and swapped the cam back to a stock cam. There was zero change in preformance or tune. The guy that owned the bike shares the “new cam” gives him better mid speed acceleration, but the timing number say it’s the same.

OK, I sorta lied to him. I told him I wanted to have him try a “new cam” but didn’t mention it was a stock cam. That is only one example, but along with the measurements I think I can say there is no real inprovment. Two weeks ago, in an equally devious move, I replaced his orange “preformance” CDI with a stock cdi and and reported back that it was much quicker and now started with a touch of the button. Of course I didn’t tell him it was a stock unit. In case your wondering, I have never charged this guy a penny for my labor, and the cam and CDI were both free. He bought his own parts for the orginal BBK.