 Guess my cam!, Any suggestions. |
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| toecutter |
 Apr 15 2005, 11:54 AM
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#1
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Kid Close Enough  Group: Members Posts: 37 Joined: 6-March 05 From: Sherman, Texas Member No.: 3,723  |
Is there any way to figure out what kind of cam the PO installed without splitting the case? The reason I ask is since I need to clean/rebuild the carbs I want to make sure they are set up for the cam. Is there a trick or am I SOL? FYI this is a 2.0 with what I am told are 1.7 heads. The carbs are Weber 40 IDF's (not 44's). I have a Compufire and SS heat exchangers. It was running like a spotted ape until recently because of grunge getting into the carbs. The fuel filters looked like they had a little poop in them. I digress. I believe the PO bought the webers and put them on right out of the box. Just looking for some advice (as always).
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| skline |
Apr 15 2005, 11:56 AM
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#2
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Born to Drive Group: Members Posts: 7,910 Joined: 26-December 02 From: Costa Mesa, CA Member No.: 17 Region Association: Southern California |
Nope, its a tear down in order to determine your cam.
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| MattR |
Apr 15 2005, 12:04 PM
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#3
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Advanced Member Group: Members Posts: 3,279 Joined: 23-January 04 From: SF Bay Area Member No.: 1,589 Region Association: Northern California |
Cant you figure out valve lift without a teardown? Duration would be tough, but if you know lift maybe you could narrow it down?
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| Dr. Roger |
Apr 15 2005, 12:17 PM
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#4
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A bat out of hell. Group: Members Posts: 3,944 Joined: 31-January 05 From: Hercules, California Member No.: 3,533 Region Association: Northern California |
Is your crank puley degreed and can you see it?
If so remove one valve cover. Then pick one cylinders intake exhaust valves. Hand crank slowly until you note the intake to just begin to open. Note how many degrees before top dead center it is (TDC). Continue turning (did I mention it must turn in correct direction) until it just closes. Note how many degrees after TDC. Do same for the exhaust. How many degrees were the intake and exhaust valves open for? Also note, this will not be accurate due to valve lash but can get you close... (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) |
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| Aaron Cox |
Apr 15 2005, 12:39 PM
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#5
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
i agree....
you can see (within a relatively close range) what your lift is by measuring lift at the rocker. how much did the pushrod move? like the above mentioned.... if you had a degreed pulley you could check your duration.... match the numbers up to web/elgin/eagle/isky cam specs and you can take an eductaed guess..... |
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| Mueller |
Apr 15 2005, 12:42 PM
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#6
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None 
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get a dial indicator and you can get a good idea on the lift of cam....
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| bondo |
Apr 15 2005, 12:55 PM
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#7
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Practicing my perpendicular parking Group: Members Posts: 4,277 Joined: 19-April 03 From: Los Osos, CA Member No.: 587 Region Association: Central California |
Have it dyno tuned.. if you make more power than should be possible with a stock cam, it must be something else (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)
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| ArtechnikA |
Apr 15 2005, 01:55 PM
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#8
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rich herzog Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
although .. measuring lift at the valve, you have to factor out the rocker arm ratio. you need to measure lift at the lifter (or pushrod) to see the same numbers the cam people use... |
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| Aaron Cox |
Apr 15 2005, 02:07 PM
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#9
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Professional Lawn Dart Group: Retired Admin Posts: 24,541 Joined: 1-February 03 From: OC Member No.: 219 Region Association: Southern California |
or divide out your rocker ratio (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) yeah... just dial indicate your pushrod.... |
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| TimT |
Apr 15 2005, 05:20 PM
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#10
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retired Group: Members Posts: 4,033 Joined: 18-February 03 From: Wantagh, NY Member No.: 313 |
(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif)
you can find out lift and duration with a degree wheel and a dial indicator. take all play out of the valvletrain ie zero lash, then measure at lift at the pushrod. You can plot reading etc max lift of X in at X degree of crank rotation, then repeat with the other lobe. you can even plot the lobe profile. to see how rapidly the valve is opening.. |
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