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Thread: Olds Cam Timing

  1. #1
    Taylorman
    I was wondering if I would see any performance increase by changing my cam timing. When I built the motor last winter and put the cam in, I just used the center slot on the cam timing gear. There is two other slots, one for 4 degrees advanced and 4 degrees retarded. I was not sure on whether to advance or retard it so I just used the center notch. I have to pull the engine out before the summer for and oil leak and was thinking about changing the timing to see if that does anything for me.

  2. #2
    fourspeednup
    Careful if you have that POS cast aluminum timing cover.

  3. #3
    Taylorman
    Originally posted by fourspeednup
    Careful if you have that POS cast aluminum timing cover.
    I did not ask anything about a timing cover. If you can't contribute to the question with useful information, please refrain from making comments about information that i did not ask about.

  4. #4
    Wet Dream
    Originally posted by fourspeednup
    Careful if you have that POS cast aluminum timing cover.
    Cast aluminum timimg cover? The majority of the ones that I've paid attention to have all been metal. The water pump plate is aluminum.
    But to your question, here is a 2 part answer...
    #1) Degree the cam. The timing/ grind might not be as accurate as you might think and over timing the cam might hurt you.
    #2) Just from the way my twisted little mind thinks, here's my take on it. Todays engines have variable cam timing. They ADVANCE as the rpms get higher. With our engines spending a majority of the time at 3000 rpms and up, it would probably run better in the higher end with the 4* adv.
    PS: What cam and grind did you go with?

  5. #5
    Mr Twister
    Wet Dream, I think that you may have confused ignition timing with valve timing on statement #2. Anyhow, degreeing a cam is important. Sometimes with production tolerances on the timing set and cam it will be off. By just lining up the marks, you really don't know where the valve timing is at. BTW a lot of "off the shelf" cams are ground 4 degrees advanced. Install the cam as per the cam card. If you are motivated, you can move the cam around (advance/retard) and see what happens. Jets have a built in dyno-the Tach, Increase in RPM's=increase in POWER.

  6. #6
    malcolm
    Are you going to stick with the year old timing set? If so, it may be stretched out just enough to use the + side. The only way to be sure is to get out the degree wheel and dial indicator and check it. Mine was almost perfect in the zero slot with a new true roller (cast cam gear) timing set. I did notice that late in the season the new chain was already getting loose. I'll be checking that out in the spring to see how much I lost.

  7. #7
    MAD-MarKist
    Originally posted by Taylorman
    I did not ask anything about a timing cover. If you can't contribute to the question with useful information, please refrain from making comments about information that i did not ask about.
    YEAH!,what Taylorman said!!

  8. #8
    TIMINATOR
    Changing the cam positioning may change the Horsepower peak by 5-10 H.P., since a typical jetboat requires 20 H.P. per mile an hour gain, its usually a waste of time. Change the cam (BIGGER!)and degree it next time so you know what you have. The smallest jetboat cam we use is 224 @ .050, the most common ones are 230 @ .050 and 244 @ .050. Depending on your motor and impeller,you may want to go larger yet. Post your specifics and we can recomend somthing. TIMINATOR

  9. #9
    Taylorman
    Its an ISKY 280 adv duration, 232 @ .050 with 517 lift and 110 lobe separation. I don't have an adjustable timing set, its a cloyes double roller with 3 positions to set the cam timing at. Im not that motivated to degree the cam cause I don't have the tools. Just wondering if advancing or retarding it will do anything for me? Thanks.

  10. #10
    bigkatboat
    Do you know your static compression? What are the other factors? Heads? Headers? Intake? Pump set-up? What cam is in the motor now, is it a secret? 8.5 to 9.0 compression, use 470/500 lift, with 210/215 @.050 intake, 215/220 @0.50 exhaust. These are on 110 centers, 3 advanced. 9.4 to 10 compression can run 230/235 @ 0.50, intake and 235/240 @ 0.50 exhaust, on 108 centers, advanced 2 degrees. This bigger cam can run, 500/ 525, intake, and 510/540 exhaust. More than 10 to 1 you will need 'race gas' @ 32 degrees ignition timing. If you want to go 'out of the box' run Isky's 280 MEGA @ 2 advanced. Run an 850 Holley (80/3.5 PV, 84) 180 degree manifold (stealth) 32 total (electronic dist), Isky Mega 280 (565/232,565/232, on 108 @ 106) Headers, external oil return hoses (NO OIL RESTRICTORS) 120 seat presure, 330 over the nose, 10 quart pan, GOOD rod bolts, .0015" oil pump clearance, TIGHT main and rods (.0015") 30 weight Kendall oil. This bitch will RUN. The pump must be A-B, not B! Good luck!

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