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new cam but have a timing problem

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by slider79blazer, May 13, 2001.

  1. slider79blazer

    slider79blazer 1/2 ton status

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    I put a comp cam 4x4 extreme cam in with new lifters and timing chain.it runs good at idle but when I put it in drive it shakes bad and barely idles. I adjusted my timing but I can't get it right. there is a quadjet on it. I changed some vacuum lines it runs a little better. it has good torque when i stomp my foot to the floor. the problem is just idling in drive.I did try my mixture screws to but not much difference.I forgot to tell you its a 79 k5 400c.i. any help greatly appreciated.

    whats a 4 letter word for farm wagon? (ford) [​IMG]
     
  2. Sparky

    Sparky 1/2 ton status

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    Do you have a timeing gun? Were you using it? Other wise, I would guess a vacume leak somewhere since you obviously just had the intake off. Maybe where the carb meets the intakemanifold. Also, if you took the heads off, maybe an exaust leak.

    Sparky

    When all else fails... Check the blinker fluid.
    78 K-5
     
  3. i agree-sounds like a vac leak. try spraying some starter fluid around the base of the carb and where the man. meets the heads. did you make sure all vac ports were hooked up or plugged? what are the specs on the cam? let me know how you like it when you get it dialed in.[​IMG]

    78, 350/350/203, 3/4 ton, 4" lift, 35" BFGs
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  4. slider79blazer

    slider79blazer 1/2 ton status

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    I didn't take the heads off and did use a timing gun but i had to advance it pretty far to make it run. i'll try spraying carb cleaner. the specs are duration @ .050"- int. 210deg. exh. 218deg. lift- int. .447" exh. .462 part# cca-12-235-2 in summit catalog. I like the cam so far it has alot of torque and power it just needs the fine tuning to make right. even running like it is I can still break the 35" tires w/3.73's loose.

    whats a 4 letter word for farm wagon? (ford) [​IMG]
     
  5. ftn96

    ftn96 1/2 ton status

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    Well, Im not real sure but it sounds like with that .218 lift is trying to turn your torque convertor nad your not letting it turn the tranny cause your holding down the brake. Thats why most people would not recommend anything over .214 lift on a street driven auto without having a higher stall convertor. The higher stall convertor while in gear will let the engine rumble and bark like it does in neutral until you reach the required RPM to make the TC turn. This may be your problem and will be my guess. Did you have any problems like this before you install ed the cam?

    Will work for beer, parts and tools.
    90-350TBI-TCI700-241-33"-10/12 bolt w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  6. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Uhhhhh when you put the cam in did you happen to leave the 2 dots on the cam and crank gear pointing at each other? Was it back firing through the carb when you were trying to get it to run? If so you put the distributor in 180degres out. It will run but run REAL bad. Both dots are up for TDC but you install the cam with them facing.

    Diging it in the dirt with my K5's
    Grim-Reaper
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  7. slider79blazer

    slider79blazer 1/2 ton status

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    I did have the timing marks lined up. I might check into the stall converter becuase it ran fine before. I also sprayed it with carb cleaner today i didn't find ant leaks.
    thanks for the help I'll keep trying.

    whats a 4 letter word for farm wagon? (ford) [​IMG]
     
  8. ftn96

    ftn96 1/2 ton status

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    Well, just cause it ran right before doesnt narrow it down to the TC. Ok, so it runs good at idle in neutral, and it runs like crap in drive at idle. Does it run good after you let off the brake and start driving? Like say anything over 5 or 10 mph?

    Will work for beer, parts and tools.
    90-350TBI-TCI700-241-33"-10/12 bolt w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  9. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Hummor me. Put it on the timming mark. Lift the distributor up. Turn the crank one time and put the distributor in. I really think your 180 out. It will idle with no load 180 out. It will not run in gear. I have made this same mistake 2 times. I bet when in gear when you hit the throttle it's poping through the carb.

    Diging it in the dirt with my K5's
    Grim-Reaper
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  10. ftn96

    ftn96 1/2 ton status

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    Grimmy, for $$ sake I hope you are right, but I just went back and read his 1st post and he said the only time he is having a problem is at idle in drive, other than that it runs good.
    With 180 out, will it (run) after you get past idle and start rolling? Have never experienced this?

    Will work for beer, parts and tools.
    90-350TBI-TCI700-241-33"-10/12 bolt w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  11. slider79blazer

    slider79blazer 1/2 ton status

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    yes it runs fine when i let off the brake. and grim i thought 180 off was it before to but my buddy said it wouldn't run when I tried to drive. I set the distibutor on #1 TDC compression and the rotor on # 1 plug wire. the problem is just holding the brake down in drive. I'm about ready to pull my hair out.

    whats a 4 letter word for farm wagon? (ford) [​IMG]
     
  12. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Ok I missed that it ran once off the brake. that didn't click.
    Hmmmmmmmm Uhhhh Not hearing a lot of his when holding the brake are you? With that much cam your probably not pulling a lot of vac at idle. Normal cam usualy pull around 20inches if the motor is tight. Have you put a gage on it and checked to see what your pulling then put your foot on the brake and check again? Maybe your booster took a dump and you got a major vac leak. if that were true then you wouldn't pull enough vac to pull the fuel through the carb.

    Diging it in the dirt with my K5's
    Grim-Reaper
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  13. slider79blazer

    slider79blazer 1/2 ton status

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    I don't have a vacuum guage but now i'll get one. the engine is stock except for the cam and headers about 177,000 miles on it.the boosters still the stock one so i'll check it out thanks.

    whats a 4 letter word for farm wagon? (ford) [​IMG]
     
  14. ftn96

    ftn96 1/2 ton status

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    From what I've been told, you will loose vacum the higher the lift. But I've never heard of anyone loosing that much with this amount of lift. Usually, again from the gears heads I know, you will loose vacum to the booster and you will losse your brakes. These are example of running $hit like lift in the .3ish area. So I wouldn't think that would be the problem. HOWEVER, like Grimmy said, you might be lossing just enuff to cause problems. I'll ask around here and see what I can find. Less you get it fixed first. Good luck man.
    Hell, just drive it for now and out it in neuttral when your stopped adn drop it in gear when the light turns green, with the gas on the floor. LMFAO!!!!

    Will work for beer, parts and tools.
    90-350TBI-TCI700-241-33"-10/12 bolt w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  15. curtis151

    curtis151 Newbie

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    I have the same comp cam in my blazer(350).I don't have any problems with it.you don't need a new torque converter my stock converter works great.i had called comp cams help line to ask what to set my timing at with the changes i made.you say you have 177,000 miles on that engine,did you replace your cam bearings?Mine were shot with a lot less miles when i rebuilt mine.......................good luck
     
  16. slider79blazer

    slider79blazer 1/2 ton status

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    no I didn't check the cam bearings how do you know if they are bad? I bought new plugs and wires I'll put those on and see. I didn't rebuild the carb either I might try that also. in my gut I think im have a fuel problem either to rich or lean i've played with the mixture screws it seems better sometimes then when i turn it off and then start it later it seems to go back to crap. thanks for the help everyone i'll keep you posted.

    whats a 4 letter word for farm wagon? (ford) [​IMG]
     
  17. ftn96

    ftn96 1/2 ton status

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    You may just need to replace your fuel pump or hell, even the fuel filter. You rig will need a lot more gas now at idle in gear, and your filter may be cloged enough to prevent that or the pump may not have enuff RPM's in gear at idle to pump enuff gas up there. These would be to cheap troubleshooting trys.

    Will work for beer, parts and tools.
    90-350TBI-TCI700-241-33"-10/12 bolt w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     

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