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Timing
Oct 9, 2010 21:37:30 GMT -5
Post by Jeff Smith on Oct 9, 2010 21:37:30 GMT -5
Ok all.. Here is the million dollar question. Got a small block chevy, Timing is jumping when I try to fire it. It will fire multiple times and run great, shut it off, then all of a sudden, timing will be off 25 to 30 degrees. I'm running mechanical injection with an enderle cover. Cam lash is .009 checked with depth mic. It is the same now as when I set the lash up. Oh... by the way, It has done the same thing with 3 different mags. I have checked all the obvious. cam walk, rotor slop, mag slipping on intake, roll pin in mag shaft, and woodruff key on crank hub and I can't figure it out. I originally had a belt drive on the pump and a stamped steel timing cover and I did find the timing cover bowed out an 1/8 of an inch so pushed the cam back in and I switched to the cast aluminum enderle cover and cam drive pump and it is still doing it! HELP!!!
Jeff
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Timing
Oct 9, 2010 23:41:41 GMT -5
Post by hyerus1 on Oct 9, 2010 23:41:41 GMT -5
HAS THE BLOCK BEEN LINE BORED ON THE CAM & THE MAINS? IF SO, YOU NEED TO COMPENSATE FOR THE EXTRA DISTANCE. ie: .005-.010 ON THE CHAIN OR GEAR DRIVE. JUST MY 2 cents. OZZIE.
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Timing
Oct 10, 2010 0:06:52 GMT -5
Post by GregM784 on Oct 10, 2010 0:06:52 GMT -5
Balance possibly broke & slipping? Key broke on the crank and the balancer is spinning on the crank?
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Timing
Oct 10, 2010 19:01:57 GMT -5
Post by Jeff Smith on Oct 10, 2010 19:01:57 GMT -5
block had mains line bored at least twice, but how do you compensate for crank being closer to cam (pete jackson gear drive, by the way) and the dampner key was one of the first things I checked. And this problem just started happening at the last ANRA race.
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Timing
Oct 10, 2010 19:26:35 GMT -5
Post by hyerus1 on Oct 10, 2010 19:26:35 GMT -5
JEFF, A COUPLE OF WAYS TO CORRECT THE PROBLEM. 1st- GET RID OF THE GEAR DRIVE. YOU HAVE TO MEASURE CENTERLINE OF CAM TO CRANK. CLOYES & COMP CAMS MAKES A .005 & .010 TIMING CHAIN SET. IF THE CENTERLINE IS OVER THE .010 CHAIN, THEN COMP MAKES A TENSIONER FOR THE CHAIN. YOU HAVE TO DRILL IN THE FRONT OF THE BLOCK TO MOUNT IT TO KEEP TENSION ON THE CHAIN.<FITS UNDER THE TIMING COVER>. HAD TO DO THIS ON MANY OLDER BLOCKS. BE VERY CAREFUL NOT TO DRILL INTO THE WATER JACKET. HOPE THIS HELPS. PS, THE CLOYES & COMP WEB HAVE INSTRUCTIONS ON MEASURING CAM TO CRANK CENTERLINE. OZZIE.
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Timing
Oct 11, 2010 22:06:25 GMT -5
Post by Jeff Smith on Oct 11, 2010 22:06:25 GMT -5
Yeah but slop in a gear drive isn't going to make it jump 22 to 25 degrees consistantly. And like I said, I've ran in the 8's with this combo. but now all of a sudden, timing is jumping. It don't make sense to me
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Timing
Oct 11, 2010 23:03:27 GMT -5
Post by hyerus1 on Oct 11, 2010 23:03:27 GMT -5
JEFF, NOT TO GET INTO A DEBATE BUT I HAD A "PETE JACKSON" GEAR DRIVE ON MY ALTERED THAT DID EXACTLY THE SAME THING. I PUT A CLOYES .005 AFTER CHECKING CENTER TO CENTER AND IT SOLVED THE TIMING PROBLEM. THE DUAL IDLERS ON THOSE GEAR DRIVES NOT ONLY CREATE SLOP IN THE TIMING & VALVE TRAIN, BUT ALSO COME APART VERY FREQUENTLY. I"M ASSUMING YOU ARE ON & OFF THE THROTTLE ON THE BIG END WHICH ONLY COMPOUNDS THE PROBLEM. YOU ASKED ANRA FOR HELP SO GREG & I RESPONDED. KEEP US UPDATED ON YOUR FINDINGS. OZZIE.
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Timing
Oct 12, 2010 18:14:06 GMT -5
Post by Jeff Smith on Oct 12, 2010 18:14:06 GMT -5
Actually no.. I can't get it to stay in time long enough to get it past the burn out box
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