Cam Question DYNO PROBLEM
VALVE TIMING @.006 INTAKE TIMING OPEN 34 DEGREES
SO AT .006 ON DIAL GUAGE AND ON MY DEGREE WHEEL I HAVE 28 DOES THAT MEAN IM RETARDED 6 DEGREES? I HAVE A 9 WAY ADJUSTABLE TIMING SET AND I INSTALLED IT DOT TO DOT IS THIS NORMAL AND IS A GOOD IDEA TO RETARD IT SO I CAN GET INTO SPEC WITH CAM CARD.
I AM DEGREEING THE CAM BECAUSE I HAD IT DYNOED AND WE HAD A PROBLEM WITH THE ENGINE GOING LEAN AT 3000rpm ON THE DYNO.THE TUNNER TRYED TO ADD FUEL AND TIMING AND TOOK SOME AWAY, BUT HAD NO LUCK FIXING THE SUDDEN LEANING PROBLEM. HE GOT IT TO GRADUALY PICK UP TROUGH THE POWER BAND AFTER THE LEANING AT 3000rpm .AND THE MECHANIC SAID THE HEADERS STARTED TO GLOW RED ON THE DYNO AT 3000rpm AND WENT CHERRY AT 5900rpm,SO THE TUNNER RECOMMENDED ME TO CHECK THE TIMING CHAIN PLACEMENT AND HERE I AM.
VALVE TIMING @.006 INTAKE TIMING OPEN 34 DEGREES
SO AT .006 ON DIAL GUAGE AND ON MY DEGREE WHEEL I HAVE 28 DOES THAT MEAN IM RETARDED 6 DEGREES? I HAVE A 9 WAY ADJUSTABLE TIMING SET AND I INSTALLED IT DOT TO DOT IS THIS NORMAL AND IS A GOOD IDEA TO RETARD IT SO I CAN GET INTO SPEC WITH CAM CARD.
I AM DEGREEING THE CAM BECAUSE I HAD IT DYNOED AND WE HAD A PROBLEM WITH THE ENGINE GOING LEAN AT 3000rpm ON THE DYNO.THE TUNNER TRYED TO ADD FUEL AND TIMING AND TOOK SOME AWAY, BUT HAD NO LUCK FIXING THE SUDDEN LEANING PROBLEM. HE GOT IT TO GRADUALY PICK UP TROUGH THE POWER BAND AFTER THE LEANING AT 3000rpm .AND THE MECHANIC SAID THE HEADERS STARTED TO GLOW RED ON THE DYNO AT 3000rpm AND WENT CHERRY AT 5900rpm,SO THE TUNNER RECOMMENDED ME TO CHECK THE TIMING CHAIN PLACEMENT AND HERE I AM.
Headers red hot: Rich fuel condition - fuel burning in your primaries. Can be caused by un-metered air being pulled in downstream of your MAF, dramatically retarded timing, low spark intensity (incomplete fuel burn)..."
Our experience is that,we seen a couple GN buicks on the dyno and the headers would glow red because the timing was so retarded at wot.
Last edited by C/Performance; Jan 2, 2011 at 09:31 AM.
VALVE TIMING @.006 INTAKE TIMING OPEN 34 DEGREES
SO AT .006 ON DIAL GUAGE AND ON MY DEGREE WHEEL I HAVE 28 DOES THAT MEAN IM RETARDED 6 DEGREES? I HAVE A 9 WAY ADJUSTABLE TIMING SET AND I INSTALLED IT DOT TO DOT IS THIS NORMAL AND IS A GOOD IDEA TO RETARD IT SO I CAN GET INTO SPEC WITH CAM CARD.
I AM DEGREEING THE CAM BECAUSE I HAD IT DYNOED AND WE HAD A PROBLEM WITH THE ENGINE GOING LEAN AT 3000rpm ON THE DYNO.THE TUNNER TRYED TO ADD FUEL AND TIMING AND TOOK SOME AWAY, BUT HAD NO LUCK FIXING THE SUDDEN LEANING PROBLEM. HE GOT IT TO GRADUALY PICK UP TROUGH THE POWER BAND AFTER THE LEANING AT 3000rpm .AND THE MECHANIC SAID THE HEADERS STARTED TO GLOW RED ON THE DYNO AT 3000rpm AND WENT CHERRY AT 5900rpm,SO THE TUNNER RECOMMENDED ME TO CHECK THE TIMING CHAIN PLACEMENT AND HERE I AM.
Headers red hot: Rich fuel condition - fuel burning in your primaries. Can be caused by un-metered air being pulled in downstream of your MAF, dramatically retarded timing, low spark intensity (incomplete fuel burn)..."
Our experience is that,we seen a couple GN buicks on the dyno and the headers would glow red because the timing was so retarded at wot.
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On a symetric lobed cam you can estimate intake centerline if you have both an opening and a closing measurement but most of the cams I see for these cars have asymentric lobes and this method may not work (or will be far more difficult).
Every cam dial in card I have seen it the past 10 years includes an intake centerline reading (intake at higest lift).
Another problem is if you are using hydraulic lifters there is NO real way besides intake centerline to degree the cam. See Tony Mamo's (AFR guru) take on this in this thread https://ls1tech.com/forums/generatio...ay-method.html
A couple of thousands lifter compression would have that much effect on timing at .006.
Along with checking for rich mixture and retarded ingniton timing I would also verify I did not have too much exhaust restriction. I'd do a "back pressure" test. take an O2 sensor out, replace with a plug that has a port to hook up a low pressure fuel/vacuum gauge. Either have a long peice of steel tubing from this plug before you get to rubber hose to gauge or use a hi temp silicone hose and do this test quickly. You can make this plug out of an 02 sensor bung plug. Be easier that checking cam timing. Anything over 1 PSI is restrictive. If you have over 3 PSI it can also cause cherry red manifolds and power would not gain as quickly (or at all) past the restrictive flow point.
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You set intake centerline at 110 degrees and then "check" it at .006 as well. I wouldn't worry too much regarding the readings being a bit off at .006
Intake centerline is a BUNCH easier to get right and maybe the only "spec" you can really determine when using hydraulic lifters as no amount of bleed down will change the point of highest lift. The point of highest lift should be real close to 110 on your degree wheel. Adjust to this point and all should be well.


