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| JG33Replica |
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Hi can someone please explain how to degree in this camshaft it is a crow cam in my 351 Cleveland. On the cam card it says Inlet Lobe lift at TDC on the overlap : .080
what I need help to understand is what is the overlap. just some simple step by step instructions would be good. I have dial indicator and degree wheel. Do I just start with it set up at TDC and then do what ??? I have degreed a cam in before but it was a little simpler. All I had to do was set the last one at 78 thou lift at 50 degrees of crank rotation from TDC. any help greatly appreciated.
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| BOTTLEDUP |
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What is the cam part number? It might be easier to just dial the cam in to the intake centreline.
TDC on overlap is referring to the end of the exhaust stroke & start of the intake, ie exhaust valve is just shutting & intake starting to open. Set your dial indicator up to work off #1 intake lifter or directly on the cam lobe if you can. Find TDC where the inlet is starting to open, then advance or retard the cam from the 0° position until you have it as close to the stated lobe lift.
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| JG33Replica |
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Hi thanks for replying I could send you a copy of the cam card but if the number helps it is Crow P/N 21649 it is hydraulic. Engine is assembled in the car. I am changing cam gear set and I just want to make sure it is dialled in or at least close. I have a lot of trouble with pinging because of high comp ratio. I will probably set dial indicator up on end of push rod and measure from there. I am using anti pump lifters and it has guide plates so should get a reasonably accurate measurement from there I hope. now what you have said to do is find the exact position where inlet starts to open then zero my dial indicator and advance or retard the gears till I get .080 lift. Am I on the same page.
regards Darryl...
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| XR9UTE |
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Be better to run your dial gauge off the edge of the lifter Darryl because the lifter will likely compress and throw out your readings. Is the high compression due to 302 heads? Did you polish the combustion chambers before fitting? That cam should help too.
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| JG33Replica |
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No I don't believe combustion chambers are polished, yes they are 302 heads. I would change them but they have had a lot of good work done and it would be a shame. so polishing the chambers must help then. I may have to give it a go.
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| XR9UTE |
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{USERNAME} wrote: No I don't believe combustion chambers are polished, yes they are 302 heads. I would change them but they have had a lot of good work done and it would be a shame. so polishing the chambers must help then. I may have to give it a go. Yep make em shiny...it really does help. |
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| xafalcon |
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Somethings not right. I can run 302 cleveland heads on a flat top 351 with a hydraulic cam 10° less @ 050 without any pinging using BP Ultimate or equivalent 98 RON pump fuel and I still run an optimised spark advance curve. So with a bigger cam you should be further away from the detonation threshold. If you are sure it's pinging, I think you're on the right track with cam timing. If the intake lobe is symetrical I would use the intake centerline method to dial it in - two measurements are always better than one. What pre-load did you run on those anti-pump lifters? They work best with only a few thou pre-load, say 5 thou. Don't set them up with the regular 40-60 thou pre-load that standard hydraulic lifters run
_________________ XA Faimont 351C, AU2 XR8 Manual 5.0, DA LTD 5.0, Mk1 Capri 5.0, 1995 Mustang 5.0, EF2 XR8 Manual, EF2 Fairmont Ghia 5.0, AU3 XR8 Auto, AU2 XR8 Auto, AU2 XR8 Manual Ute, TE Cortina 5.0 Manual, DU LTD 5.0 soon to be manual |
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| JG33Replica |
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thanks for the advice It is pinging no doubt. I have even wondered about the dizzy if it may not be operating correctly. something I will do is send another I have away to be curved. I have YT roller rockers and have set pre load at just half a turn on the nut. so don't know exactly what that amounts to. so you would be suggesting maybe set them at close to zero lash. how would you measure 5 thou preload.
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| xafalcon |
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Adjuster thread pitch is 7/16-20. So 20 full (360°) rotations = 1 inch, 1 rotation = 50 thou. etc.
Put a timing light on the motor, remove the vacuum advance hose if you have one & block it off, check timing @ idle, 1000rpm, 1500, 2000, 2500 etc up to about 5500rpm. A good advance curve should start advancing around 1250-1500, and be at full advance by around 3250-3500. Full advance (incl initial, excl vac) with 302C heads & 98 octane fuel should be around 32-34°. This is a generalisation, but will be close to optimum
_________________ XA Faimont 351C, AU2 XR8 Manual 5.0, DA LTD 5.0, Mk1 Capri 5.0, 1995 Mustang 5.0, EF2 XR8 Manual, EF2 Fairmont Ghia 5.0, AU3 XR8 Auto, AU2 XR8 Auto, AU2 XR8 Manual Ute, TE Cortina 5.0 Manual, DU LTD 5.0 soon to be manual |
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| JG33Replica |
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Thanks as soon as I get cam dialled in I will set up as described and let you know.
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