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Old 07-13-2020, 05:29 PM
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Default adjusting hft

so I'm setting my Rhoads v max on my hft crower cam. Supposedly when the exhaust valve begins to open you adjust the intake which is what i did. With a .015 you can spin the pushrod but with a .017 you can't. Good. Supposed to be between. 010 and .020. If I then rotate the engine til that exhaust valve is fully open the .017 feeler gauge loosens up some. Then as the exhaust starts to close it tightens back up on the feeler. Am I not fully on the base circle if the feeler loosens up a little when the exhaust is fully open instead of just starting to open?

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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007
(cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD
1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86'
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Old 07-13-2020, 05:47 PM
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I'm not a fan of the IE method. It's just a faster way to run through the valves for those in a hurry, but I find it doesn't always get you "exactly" on the base circle, and on some of these aftermarket cams that can vary a bit depending on the lobe used.

The way I prefer to get them exactly on the base circle for a precise adjustment is one at a time. Rotate the engine until peak lift is reached on the lobe you're adjusting. I mark the balancer (piece of tape) and turn the engine one complete revolution, which turns the camshaft exactly 180 degrees and puts that lobe dead center on the base circle. Make my adjustment and move on to the next one and repeat procedure.

Most don't do it this way because it's time consuming and many don't like the effort needed to turn the engine over that much, but it's precise and accurate no matter what lobe profile is used and the only way I'll adjust a hydraulic or a solid.

Try that on a couple lobes and see if you get a different result. If you do, that tells me the IE method isn't working well for your lobe profile.

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Old 07-13-2020, 06:17 PM
grandam1979 grandam1979 is offline
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i have never done it like that but that’s a great idea a specially if you have a stock balancer. Like you said time consuming but removing the plugs would make it much easier also.

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Old 07-13-2020, 06:19 PM
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Originally Posted by grandam1979 View Post
i have never done it like that but that’s a great idea a specially if you have a stock balancer. Like you said time consuming but removing the plugs would make it much easier also.
Yes I highly recommend removing the plugs My arm gets tired after a while even with the plugs out, but, I just like the accuracy of doing it this way.

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Old 07-13-2020, 06:20 PM
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Quote:
Originally Posted by scott70 View Post
Am I not fully on the base circle if the feeler loosens up a little when the exhaust is fully open instead of just starting to open?
Something else is going on. The base circle is everywhere outside of the ramps.
Example Magnum hyd flat lobe 5217 that is 253 @ .050 --- from ramp edge to ramp edge is about 346 crankshaft degrees. So there is about 374 crankshaft degrees of base circle. Exhaust just opening will be safe to adjust the intake.

Maybe you're catching runnout?

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Old 07-13-2020, 06:59 PM
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plugs removed already. I started on the driver side now. The 1st one I did comes out the same way. Exhaust valve just starts to open and I had the intake to where I can get a .015 feeler and spin the push rod but can't spin it with a .017 feeler. Rotate the engine a little more until the exhaust valve is fully open and with a .018 feeler I can spin the push rod but can't with a .019. So it loosenes up an additional. 002. Still within the 010 the 020 range for these lifters but odd. Ill experiment with the exhaust valve and see if it is the same way

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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007
(cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD
1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86'
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Old 07-13-2020, 10:22 PM
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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007
(cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD
1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86'
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Old 07-14-2020, 05:55 AM
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Intake fully open set the exhaust beside it.

Exhaust just starts to open set the intake beside it.

The OF roller can in my engine is all over the map across the base circle, not sure which chainsaw Comp used to cut it back in 2009, but it’s been doing fine now for over ten years tight lashed at .005” with Crower HIPPO solid roller lifters.

I just don’t get to fussy about slight deviations when checking it, and it’s even less critical with your hydraulic lifter set up ....

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Old 07-14-2020, 08:12 AM
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Quote:
Originally Posted by Cliff R View Post
Intake fully open set the exhaust beside it.

Exhaust just starts to open set the intake beside it.

The OF roller can in my engine is all over the map across the base circle, not sure which chainsaw Comp used to cut it back in 2009, but it’s been doing fine now for over ten years tight lashed at .005” with Crower HIPPO solid roller lifters.

I just don’t get to fussy about slight deviations when checking it, and it’s even less critical with your hydraulic lifter set up ....
All the stuff I read was adjust the exhaust when the intake is almost closed. Does it make a difference doing it the other way of intake fully open adjust exhaust? Probably im close enough anyways.

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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007
(cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD
1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86'
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Old 07-14-2020, 10:47 AM
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Adjusting the exhaust with the intake fully open to closed should result it the same lash. Base circle for the exhaust should be through that entire rotation from max lift on the intake through the majority of the compression stroke. We usually rotate the engine so the intake is past well past full open on the closing side of the ramp then set the exhuast lash.

What you are describing does describe run out on the cam. FWIW. Setting the vmax lifters for function I would go by the tighter lash that was measured. Setting vmax for noise probably would use the loose lash reading.

Like you said though. You have it close enough.


Last edited by Jay S; 07-14-2020 at 10:48 AM. Reason: Edit
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Old 07-17-2020, 02:17 PM
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Quote:
Originally Posted by Cliff R View Post
Intake fully open set the exhaust beside it.

Exhaust just starts to open set the intake beside it.

The OF roller can in my engine is all over the map across the base circle, not sure which chainsaw Comp used to cut it back in 2009, but it’s been doing fine now for over ten years tight lashed at .005” with Crower HIPPO solid roller lifters.

I just don’t get to fussy about slight deviations when checking it, and it’s even less critical with your hydraulic lifter set up ....
you are right cliff,,,with intake fully open the exhaust is at its loosest instead of using almost closed.

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72 lemans,455 e-head, UD 255/263 solid flat,3.73 gears,,,10" 4400 converter,, 6.68 at 101.8 mph,,1.44 60 ft.2007
(cam 271/278 roller)9"CC.4.11gear 6.41 at 106.32 mph 1.42 60 ft.(2009) SOLD,SOLD
1970 GTO 455 4 speed #matching,, 3.31 posi.Stock manifolds. # 64 heads.A factory mint tuquoise ,69' judge stripe car. 8.64 @ 87.3 mph on slippery street tires.Bad 2.25 60ft.Owned since 86'
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