lots of posts about the tick tick tick sounds... none seem to be conclusive. I'm asking if anyone has found a definitive answer to the ticking noise coming from the valvetrain? i've seen a post about comp magnum hydraulic roller lifters. but what is the difference between these http://www.summitracing.com/parts/CCA-885-12/ and these http://www.summitracing.com/parts/CCA-875-12/... any information on ticking or noise associated with valvetrain on a high lift cam would be appreciated. cam specs on a 1.5 rocker = .498/.498 218/226@.050 on a 114LSA... planning to go to a 1.6 rocker .530/.530 220/228?@.050 114lsa. thanks in advance guys
just want to clear things up
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Quickstop [UK]
Combating adversyty.
Re: just want to clear things up
The 885s look like they are meant to be in direct contact with the cam and the rocker arms and not for our trucks. The 875s are a push rod variant.
875s differ from the stock lifters/850-12 in that the retainer is a better design instead of a paper clip. Also, the spring inside the 875 is firmer.
I have had bad luck with lifters that are not retaining oil pressure and this means that when the cam lobe comes round, the slack in the lifter is taken up by the spring. The lifter compresses and the internals collide = tick.
If the oil pressure was maintained then the lifters would have 0 gap and the engine would run smooth as silk.
The definitive answer has been found - poor manufacturing control = lifters that aren't quite good enough. I am going to write to Comp Cams and see if they have any comment.
The 885s look like they are meant to be in direct contact with the cam and the rocker arms and not for our trucks. The 875s are a push rod variant.
875s differ from the stock lifters/850-12 in that the retainer is a better design instead of a paper clip. Also, the spring inside the 875 is firmer.
I have had bad luck with lifters that are not retaining oil pressure and this means that when the cam lobe comes round, the slack in the lifter is taken up by the spring. The lifter compresses and the internals collide = tick.
If the oil pressure was maintained then the lifters would have 0 gap and the engine would run smooth as silk.
The definitive answer has been found - poor manufacturing control = lifters that aren't quite good enough. I am going to write to Comp Cams and see if they have any comment.
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Re: just want to clear things up
After discussing valve train noise with my engine builder, he advised that full roller rocker arms have a clicking sound as they operate. The cross shaft taps against the bottom of the poly-locks as the rocker arms goes through their normal motion. Some often confuse that with lifter noise .Always use self aligning rocker arms and never use SB Chevrolet V8 guide plates or you will hear the push rods tapping against the plates. Compare the intake to exhaust valve spacing of a 4.3L V6 and a 5.7L V8 engine.
I am using CC-875 lifters, CC-1015 roller rocker arms with a CC .500" lift camshaft and the ticking noise at idle that I have is coming from the rocker arms. I also used CC-611 Super Locks that have lash cap recess in order to provide addition clearance for the CC-1015 self aligning rocker rails.
After discussing valve train noise with my engine builder, he advised that full roller rocker arms have a clicking sound as they operate. The cross shaft taps against the bottom of the poly-locks as the rocker arms goes through their normal motion. Some often confuse that with lifter noise .Always use self aligning rocker arms and never use SB Chevrolet V8 guide plates or you will hear the push rods tapping against the plates. Compare the intake to exhaust valve spacing of a 4.3L V6 and a 5.7L V8 engine.
I am using CC-875 lifters, CC-1015 roller rocker arms with a CC .500" lift camshaft and the ticking noise at idle that I have is coming from the rocker arms. I also used CC-611 Super Locks that have lash cap recess in order to provide addition clearance for the CC-1015 self aligning rocker rails.
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Re: just want to clear things up
IMO, the use of CC-875 reduced travel lifters and at least 125 lb. valve spring seat pressure is mandatory with any camshaft that has over .480" valve lift. Standard lifters that have .120" - .160" travel and less than 125 lb. valve spring seat pressure cannot follow a radical cam lobe profile. That is why some have the opinion that CC-875 limited travel lifter are for "race only." I feel like if the proper valve train equipment is used, the CC-875 lifters can be used in a engine for a daily driver. I used limited travel flat tappet lifters for many years in a 455 Pontiac engine that was a daily driver. Those were the now obsolete Melling JB-951R limited travel hydraulic flat tappet lifter for use with the 1969 - 1970 Pontiac Ram Air IV camshafts. They also set at ,.005" pre load.
At high RPM, standard .060" - .080" pre load lifters and standard valve spring rates will allow the lifters to loft over the nose of a radical cam lobe, the lifter will receive negative oil pressure, fill the pre load area with air and will prevent the valves from seating and the lifters will then smack the return flank of the cam lobe. That is the dreaded "valve float" with an immediate loss of power and possible engine damage. That must be avoided by using valve spring rate that forces the lifter to stay in contact with the cam lobe, and lifters with a maximum pre load of .005. Due to the high spring load the lifters cannot loft over the nose of a radical cam lobe profile and cannot pump up with air because they have no where to pump up to.
IMO, the use of CC-875 reduced travel lifters and at least 125 lb. valve spring seat pressure is mandatory with any camshaft that has over .480" valve lift. Standard lifters that have .120" - .160" travel and less than 125 lb. valve spring seat pressure cannot follow a radical cam lobe profile. That is why some have the opinion that CC-875 limited travel lifter are for "race only." I feel like if the proper valve train equipment is used, the CC-875 lifters can be used in a engine for a daily driver. I used limited travel flat tappet lifters for many years in a 455 Pontiac engine that was a daily driver. Those were the now obsolete Melling JB-951R limited travel hydraulic flat tappet lifter for use with the 1969 - 1970 Pontiac Ram Air IV camshafts. They also set at ,.005" pre load.
At high RPM, standard .060" - .080" pre load lifters and standard valve spring rates will allow the lifters to loft over the nose of a radical cam lobe, the lifter will receive negative oil pressure, fill the pre load area with air and will prevent the valves from seating and the lifters will then smack the return flank of the cam lobe. That is the dreaded "valve float" with an immediate loss of power and possible engine damage. That must be avoided by using valve spring rate that forces the lifter to stay in contact with the cam lobe, and lifters with a maximum pre load of .005. Due to the high spring load the lifters cannot loft over the nose of a radical cam lobe profile and cannot pump up with air because they have no where to pump up to.
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Quickstop [UK]
Combating adversyty.
Re: just want to clear things up
Where is the air coming from? If the lifter causes the pushrod or the rocker arm to float due to weak spring pressure, the lifter will fill with oil immediately - at high RPM, you'll have a correspondingly high oil pressure. There is no air in there. The whole point of the lifter design is to immediately fill with oil if there is a gap to thus reduce the distance beween the push rod and the rocker arm to 0.
Valve float will give the opportunity for the lifter to fill up more and the potential consequences are that all of a sudden, the preload has increased. Immediately after this event, the valves will not close fully due to the preload and the engine will run rough because of this.
Where is the air coming from? If the lifter causes the pushrod or the rocker arm to float due to weak spring pressure, the lifter will fill with oil immediately - at high RPM, you'll have a correspondingly high oil pressure. There is no air in there. The whole point of the lifter design is to immediately fill with oil if there is a gap to thus reduce the distance beween the push rod and the rocker arm to 0.
Valve float will give the opportunity for the lifter to fill up more and the potential consequences are that all of a sudden, the preload has increased. Immediately after this event, the valves will not close fully due to the preload and the engine will run rough because of this.
Re: just want to clear things up
The lifter expands when it lofts over the nose of the cam lobe, creates negative oil pressure and air is taken into the lifter above the plunger which reduces the pre load to zero. The valve is then held off the seat by the amount of the pre load when the lifter returns to the base circle of the cam lobe.
Actually lifter "pump up" is referring to the lifter being pumped up with air, not oil. If all the lifters pump up at once and overcome the plunger spring in the lifters, , the engine will shut off completely just as if someone turned off the ignition key. If only a few lifters pump up, the engine will stumble but will not completely lose power. Then when you let off the gas, the engine speed is reduced, the air bleeds out, the lifter pre load is restored by the internal plunger spring, the valve seats and the engine regains compression and resumes power. All this must be thought of in slow motion.
"High ball" hydraulic lifters were introduced by GM in 1965 on the high performance engines when solid flat tappets lost favor because of the engine oiling problems they create. The high ball hydraulic lifters have a check ball that is held up against the piddle valve by an additional spring which reduces the ability of the lifter to pump up with air at high RPM. Those lifters alone are worth an additional 500 RPM compared to standard lifters. Most lifters today are those type and were called "anti-pump up" lifters when they were first introduced. Those type lifters are still in use in all high performance engines but since 1987, they are roller tappets . Lifter pump up is why solid or limited travel hydraulic lifters are important to use for optimum high RPM performance. Those type lifters cannot pump up with air and hold the valves open because they have no where to pump up to.
The lifter expands when it lofts over the nose of the cam lobe, creates negative oil pressure and air is taken into the lifter above the plunger which reduces the pre load to zero. The valve is then held off the seat by the amount of the pre load when the lifter returns to the base circle of the cam lobe.
Actually lifter "pump up" is referring to the lifter being pumped up with air, not oil. If all the lifters pump up at once and overcome the plunger spring in the lifters, , the engine will shut off completely just as if someone turned off the ignition key. If only a few lifters pump up, the engine will stumble but will not completely lose power. Then when you let off the gas, the engine speed is reduced, the air bleeds out, the lifter pre load is restored by the internal plunger spring, the valve seats and the engine regains compression and resumes power. All this must be thought of in slow motion.
"High ball" hydraulic lifters were introduced by GM in 1965 on the high performance engines when solid flat tappets lost favor because of the engine oiling problems they create. The high ball hydraulic lifters have a check ball that is held up against the piddle valve by an additional spring which reduces the ability of the lifter to pump up with air at high RPM. Those lifters alone are worth an additional 500 RPM compared to standard lifters. Most lifters today are those type and were called "anti-pump up" lifters when they were first introduced. Those type lifters are still in use in all high performance engines but since 1987, they are roller tappets . Lifter pump up is why solid or limited travel hydraulic lifters are important to use for optimum high RPM performance. Those type lifters cannot pump up with air and hold the valves open because they have no where to pump up to.
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Quickstop [UK]
Combating adversyty.
Re: just want to clear things up
Again - where is the air coming from? There is none. Air is compressible so you would get no effect - no spring is going to be overcome by the tiny amount of air in the lifter. Any lowering of oil pressure internally is overcome immediately by the 70psi in the lifter galley and the oil floods in to the lifter.
When the lifter lofts over the cam, the oil forces its way into the lifter to take up the slack. The resultant absence of preload keeps the valve open.
Pumping up is oil, not air.
Again - where is the air coming from? There is none. Air is compressible so you would get no effect - no spring is going to be overcome by the tiny amount of air in the lifter. Any lowering of oil pressure internally is overcome immediately by the 70psi in the lifter galley and the oil floods in to the lifter.
When the lifter lofts over the cam, the oil forces its way into the lifter to take up the slack. The resultant absence of preload keeps the valve open.
Pumping up is oil, not air.
Quickstop [UK]
Combating adversyty.
Re: just want to clear things up
The 875s are apparently a bit noisier so if you can get new old stock ones, not used, from the dealer, I would recommend that.
I bought a set of 875s and had two that didn't pump up properly so I had to buy another set in order to get 12 that work. That's what I mean about quality control.
I don't think there is any guarantee. HTH.
The 875s are apparently a bit noisier so if you can get new old stock ones, not used, from the dealer, I would recommend that.
I bought a set of 875s and had two that didn't pump up properly so I had to buy another set in order to get 12 that work. That's what I mean about quality control.
I don't think there is any guarantee. HTH.
Quickstop [UK]
Combating adversyty.
Re: just want to clear things up
I have no idea if the lifters from a 5.0 v8 will work with a 4.3 v6. :dunno:
I have no idea if the lifters from a 5.0 v8 will work with a 4.3 v6. :dunno: