Solid Roller Lifters on a Hydraulic Roller Cam?
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And one of the smartest guys in the industry did not say to aim for zero HOT lash......
What he said was to set zero lash COLD.....& then when the engine heats up, because of thermal expansion, the lash will be 0.002-3". He also doesn't say how you measure zero lash, maybe using the illusionary 0.000" feeler gauge. This is important when you only have 0.002" hot lash.
While I have great respect for Steve Brule, he has given bad advice.....
Hyd cam systems self adjust/compensate for any wear. Sol lifter cams have no compensating, other than the lash. 0.002" lash at operating temp as a starting point is asking for trouble.....
What he said was to set zero lash COLD.....& then when the engine heats up, because of thermal expansion, the lash will be 0.002-3". He also doesn't say how you measure zero lash, maybe using the illusionary 0.000" feeler gauge. This is important when you only have 0.002" hot lash.
While I have great respect for Steve Brule, he has given bad advice.....
Hyd cam systems self adjust/compensate for any wear. Sol lifter cams have no compensating, other than the lash. 0.002" lash at operating temp as a starting point is asking for trouble.....
dart_68
Well-Known Member
I got a HR cam from Oregon and asked them about running solid roller lifters on my HR and they said not to do it. Reason was that no lash allowance was ground into the cam. I think the best idea for the OP is to get a SR cam with the specs he likes and be done with it.
TT5.9mag
Two atmospheres are better than one
Once again I am speaking theoretically Bewy. Because of the lack of a clearance ramp the perfect scenario is zero lash hot. Even though we know it won’t work there. It’s a point made to show that a hydraulic roller lobe with a solid roller lifter on it will work best and not beat itself or the wheel up when there is no lash. Brule was not passing on bad info and neither am I. When cold set to zero lash (and on mine I use a very light zero lash) and with my iron heads, I see .002-.004 when hot. It’s hard to get a good measurement with feeler gauges that thin. And once again mine has been running this way for LOTS of miles. You do you, I’ll keep doing me and saying here what has worked in my experience.
Dale Davies
Well-Known Member
No. Just no. Solid grind cams have "takeup ramps" built in to take up the lash gently. Hydraulic cams do not have this as they are not needed. You may get away with it for a while, even setting the lash fairly tight. Problem is you do not want the valvetrain to go into no lash where you loose valve seal. On the loose side can hammer components.
I get the idea you like the specs of the hydraulic cam, so run it with the matching hydraulic lifters, or look for a solid lifter cam that will give equivalent valve event timing and lift.
Any engine build is a compendium of give and take, so you want the cam you live with the lifters.
Dale Davies
Well-Known Member
Or you can do as David Vizard describes. Set the hydraulic lifters before priming the oil system and the lifters are MT of oil. Bottom until the valve just lifts of the seat, back adjustment until the valve is back on its seat and back off 1/4 to 1/3 turn more. With proper valve springs you will not get pump up and they will work like tight lash at a fraction of the cost.
TT5,
Aim for zero lash....theoretically. Whatever, semantics, playing with words. If somebody aims for zero lash...& attains it, then they have zero lash which is bad for reasons already explained. I do not know how much more simple I can make it.
Brule was doing a dyno comparison, maybe his zero lash was in that context, not on an engine that will be driven for 000s of miles.
See if you can find anyone else who recommends zero lash.....
Your claim & Dale Davies claim that hyd cams do not have clearance ramps is nonsense. So is the claim that the roller will get beat up because of lash. You evidently know little about cams. at low speeds, hyd lifters [ FT & roller ] have enough time to bleed down such that as the valve seats, there is clearance [ lash ] in the valve train. Bleed down lifters like Rhoads, you can hear the noise it makes. The rollers are not getting beaten up.
Clearance ramps. Both sol AND hyd cams have them. Hyd cams haver much shorter clearance ramps [ shorter duration ] but they DO have them. This is why it is so important when running sol lifters on a hyd cam to keep the lash low.
As for not using sol on a hyd lobe, Comp Cams have a number of lobes that can have be used with sol or hyd lifters: Max area lobes, DHI & DHX lobes.
A Comp Cams 288* hyd roller cam I degreed measured 307* @ 0.002" tappet lift; 288* @ 0.006" [ the adv duration ]. Clearance ramp of 19* duration, NOT zero. Another one: hyd FT Isky cam 280* adv duration [ @ 0.006" tappet lift ], measures 295* @ 0.002", so 15* ramp duration. Comp Cams hyd cam 286* @ 0.006" measured 305* @ 0.002" tappet lift.
Aim for zero lash....theoretically. Whatever, semantics, playing with words. If somebody aims for zero lash...& attains it, then they have zero lash which is bad for reasons already explained. I do not know how much more simple I can make it.
Brule was doing a dyno comparison, maybe his zero lash was in that context, not on an engine that will be driven for 000s of miles.
See if you can find anyone else who recommends zero lash.....
Your claim & Dale Davies claim that hyd cams do not have clearance ramps is nonsense. So is the claim that the roller will get beat up because of lash. You evidently know little about cams. at low speeds, hyd lifters [ FT & roller ] have enough time to bleed down such that as the valve seats, there is clearance [ lash ] in the valve train. Bleed down lifters like Rhoads, you can hear the noise it makes. The rollers are not getting beaten up.
Clearance ramps. Both sol AND hyd cams have them. Hyd cams haver much shorter clearance ramps [ shorter duration ] but they DO have them. This is why it is so important when running sol lifters on a hyd cam to keep the lash low.
As for not using sol on a hyd lobe, Comp Cams have a number of lobes that can have be used with sol or hyd lifters: Max area lobes, DHI & DHX lobes.
A Comp Cams 288* hyd roller cam I degreed measured 307* @ 0.002" tappet lift; 288* @ 0.006" [ the adv duration ]. Clearance ramp of 19* duration, NOT zero. Another one: hyd FT Isky cam 280* adv duration [ @ 0.006" tappet lift ], measures 295* @ 0.002", so 15* ramp duration. Comp Cams hyd cam 286* @ 0.006" measured 305* @ 0.002" tappet lift.
Dale Davies
Well-Known Member
Where is your proof? What credentials do you posess?
Dale Davies
Well-Known Member
Fair enough. As a mechanic; automotive, heavy duty and instrumentation, I had been taught in trade school that hydraulic cams did not have takeup ramps as they are not necessary. Appears as you stated that they are used, but of lesser dimension than on solid lifter cams.
Even so, I would be highly reluctant to use solid lifters on a hydraulic lifter cam. That is a personal choice and what others choose is totally their choice.
famous bob
mopar misfit
What about hyd. rollers on a solid roller cam ???
anotheridiot
Active Member
Was this the episode they ruined the hot rod garage hemi? Lash are specs used for the lifter to pump oil
33IMP
Well-Known Member
Don't think so, but now you made me look it up. I think I have it on my DVR.
Edit: can't find it.... but memory says it was tested on a bbc.... or maybe a 440. My bet would be the chevy.
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Dale Davies
Well-Known Member
19_Dart_68
Well-Known Member
Season 4 episode 7
Hyd lifters on a sol cam is a NO-no. Sol lifter cams have long-er opening/closing ramps to cushion valve train shock [ no oil cushion as in a hyd lifter ]. Using hyd lifters will give a very rough idle because of the longer time the valves are off the seat. It can be done, but why would you?
famous bob
mopar misfit
Cause I have to set my valves about once a year ...LOL
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