Why dont ecotecs perform better with cams
01-16-2015, 08:25 PM
#27
I don't think the stock LSJ cam is hardly considered "good". It works the way it was intended for an oem application. Fuel economy, idle, emissions, and power, all things considered it balances nicey. From a purely power gain perspective, any bigger cam profiled properly for a supercharger will be superior, the issues come into play with the valvetrain like the original post talks about where you run into diminishing returns from those limitations. Im sure debate will rage over solid lash adjuster performance as well. Japeatr would be in a good position to clarify on that since he is working with them now.
01-16-2015, 09:12 PM
#28
Curious question but, I have always been under the assumption that our hydraulic lash adjusters behave in a similar fashion to honda lost motion adjusters on vtec engines. Honda upgraded that design years ago to go from a oil fed piston setup to a spring assembly as shown in the picture below, I wonder if something similar could be adapted to maintain zero lash.
keeping zero lash is not the problem keeping the lash adjuster from colapsing is even when it colapses it still maintains zero lash just lift and duration is lost
lmfao
I don't think the stock LSJ cam is hardly considered "good". It works the way it was intended for an oem application. Fuel economy, idle, emissions, and power, all things considered it balances nicey. From a purely power gain perspective, any bigger cam profiled properly for a supercharger will be superior, the issues come into play with the valvetrain like the original post talks about where you run into diminishing returns from those limitations. Im sure debate will rage over solid lash adjuster performance as well. Japeatr would be in a good position to clarify on that since he is working with them now.
the stock cams are dam good they give a well rounded performance window but there are improvements to be made
01-19-2015, 06:14 PM
#32
Reading all this, but doubting that our lash adjusters work as described... Isn't there a small valve inside the hydro adjusters that trap the oil inside, making it solid as liquid is pretty incompressible...
The oilpressure is needed to extend the adjuster in the unloaded cam phase untill it reaches zero lash to the base circle.
Can see this one failing if the internal valve is not closing well (collapsing lifter), or there is some air in the oil (areated oil...)
Hydro cams have quicker ramp-up than solid cams, just to close this valve shut, right?
The oilpressure is needed to extend the adjuster in the unloaded cam phase untill it reaches zero lash to the base circle.
Can see this one failing if the internal valve is not closing well (collapsing lifter), or there is some air in the oil (areated oil...)
Hydro cams have quicker ramp-up than solid cams, just to close this valve shut, right?
01-19-2015, 06:38 PM
#33
Reading all this, but doubting that our lash adjusters work as described... Isn't there a small valve inside the hydro adjusters that trap the oil inside, making it solid as liquid is pretty incompressible...
The oilpressure is needed to extend the adjuster in the unloaded cam phase untill it reaches zero lash to the base circle.
Can see this one failing if the internal valve is not closing well (collapsing lifter), or there is some air in the oil (areated oil...)
Hydro cams have quicker ramp-up than solid cams, just to close this valve shut, right?
The oilpressure is needed to extend the adjuster in the unloaded cam phase untill it reaches zero lash to the base circle.
Can see this one failing if the internal valve is not closing well (collapsing lifter), or there is some air in the oil (areated oil...)
Hydro cams have quicker ramp-up than solid cams, just to close this valve shut, right?
01-19-2015, 08:26 PM
#35
thre really isent that much oil in the lash adjuster and when the exh lash adjuster is trying to suppport the valve being shoved through spring pressure and post combustion pressure it blows through its travel by blleding off oil pressure and internal spring pressure also collapsing
thanks man photobucket is being a **** sucker tonight
thanks man photobucket is being a **** sucker tonight
01-21-2015, 08:19 AM
#44
Our stock lash adjusters bleed down easily. You can do I with a pair of channel locks and moderate pressure.
There is clearance between the body and piston, obviously. Push it hard enough and oil will flow through.
There is clearance between the body and piston, obviously. Push it hard enough and oil will flow through.
01-21-2015, 11:03 AM
#46
i think they all work the same they just change the end up or maybe the spring in the bottom but you also have to look at they restrict the volume and pressure going to the lash adjusters which is part of the problem and how much oil the lash adjuster holds is another. if you open up the restrictor in the head you pull oil awy from the crank
01-21-2015, 11:29 AM
#49
Senior Member
