Can hydraulic rocker arms be used safely with an older cam in place of the mechanical rockers?
Thanks
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Ian
Calgary AB, Canada
93 L B6T: June 2016 FOTM
59 Austin Healey "Bugeye" Sprite
"It's infinitely better to fail with courage than to sit idle with fear...." Chip Gaines (pg 167 of Capital Gaines, Smart Things I Learned Doing Stupid Stuff)
Yes they can ! You just can't use the roller rockers with non roller cams ! You will find thou the hydro rockers cost you a couple horse and don't seem to rev as far out !
Which brings me to my next question. What clearance should the valves be set at cold? Haynes call for 0.12" with the engine warm but nothing about cold.
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Ian
Calgary AB, Canada
93 L B6T: June 2016 FOTM
59 Austin Healey "Bugeye" Sprite
"It's infinitely better to fail with courage than to sit idle with fear...." Chip Gaines (pg 167 of Capital Gaines, Smart Things I Learned Doing Stupid Stuff)
I think the older mechanical rocker cams were a different profile than the HLA cams. Not saying you can't run HLAs on the old cam, but I seem to recall the old cams had less lift and maybe more duration. I would agree that the HLAs most likely cost you some HP and throttle response. I'd take the old adjustable rockers over the HLA ones any day. Setting valve lash once once a year is a small price to pay to not have to deal with sticking and/or collapsed HLAs.
Should I set them at the 0.12" cold to start with? The engine is going in the car tomorrow with a rebuilt head.
Sent from somewhere west of here via Tapatalk!
Ian
Calgary AB, Canada
93 L B6T: June 2016 FOTM
59 Austin Healey "Bugeye" Sprite
"It's infinitely better to fail with courage than to sit idle with fear...." Chip Gaines (pg 167 of Capital Gaines, Smart Things I Learned Doing Stupid Stuff)
Note what Movin said^^^The lash is .012" hot (not .12")....personally, I would start out a little looser than .012" when cold. That way, when they get hot and everything grows, the lash will decrease down to .012". I would start out cold at maybe .015". I don't know how much the valves change on these things. Matt Dickmeyer or FB71 may be able to give you a better idea.
Last edited by blkfordsedan; 05-26-2013, 10:19 AM.
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