hot cam+ 1.8 rockers +push rod help

**blackbirdbrain89** · 11-30-2007, 06:54 AM

ok i have a hot cam its 218 228 @.050 with .525 .535 lift.. im geting all the parts im going to want/ need.. i was looking at push rods when i came across longer rods.. like .050 longer is what i would like to get . i have 1.8 roller tip rockers all ready as well.. will the added .050 longer rod flot my valves with all that i did the math and came out with .6088 lift.. i plan on geting better springs then the ls6's that my cam came with.. ones that can handle 650 lift.. and one more ? how much lift can u run b4 u have to think about pistons valve problems? can some one help me.. it would be veary usefull

**superbird496** · 11-30-2007, 07:48 AM

1 longer pushrods will not increase cam lift values. 2 valve train georomatry is very important and with the wrong pushrod length u could very easily ruin ur valve guides .3 bigger isnt allways better u need supporting mods 4 large camshafts 2 work. 4 when installing large lift camshafts the pistons should allways b clayed 2 check clearance. 5 u really need 2 do ur research so u dont screw somthing up cam selection is very touchy.

**blackbirdbrain89** · 11-30-2007, 10:13 AM

that is what im doing right now.. thanks

**cam99** · 11-30-2007, 12:12 PM

Longer Push rods as well as higher ratio rockers will increase the lift. - EDIT I stand corrected PR DO NOT increase lift.
Lift doesn't play into ptv, duration does! Longer PR will not center the rocker contact point on the valve properly as well as putting too much preload on the lifter. I think it could possibly open the valve a little.

When the cam is at it peak ( intake) lift the piston is moving away from the valve. The exhaust valve is open the widest as the piston is rising.

I believe that you have a small cam, so PTV shouldnt be an issue, but it's always safer to check than to be sorry especially if the heads have larger that stock valves.

**mrr23** · 12-01-2007, 09:35 AM

Originally Posted by cam99

Longer Push rods as well as higher ratio rockers will increase the lift.

longer pushrods DO NOT increase lift. they are used to correct geometry issues and for the LSx motors, they set preload on the lifters with it's non-adjustable valvetrain.

**Olde Skoole** · 12-02-2007, 06:54 AM

Thank-you...
Also, i would not use high-lift (1.85) rockers with high-lift cam....ur begging for trouble.
A well-known aftermarket speed shop (sorry, can't post the link because they're not a sponsor of LS1.com) carries a tool that is invaluable for checking rocker geometry.
longer or shorter push-rods are used to correct valve-train geometry,
valve tip height, block deck height, cam base circle and head surface all
affect required pushrod length.