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stock valve spring specs.
Posted: March 13th, 2008, 6:03 am
by dwg86
I got these stock spring specs from alldatapro.com. Installed height 79lb/
[email protected] Open 218lb/
[email protected]. That makes the valve lift .424 (1.216-1.64=.424). Doing the calculations for spring pressure would make the stock springs 327lbs/in. Spring rate x max valve lift ( 327x.424=138.648 rounded up would be 139 ) plus closed spring pressure ( 79+139=218) the stock spring rate 218 @ 1.216. So the stock spring pressure is 327lbs/in. Just some info when looking into replacing springs for higher lift cams.
Re: stock valve spring specs.
Posted: March 13th, 2008, 7:38 am
by Shark
thanks, that should come in handy later on.
Re: stock valve spring specs.
Posted: March 13th, 2008, 2:29 pm
by dwg86
Lunati has some valve springs part # 73084 O.D. 1.450 / I.D. 1.080 270lbs/in. That would be 101.5lbs @ installed hieght @ 1.700 and 236lbs at .500 lift. Max lift .560 . These may be easier on cam lobes. Any comments/suggestions????
Re: stock valve spring specs.
Posted: March 14th, 2008, 3:06 pm
by jeepinwi
dwg86 wrote:Lunati has some valve springs part # 73084 O.D. 1.450 / I.D. 1.080 270lbs/in. That would be 101.5lbs @ installed hieght @ 1.700 and 236lbs at .500 lift. Max lift .560 . These may be easier on cam lobes. Any comments/suggestions????
How can a spring with less pressure be rated for more lift?

Re: stock valve spring specs.
Posted: March 15th, 2008, 1:30 pm
by Flash
jeepinwi wrote:dwg86 wrote:Lunati has some valve springs part # 73084 O.D. 1.450 / I.D. 1.080 270lbs/in. That would be 101.5lbs @ installed hieght @ 1.700 and 236lbs at .500 lift. Max lift .560 . These may be easier on cam lobes. Any comments/suggestions????
How can a spring with less pressure be rated for more lift?

This may not answer your question compleatly but, the first spring was a install hight of 1.62"...... and this one seat install hight is taller at 1.700" which would reqire a diferant hight retainer or longer valve stem.................
Flash.
Re: stock valve spring specs.
Posted: March 17th, 2008, 7:35 am
by dwg86
How can a spring with less pressure be rated for more lift?
Because of coil bind. The spring might not have as many coils allowing it to have more lift before the coil binds. Go to cranecams.com and ckeck out "how to choose a valve spring" in their master catalouge.