dwg86 wrote:Oh, I have stainless, undercut, swirl polished 1.94/1.50 sbc valves that I will be using. I like the mopar valve springs or lunati 73084(270lbs/in), haven't decided yet. I have a 7120 head that I will be cleaning up the runners (no major porting). I have already opened up and polished the combustion chambers to 61.4cc's. I will do a final measure after the new valves are installed and the head is milled flat. Hopefully it will only take a few thousands. Is opening and closing the valves fast a bad thing? Wouldn't that be more like a roller?
Can be if it land on the seat and bounces.....or even worse,(for the cam) jump of the top of the cam lobe and then is slammed back on the return ramp of the lobe, causing premature cam ware.
Yes a faster ratio rocker arm is causing the valve to open up much faster..........Like a roller cam profile and stock rocker ratio would.
For a similar cam spec, a roller would require a stronger spring pressure due to the increased speed of the valve, so a faster rocker arm ratio(1.6 to 1.7) would require more spring pressure just the same.
Flash
89 XJ with 300,000 on the original eng
"I've also never completed a motor, yet. My mouth (fingers) is also writing checks my ass can't cash."
Whats wrong with the shoes? And those are sometimes my work clothes when I get a brainstorm on a project.
Just thought I would park Barney's old car for a while.
John
That's a keeper,.......No, not you self portrait, the link above
Haven't read it all just yet. After the 3d paragraph, decided i want too save this one, in a folder on my desk top.
I will get to the rest of it tomarrow, as it's late tonight!
Flash
89 XJ with 300,000 on the original eng
"I've also never completed a motor, yet. My mouth (fingers) is also writing checks my ass can't cash."
John wrote:dwg86 are you still considering the higher ratio for the exhaust side?
John
No, I don't think so. I Bought these cams because of the wider cam lobes. I don't know what the duration @ .050 is, and I don't know the lobe seperation. I did find a formula for mopar performance cams for [email protected]. You are supposed to mutiply the advertised duration by .850. That would be 218 @ .050. I am not sure how this cam will perform. I was originally wanting a split lift/duration cam with a little less duration and more lift than the 30AB has. Looking at Reed cams web site(custom grinds and local to me) I was looking at some grinds I thought I might use...
Cam option 1... Int [email protected]/lift 205/459 Exh [email protected]/lift 217/480
Cam option 2... Int [email protected]/lift 210/470 Exh [email protected]/lift 218/491
Cam option 3... Int [email protected]/lift 205/459 Exh [email protected]/lift 214/480
Cam option 4... Int [email protected]/lift 210/470 Exh [email protected]/lift 217/480
All cams ground with a 112 degree lobe seperation with 4 deg advance ground into the cam (installed intake centerline @ 108).
I should be able to have these cams reground, but that is more $$$$. It would be nice to find cam blanks with wide lobes. I'm not sure what I am going to do?
And those are sometimes my work clothes when I get a brainstorm on a project.
