Trick Flow 190 Heads, hydraulic roller cam, and pushrod angle Question.
AJ, how much duration is eaten up by the lash needed for a solid roller tappet on a Hyd. roller cam?
How much lash are you giving it?
Not me Rob, jus asking , for personal understanding.
YR mentioned .002 lash.
Here are my thoughts;
Ima thinking of a 284/292/114+4 HR cam, with an .050 of say 230*.. That makes the advertised intake ramps to be 54* . And say it it's at .008 tappet rise. Sound fair? Well let's just say it is.
so, in at 110,the Ica at .008 tappet-rise is 72*ATDC
So now from .008 tappet rise to when the intake valve finally gets on the seat and not leaking, I have no way of knowing. But I can guess at least another 12 degrees, So the intake might be closed at 84* ATDC. ....... Now, lets give back,say 3* for the .002 lash, and we see the intake closing at 81* ATDC, leaving just 99* for compression.
>Right away a redflag goes up for me, cuz 99* is a very short time to build compression.To make this work in the typical stall to 3500rpm range, this engine is gonna need, either; a very lotta Static Compression Ratio, or, a hi-stall TC.
>This is immediately followed by a second redflag, in that while the piston is coming up on compression, the first 81* is going to be pumping the just inducted A/F charge, back up into the intake plenum. This, at low engine speeds is gonna really suck.
>And the third redflag I see is; in that it is now a really really long time until we hit the 050 point. Thankfully this happens during overlap. Or is it thankfully? With headers, this gives them, a really really long time to pull A/F charge right across the piston and out the back door.
None of these things are good things for a streeter to have.
Am I wrong? I really want to know.
