Howard1784
Well-Known Member
What cooling temp. differences did you experience when switching from iron heads to aluminum heads??
alum. caries off heat faster, letting u run a higher comp. ratio.I was under the impression there was a cooling benefit due to the better transfer of heat
alum. caries off heat faster, letting u run a higher comp. ratio.
Moving pushrod holes in the head (w2 style) and fully porting with oversize valves is not what most would consider "light head work"I was pondering what I may encounter. I put eddy s on my 380 h.p. crate motor with comp rollers. No cr ratio gaskets added. Gasket matched. Ported. M1 intake ported and runners cleanup up etc.
All new experience with me.
Engine masters boasted a 92 hp gain with
Light h eadwork on their 360.
Moving pushrod holes in the head (w2 style) and fully porting with oversize valves is not what most would consider "light head work"
MY aluminum heads seem to take a couple of minutes longer to warm up in the morning. But once up to temp the stat sets the minimum, and the ability of the cooling system to shed heat, sets the max.
The aluminum sucks heat out of the chambers and delivers it to the cooling system, as well as to the underhood area, as well as into the exhaust. Because it it extracts heat so well, you pretty much have to bump up the compression to keep up with iron heads. If you don't the effective C/R takes a dump and performance suffers. The heat is what makes the power. The more heat,the more power, until you get into detonation or something melts,lol. Heat is the secret.
I run 205*F at the stat-house,all the time.Some adventurous types run even hotter.Modern EFI engines run 220 or a bit more. That's partly how those NA teensey 2.5/3.3 engines pull 3200 pound cars around reasonably well.
When running al heads Data seems to indicate that the DCR should be run at least a half point higher, than with iron, and some fellows are pushing over 9.3Dcr in their well executed combos. I run 8.9Dcr on 87E10. That's 10.9 Scr. I can run 36* power timing at 3400, but the engine performs just as well (by seat of the pants) on 32* so I compromised and have run 32/34 since 1999.
She does like a lot of cruise timing tho. I have experimented with up to 60*@2200. Typically I run 44/56 on flat hard pavement.(dial-back timing device)
That's another nice thing about Al heads with a tight Q (mine is .034), it's hard to find detonation on a typical 360 or smaller engine. Well maybe not if you get greedy with timing below 3000,lol.
Are you sure about the 9.35 DCR?AJ,,,,,,do you have an idea what your timing curve looks like, I'm messing with my FITech timing control and I feel it should be higher but I'm a little leary to put too much in there. It's a .030 over 340, .039 quench with AL Eddy RPM's, 222/226 @ .050, .540/.555 lift, 10.1 CR, 9.35 DCR on 91
No it doesn't; that is the .050 tappet lift number. In other words the valve is still open; .050 times the rocker ratio, less that portion lost to pushrod angularity.I could guess the valve is still open close to.067 with 1.5 stamped arms. You cannot start building compression until the valve is right on the seat. Fully closed.intake closes @ 37 abc,
This is all chinese to me.base timing 10*, idle timing 22*. Engine starts at 10 and computer adds 12* for 22* after start, dizzy is locked out.