XE285HL in 360

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OLFOOL

OLFOOL

OLFOOL
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New South Wales, Australia
Just after some timing numbers for a XE285HL Comp Cams hydraulic flat tappet cam for my 360 that I am currently building. I am using the KB Pistons calculator to work out compression, it asks for the Intake Closing Point (degrees) ABDC @ 0.050 lift plus 15 degrees, I have the cam specs but not sure if the figure is at .050" ABDC ?? Any help or full timing figures would be helpful. I have attached a couple pics of cam info/specs and compression calculator with my measurements, as you will see using these cam specs from Comp Cams gives an incredibly low dynamic compression. .

Any help appreciated.

Comp -.010.png

Comp Cams XE20-228-4HL.png
 
Yeah the .050" timing plus 15 degrees isn't that accurate - depending on the lobe profile you could be way off. (Old school easy on the valvetrain grinds vs agressive lobes designed for a .904" lifter).
The timing on the summit description are at .006" lift and probably closer than the 84° you've got plugged into the calculator.
 
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It’s not a bad cam, that’s what I had in my car, just not a good cam for a 4 speed.

You would be better off selecting a cam for how the rest of your car is than the Hing to build your car around a cam..
 
Ted265 said:
Yeah the .050" timing plus 15 degrees isn't that accurate - depending on the lobe profile you could be way off. (Old school easy on the valvetrain grinds vs agressive lobes designed for a .904" lifter).
The timing on the summit description are at .006" lift and probably closer than the 84° you've got plugged into the calculator.
Click to expand...
That spec info is off the comp cams site
 
OLFOOL said:
That spec info is off the comp cams site
Click to expand...
Yes, but they are advertised timing numbers not timing at .050" lift.
(37° to TDC + 180° to BDC + 69° after BDC = 286° ) there would only be a few degrees between .006" lift and fully closed.
Someone here may have a cam card with the .050" timing numbers. But it will close the valve well before 84° ABDC.
 
If you are using 'that' to calculate the Dyn Comp Ratio as a means of selecting the static comp ratio, DCR is absolutely useless. It takes no account of how much air mass actually enters the cyl because IVC on it's own does not reflect:
- actual port flow efficiency
- the type of int man & efficiently it flows
- & how well the exh system scavenges.
These all have an impact on the net mass of air drawn into the cyl.

If you are going to run our 98 octane & 10.8:1 static CR, there is a good chance you will get detonation with alum heads & almost guaranteed with iron heads.
 
Bewy said:
If you are going to run our 98 octane & 10.8:1 static CR, there is a good chance you will get detonation with alum heads & almost guaranteed with iron heads.
Click to expand...
What are the 3 basic numeral grades available to you In Australia?
In the U.S., it 87-89-93. Where does your 98 fit in. Normally it’s the top grade available correct?
 
We have 4 readily available pump octanes available here: 91, 94, 95 & 98. 94 contains 10% Eth, all the rest are non-Eth. Selected service stations have E 85, but I am not sure of it's octane rating or whether it is marked on the pump.
My understanding is that our #s are 3-4 numbers higher than yours. So your 87 is close to our 91.
 
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