Compression ratio

[broncobuckinaround]

Stock 91 f350 460 compression ratio. I can find it.
Anybody know what it is.

 

[alwaysFlOoReD]

WAG; 8.5-1
I don't know but am interested as well.
My 68 c8ve is about 10.5-1

 

[pjtoledo]

WAG; 8.5-1
I don't know but am interested as well.
My 68 c8ve is about 10.5-1

yep, 8.5:1 per Chiltons

 

[broncobuckinaround]

This would be a good thing if it is. Because it means I can either put flat top pistons in or deck the heads til it would be at least 10 to 1

 

[alwaysFlOoReD]

I've been trying to figure out what to do with my 68 460. The high compression means premium fuel and I can't afford that. While looking for some other parts I stumbled on a propane system that I had squirreled away. Ding! I have a non-running very high mileage van I use for storage that has a complete propane system. IIRC propane will support up to 13-1 compression.....the wheels are turning....

 

[broncobuckinaround]

wont you loose a ton of power tho. propane will last longer but you sacrifice power. correct me if im wrong

 

[alwaysFlOoReD]

Propane is less btu than gas, but you can run much higher compression ratios than with gasoline. If the motor is built for propane you can get almost as much, if not equal, power.

 

[RonD]

Octane = 8(oct) carbon molecules with 18 hydrogen molecules, and is a very stable chemical "string"

If there are less then 8 carbons in the "string" it becomes less stable, easier to break apart, i.e. ignite

Octane rating is the amount of stable strings in the volume
Gasoline runs 87 to 92 octane
Propane 104 to 112 octane

Octane is not power related, just the rating of 8 carbon strings

Compression is heat, it is also power, like winding a rubber band, more winding releases more power.
With too much heat low octane fuel will self ignite, so 87 octane gasoline needs 9.4:1 or lower compression ratios

Propane does have less stored energy per "gallon", but with it's higher octane rating it could be used in higher compression engines to balance that out, but then that engine couldn't run 87 octane gasoline.

Diesel uses Cetane(Hexadecane) rating, 16 carbons with 34 hydrogen also a very stable string and also harder to ignite