I just got a 2000 Ranger with the 4.0, 5 speed, 4x4, ex cab, and love it (this is my 3rd ranger)

My question is this... the bottom end is from a 96... heads are from the original 2000. This combination I was told bumped up the compression and therefor requires Premium gas. I am ok with the Premium gas but what I wonder is this...

What would that combo put my compression at, anyone have a clue? lol

 

Welcome to the forum.

You have a 4.0l OHV engine in a 2000 Ranger, used from 1990 to 2000
2001 Rangers got the 4.0l SOHC engines.

You were given some bad info.

1990-1994 4.0l OHV pistons had a shallow depression and large head chamber.
1995-2000 4.0l OHV pistons had deeper depression and smaller heart shaped head chamber.
So both had same compression ratio

Your compression with '96 pistons and 2000 heads would be stock, 9.0:1, no need for premium gas.

'94 or earlier pistons with '95 or later heads can get about 10:1 which would need premium gas.

People prefer the '95-'97 heads for this because in '98 the exhaust ports were made smaller to increase the velocity of the exiting gases, the increased velocity heated up O2 sensors and Catalytic converters faster for better cold start emission numbers.

Have a read here about changes to the 4.0l OHV over its life: http://www.therangerstation.com/tech...0rebuild.shtml

 

Hmm... ok, well thank you for the info. I will double check the years with him.

 

The bottom end could have come from a 1996 Aerostar van, it still used the '90-'94 shallow pistons, not likely but possible.