3.7litre 224cu. in. Compression

Capt. Click

Cadet
Joined
Jul 19, 2012
Messages
13
Hey, I have the 3.7 litre 4 cyl. 165hp. (Serial #b517066) I was wondering what the compression should be for the cylinders. I rebuilt this engine several years ago, top and bottom end, complete rebuild. Cylinders were bored .030 over. I know you want to have even compression through out all cylinders. What kind of compression should the cylinders have? Any help would be appreciated. "GET'EM OFF THE BOTTOM"
 

Capt. Click

Cadet
Joined
Jul 19, 2012
Messages
13
Hey, thanks for the reply. I checked the compression last night. I have 150lbs. in all 4 cylinders. Not 149 or 151 they are 150 in all 4. This is a GREAT running motor. This engine was cold when I checked the compression. May be a little more compression if the motor was warm. I did remove all spark plugs and I had the throttle wide open. "GET'EM OFF THE BOTTOM"
 

aerobat

Master Chief Petty Officer
Joined
Jun 1, 2011
Messages
843
I have 150lbs. in all 4 cylinders. Not 149 or 151 they are 150 in all 4.

check your compression gauge since not even factory new engines tend to have exactly the same compression on all cylinders . some few psi offset with overall good numbers indicates a great condition - your results indicate a stucked gauge.
 

Capt. Click

Cadet
Joined
Jul 19, 2012
Messages
13
Hey thanks for the reply. I did check the gauge with my air compressor. The gauge would read whatever pressure I had the compressor to, up to 120lbs with the compressor. When I first rebuilt this motor I would get 145 across all cylinders, that was with the throttle at idle location. I get 150 with the throttle wide open now. I rebuilt this engine close to 10years ago. It has not had many hours running time in the last 5 years or so. I do run it about every month though. I hear some of the 3.7 are good and some are bad. I will say that this is a really good running motor and I love it. I have been buying any old 3.7 engines I can find. I have one extra now and have my eyes on another also. Neither of the two have ever been rebuilt or cylinders have not been cut. It's getting hard to find certain parts for this engine. I'm going to stock up on all I can get. "GET'EM OFF THE BOTTOM"
 
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