I checked compression on my rebuilt 6V system 1945 Ford 2N engine: only 40 PSI at each cylinder. This is after new sleeves/pistons/rings/valves. I used the original connecting rods, cam-timing shaft, and drive shaft since all gear teeth & journals looked great & measured in spec. The 40PSI is consistent but far from the 95 PSI target. The ring gaps were all in-spec prior to installation of the pistons with the new sleeves. All 8 new valves were lapped and seals verified prior to adjustment.
My initial concerns are with the head-gasket & would like feedback on these 3 next steps.
1) I installed a head gasket (the type with metal rings around each cylinder) and have seen other bloggers complain about this design. Has the type of head-gasket really been an issue for others? Now is the time for me to try another type.
2) I installed the head-gasket dry: others claim to use copper spray for a better seal. I have a can of the Permatex copper gasket-seal spray: does this stuff really help to improve compression?
3) Lastly, I torqued the nuts on the head stud bolt to 55 ft/lbs: that seems low given the diameter of these grade 8 stud bolts. I've seen conflicting (higher) stud bolt nut torque specs but don't want to go above 55 ft/lbs unless others have.
My thinking is perhaps a consistently under-torqued head gasket (or poor-design, or without sealant) loses compression equally across all 4 cylinders. I have a running 2N (12V system) also 1945. For reference, I'm going to use my torque wrench and see where my 2nd 2N tractors head stud bolt nuts are set (where my torque wrench trips). Compression readings on two of the four cylinders on my running tractor are 90/92PSI so the compression gauge seems to be working.
Any other ideas/suggestions would be appreciated. Clearly, I don't want to start pulling new pistons/rings unless I absolutely have to. Thanks!
My initial concerns are with the head-gasket & would like feedback on these 3 next steps.
1) I installed a head gasket (the type with metal rings around each cylinder) and have seen other bloggers complain about this design. Has the type of head-gasket really been an issue for others? Now is the time for me to try another type.
2) I installed the head-gasket dry: others claim to use copper spray for a better seal. I have a can of the Permatex copper gasket-seal spray: does this stuff really help to improve compression?
3) Lastly, I torqued the nuts on the head stud bolt to 55 ft/lbs: that seems low given the diameter of these grade 8 stud bolts. I've seen conflicting (higher) stud bolt nut torque specs but don't want to go above 55 ft/lbs unless others have.
My thinking is perhaps a consistently under-torqued head gasket (or poor-design, or without sealant) loses compression equally across all 4 cylinders. I have a running 2N (12V system) also 1945. For reference, I'm going to use my torque wrench and see where my 2nd 2N tractors head stud bolt nuts are set (where my torque wrench trips). Compression readings on two of the four cylinders on my running tractor are 90/92PSI so the compression gauge seems to be working.
Any other ideas/suggestions would be appreciated. Clearly, I don't want to start pulling new pistons/rings unless I absolutely have to. Thanks!