Compression test

[rboltz]

If I do a compression test on the 230, what pressure is "normal"?

[97XJSP]

C-8. Check Compression
A compression test is one method to determine the condition of the valves, piston, piston rings, cylinder bore, cylinder head, and cylinder head gasket. The engine must be at normal operating temperature when a compression test is performed. Block the carburetor throttle and choke valves in the wide open position.
Take compression readings with a compression gauge, as shown in Fig. C-6, at each cylinder while cranking the engine with a starter motor. Allow only four compression strokes at each cylinder,
and record only the first and fourth readings. Interpret the readings as follows:
a. When pressure quickly comes up to specified 145 to 155 psi., and is uniform between all cylinders within 15 psi., it indicates that the engine is operating normally with a satisfactory seating of rings, valves, valve timing, etc.
b. When pressure is low on the first stroke, and builds up to less than specified 145 psi. minimum, it indicates compression leakage usually attributable to rings or valves. To determine which is responsible, pour 1/2 oz. of tune-up oil into each cylinder. Allow a few minutes for the oil to leak down past the rings to form a seal; then again test compression. If compression pressures improve over the first test, the trouble is probably worn piston rings and bores. If compression pressures do not improve, the trouble is probably caused by improper valve seating. If this condition is noticed on only two cylinders that are adjacent, it indicates that there is a possible head gasket leak between these cylinders. If inspection of the spark plugs from these cylinders discloses fouling or surface cracking of electrodes, gasket leakage is probable.
c. When pressure is higher than specified 155 psi. maximum, it indicates that carbon deposits in the combustion chamber have reduced the size of the chamber enough to give the effect of a raised compression ratio. This will usually cause pinging under load that cannot be satisfactorily corrected by ignition timing. The carbon must be cleaned out of the engine to correct this trouble.
d. Reinstall the spark plugs. Torque with a wrench to proper setting of 28 to 30 lb-ft. If compression is not satisfactory, it must be corrected before there is any value to continuing the tune-up procedure.

http://www.m715zone.com/vb/view.php?pg=24_tuneup

[rboltz]

I found my problem and it was a fouled plug on #1. I try to drive the truck at least once a month and yesterday I took it out. It started to miss as soon as it was started up but I went a few miles hoping it would burn clean if it was a plug. It did not. #1 manifold was warm while the others were hot. It made quite a bit of racket and I suspected a valve. I couldn't do anything yesterday so today I pulled the plugs. #1 was soaked and fouled. The rest were nice and light brown with no build up. So, I checked compression while the plugs were out and we are OK. Replaced the plug and it runes fine.

I really need to get to my new "stock plugs and ignitor" project and get rid of the civvy distributor. The civvy one worked great but the advance died so back to stock.