Newbie Compression Help

[ClarksvilleFJ60]

Good morning all,

I've searched but still need to ask the group:

My '82 FJ60 has 152,000 miles. I got in in June and it had only been driven 50 or so miles a month for years until I got it, now its about 1,000 miles a month and is my DD. I got the compression tested while it was in for I was sure was an exhaust leak (didn't find one but I still smell exhaust in the cab) and ran the numbers.
Cylinder #1 - 119, #2,3,4,5 - 92, and #6 - 125. It smokes white at start up and a little while driving. Are the high pressure cylinders the ones burning? There is some noise in the top end and I have not done a valve job yet.

Think I have some time/life left on this 2F?

Thanks in advance.
Tandy

 

[2mbb]

You should probably adjust the valves before performing the compression test. Generally, low compression values indicate a problem, not high. White smoke is usually an indication of water and blue smoke means oil is burning. Water is one of the normal gasoline combustion products and when the engine is hot it exits the exhaust pipe as water vapor. When you shut the truck off and let it cool down, the water condenses to liquid water in the exhaust piping. When you start up again, this can come out as white smoke.

Compression test numbers should be more or less the same (plus/minus 15%). Some of yours are outside that range. Your numbers also seem a little low (I get around 150 - 160 on my 2F with ca. 200K miles), but the low values and variation could have something to do with how the test was done. I do the test with the engine warmed up to operating temperature. I remove all the spark plugs. I hold the carburetor throttle wide open. I make sure my battery is fully charged. I measure the compression for each cylinder through four or five compression strokes. Talk to your mechanic to find out how he did the test, or purchase a compression tester and do the test yourself.

You don't say how the truck runs otherwise (besides the white smoke). Do you suspect something is wrong other than the compression test results?

 

[ClarksvilleFJ60]

Thanks. I'll ask the guy that tested it how he did it. Smoke is white, not blue....a good sign.

It runs pretty good, its a little hard to start first thing in the morning and hesitates at first, but the rest of the day its fine. Long hills make it work hard.

I appreciate the advice.

 

[lehiguy]

When you tested the compression, did you remove ALL the spark plugs and hold the throttle wide open as you cranked the engine? If you didn't, you're getting low readings. Your white colored emissions may be steam, like you see on a cold morning, or they may be from oil. It's possible given the vehicle's age that the valve seals are tired and are allowing some oil to enter into the engine that way. The tell-tale sign of bad valve seals is a puff of smoke after you use the engine as a brake, coasting down a hill with the throttle closed for example. The increased vacuum pulls the oil in, and then when you open the throttle again, it burns out and produces a white puff of smoke. My old FJ40 burned through several quarts of oil on a Moab trip once, I got a valve job and it stopped consuming oil. It did blow puffs of white smoke after closing the throttle and hitting the gas again, so I knew what it was.