Re: Shop jerk
Usually compression is checked after the engine has been brought to normal operating temperature. He may not have done this.<br /><br />Next, and prior to checking the first cylinder,
all the spark plugs should be removed. He may not have done this.<br /><br />When checking compression the throttle should be in the wide open position. He may not have done this. In fact he may have checked the compression after the carbs were removed?<br /><br />It's usually ok to do a dry compression test, unless you are cranking for ungodly long times. There should be enough residual oil in the engine to give accurate results, especially if you just ran it up to normal temps.<br /><br />The engine must be cranked fast enough and long enough until the gauge shows no further rise in pressure. This takes a good battery...or fast pulling. Normally the first compression stroke will run the gauge indicator needle a considerable distance up the scale. Succeeding strokes will raise it more until the highest level is shown.<br /><br />My rule of thumb is that the variance should not be between 10-15 lbs. The mechanic's readings are border-line...if they are true.<br /><br />Watch the action of the gauge. If it rises only a small amount on the first stroke and a little more on each succeeding stroke to a moderate reading, you may have stuck or worn rings. If two adjacent cylinders are low you may have a bad head gasket or warped head.<br /><br />If you get a low reading in one cylinder, add a teaspoon of oil to that cylinder and crank a few extra strokes. If the compression goes up a considerable amount you have worn rings. If it doesn't go up you have intake/exhaust problems, a broken piston, or blown gaskets.<br /><br />With only 6 hours, the engine is probably barely broken-in. And sitting 3 years is nothing if it was properly put away. Regardless, your mechanics numbers seem low. <br /><br />Do your own test with good equipment. Then you know what you have.
<br /><br />By the way, there's nothing wrong with telling a mechanic that if he didn't do the job right, he's going to see you again. If he takes that as a threat, then he has little confidence in his work.
