Compression Testing

[bowtietillidie]

Compression test
        This is how I was taught to do it at GM tech school in 1964

Before you start you will need (1) A piece of note book paper and a pencil
draw a line vertically down the center of the page.    To the left side of the vertical line and at the top write the word DRY.  At the right side of the vertical line and at the top write the word WET. ( Don't loose that pencil)
(2) A large squirt can of oil with a flexible spout  and the tools for the job.
(3)  A Good Compression Tester I use a Snap on tester with a flexible hose .
Next start the car and let it run till it reaches operating temperature. Shut engine down and disable engine from starting . Remove air cleaner check  
the choke make sure it is wide open pin it so it can not move . Unhook the throttle spring hold the throttle wide open and pin it also.   It is VERY important that the choke and throttle remain wide open during the test as you want the engine to be able to take in as much air as possible.  If this is a late model car with catalytic converter unhook exhaust at the exhaust manifold .
Next remove spark plugs do your compression check( spin engine over with the starter for a count of 15 or fifteen seconds for each cylinder) record each cylinder  
under the column on the note book paper marked DRY.  Do your compression check again BUT with this difference use that oil squirt  to put (5) five full squirts in each cylinder as you do your second test. Record results under the wet column on your note book paper . Now we have two sets of figures. One wet and one dry for each cylinder. Comparing these figures for with any of the cylinders gives us the information we seek.
                        Small example to follow  
Number (4) four cylinder  shows a marked increase between the wet and dry test  this tells us that the rings are weak in this cylinder .  Next we look at number (1) one it showed no change whats so ever between the wet and dry test . This cylinder is telling us that it has worn,burnt, bent, sticky valves or a burned piston.   These examples are just a couple that come to mind.   A properly performed compression test can reveal lots more than we have space here to discuss here.

[enjenjo]

Which GM tech school did you attend, I went to the one in Warren Mi.

[bowtietillidie]

In 1964 I attended School at Warren Mich Two times that year . Once I belive was the third week of January and again in October, I think that was the first week.   I still have the cert papers some where but it would take a large bomb to uncover them .    Do you remember what our title was back then .   It was noway near as fancy as now.     Today's line mechanic are called technician's   The second school was for the new and improved    
Rochester Fuel injector.    It really was a good injector once I learned it's    
quirky mannerisms.   I fixed a lot more of them at home than at the dealership  They wanted to run and hide every time one showed up.  
I was the only one that worked on them and word got around so I was busy but it took so long to dial one in and the costumer was always complaining    
about expense.   I finally was lucky enough to buy the injection tools and set up a little shop of my own .   Later somebody told somebody about me
and  I went to Columbus and worked for a independent garage and started hanging around National Trails Race way. From the Trail Ways connection I started to work on Eight stack injectors Like Hilborn .  If you are not doing anything for the next three or four days I could tell you about
a lot of fun and funny stories

[enjenjo]

I took a 12 week dealer sponsored course in 1965 with the Oldsmobile division. It covered every thing. I still draw on that training.

[bowtietillidie]

The dealer I worked for ( Glockner Chevrolet) in Coshocton Oh.
 never sent any one to the big course because of the help turn over.  
 He always said they never stayed long enough for him to recoup his
 money .  We worked flat rate and min hr. rate .  It was hard to make any  
 money unless you were fast and had no come backs. I worked for Glockner      
 several times between 1963 and 1970.  He sent me to several other GM  
 Tech Schools.   I worked several times for Glockner and Connard in  
  Columbus .    The Glockner line mechanic's use to tease me about quiting  
 all the time .  One of the old timers told me once that I could throw a tool box in the trunk of a car faster than Jesse James could draw draw his six gun at a bank hold up

[enjenjo]

I got a job at a Chevy dealer here in Toledo, working on trucks. They pumped me up like always to take the job.

Started at 630AM, unloading my tools, the Service manager came over, started chewing on me, and letting me know how it was going to be. I loaded the tool box back up, closed the trunk, and left. I went back to the other job I had, it started at 730 am, and started to work.

My brother worked at the Chevy dealer too, in the body shop, and the service manager asked him where I went. My brother told him, "you * Frank off, he won't be back" and he was right.

[kb426]

Good stories.