Compression Test

[Marccus]

I need to perform a compression test on my '89 (440K) and have never done this before.

There are many compression testers on the market ranging from inexpensive ($30) to kits in blow molded boxes (Snap-On is $200).

(1) Any suggestions for a manufacturer?

(2) Does the engine need any particular extension (or Ford Type adapter / extension) for the recessed plugs for the SHO?

I've read that "screwed in connections are better than push lock".

I would think that the comment refers to attaching an extension to the hose that is screwed into the spark plug receptacle.

So I assume this means that it is better that the connection of the extension to the hose be made by a screwed-in connection rather than a push lock connection.

(3) Is this correct?

The Snap-On literature states that the kit has push lock couplers at the gauge end.

Dumb question coming up ==>
(4) How does one get at the spark plugs closest to the fire wall?
I assume that the intake manifold has to stay on.

I have a Hayne's Manual that describes how to do a compression check for a regular Taurus that includes the 1989 model year.

(5) Is this OK to follow for the SHO, or there a particular procedure that is best to follow for the SHO?

Also, the procedure talks about adding oil through the spark plug hole after running the test and seeing if the compression changes. This will determine if there is a problem with the rings.

Dumb question coming up ==>
(6) But isn't oil getting to the bearings and the rings because the oil pump would be pumping oil as the crankshaft turns when you run the compression check?

I hope no one minds the fonts. I like colors.

Thanks for your help. :thankyou:

 

[bigblock]

(2) Does the engine need any particular extension (or Ford Type adapter / extension) for the recessed plugs for the SHO?

I've read that "screwed in connections are better than push lock".

I would think that the comment refers to attaching an extension to the hose that is screwed into the spark plug receptacle.

the kind i used threaded into the the spark plug hole. never heard of a kind that would push in. at the end of the hose the gauge snapped on like a regular compressed air line. the kit should come with multiple hoses with different threaded ends.

Dumb question coming up ==>
(4) How does one get at the spark plugs closest to the fire wall?
I assume that the intake manifold has to stay on.

well if you can get the spark plugs out the tester should be pretty easy to put on since its a rubber hose. the manifold does not need to be on. when you test you hold the throttle at wot so it wouldn't matter.

I have a Hayne's Manual that describes how to do a compression check for a regular Taurus that includes the 1989 model year.

(5) Is this OK to follow for the SHO, or there a particular procedure that is best to follow for the SHO?

Also, the procedure talks about adding oil through the spark plug hole after running the test and seeing if the compression changes. This will determine if there is a problem with the rings.

the procedure it basically the same for all engines. its the chart for that engine that tells you if your compression is good. the max amount of cranks is 7 and excellent compression is around 200lbs low is around 130. it should still run at 130 just not that strong. and all cylinder should be with in 10% of each other not totally sure if that's right though. its something like that

putting oil in the cylinders will raise the compression of any engine. if you have a dramatic increase that means rings but its not sure proof. only a SMALL squirt of oil!

Dumb question coming up ==>
(6) But isn't oil getting to the bearings and the rings because the oil pump would be pumping oil as the crankshaft turns when you run the compression check?

I hope no one minds the fonts. I like colors.

Thanks for your help. :thankyou:

yes but the pressure is so low it doesn't matter.

 

[Marccus]

Thanks for an excellent reply. I appreciate it.
:thankyou: