compression on used engine

dakotaflstf

Registered User
Looking at an engine out of a SC with 71,000 miles. What kind of compression should I expect and bleed down?

What other things should I look at to make sure the engine is good?
 
130-140 PSI cranking pressure. Remove ALL plugs and hold the throttle open.All cylinders should be within 5-7%. I don't usually do a leakdown test unless I suspect another problem.

Jeff
 
the engine is out of the vehicle. Will you be able to get the same results by hand? What are other inspections I should be doing?
 
If it’s out of the car then the only easy thing to do is a leakdown test, but you have to have the tools to do it. If you have the starter on the engine, and the engine on a sturdy stand, then you can hook up a battery to the starter to turn the engine over to check cranking compression. If you are going to put the engine in the car ASAP, then I would check at least the main and rod bearings, remove the valve covers and check the springs and valvetrain.


Jeff
 
oh and if i were you, with 71k on the motor, id invest in some new HEADGASKETS... they arent too hard to change with the motor out of hte car and for $200 bux or thereabouts for the gaskets and a head mill job its a good insurance policy.
 
Not to sound stupid, but what am I looking for when I'm inspecting the bearings and springs?

As far as the head gaskets, didn't 94 and 95 models come with the updated gaskets already? Should I worry about it with only 71,000 miles?

Thanks for all the help everyone :)
 
i would say YES worry about them.... ford had a recall in 1994-95 due to the bad headgaskets...they usually go between 70-100k
 
Do you know any history on the engine? When you check the bearings, you are looking for nice even color with no copper color coming through, and no scratches, should be gray in color. Just look at the springs and make sure none are broken, look between the coils for contact marks (it’s not that likely but check anyway). If you do a compression check and a leakdown test there should be no reason to change the headgaskets, especially on a 70K engine. Don’t over heat the engine. Running low on coolant is very easy to do in these cars because the Rad hose is higher than the engine. Engine temp should not change very fast it should take several minutes to move, if it all of a sudden jumps from the left side to the N you are low on coolant, and that’s probably the cause of at least half of the people that blow them.

Jeff
 
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