Compression Question?

[GTRAAH]

thanks for the comments guys steve im using 10w40w royal purple only because i was told 10w 40w. im going to get a proper test done and a print out. i think the engine wasnt turning over fast enough when i was doing compression so ill use a battery booster and a proper gauge

[Daewoo]

GTRAAH,

Asking if an engine is ok by based only upon a compression test is like asking if a chick is hot because she wears nice shoes.

What this test has shown is that the guage you used showed a reading at the lower end of OK. The guage might be worng, it might have had this reading from the factory, it might have low compression pistons, or it might have a problem.

I wouldn't worry too much about the booster battery. If it spun over OK, and you kept cranking until the guage stayed at a stable reading, then you most like go the correct reading (for that guage).

Do liketridentt150v said and put some oil down the plug hole to make a better seal. What you are doing is increasing the seal between the piston rings and the cylinder wall. (Testing first without oil, then with)

If there is a big difference in the readings, it is most likely because the rings are worn, although this would also usually show up as the car using oil and smelling of burnt oil as well, and constantly fouling spark plugs).

(As a bonus when you drive after doing this test you will do the whole Batman smoke screen thing until all the oil in the cylinder burns up ).

If there is no difference between the two readings, your valves most likely aren't sealing properly (or maybe you have a big cam ).

One last thing, high compression doesn't give you better performance, correct compression does. (too high you need to retard the timing to stop the engine from pre-ignition and loose a lot more than you gain).

Cheers,

Daewoo

[GTRAAH]

GTRAAH,

Asking if an engine is ok by based only upon a compression test is like asking if a chick is hot because she wears nice shoes.

What this test has shown is that the guage you used showed a reading at the lower end of OK. The guage might be worng, it might have had this reading from the factory, it might have low compression pistons, or it might have a problem.

I wouldn't worry too much about the booster battery. If it spun over OK, and you kept cranking until the guage stayed at a stable reading, then you most like go the correct reading (for that guage).

Do liketridentt150v said and put some oil down the plug hole to make a better seal. What you are doing is increasing the seal between the piston rings and the cylinder wall. (Testing first without oil, then with)

If there is a big difference in the readings, it is most likely because the rings are worn, although this would also usually show up as the car using oil and smelling of burnt oil as well, and constantly fouling spark plugs).

(As a bonus when you drive after doing this test you will do the whole Batman smoke screen thing until all the oil in the cylinder burns up ).

If there is no difference between the two readings, your valves most likely aren't sealing properly (or maybe you have a big cam ).

One last thing, high compression doesn't give you better performance, correct compression does. (too high you need to retard the timing to stop the engine from pre-ignition and loose a lot more than you gain).

Cheers,

Daewoo

Thanks for the tip interesting shit im getting from all these replies.