is this good compression??
02-14-2005, 03:55 AM
#1
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Join Date: Feb 2005
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Posts: 7
is this good compression??
hi naybody wanna help out a mustang gal?
i just bought a motor for my 89 lx 5.0 compression is (left side)180,175,175,180(right side)180,175,170,190 is this good compression on this motor> thank you appreciate the help
[IMG]local://upfiles/12818/E9899A8702F34085B77C0540EF892B43.jpg[/IMG]
i just bought a motor for my 89 lx 5.0 compression is (left side)180,175,175,180(right side)180,175,170,190 is this good compression on this motor> thank you appreciate the help[IMG]local://upfiles/12818/E9899A8702F34085B77C0540EF892B43.jpg[/IMG]
02-14-2005, 12:27 PM
#2
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RE: is this good compression??
the left side looks good but the right side has that one cylinder at 170 which is slightly more than 10% lower than the highest reading of 190, so I would restest it and see is this remains the same or not. if it stays down relative to the others, you might have a slight valve sealing problem on that cylinder only. welcome to the forum by the way!
02-15-2005, 12:55 AM
#3
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RE: is this good compression??
if the compression stays at were it is (170) do i need a valve job? would this make my performance bad? what should i do or not do??[&o] dont know much about compression wish i did thanks.
thanks.
02-15-2005, 12:59 AM
#4
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RE: is this good compression??
Welcome to the forums !! No doubt better luck with your tech question in the Tech area. No I am not pretending to be a moderator. I was always told the with compression, the difference is the issue, or a weak cylinder, as pointed out. If it runs good, and doesn't smoke..... drive her.
02-15-2005, 01:05 AM
#5
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RE: is this good compression??
ORIGINAL: mustangsallys89lx
if the compression stays at were it is (170) do i need a valve job? would this make my performance bad? what should i do or not do??[&o] dont know much about compression wish i did thanks.
if the compression stays at were it is (170) do i need a valve job? would this make my performance bad? what should i do or not do??[&o] dont know much about compression wish i did
thanks.
seems like you are susposed to put a small amount of oil in the week cylinder through the spark plug hole, not much or you can hydaulic and bend a rod or something. You don't start the engine, but crank it with that small touch of oil to seal the rings better for the test. If the comp. is still low, it points to a valve seat seal problem. I am not a mechanic, so run this idea past others. I did have a friend who builds a lot of big blocks suggest it to me once. Before doing it I found a different problem, that made burnt valves seem likely. When I took the heads off, I had pie shaped notched in two of the exhaust valves...leaked it did.
Good luck !!
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