Hi Dave,
The readings are a bit low. Low readings could be caused by higher
altitude, the manual would be based on sea level. Air density &
resultant compression readings would drop about 3.4% for each 1,000 feet
elevation above sea level. In your case, about 6 psi/1,000 ft.
Compression gages could have an equal or greater amount of error.
Since the readings are uniform, I doubt if anything is ready to
immediately fail. Worn engines usually don't fail suddenly, the just get
gradually worse until low power output & hard starting become annoying.
I suspect that the low readings combined with somewhat low oil pressure
indicate "some" engine wear. As long as the engine starts & runs ok, I
would wait for it to get worse before rebuilding the engine. At least
wait for a convenient time & budget to rebuild it. You may be surprised
at how much better it runs with a rebuild. If that time is now, go ahead
& rebuild it. Otherwise, it will probably go another 10,000 miles before
getting really bad.
Regards,
Dave Russell
Dave Leland wrote:
> Does anyone have any thoughts on my compression readings below? My
> Haynes manual says to expect about 175 lbs and I'm lower (but
> consistently lower).
>
> How long can I wait for a rebuild is my main concern.
>
> #1- 147 lbs #2- 150 lbs #3- 149 lbs #4- 151 lbs #5- 148 lbs #6-
> 150 lbs
>
> The car is a BJ7 with probably 80k miles and oil pressure is 30-35lbs
> when warmed up at cruising speed. Thanks for your thoughts.
>
> Dave Leland Nashville, TN
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