>
>What is typical compression (lbs) on an unmodified 1991cc TR3A engine?
>
>Any opinions on how wide a variance I should see among cylinders before
>I become concerned that there's a problem?
Compression is a funny thing to measure accuratly. Clearences are looser
(with lower pressure readings) on a cold engine than a hot engine and
cheap gauges are not always accurate.
Personally I do not like to burn my hands removing plugs at hot engine
temperatures so I run my compression tests cold and look for pressure
differences between cylinders instead of the elusive correct operating
temperature compression.
I'm happy if I see everything within 5 pounds of each other but don't get
concerned until the lowest drops below 15 pounds from the highest. I
would then start thinking about finding a convient time to do a valve job.
One thing I like to do is run a compression test a few hundred miles
after a valve job and record the readings for each cylinder. Sucessive
readings would be compaird against those readings. There are individual
differences in the cylinders that can make for a few pounds difference.
So having a reference reading to compaire against helps me keep track of
individual cylinder changes.
I would say that as long as your compession is within 15 pounds across
all the cylinders, you have oil pressure and no noticable colour out the
exhaust you have a drivable TR. Mabybe a little over simplified but
basically true. I would be more concerned about stresses from cylinders
with radically different compression than an overall uniform low
compression.
Take care
TeriAnn Wakeman Coming soon
Santa Cruz, California New hub web site for
twakeman@cruzers.com everything Rover and expedition equipment
http://www.cruzers.com/~twakeman Links-cars for sale-special equip.
equip. reviews-Books-expeditions
& much more!!
|