Richard, You need to hold the throttle open so that you have free flow through
the
intakes, and no false readings due to vacuum pulled against closed throttles.
Compression tests seldom are diagnostic of true condition, i.e. engine wear. It
will detect one or more cylinders that has a problem compared to the others.
Test
warm to get a real picture of clearences at operating temp. If you want to
assess
true condition, leakdown is far more precise. John
rtriplett@bjservices.com wrote:
> > Greetings to the Group!
> >
> > I am in the process of purchasing my first TR6 :)!
> > A mechanic suggested that I have the owner check the compression.
> >
> > How easy is it to test the engine compression?
> > Do you need any special tools (Can you tell I don't know my way
> > around
> > the engine compartment !)
> >
> > Is it time consuming?
> > Is it expensive?
> >
> > Best regards,
> >
> > Jim
> > Soon to be TR6 Owner
>
> Jim, If you don't have a compression tester and don't want to buy one, many
> auto parts stores now offer "free" use of tools and I believe a compression
> tester may be available that way. You pay the value of the tool and then get
> the money back when you return it.
>
> >Its simple. You will need a compression gauge that screws into the spark
> >plug hole. Remove all plugs, fit gauge, hold throttle wide open, spin engine
> >with starter until the gauge reaches its highest value. repeat on all
> >cylinders. Do with the engine warm. Look for essentially equal compression
> >in all cyls. Variance should not be more than 5-10 %. Leakdown is more
> >diagnostic, but more complicated. John
>
> BTW good information on compression testing, but why do you recommend opening
> the accelerator all the way? Also, I've found that more information on the
> cylinders' actual condition is found when the engine is cold, because when
>it's
> warm sometimes even a worn engine will test ok.
> Regards,
> Richard
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