On Sat, 27 Mar 2004, Mark Martin wrote:
[stuff deleted]
> I've never adjusted the rockers with the engine running. Can anyone explain
> to me how to actually do this and what the pros/cons are?
The method is fairly simple. You run the engine with the valve cover off.
Note: you will get oil all over the engine compartment!!!! So, putting
some "fender covers" over the inner fenders will aid in any potential
cleanup!
Most times that I've followed this procedure, I "crack" all the nuts and
leave them snug but not tight. This helps to unlock them. Note: The rocker
does not move all the time, so you get about one revolution on the motor
to crack the nut, insert the feeler gauge, insert the screwriver, etc.
Remember that the lash is set when the valve is on the seat.
Start the motor and start from the front to the back. If you have a "cam"
then the exhausts are likely set different than the intakes, so do all the
exhausts first and then the intakes (or visa-versa). Offer the feeler
gauge to the rocker tip. When the valve is in the seat, the gauge will
slip in.
Note: it helps to have two people for this job, but it you work from the
right side of the car, the insertion of the feeler gauge is easier. If you
do have an assitant, one works the the feeler gauge and tells the other to
tighten or loosen (as appropriate).
Insert your screwdriver in the adjuster screw and twiddle as appropriate.
Once you get it feeling correct, snug the nut. Move to the next valve (of
tha appropriate type. Exhausts (from the front of the motor) are 1, 4, 5,
8, 9, 12. Intakes are 2, 3, 6, 7, 10, 11.
Once you get them all adjusted, turn the motor off and "lock" the nuts
tight. Then run the motor again and verify that by locking the nuts you
didn't tighten the lash! If you did, crack the nuts and repeat (for just
the valves that are now "tight").
Believe it or not, when you've done it a few times, you can to the whole
job in well under 30 min.
BUT if you drop anything while you're doing this job remeber that
_everything_ will be hot to the touch and that if stuff drops in the
lifter galleries that you can damage the lifters.
The advantage here is that the exhausts get set HOT which is what matters.
The exhaust valves "grow" quite a lot when the motor is running, so the
valve lash changes from whatever you set it to cold. So adjusting this way
gives you the best "real world" valve lash. Also note that this exhaust
valve lash is much more important the more aggressive your cam is.
The job takes practice to do right!
> Thanks,
>
> Mark
> '72 TR
regards,
rml
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