clockwise/anticlockwise, very confused

Hi everyone,
I am trying to adjust the valve clearance on a 90 Accord. Hayne's manual
says to turn the crankshaft pulley clockwise to get at TDC on no. 1 cylinder
and adjust the valves. To adjust no.3,4 and 2 valves, turn the crankshaft
pulley anticlockwise. Is it a typo error to turn the shaft clockwise ? If it
is Hayne's error and I have already done that, what should I do? Will it
harm the belts ? Should I readjust the belt tension first ? Very confused.
Many thanks for replying
Don

 

I don't know about the Accord, but I've been adjusting valves on my
trusty VW for about 15 years now. Which way does the engine rotate when
running. If it runs counterclockwise AND the firing order is 3-4-2-1
(AKA 1-3-4-2, AKA 2-1-3-4, you get the idea, it's start anywhere) then
the manual is correct and you should find TDC on #1 (by distributor
rotor position I presume), then move back (CCW) to #3.

One way to find out what cylinder is at TDC is to just wiggle the
rockers, if you have rockers. Could be you're dealing with an overhead
cam here. In which case you can only do your investigating with a feeler
gage.

Anyway if you put a feeler gage in and find that both valves are REALLY
tight, then you probably have the wrong cylinder. Experimenting a bit
with this will quickly tell you if you're going in the right direction
and have the right firing order. Be warned, however, that sometimes the
piston that is 180-degrees out of phase with the TDC piston can look
like it's valves are closed (nice feeler gage gaps) but one valve can
feel just a tad tight. This probably isn't TDC.

As a general rule if you find tight valves on an old engine (10,000
miles on it or more) then you've got the wrong cylinder. Valves will
loosen with age except during the run-in period when they are seating.

Hope this helps,

John

 

Short answer: The Hayne's manual directions are fine.

Other manuals for circa early 1990s Hondas say just get the #1 cylinder at TDC
*without* specifying which direction one should rotate the crankshaft.

See for example these directions for a 1991-1993 Accord, especially step 2:

http://www.honda.co.uk/owner/AccordManual/400/5-14.pdf

Also, for a circa 1990 Honda Concerto:

http://www.honda.co.uk/owner/ConcertoManual/62sk301/5-13.pdf

And for a circa 1990 Prelude:
http://www.honda.co.uk/owner/PreludeManual/62sf100/5-8.pdf

Also, the steps for removing the rocker arm on a 1990 Accord also have you
rotating the crankshaft so #1 cylinder is at TDC, but again no rotational
direction is specified. From the www.autozone.com site, see
http://tinyurl.com/2yjta

While driving, the crankshaft pulley rotates COUNTERclockwise while standing
next to the front left wheel and looking across the engine to the passenger
side. When one is doing this maintenance, will it hurt to rotate the engine in
the clockwise direction? I can't really imagine how. The pistons move up and
down regardless. I can't think of a part in the crankshaft system that would be
hurt by rotating clockwise.

I checked my car's valve clearances a few months ago for the first time. I think
you should just rotate the crankshaft manually in the direction that requires
the least amount of rotation to get #1 cylinder at TDC, per the description in
the manuals above.

Correct. I think the only reason for this is simply that the correct firing
order is 1,3,4,2. Thus as the crankshaft rotates COUNTERclockwise 180 degrees,
the next valves that are correctly positioned for TDC are #3's. Another 180
degrees, and #2's valves are correctly positioned for checking the valve
clearance. Etc.

I trust you are aware that your car has a 4-stroke engine, so two revolutions of
the crankshaft occur to complete one cycle. During these two revolutions, each
cylinder fires exactly once.

Good question. Maybe there's some minor advantage to rotating first clockwise
and then counter clockwise, like lubrication will be more even while doing this
maintenance.

Perhaps one of the very experienced technicians who hang around here will
comment.

Like I say above, I think you have done no damage to your car.

No and no.

 

Hello, thank you for your prompt replies..
The reason why I am confused is normal rotation for that engine is
anticlockwise when facing the crankshaft pulley side, yet Haynes manual say
to turn it clockwise for No.1, but anticlockwise for the rest; another
confusing point is that they say you can use a remoter starter to turn the
crankshaft until it is close enough to turn it manually, now if you use the
remoter starter, then it has to be counterclockwise ?? The question is what
to do about the timing belt which have been turned clockwise ?
Don

 

you use the remote starter to go clockwise just past, then manually back
counterclockwise.

 

always turn it counter-clockwise. going clockwise will put the slack
on the wrong side, not harmfull but it does affect tdc at the cam.

got to tdc on #1 adjust them, then turn the crank 180 degrees
counter and go for 3, repaeat for 4 and 2.
Chip