Hynes said it should be started from TDC at compression stoke while the Honda service manual just said that the arrow on camshaft pulley points up. from my understanding, the position when the arrow on camshaft pulley points up may not be the TDC position at the compression stoke. which is correct or it really doesn't matter.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chibiko &raquo;</TD></TR><TR><TD CLASS="quote">Hynes said it should be started from TDC at compression stoke while the Honda service manual just said that the arrow on camshaft pulley points up. from my understanding, the position when the arrow on camshaft pulley points up may not be the TDC position at the compression stoke. which is correct or it really doesn't matter.</TD></TR></TABLE>

you have to match it up, the arrow on cam marking is indicating cylinder number one at TDC, not all of them.

so after you did the work on number one then you have to crank it(90degreecam/180 crank, if i remember right ) to make cylinder number three at tdc

same for the rest.

do you have to do that? yeah.

 

if the piston is not on the compression stroke, the valves wont be closed, so how are you supposed to adjust them properly? If it wasnt important, it wouldent be in the manual

 

i mean do i need to also check the distributor or the TDC mark on the flywheel when the arrow on the camshaft pulley is pointing up. Haynes said that but the Honda service manual didn't say that.

or my question is when the arrow points up, it must be the TDC position of number 1 cylinder at its compression stoke?

 

did some research on 4-stroke cylinder engine. now i understand the follows, waiting to be confirmed:

1. in one cycle, intake-compression-combustion-exhaust, the crankshaft pulley rotates 720 degree (two complete turns), while the camshaft pulley rotates 360 degree (one complete turn).

2. so the TDC mark on the crankshaft pulley does not have to be the TDC position on the compression stroke of the number 1 cylinder. it may also be on the exhaust stroke.

3. but the up arrow on the camshaft pulley pointing up always mean the TDC on the compression stroke of the number 1 cylinder.

4. so for valves adjustment you don't need to check the distributor (whether the rotor is pointing to the number 1 wire connection) since you can see the camshaft pulley directly once the cylinder is opened.

need confirm!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chibiko &raquo;</TD></TR><TR><TD CLASS="quote">

3. but the up arrow on the camshaft pulley pointing up always mean the TDC on the compression stroke of the number 1 cylinder.

need confirm!</TD></TR></TABLE>


This is not true. The arrow will also point up on tdc of the exhaust stroke, so you have to verify that the rotor is pointing at #1 to verify that you are on the intake stroke which is what you want.

 

This might help you a little bit; The cam lobes are at 7 'O' clock and 4 'O' clock when the piston is at compression TDC.
this will help those that want to cheat and not turn the crank any more than needed.
For instance with #1 at TDC you can look along the cam and adjust anything else that has the intake cam lobe @ 4 'O'clock or the Exhaust lobe @ 7'O'clock.
The method is called adjusting by 'bank'.
Flat rate fever leads to many discoveries.

 

no. there is only one arrow on my 97 accord camshaft pulley and other two marks which are 90 degree from the arrow. since one turn of the camshaft is a complete 4-stroke process, the arrow can only correspond one stroke - the compression stroke.

however, the TDC mark on the crankshaft pulley is not necessary the compression stroke. it may be at the exhaust stoke of the cylinder 1, which is just the opposite stroke of the compression stroke in all 4 strokes.

i did my car's valve adjustment today and it looks good.