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Discussion Starter · #1 ·
Do ALL the valves on the front cylinder head closed or partially opened when the front camshaft timing mark is aligned on the TDC #1 piston. I am trying to figure out the least amount of force push down on the valves spring when removing and installing the rocker arm assembly. Looking at these lobes on front camshaft , when the TDC is at #1 piston, all the rocker arms are sitting at the lowest side of the lobe, which mean all the valves are closed or partially opened . Just want to confirm these with you guys.


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Discussion Starter · #3 ·
No, they cant all be closed so you will have to push down.


Ok. But when the TDC at #1 piston all the valves are at their minimum openings( based on the front camshaft profile I observed) and that is the reason why Honda tells you to turn the crankshaft until the TDC is at #1 piston to do the Timing belt to avoid valves hitting each other and the pistons.


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Ok. But when the TDC at #1 piston all the valves are at their minimum openings and that is the reason why Honda tells you to turn the crankshaft until the TDC is at #1 piston to do the Timing belt.
No, that is not why honda tells you to do the timing belt at #1-TDC. You use that point because it is a "known" point and the camshaft sprockets and crank pulley are all marked for it. It is easily identified, and repeatable.

Theoretically you could change the timing belt at any position as long as you ensured neither the crankshaft nor any camshaft sprockets moved, and you maintained the correct # of teeth on the belt between these three. But that is hard to do -- and frankly, silly.
 

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Just confirmed. All the valves on the front cylinder head are closed when the TDC is at #1
Can you post your source? That does not sound correct to me.
 
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Discussion Starter · #9 ·
Can you post your source? That does not sound correct to me.


If study pictures #1-4 closely and try to visualize the camshaft and cam pulley fitting together, did you see the #1 mark on the cam pulley is perfectly lined up with the vertical line mark on the cylinder head housing? And look at the picture #5 and notice all the valves are closed or almost closed. Picture #1 and #5 are from the same head sale on eBay


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Discussion Starter · #10 ·
I got it. I figured it out based on these pictures. When I am removing the rocker arm assembly i will feel some minimum force from the valve springs. If some of these valves are half-way or fully opened then I would felt maximum force pushing against the rocker arms.

I might save some labor not to loosen the valve nuts/screws


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If study pictures #1-4 closely and try to visualize the camshaft and cam pulley fitting together, did you see the #1 mark on the cam pulley is perfectly lined up with the vertical line mark on the cylinder head housing? And look at the picture #5 and notice all the valves are closed or almost closed. Picture #1 and #5 are from the same head sale on eBay
No, that's not how that works. You have access to the Acura Service Manual, right? Read that. The camshaft sprockets are marked for each piston. When doing a valve adjustment, you must rotate the camshaft sprockets and adjust each cylinder when it is in the correct position. There is no single position where all valves on all cylinders are closed.
 

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Discussion Starter · #12 ·
I asked the seller on Ebay to confirm and he told me the TDC was set to #1 and all the valves on the front head are at their neutral position ( barely opened as you can see in picture #5). Another words all the rocker arms are sitting at their lowest point on the lobes.

Notice all the exhaust lobe height profile (picture #2) is higher than the intake at their lowest point and you can see that correlated to the the exhaust valves are partially opened in picture #5


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