TDC on an RB30

[Anthony1016 0]

Hi guys, so I had a go at taking my R31's (RB30) head off. Made sure to TDC and aligned the crank pulley with the markings, used a screwdriver in cylinder #1 spark-plug whole to make sure it was at the top of the stoke. Also took the rocker cover off to make sure the valves on #1 and #6 weren't open (turning the crank until neither rockers were moving) to know I was on the compression stroke. However, as per attached photo the exhaust valve on cylinder #2 and intake valve on cylinder #3 are open. All the other valves are closed. 

Questions are:

1. Did I mess up TDC?

2. Could the valves be possibly stuck open? 

Cheers for any responses, hopefully I didn't mess up too bad. 

IMG_1341.HEIC

[GTSBoy 2,179]

HEIC file not all that openable. Try JPG or PNG or something. f**king phones!

I'm not sure you understand what is supposed to happen at TDC. Only #1 and #6 will be at TDC (when you're on the TDC mark on the crank pulley). One will be closed valve, because ignition point, the other will have the valves both open, because it is the overlap period between exhaust and intake, where the ex valve is very nearly closed, and the intake valve is opening. They will be nearly closed, but they will not be closed.

The other cylinders will be all over the place. Some valves will be closed, some will be open, reflecting the fact that one is on power stroke, one is on intake, one is on exhaust, and one or more are partway between (ie the ones at BDC are either at end of intake stroke or at end of power stroke).

Edited April 9 by GTSBoy

[Anthony1016 Topic Author 0]

Cheers, that exactly what I needed to know. Was super confused because a mate had a head and all the valves were closed. Since this was the first time doing this I thought I must of mucked something up because it wasn't the same. 

Edited April 9 by Anthony1016

[GTSBoy 2,179]

8 minutes ago, Anthony1016 said:

a mate had a head and all the valves were closed

Can only be true if the cam is not installed.

[Anthony1016 Topic Author 0]

1 hour ago, Anthony1016 said:

Hi guys, so I had a go at taking my R31's (RB30) head off. Made sure to TDC and aligned the crank pulley with the markings, used a screwdriver in cylinder #1 spark-plug whole to make sure it was at the top of the stoke. Also took the rocker cover off to make sure the valves on #1 and #6 weren't open (turning the crank until neither rockers were moving) to know I was on the compression stroke. However, as per attached photo the exhaust valve on cylinder #2 and intake valve on cylinder #3 are open. All the other valves are closed. 

Questions are:

1. Did I mess up TDC?

2. Could the valves be possibly stuck open? 

Cheers for any responses, hopefully I didn't mess up too bad. 

 

 

[GTSBoy 2,179]

Some of those valves are open. Ergo the cam is installed.