Having reviewed the question and answers in the above mentioned review questions, can i get a review of the question please.

GK1/39 - During the COMPRESSION and POWER strokes on the 4 cycle engine, on a HO engine

a. The exhaust valve remains closed.
b. both inlet valves remain open.
c. the inlet valve closes.
d. both valves remain open.

So my thinking here is;
a is correct IF we're talking about compression but as it opens on the power stroke, not the most correct.
b is what the answer keys indicates as correct (videos show during the compression stroke the inlet valve closing as the piston leaves BDC and is closed on the power stroke, )
c. the inlet valve is ALREADY closed as the compression stroke starts
d. inlet is closed and exhaust is opening

Looks like C should be the right answer.

I picked (c) then changed it to (a) as in my mind (b) and (d) arent correct

Keen for some guruness here.

The wording you have indicated is not the same as that of the question in the book. Choice (b) in the book says.

"the inlet valve closes during the compression stroke and the exhaust valve opens during the power stroke"

That is the correct answer.

Hi Bob

Thats not the question in my book

That's odd. Thanks for your feed-back. It is appreciated.

Bob

Yes, weird. Thanks for the clarification.