haroldsson
New Member
The manual says to turn the engine until the valves in one cylinder are "rocking". What does this mean?
Valve clearance adjustment, Volvo2003
- Thread starter haroldsson
- Start date
bazobeleza
Well-Known Member
that the rocker arm on the cylinder head rocker shaft rocks! ie that the rocker can be rocked back and forth so that you may get you feeler guages in the gap between the valve and rocker, this is adjusting the tappets. the rocker arm is the arm that opens the valves.
It is important that both the inlet and exhaust rocker arms are s rocking at the same time for any given cylinder as that is when the piston is at TDC (Top Dead Centre) when this is so then the vales are shut and you can adjust the valve clearance
It is important that both the inlet and exhaust rocker arms are s rocking at the same time for any given cylinder as that is when the piston is at TDC (Top Dead Centre) when this is so then the vales are shut and you can adjust the valve clearance
pvb
Well-Known Member
Correction...
[ QUOTE ]
that the rocker arm on the cylinder head rocker shaft rocks! ie that the rocker can be rocked back and forth so that you may get you feeler guages in the gap between the valve and rocker, this is adjusting the tappets. the rocker arm is the arm that opens the valves.
[/ QUOTE ]No, the original poster is querying the instructions in the Volvo manual. This says to turn the engine "until the valves in valves in one cylinder are rocking, Then turn the engine one turn more and adjust the valves for this cylinder." What the term "rocking" means here is that the inlet and exhaust valves operate, with movement of the rocker arms. Turning the engine one more complete turn from this point will ensure that the valves are fully closed, and facilitate correct valve adjustment.
[ QUOTE ]
that the rocker arm on the cylinder head rocker shaft rocks! ie that the rocker can be rocked back and forth so that you may get you feeler guages in the gap between the valve and rocker, this is adjusting the tappets. the rocker arm is the arm that opens the valves.
[/ QUOTE ]No, the original poster is querying the instructions in the Volvo manual. This says to turn the engine "until the valves in valves in one cylinder are rocking, Then turn the engine one turn more and adjust the valves for this cylinder." What the term "rocking" means here is that the inlet and exhaust valves operate, with movement of the rocker arms. Turning the engine one more complete turn from this point will ensure that the valves are fully closed, and facilitate correct valve adjustment.
vyv_cox
Well-Known Member
Re: Correction...
Yes, I agree. When the valves are 'rocking' indicates that the four-stroke cycle is half way through, so the exhaust valve is just closing and the inlet is just opening, prior to drawing in a fresh charge. At one full revolution from this point the charge will have been drawn in and compressed, when ignition takes place. Both valves will be fully closed and tappet clearances at their maximum.
Yes, I agree. When the valves are 'rocking' indicates that the four-stroke cycle is half way through, so the exhaust valve is just closing and the inlet is just opening, prior to drawing in a fresh charge. At one full revolution from this point the charge will have been drawn in and compressed, when ignition takes place. Both valves will be fully closed and tappet clearances at their maximum.
Sans Bateau
Well-Known Member
Re: Correction...
With (older?) 4 cylinder engines with a 1,3,4,2 firing cycle, one was able to use the tappet adjustment sequence - with no 1 valve fully opened adjust tappet 8, then 2 open adjust 7, 3 and 6, 4 and 5, etc. Is there not a similar sequence for a 3 cylinder engine (VP 2003 etc)?
With (older?) 4 cylinder engines with a 1,3,4,2 firing cycle, one was able to use the tappet adjustment sequence - with no 1 valve fully opened adjust tappet 8, then 2 open adjust 7, 3 and 6, 4 and 5, etc. Is there not a similar sequence for a 3 cylinder engine (VP 2003 etc)?
bromleybysea
Well-Known Member
Re: Correction...
When you reassemble, make sure you get the head gasket the right way round- there is a small hole to line up with the crank-case breather. If you get it wrong you pressurise your crank-case and blow all the oil out of the dip-stick hole. Guess how I know!
When you reassemble, make sure you get the head gasket the right way round- there is a small hole to line up with the crank-case breather. If you get it wrong you pressurise your crank-case and blow all the oil out of the dip-stick hole. Guess how I know!
Sans Bateau
Well-Known Member
Re: Correction...
Thanks for the tip. But I dont think anyone will be removing the cylinder head just to adjust the tappets. well I hope not anyway!
Thanks for the tip. But I dont think anyone will be removing the cylinder head just to adjust the tappets. well I hope not anyway!
bromleybysea
Well-Known Member
Re: Correction...
I meant the rocker box cover gasket.
I meant the rocker box cover gasket.
MILLMAR
New Member
The phrase rocking means the exhaust valve is shutting and the inlet valve is opening(the end of the 4 stroke cycle and the beginning of the next. You will see one valve spring releasing (exhaust) and one starting to compress( Inlet) Now because the camshaft which opens and closes the valves turns at half the speed of the crankshaft one turn of the crankshaft pulley will turn the the rocking valves (camshaft) 180* which means it is now face down and the maximum clearence is there to adjust
Easy
SUCK SQUEEZE BANG BLOW
Easy
SUCK SQUEEZE BANG BLOW
haroldsson
New Member
Thanks to everyone who replied. I understand now. Next thing is to do it!