Triumphrat

dollardriven · 05-14-2003

Please somebody explain what are valve adjustments and do they have to be adjusted. I understand what valves are and what they do. I have a 2001 Sprint. Thanks :-D

dollardriven · 05-14-2003

Please somebody explain what are valve adjustments and do they have to be adjusted. I understand what valves are and what they do. I have a 2001 Sprint. Thanks :-D

Slinky · 05-14-2003

The valves need to be adjusted (or checked) while the engine is cold, in order to ensure that there is a working clearance between the cams and the cam followers when the engine reaches normal operating temperature.

The valve clearances on Triumphs are set by using the appropriate sized shims. Some other engine designs use different methods.

It is not something you should think about doing yourself unless you are sure you know what you are doing.

Slinky · 05-14-2003

The valves need to be adjusted (or checked) while the engine is cold, in order to ensure that there is a working clearance between the cams and the cam followers when the engine reaches normal operating temperature.

The valve clearances on Triumphs are set by using the appropriate sized shims. Some other engine designs use different methods.

It is not something you should think about doing yourself unless you are sure you know what you are doing.

MickMaguire · 05-14-2003

To add to Slinky's post:

As our engines wear the valves will receed into the cylinder head (move away from the piston and towards the cam).

This recession means that the running clearance between the camshaft and the bucket tappet (which sits atop of the valve) is reduced. Much of this running clearance is there to take up expansion through heat as the engine warms. If the clearance is too small when the engine heats up the valve will not be able to close properly. Because of the recession mentioned before, over time the clearance will be reduced to this point. if the valve doesn't close properly gasses will blow by the valve and cause a loss of compression and burning and pitting of the valve seat, eventually leading to valve failure and potentially a blown engine.

to aviod this we need to compensate for the valve recession peiodicly by setting the valve clearance. The clearance is set by use of shims which come in a great range of sizes. the shim is positioned between the cam and the valve bucket tappet (it is actually seated in the top of the bucket). You select the shim to give you the correct cold running clearance. As the engine wears and the valves receed you swap in new, smaller shims at the adjustment time to maintain the clearance. Often the recession will be small or non-existant on any one valve, but often it will change quite a bit between adjustments.

All this info is provided solely for interest and to explain what it's all about. I have left out quite a few of the finer details for clarity. I am with Slinky that it is not something you should think about doing yourself unless you are sure you know what you are doing. This adjustment should be carried out every 12000 miles (although many do it at 6000).

[ This message was edited by: MickMaguire on 2003-05-14 09:25 ]

MickMaguire · 05-14-2003

To add to Slinky's post:

As our engines wear the valves will receed into the cylinder head (move away from the piston and towards the cam).

This recession means that the running clearance between the camshaft and the bucket tappet (which sits atop of the valve) is reduced. Much of this running clearance is there to take up expansion through heat as the engine warms. If the clearance is too small when the engine heats up the valve will not be able to close properly. Because of the recession mentioned before, over time the clearance will be reduced to this point. if the valve doesn't close properly gasses will blow by the valve and cause a loss of compression and burning and pitting of the valve seat, eventually leading to valve failure and potentially a blown engine.

to aviod this we need to compensate for the valve recession peiodicly by setting the valve clearance. The clearance is set by use of shims which come in a great range of sizes. the shim is positioned between the cam and the valve bucket tappet (it is actually seated in the top of the bucket). You select the shim to give you the correct cold running clearance. As the engine wears and the valves receed you swap in new, smaller shims at the adjustment time to maintain the clearance. Often the recession will be small or non-existant on any one valve, but often it will change quite a bit between adjustments.

All this info is provided solely for interest and to explain what it's all about. I have left out quite a few of the finer details for clarity. I am with Slinky that it is not something you should think about doing yourself unless you are sure you know what you are doing. This adjustment should be carried out every 12000 miles (although many do it at 6000).

[ This message was edited by: MickMaguire on 2003-05-14 09:25 ]