MG Car Repair: Rocker Assembly Installation, correct torque, head gasket

Question
QUESTION: Hi Howard,

I am in the middle of replacing the head gasket on my 1980 MGB.  I had the head checked and they say it's ok - no cracks, etc.  I installed a new head gasket and the cylinder head (did not install/torque the nuts yet)and pushrods.  When installing the rocker assembly it does not settle onto the head.  There is a gap of maybe 1/16" (maybe less).  One of the pushrods/valves is so tight it won't allow the rocker assemblyto settle onto the head.  Should I loosen the valve adjusting screw to allow the rocker to settle to the head, and then adjust all of the valves after torquing everything?  I don't even know if there would be enough adjustment to do that.

When adjusting the valves how do I get the engine to turn over to do the adjustments on the different valves?

Another question:  The sending unit in the fuel tank was missing the cylinder mesh/filter on the end when i pulle dit out. I assume it is in the fuel tank, but have not been able to get it out if it is in there. I have replaced the sendin unit with a new one, but wonder if this could have caused a problem with fuel flow to the fuel pump - especially while under heavy load?

Thanks.

Wayne

ANSWER: Hi Wayne,

It is standard procedure to loosen all of the valve adjusting screws when installing the rocker arm assembly. Then torque the head in the correct pattern and to the correct torque. It is advisable to torque the head down in two progressive steps.

The easiest procedure I use to adjust the valves is to remove all the plugs and put the car in 4th gear with the brake off and the car on level ground. I use the "Opposite valve down" method outlined in most manuals. I role the car until a valve is compressed and sent the opposite valve. Example, when #1 is compressed set #8 and when #2 is compressed set #7 etc. when #7 is compressed set #2 and so on. Note that there are two valves compressed at one time so you can always set two at a time. For example, when #1 is compressed #3 is also compressed so you can sent #8 and #6 at the same time. This way you don't have to role the car very far to set all the valves.

I found that many gasket sets say that re-torque is not necessary but I don't go by that and always re-torque after about 300 to 500 miles and only when the engine is left for many hours to be sure it is stone cold. Then adjust the valves again after the head torque.

Howard


---------- FOLLOW-UP ----------

QUESTION: Thanks Howard.  That info helps.  What about my second question about the sending unit?

Wayne

Answer
The new one needs a screen on it so it don't pick up trash and put it in the fuel pump and cause a problem. You can easily put an inline filter (if it don't have one) after the pump to keep trash out of the carburetor. The old screen will not be a problem if you have a new one on the pipe.

Howard