With the valve cover off, spin the eng over by hand (slowly by hand only) you can watch both rockers open the valves then close....now when the Ex valve opens and it closes the Int valve will open next,as soon as it closes, look in the cyl to see when the piston is at TDC. Make sure piston is at TDC or you can still be on EX compression release.
As TDC approaches on the compression stroke a screwdriver is recommended to place in the spark plug hole to observe when the screwdriver quits moving TDC has been reached. I wouldn't put a screwdriver in my worst enemy's spark hole. I've seen too many engines that could be damaged because of the geometry of the spark plug hole angle and the cylinder bore. Use a drink straw in place of a screwdriver.
I'm aware there will be mechanics that will say - " I been usin a screwdriver for years, spit, spit " - you go right ahead but remember possibly a novice ask the question.
#4
Scrubcadet10
2nd what senior citizen said. I usually use a wooden dowel, or a straw.
BBQ skewers used by this little black duck for the same reason.
#6
cpurvis
You don't need to find TDC to set valve clearance. In fact, you'll do a better job of setting the valves if you don't.
Exhaust Opening, Intake Closing Method.
Rotate the engine in the direction it runs until the exhaust valve just starts opening. Set the intake valve lash.
Rotate the engine in the direction it runs until the intake valve is nearly finished closing. Set the exhaust valve lash.
You will be setting the clearance with the cam follower on the base circle of the cam, directly opposite the peak lift portion of the cam lobe. No other method does this.
Exhaust Opening, Intake Closing. E O I C That's all you have to remember.
" a screwdriver is recommended to place in the spark plug hole to observe when the screwdriver quits moving TDC has been reached. I wouldn't put a screwdriver in my worst enemy's spark hole."
Well first off, the Service Manual *does not* recommend using a screw driver to find TDC. Second, B&S knows how to set the valve clearance on their engine which is piston 1/4" down after TDC.
Walt Conner
#8
cpurvis
There are TWO "1/4 inch down from TDC" piston positions in a 4-stroke engine.
With what you're talking about, it would be 1/4" past TDC of compression stroke but, there is no need to try to find 1'4" past TDC...if you set your valve lash as described in my earlier post which is TDC of compression stroke, it will run just fine!
Millstone, OP, you are obviously a novice. As such, you should use the factory recommended procedure when working on an engine. When you become more experienced and know more about the engine than the people who designed and mfg. it, then you can develop your own procedure.
" Make sure piston is at TDC or you can still be on EX compression release."
Contrary to what this post by the Master Service Tech. says, B&S Intek, as most B&S engines, releases compression via the INTAKE Valve and this and other forums are full of problems caused by people setting their valves AT TDC. B&S Vanguard TWINS do use the Exhaust Valve for compression release.
I can send you a Service Manual for your engine IF you like, stop guessing and getting a proliferation of different opinions. Address below, put in proper format and remind me engine model number and what you want.
