[Steve Johnson]

Installing a Cloyes true roller timing set and I'm looking for TDC on the #1 piston. So do I rotate the crank until the sprocket mark is at twelve and run the stop in and get all happy :hurray: when the it doesn't go in it's total length or do I screw in the stop and get happy when I rotate the crank by hand and I can't turn the crank any farther? Seems to me that depending on how much I screw the stop into the cylinder that I could have the piston make contact before It reaches it's highest point.
what am I missing here ?

 

[Tod74]

You rotate it one way until it hits the stop, put a mark on the degree wheel where your pointer is. Rotate back the other direction until it hits the stop ,mark your degree wheel. Take the stop out and half way between your two marks is TDC.

Doesn't matter where the stop is as long as you don't move it. Just put anything that the piston can touch somewhere. It doesn't need to be with the piston at the top of the cylinder.

 

[Steve Johnson]

So I don't worry about where #1 piston is while I'm installing my timing chain. Get the two sprockets lined up and the timing set all installed and then play with the piston stop. Does it matter how far the stop goes into the cylinder?

 

[jackie schmidt]

You do understand that the only thing the piston stop is establishing is the correct position of your timing cover pointer at true top dead center.

So no, it makes no difference how far down the piston stop is, just as long as it contacts the piston.

Of course, for the purpose of finding the spot exactly between the two marks, you dou't want it too far down, the further down in the bore that the stop makes contact, the further your two marks will be apart from each other.

 

[Tod74]

If you are just installing a timing chain without degreeing the cam, put the dot on the cam gear at 6:00 and the dot on the crank at 12:00. Both dots at 12:00 would be correct also since the crank turns twice for every one turn of the camshaft.

The piston stop is used to find true TDC .

 

[von]

Be aware if it's a BBC with flat top pistons it may not contact the piston enough to stop it. I ran into this last week with a friend's car. Also, you should loosen the rockers on that cyl enough to free the pushrods so the valves don't open against the stop. Remove all spark plugs to make the engine easier to turn and if you loosen all the rockers it will be easier yet. Disconnect the battery so the there's no way the started can accidentally get engaged.

 

[Steve Johnson]

I am installing a new cam so I will be using the degree wheel. No lifters or push rod yet.

 

[Steve Johnson]

Let's try this from a different angle. A piston stop will get me in the neighborhood and then I should remove it and put my crankshaft timing mark at 12 o'clock. Since I am doing a cam change only on a good running engine I should be able the trust that the crank is right. So if the dot on the camshaft pulley is directly above the O on my Cloyes true roller timing set I can set my degree wheel to zero and degree the cam. Does this sound right?

 

[Bluegoose1970]

Let's try this from a different angle. A piston stop will get me in the neighborhood and then I should remove it and put my crankshaft timing mark at 12 o'clock. Since I am doing a cam change only on a good running engine I should be able the trust that the crank is right. So if the dot on the camshaft pulley is directly above the O on my Cloyes true roller timing set I can set my degree wheel to zero and degree the cam. Does this sound right?

To START align 0 deg marks on crank and cam gear, THEN you need to find TDC. The video link I have shows how to use a piston stop, there are others, this one is for determining if balance mark is correct. You are using a degree wheel, install degree wheel with a wire pointer that can be bent . Use the piston stop, find TDC. Adjust wheel to TDC, then degree cam. There are lots of videos on this, most have heads off.
Again video link is to show how to use a piston stop.