Piston to valve clearance

[661_Minis]

Hello, I’m currently building a 212 non hemi and have ran into some issues with my piston to Valve clearance.. I aligned the cam dots and put the side cover on, put in my pushrods and spun the engine over and my piston is hitting the valves, I personally think my pushrods are way too long ( there the stock pushrods) do you guys have any suggestions as to what can be causing this?

(ENGINE PARTS)
Stock rtc15 cylinder head milled .40”

26lbs spring installed too the correct spring height

1.1 ratio champion rockers

mls .36” head gasket

nr racing 292 camshaft

stock length billet rod & billet flywheel

everything else is stock internally and also the piston is the stock dished piston sitting at about .15” in the hole.

 

[ole4]

Are the valves adjusted correctly? Which valve is hitting? take off rocker cover and carefully and slowly turn over the engine with the plug out and see which valve is hitting. They will only make contact during the overlap period between 15 degrees before TDC thru 15 degrees after. Also take out the pushrods so there is no way the valves could hit anything and make sure the engine turns over ok. (again with the plug out so you can turn it over by hand. The two main reasons for lack of space between valve and piston is duration and LSA. Your cam is very radical for what is basically a stock engine. the 260 degrees and 108 should not cause the valves to hit unless the cam is advanced or retarded or maybe your head is milled too much. As you approach TDC on the overlap period the piston is chasing the exhaust valve which is closing, the intake is just starting to open as well and they will both be about even at TDC unless the cam is advanced or retarded.

 

[SAS289]

Are you using the stock rocker cover? With Champion rockers you need to check for clearance because the lash adjusters will contact the baffle. This will hold a valve open when it shouldn't be opened. Like Ole said turn the engine over with the rocker cover off. If there is no valve hitting then it's probably rocker to baffle clearance.

When I put Champion rockers on my 196 I packed play doe in there (about 1/16" thick) to find the points that needed clearance. Another option is an aftermarket rocker cover that has plenty of clearance.

With .040 off the head and everything else you should check rocker geometry. I like the Champion rockers but they are not just bolt on and go. I think they are worth it even on a stock engine.

 

[ole4]

Are you using the stock rocker cover? With Champion rockers you need to check for clearance because the lash adjusters will contact the baffle. This will hold a valve open when it shouldn't be opened. Like Ole said turn the engine over with the rocker cover off. If there is no valve hitting then it's probably rocker to baffle clearance.

When I put Champion rockers on my 196 I packed play doe in there (about 1/16" thick) to find the points that needed clearance. Another option is an aftermarket rocker cover that has plenty of clearance.

With .040 off the head and everything else you should check rocker geometry. I like the Champion rockers but they are not just bolt on and go. I think they are worth it even on a stock engine.

Good point and i did not even think about that. I always remove the baffle plate as I always am using aftermarket rockers. I just add a powerbrake check valve to the outside of the valvecover to act as a one way valve.

 

[SAS289]

Good point and i did not even think about that. I always remove the baffle plate as I always am using aftermarket rockers. I just add a powerbrake check valve to the outside of the valvecover to act as a one way valve.

Nice. This may be a better option for the OP.