dgordner

I am building a 350 (355) for my circle track car. I am using the double hump 206/160 valves with a solid cam. I was running a hydrolic cam last year. Not real sure what the lift was but it was a slobberer!! When I took the piston to valve clearance on the intake, I had .280 @ 10 degree btdc. The exaust was .305 @ 10 degree atdc. Was that the correct way to check for that clearance? Also, how does one check for valve spring installed height and how does one know where coil bind will occur? Don

Tod74

Take the spring off and instal a height micrometer on the valve stem,put the retainer and keeper back on and adjust the mic up until it is against the retainer and read the measurement.
To check the coil bind height you compress the spring all the way and measure the height of it.I am no head guy but I think the best way is in a spring checker. You could put it in a vise I think but I don't know if that is a good idea (someone will let you know on here.) not sure if it will hurt the spring if put in a vise because you don't want to put any burrs or anything on the spring. The spring manufacturer will provide the coil bind height if you know the part number but I believe you should still check it to be sure.

johnracer

This the way I check piston to valve clearance:
1. degree the cam
2. install the lifters, pushrods & rockers you intend to run
3. adjust valves to the proper clearance
4. turn engine by hand & watch the exhaust valve. Stop at 10 degrees btdc as exhaust is closing. Install & zero a dial indicator on the exhaust valve, and lever the valve open until it gently touches the piston and measure clearance.
5. turn engine to 10 degrees atdc and repeat the process on the intake.

I like to check it with the springs I'm using to duplicate the operating conditions as closely as possible.....

Tod74

How can you do that? How do you push the valve open?especially If you have a dial indicator on top.

johnracer

Set up the dial indicator off to the side of the rocker on the retainer. I made a tool that pushes on the rocker to open the valve. Similar to some spring pressure testers....

SPEEDNEEDS1

No special tools required to do it my way, but it has to still work the same way. Adjust your valve, after adjusting the valve back it off 2 turns. Install .100 from you feeler gauge between the rocker and the valve tip and tighten your poly lock 2 turns. Turn the engine 1 complete turn(gently) if it turns you know you have at least .100 valve to piston clearance. I guess some could say you might be a redneck if you do this, but I have built several different combos and have never had any issues doing it my way!!!!!!!

dgordner

Thanks to all of you who helped with my question about the valves and springs. Next question. How much clearance is exceptible between valve and piston?

Tod74

JMO

.080 intake
.100 exh