Valve to piston clearance?

dlowe01 · #1 (**permalink**) 01-22-2004, 01:45 PM

Any one know what the piston to valve clearance should be on a 408 storker? Or what the min. is.

HighPlainsDrifter · #2 (**permalink**) 01-22-2004, 02:12 PM

Hi,
The minimum clearance should be .080 , more is better.
Perry.

rdorman · #3 (**permalink**) 01-22-2004, 02:13 PM

I would go .08 on the intake and .1 on the exhaust, minimum. Maybe more with aluminum rods.
Rick

dlowe01 · #4 (**permalink**) 01-22-2004, 03:52 PM

I just used some clay to check the #1 cy. and it is .25. Is this way to much or O.K. They are aluminum heads and inverted dome -19cc JE pistons.

408cobra · #5 (**permalink**) 01-23-2004, 12:06 AM

You are measuring this to ensure your piston does not hit your valves more clearance is better. The exhaust valve is usually the one to look at as the valve is closing as the piston comes up. When you run a long duration cam you can run into problems when clearances get close or you incur valve float.

trularin · #6 (**permalink**) 01-23-2004, 05:27 AM

.25 is a lot. You should be able to run around town with the cheapest Sunoco pump gas if that clearance is any indication of the compression you will have.

Do you own the pistons? Can you switch to a flat-top?

I agree with these other guys at the .08 to .1 range.

Mr.Fixit · #7 (**permalink**) 01-23-2004, 11:16 AM

You can't have too much clearance between the pistons and valves. Some motors are even "zero interference" so even if the valves got stuck open, ths piston couldn't touch them even at TDC.

dlowe01 · #8 (**permalink**) 01-23-2004, 09:57 PM

With the lift on the cam 541 intake and .544 exhaust and 240 / 246 duration I just figured there would be a lot less clearance. Also with the set up I have it is supposed to be 10.1:1 so I don't think I will be able to run on cheap pump gas but that would be nice, I think I will stick with the 93 pump gas.

auto10x · #9 (**permalink**) 01-24-2004, 07:25 AM

.030" extra for aluminum rods.
auto10x
Bill