Box Stock

Valve Lash

The engine will fire on 40 lbs of compression. If you preloaded much more than .003 it won't start. Also, builders will preload after a break in run on the Dyno when the engine is hot. Even then, sometimes it won't start when cold. Why do you think the electric starter made it's appearance
 
If you'll crank the engine and run it up too 200 degrees and then adjust the valves too barely have compression-- you'll be very close. Let the engine cool completely--ya shouldn't have any compression. See if it'll start-- if not do again.
 
1fasttiller said:
I've tried preloading like this and no matter what I do I can't seem to get the engine to start with any preload I lose all compression. As soon as I back it off to "0" lash or .0005" it fires right up and my engines run strong. I'd love to know what I'm doing wrong...
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As you tighten the jam nut the play in the threads opens the valve more. Need to watch the dial indicator as you tighten the jam nut. Otherwise your not at TDC with the Exhaust compression relief closed.
 
Kart43 said:
10mm ,14mm box end wrenches. Loosen 10mm lock nut, rotate engine to a few degrees beyond TDC on the compression stroke. Both valves fully closed carefully turn 14mm until the push rod has very slight resistance when you try to turn it with your thumb and finger.hold 14
mm snug 10mm lock nut down check the rotation of the push rod.
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Are you saying to set valves at Zero Lash. No Clearance. Your not using a feeler gauge at all?
 
Yes , zero , just so you can rotate the push rod . With your thumb and fore finger .
The hot setup is to preload with a dial indicator .
 
Someone explain this to me. I had an engine in my shop that the customer complained about not having h.p. When I put it on the dyno, it was down on h.p. Upon pulling the valve cover and checking left I noticed both intake and exhaust valves were pre-loaded by .002 hot with a running lift of .235 intake, and .238 exhaust. Nothing new to me because this is what I have seen during tech. So for poops and giggles, I decided to set the lift at exactly 2:38 and 2:42. The engine picked up horsepower.
 
Taking into consideration that the valve setting will change on an average of .003 when hot would mean that a preload of .003 when hot would actually be 0.
 
You altered the lift, duration and cam advance
(More lift. More duration/area under the lobe. Cam timing advanced)
when you reset to .238/.242 from .235/.238
and it affected HP in a positive direction.
Be nice to know how much HP it picked up.
 
Bumpy said:
You altered the lift, duration and cam advance
(More lift. More duration/area under the lobe. Cam timing advanced)
when you reset to .238/.242 from .235/.238
and it affected HP in a positive direction.
Be nice to know how much HP it picked up.
Click to expand...
I was waiting for someone to catch on to what actually took place.
 
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