Valve clearances

[peter]

Did some research here and found an old post by "98Valk" regarding a lad named "VGER" who conducted a bunch of dyno runs and concluded both valves should be set .001 over spec.

Is there any conventional wisdom on valve clearances? I'll stick to spec but this suggests leaving them on the "loose" side...

Thanks,
Peter
'98 Valk

[Hook#3287]

Don't know about "VGER" but my understanding is, a little loose won't hurt, but a little tight will.

[98valk]

Vger is a race engine builder who did a lot of dyno work on his valkyrie.

.001 over gave better overall performance. he tried up to .003, but .001 was best for street.

good explanation

http://www.centuryperformance.com/valve-adjustment-procedure.html
 Using Valve Lash to "Tune" Engine Performance
This is a little extra tip often unknown to many engine builders and tuners. Most people do not realize that you can make subtle performance improvements by slightly reducing or increasing the recommended lash settings. NOTE: This is for SOLID LIFTER camshafts ONLY (tappet or roller)!
 
The intake and exhaust valves cannot move until all the running clearance (valve lash) has been taken up. Therefore, the amount of valve lash you use affects the engine's performance. For example, by reducing the amount of (hot) valve lash, the valve will open slightly sooner, provide slightly more lift (valve opening), and will close slightly later. This makes the camshaft look bigger to the engine, due to this slight increase of duration and lift. Increasing the amount of (hot) lash the opposite occurs. The valve will open later, provide slightly lift less, and close slightly sooner. Now the engine sees a smaller cam with slightly less actual duration and lift. BE CAREFUL - I am suggesting you start with only 0.001 - 0.003" of change in lash. Crazy experimentation can destroy your engine! A timebomb waiting to explode.
 
Use this tuning method to experiment, finding what the engine responds to, then keep the setting that works the best. Just remember, the more lash you run, the noisier the valve train will be, and damage may occur if you are not careful. If the clearance is excessive it can be harsh or damaging to other valve train components as well. Therefore, prolonged running of the engine is not recommend to increase the amount of lash by more than +0.004" from the recommended setting. Nor is reducing the lash by more than -0.008" recommended.
 
Common gains or performance differences include:

    Reducing the lash will increase top end (upper RPM power) horsepower
    Increasing the lash can improve low end torque and acceleration.

[Pete]

Although not applicable to the Valkyrie, hydraulic valve lifter adjustment can also affect performance.
Usually by loosening the lash adjustment 1/4 to 3/4 turn for more valve lift.

WARNING - loosen to much self destructs the valve train.

[peter]

Thanks for the explanation.  I'm not running from police anymore so I'm just going to stick with spec settings where the feeler blade slides easily.

Thanks again.

[Patrick]

Vger [ Mike] was around during the early days of this board.

He liked setting them at .001" over spec. Nothing wrong with that. Any power increase from that setting would be so minuscule that it couldn't be noticed, a change in humidity would be more noticeable.

Many folks here use go-no-go gauges, so, 001" isn't going to mean a thing.