Valve lash, With WEBCAM #494 Options

[jeffdon]

Ran the 2056 on the stand for a last time to get the oil warm, and do the initial change, and get her ready for installation. Did another valve check. Which got me to thinking.

I am setting it to the spec that came with the cam, .006 for both exhaust and intake. Lift (.465) and duration (280 deg.) are the same for both valves.

Question is, if exhaust valves expand more due to heat than intake, why does webcam recommend .006 for both? Why not .006 and .008 as is standard?

It SEEMS to be running pretty well, but I know i have a good deal of fooling around with jets and such once its on the road and i can test her under load. At one point at about 3500 rpm it started firing back through No 4., but that was right about the time i was running out of gas in my temp. tank. I shut it off, and got a big pop and some flame out the tail pipe.

I would really like address/double check anything now, as its way easier accesing things on the stands.

[ME733]

...........well I guess some of the other engine experts just don't want to be next....So ok he is what I recommend......USE .oo6ths on the INTAKE, USE .oo8ths on the EXHAUST.after the engine is broken in. ....If the truth be known-EVERY camshaft I have had analyzed came out to be-->008ths as a standard base /radus/lobe/ideal valve lash....This is compatable with all GERMAN cam-grinder design specifications.(for damn near any camshaft for any car)...This subject can get ,lengthly and very complex..(..and i,m just on my first cup of coffee.)...IF YOU HAVE JUST assembled and are running in a new engine---use a -loose .008 ths on intake and exhaust---for about 500 miles., and check your lash a few times. this will ensure that as your NEW valve job, VALVES are seating, there will be a little extra clearance for them to do so.....and NOT hold any valve off it,s seat.....YOU want to hear a little valve rattle.(good)....no valve rattle.(bad) ..(excepting hydrolic lifters)...and you should listen for intake-"cough". which is a sure sign of too tight a valve lash.(assuming everything else is perfect). MY opinion is on a new engine go with a larger valve lash during the break -in -period.->008 ths is a good number, intake and exhaust.................M.M.

[jeffdon]

...........well I guess some of the other engine experts just don't want to be next....So ok he is what I recommend......USE .oo6ths on the INTAKE, USE .oo8ths on the EXHAUST.after the engine is broken in. ....If the truth be known-EVERY camshaft I have had analyzed came out to be-->008ths as a standard base /radus/lobe/ideal valve lash....This is compatable with all GERMAN cam-grinder design specifications.(for damn near any camshaft for any car)...This subject can get ,lengthly and very complex..(..and i,m just on my first cup of coffee.)...IF YOU HAVE JUST assembled and are running in a new engine---use a -loose .008 ths on intake and exhaust---for about 500 miles., and check your lash a few times. this will ensure that as your NEW valve job, VALVES are seating, there will be a little extra clearance for them to do so.....and NOT hold any valve off it,s seat.....YOU want to hear a little valve rattle.(good)....no valve rattle.(bad) ..(excepting hydrolic lifters)...and you should listen for intake-"cough". which is a sure sign of too tight a valve lash.(assuming everything else is perfect). MY opinion is on a new engine go with a larger valve lash during the break -in -period.->008 ths is a good number, intake and exhaust.................M.M.

never heard this. Are you sure that you dont mean break in as in the 20 mins or so of initial Cam break in? Not really relishing the thought of frequent valve measurements under the car.

[ME733]

...........well I guess some of the other engine experts just don't want to be next....So ok here is what I recommend......USE .oo6ths on the INTAKE, USE .oo8ths on the EXHAUST.after the engine is broken in. ....If the truth be known-EVERY camshaft I have had analyzed came out to be-->008ths as a standard base /radus/lobe/ideal valve lash....This is compatable with all GERMAN cam-grinder design specifications.(for damn near any camshaft for any car)...This subject can get ,lengthly and very complex..(..and i,m just on my first cup of coffee.)...IF YOU HAVE JUST assembled and are running in a new engine---use a -loose .008 ths on intake and exhaust---for about 500 miles., and check your lash a few times. this will ensure that as your NEW valve job, VALVES are seating, there will be a little extra clearance for them to do so.....and NOT hold any valve off it,s seat.....YOU want to hear a little valve rattle.(good)....no valve rattle.(bad) ..(excepting hydrolic lifters)...and you should listen for intake-"cough". which is a sure sign of too tight a valve lash.(assuming everything else is perfect). MY opinion is on a new engine go with a larger valve lash during the break -in -period.->008 ths is a good number, intake and exhaust.................M.M.

never heard this. Are you sure that you dont mean break in as in the 20 mins or so of initial Cam break in? Not really relishing the thought of frequent valve measurements under the car.

.............I,m sure........You may get a different opinion from every engine builder thats alive/or dead....This technique ain't the simple way....It does ensure seated valves., which is a good thing for longevity. After all how long does it take to check the valve lash?.....you'll get good at it, and it won't be nearly such a chore as you think.....................M.M.