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Valves with Brothers

Started by moparman70, July 27, 2014, 11:08:47 PM

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movenon

Quote from: simi_ed on August 03, 2014, 12:14:45 PM
Run your exhaust at 0.008" and don't worry.  They'll take a bit longer to tighten up that way.

My 2ยข

+1
Good that you are getting them dead on but you are only talking .001 ! On the loose side. IMO, not a problem.  I have a 4 or 5  at .006 and they close just fine. But it is an old well broken in valve train.  Been that way for about 3 years.  Probably heresy, but I think to many people want to "blueprint" the spec's..  IMO if you are in range then you are good,  but if you have to adjust go to the loose side especially on the exhaust side, never notice .001 looser in street performance.

Just a question that Randy probably can only answer.  On the oil under the shim, approximately what difference are we talking about on the average ?  Just curious.  .002, .001. .0005 tighter ?  Next time I change a shim I will try to measure it. 

Please don't miss understand me Mike, you are doing a great job going that extra step :good2:  I am just throwing a thoughts out. 
George
Life isn't about having the best, but about making the best of what you have...

1990 FJ 1200

racerrad8

Quote from: movenon on August 09, 2014, 11:26:06 AM
Just a question that Randy probably can only answer.  On the oil under the shim, approximately what difference are we talking about on the average ?  Just curious.  .002, .001. .0005 tighter ?  Next time I change a shim I will try to measure it.  
George
Well, I guess I can use of of Pat's saying here...

"how much does a bag of groceries cost..."

But I digress, there are just too many factors to be able to put an accurate number on the thickness added by the trapped oil.

You have...
the actual viscosity of the oil
the life span of the oil; new or at 3000 miles
the ambient temperature that will affect the viscosity as well as the expansion/contraction rate of the metal parts of the engine.

I honestly have never taken the time to study the difference of the displacement because of all of the above factors.
When a bike/car/engine come in, I make sure the engine has not been run or properly cooled down. I check them, document the lash numbers, I remove the shims and use the chart to install the proper shim. That is the best way to measure & adjust the valves.

There is a reason that Yamaha provided a "range" of adjustment and only offer "0 & 5" rated shims, because you can get into the range using just those shims and "2 & 8" (or half sizes) are not required. I always adjust to the larger side of the "range". The reason for this is the fact the valves almost always do not get looser because there are no rocker arms, push rods or lifters to wear out.

Randy - RPM
Randy - RPM

movenon

Thanks Randy.  I know the variables.  I was just wondering if there was a ball park figure since it was brought up.  I adjust the valves as you do.  I was just trying to say you don't have to be dead on the number especially on the loose side.  If .007 is the target the .008 is just as good as .006 IMO.

Talk about variables at .001 inch. Feeler gauge accuracy (the gauge it's self), my "feel" and someone elses "feel" could be off as much as .001 then throw in oil on the blade, technically the spec of .007 is at one specific temp not just stone cold.  If I adjust my valves during the winter then I better readjust for the summer :)..  I am getting nervous now  :lol:  It gets pretty anal after a while.  About like 2.7 ohms at exactly at 68 degrees.

Just throwing crap, have a good week.  It nice to hear from all that are maintaining, fixing, modding and restoring there FJ's.
George

Is it gage or gauge. Another dilemma. Think I will have a gage of beer.
Life isn't about having the best, but about making the best of what you have...

1990 FJ 1200