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valve lash adjustment
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Greg Riddle
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PostPosted: Tue May 13, 2014 8:48 pm    Post subject: valve lash adjustment Reply with quote

What is everyones thoughts on valve lash adjusting. The specs for the stock cam on my honda vtx 1300 is .006 intake and .012 exhaust. I have an aftermarket cam. I have already found out the hard way the I had to change the valve adjusting procedures for the new cam. Is it possible the clearance specs are not correct also. The valves tap a good bit louder now. Im wondering if the valve lash should be tighter. If so how would I figure out what set them at.
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af2
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PostPosted: Tue May 13, 2014 9:11 pm    Post subject: Reply with quote

They tap louder??
Lashing on the clearance ramp is the only way to lash. It might be a few degrees more than what you are used to.
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Greg Riddle
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PostPosted: Tue May 13, 2014 9:22 pm    Post subject: Reply with quote

Yes they tap louder. The new cam profile changed the position you set the balves from tdc oc compression stroke to the smallest circle on the cam. This ended up being different in that now if im adjusting the exhaust valve I turn the crank until the intake valves on the same cylinder reach there fully open position. If im setting the intake valves, I turn the crank until the exhaust valve reaches its fully open position

When I first set the valves after the new cam I used the honda specs and procedure. The valves where very loud. I contacted the cam manufacturer and they said find the smallest circle on the camand set them there. Thats where I came up with the new position

Now im wondering if I should change the honda spec on
clearance to help quiet the valves
Probably should mention it has overheard cam solid tappet racker arms two intake valves and one exhaust
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10sec.et
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PostPosted: Wed May 14, 2014 2:49 pm    Post subject: Reply with quote

you need to run the engine until its FULLY warmed up and adjust them hot. if it cools down, you have to heat it up again. dont adjust them cool.
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af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

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Greg Riddle
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PostPosted: Wed May 14, 2014 5:43 pm    Post subject: Reply with quote

10sec.et wrote:
you need to run the engine until its FULLY warmed up and adjust them hot. if it cools down, you have to heat it up again. dont adjust them cool.


Please explain
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Big Dave
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PostPosted: Thu May 15, 2014 12:24 pm    Post subject: Reply with quote

Greg Riddle wrote:
10sec.et wrote:
you need to run the engine until its FULLY warmed up and adjust them hot. if it cools down, you have to heat it up again. dont adjust them cool.


Please explain


Metal expands when it heats up. Not all metal expands at the same rate. So if you have aluminum heads instead of cast iron heads the valve lash will differ due to the difference in the rate of expansion.

If you adjust the valves cold (which you can do by noting the lash of your properly hot lashed engine and writing it under the hood so you will know what the cold lash is) you risk valve to piston interference or a valve that is sacrificing valve lift and accelerating valve train wear.

Since we are talking about valve lash I assume we are talking about a solid lifter. With solid lifter a tighter lash increases overall valve lift but also increases the possibility of a valve hitting some thing such as a piston or another valve. Too loose and you sacrifice valve lift, make more noise, which is the sound of two pieces of metal slamming together. This causes excessive wear that requires replacing parts sooner than intended.

Big Dave
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Greg Riddle
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PostPosted: Thu May 15, 2014 12:59 pm    Post subject: Reply with quote

Big Dave wrote:
Greg Riddle wrote:
10sec.et wrote:
you need to run the engine until its FULLY warmed up and adjust them hot. if it cools down, you have to heat it up again. dont adjust them cool.


Please explain


Metal expands when it heats up. Not all metal expands at the same rate. So if you have aluminum heads instead of cast iron heads the valve lash will differ due to the difference in the rate of expansion.

If you adjust the valves cold (which you can do by noting the lash of your properly hot lashed engine and writing it under the hood so you will know what the cold lash is) you risk valve to piston interference or a valve that is sacrificing valve lift and accelerating valve train wear.

Since we are talking about valve lash I assume we are talking about a solid lifter. With solid lifter a tighter lash increases overall valve lift but also increases the possibility of a valve hitting some thing such as a piston or another valve. Too loose and you sacrifice valve lift, make more noise, which is the sound of two pieces of metal slamming together. This causes excessive wear that requires replacing parts sooner than intended.

Big Dave


I understand your post
I dont have lifters or a hood but the principles still apply. The issue I have is I dont have a clearance measurement. The only measurements I have are for the stock cams. Im also thinking the stock springs might not be strong enough for the cam profile
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Big Dave
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PostPosted: Thu May 15, 2014 1:20 pm    Post subject: Reply with quote

You can not run hydraulic valve springs with a solid cam as they are not stiff enough to control the valves at the speeds a solid cam can operate. Generally you need a spring rate that is 40% stiffer than the stock spring.

As to what is your initial valve lash I haven't a clue as I only play with Chevy's and for the past forty years I have been playing with big block Chevys exclusively though I did build one small block with a solid cam that was lashed at 0.018". Newer cam grinds are using a tighter lash than the solids I played with in my youth. The 30/30 Duntov cam is called that because that was the lash; 0.030". On big blocks of the same time period they ran a solid valve lash of 0.032" to 0.034".

Big Dave
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10sec.et
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PostPosted: Thu May 15, 2014 2:28 pm    Post subject: Reply with quote

hondas are real picky about the lash. they MUST be hot! if it takes you more than about 15 minutes, you need to heat it up again. if it cools off, your clearances will change... a LOT. i would use factory specs.
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af2
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PostPosted: Thu May 15, 2014 4:35 pm    Post subject: Reply with quote

10sec.et wrote:
hondas are real picky about the lash. they MUST be hot! if it takes you more than about 15 minutes, you need to heat it up again. if it cools off, your clearances will change... a LOT. i would use factory specs.


Agree big time!! And when the lash ramps changes as in your deal you need to know where and you can no longer lash what you have been accustomed to.
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Greg Riddle
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PostPosted: Thu May 15, 2014 5:44 pm    Post subject: Reply with quote

I talked to an engine builder and he recommended a bit of trial and error in finding the correct measurements
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Big Dave
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PostPosted: Thu May 15, 2014 6:01 pm    Post subject: Reply with quote

That is fine if he is paying for the errors. Otherwise it will be a trial. If you have stock parts there should be information as to the proper procedure and valve lash specs, though I wasn't aware that Honda used a solid lifter in a factory built car. Which just accentuates that I don't know anything about Hondas. From what Keith and Af2 are stating you don't want to make an error as it could be potentially expensive.

Big Dave
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Greg Riddle
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PostPosted: Thu May 15, 2014 6:08 pm    Post subject: Reply with quote

Big Dave wrote:
That is fine if he is paying for the errors. Otherwise it will be a trial. If you have stock parts there should be information as to the proper procedure and valve lash specs, though I wasn't aware that Honda used a solid lifter in a factory built car. Which just accentuates that I don't know anything about Hondas. From what Keith and Af2 are stating you don't want to make an error as it could be potentially expensive.

Big Dave


Not sure about honda cars but there bike dont have lifters. I dont have stock cams anymore. That is why im searching for the info

I dont have to worry about clearance. I have way more room than I could ever make up adjusting the valves
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Greg Riddle
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PostPosted: Thu May 15, 2014 6:59 pm    Post subject: Reply with quote

I talked with wen cam the manufacturer of my camshafts, they said with there cams valve lash clearance should be .004"intake and .005" intake.
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Greg Riddle
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PostPosted: Fri May 16, 2014 8:30 pm    Post subject: Reply with quote

Ive got the intake valves set at .005" and the exhaust valves set at .007"
I. Can hear the exhaust valves are still tapping but its more of a light tick now. Im going to ride it like this for a bit and see how it runs. I may tighten the exhaust valves to .006"
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