optimal valve adjustment for M30B34....

E28 technical advice asked and given! Troubleshooting, modifications and more.
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dasMafia
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Post by dasMafia »

hello all, need to adjust the valves on my swapped motor, and want to do whatever I can to give me a little more power up top....

any ideas? or am I stuck with 13?
shifty
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Post by shifty »

If you want more power up top, replace the cam while you're in there. ;)
dasMafia
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Post by dasMafia »

funds not currently available. sorry shifty.... IIRC 0012 is the nominal value from the factory, but everyone I kow uses 13 for some reason... I will likely go with 12 as IIRC 13 sacrifices a little up top power....
Rich in Tupelo
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Post by Rich in Tupelo »

you can play around with time some too to see what your car likes. I have seen people put them as low as .0010.
Shawn D.
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Post by Shawn D. »

[QUOTE="Rich in Savannah"]you can play around with time some too to see what your car likes. I have seen people put them as low as .0010. [/QUOTE]

Methinks you mean 0.010! ;)
Rich in Tupelo
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Post by Rich in Tupelo »

Sorry Shawn, Yes, .010. I'm still aching from the yard and the Sat. night brew fest.

:D
Rich in WI
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Post by Rich in WI »

I'm a fan of using Shawn's method of checking valve clearance at the cam and not the valve stem. I did this on my last valve adjustment and I felt I got better running and a smoother idle. Much easier, too. IIRC the gap at the cam should be 0.090.

Rich


[Edit by Rich in WI on [TIME]1110209224[/TIME]]
Shawn D.
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Post by Shawn D. »

Rich in WI wrote:I'm a fan of using Shawn's method of checking valve clearance at the cam and not the valve stem. I did this on my last valve adjustment and I felt I got better running and a smoother idle. Much easier, too. IIRC the gap at the cam should be 0.090.
Thanks for the good words, Rich! For reference, here's the thread from the Roachfly archives:

"Quiet valves at last! All I had to do was"
Last edited by Shawn D. on Feb 13, 2009 10:01 AM, edited 1 time in total.
Rich in Tupelo
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Post by Rich in Tupelo »

Hmmm. Very good info. Will add that to my favorites.

Rich
louielouie
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Post by louielouie »

0.010 on a M30B34? I *thought* 0.012 was appropriate for the big 6 - that's what I set mine to this weekend (using Shawn's method of course)
Velocewest
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Post by Velocewest »

[QUOTE="Rich in WI"]I'm a fan of using Shawn's method of checking valve clearance at the cam and not the valve stem. I did this on my last valve adjustment and I felt I got better running and a smoother idle. Much easier, too. IIRC the gap at the cam should be 0.090.[/QUOTE]

[QUOTE="Shawn D."]Thanks for the good words, Rich! For reference, here's the thread from the Roachfly archives:

"Quiet valves at last! All I had to do was" [/QUOTE]

Damn! Why didn't I think of that?!

I use .010 to .011 as the range (at the stem, so I guess I'll go .090 or maybe .085 at the cam?). I check the adjustment 2-3 times a year, so I don't worry about them being a little tight.



[Edit by Velocewest on [TIME]1110222516[/TIME]]
dworthy
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Post by dworthy »

If you go down too tight, like around .008 then you start running in the looping idle area. I have been setting my clearance around .010 for a while now. Just make sure the car is cold, like overnight kind.
Rich in Tupelo
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Post by Rich in Tupelo »

0.010 on a M30B34? I *thought* 0.012 was appropriate for the big 6 - that's what I set mine to this weekend (using Shawn's method of course)

louielouie


If your going straight by the book then yes. However, as you can see, many of us use tighter setting. Some engines like the valves a little tighter, some don't.

Rich
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