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#1
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valve lash theory
Ok so all you solid lifter guys out there. What can be done with valve lash to alter performance? The cold specs for the m110 are 0.10mm intake and 0.25mm exhaust. I was thinking of increasing the intake lash to 0.15mm to allow the valves to seat better and cool( supercharger) and to reduce the exhaust valve lash to 0.15mm to quieten down the valves and increase the exhaust duration a tiny amount. My exhaust is not restrictive at all. Will this affect the overlap?
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#2
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Having them adjusted correctly is the best thing you can do in terms of performance. Make sure they are spot on factory specs and leave them alone.
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#3
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That's what I thought too. They obviously designed it that way for best cylinder filling on the intake side and protection against valve burning on the exhaust side. Just wanted to see if there were any other theories. I'm still open to any other suggestions
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#4
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The intake valves don't get very hot since they only see intake air so cooling them isn't an issue.
Moving lash around will make minor changes to how " big " the cam looks to the valves. Loose lash gives less duration and overlap, this helps idle and low speed. Tighter lash makes the cam look larger to the valves and will help higher RPM, however if the lash to too tight the valve will be held off the seat. If this occurs on the intake side, you will have the effect of EGR, and power will drop off. If on the exhaust side the valve will overheat and burn. None of this gives dramatic gains, put a degree wheel on the crank and a dial indicator on the valve retainer. Take a reading at the stock lash and one at the new lash. Stock lash is more a function of noise, valve seating, expansion rates and allowing for wear between adjustments. The engine designer can have any cam they want and won't make changes via lash. You are likely to get greater gains by advancing / retarding the cam. With the M110 dual cams , altering the timing between the two would give some gains. Some M104 (3.2 inline 6 ) guys were using exhaust cams on the intake as they have higher lift / duration. If the M110 came without a supercharger, have a look at the cam timing for both motors then make a decision from there. Try 190rev.com for M110 info and be sure to post some results here. |
#5
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valve adjustment done
Pulled the plugs and got them soaking in fuel. Going to wire brush them tomorrow, God willing. I was so surprised to see such shiny cams when I took off the cam cover. After 32 years there's only very minor scratches on them!!!
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