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valve cover breather hose

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74tii May sound goofy, but need quick confirmation. had the head re-built, got everything back together. Started her and was having a little idle surge problem that I didn't have before.

Read the archives and the only answer available, it mentioned to check the valve cover breather hose as a culprit. Mine was off, due to thought may need to pull the coverback off.

Would the hose being off the valve cover cause idle surging? Any other wierd symptoms that will occur with it off.

Think I'm going to adjust the valves. from listening for a few minutes, the machine shop didn't get everything set excatly right.


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That shouldn't cause surge or really anyother problem except maybe oily residue under the hood. Make sure the breather hole thingie isn't blocked, though.

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There are far more knowledgeable tii folks on this board than myself (as evidenced my bonehead remark yesterday re: intake valves!) ;-) - but I'd suggest to you - or anyone that installs a cylinder head - no matter WHO adjusted the valves - always double check them before start up.

Even if I've adjusted them 30 minutes before torquing the head bolts down - I always check them again before firing the motor. I've had 'em change..not much mind you - but enough. (don't ask me to explain why...I've just experienced it more than a few times on M10 and M20/M30 motors) After a heat cycle or two I'll check them again if I have any doubts. (say...after final torque post engine heat up).

Then there's the standard re-adjustment after 1000 miles.

Check for vacuum leaks! if you're lucky enough to know a shop with a "smoke machine" (professional ones are MUCHO expensive) - they're AWESOME tools for finding sneaky air leaks. Slide 'em $20-30 and watch for where the smoke escapes the motor.

Alternatively - some folks swear by (un lit) propane or aerosol solvent spraying to see if idle changes - indicating a leak. Not a big fan of the errant spray of flammable stuff myself.


Paul Wegweiser

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Check the hose that runs from the K-F warm up regulator to the bottom of the throttle body.

Also, check the small vacuum line that runs from the valve cover vent hose to the side of the throttle body.

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