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620 confused

620 Walt

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valve lash correct. if too tight wont start or maybe idle

fire order, dist set correctly timed? 1 3 4 2 counter clock wise

Fuel in carb, hear it squirting gas when you cycle the linkage.


stock or aftermarket ignition???was changed? coil different?


otherwise it should start if cam was timed and distributor oil pump is correct

Edited by banzai510(hainz)
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No not really when I got it engine was used for road race had to have head milled and put new timing chain both cam timing and ignition timing is dead on valve lash is supposed to be right but can't find what lash is supposed to be set at with cam size man that did head passed on cam size is 485 lift 235 duration

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Try 0.010" intake and 0.012" exhaust on a hot engine. These are the hot specs for the L series cam. A regrind only changes the lobe profile not the valve and rocker so they should require the same clearance.


If this has never run for you it could be anything

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stock ignition mean stock coil sand ballast resisitor.???  sometimes they arch out if not ballast or bad condenser or a worn out bushing that causes point bounce, wiggle the dist shaft.  if loose sideways then the bushing worn.


If its timed maechanicall and eleltrically it should fire off.


Im not a single sidedraft carb setup expert. I know my carbs are good but has this setup run before.

Maybe run on a downdraft set up first to make sure its working.


I do my cam 0006 and 008 cold.. but long as the rocker arm wiggles on back side of the cam then you know its closing fully to get compression

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I published the Nissan FSM clearances for hot setting. (0.010" intake and 0.012" exhaust )  Cold assumes that it will expand to the correct clearance while setting them hot is what it runs at. No where does it recommend a cold setting though you can if things have been replaced and you have to start somewhere..... followed by setting them hot later when running. 

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