rwbakk Posted September 8, 2015 Share Posted September 8, 2015 I just fired up my l28 f54 block with a n47 head with a comp cam. The engine will hardly idle with the base timing at 16* won't idle with it at 10* idles fine at around 20* or more . The distributor (Mallory) adds 24* of mechanical advance. Witch put my total around 40* witch is to much. I did not degree the camshaft I just used the #1 hole Question is do you think the camshaft being off a bit will cause my problem?Does anyone have a link on degreeing a camshaft on a l28? Quote Link to comment Share on other sites More sharing options...
madkaw Posted September 8, 2015 Share Posted September 8, 2015 FAQS section Quote Link to comment Share on other sites More sharing options...
NewZed Posted September 8, 2015 Share Posted September 8, 2015 Doesn't Comp Cams supply instructions? Most cam grinders keep the original reference marks. #1 should work. You didn't say anything about carbs or EFI or Megasquirt. Could be that your problem has nothing to do with cam or ignition timing. Or your damper timing marks are off. Quote Link to comment Share on other sites More sharing options...
madkaw Posted September 9, 2015 Share Posted September 9, 2015 You need more info if you want help and not guesses Quote Link to comment Share on other sites More sharing options...
rwbakk Posted September 9, 2015 Author Share Posted September 9, 2015 It is a carbed motor, I checked the tdc mark on the damper, it is true.The head was trued up about .010, I assume that would retard the cam timing slightly, I have the cam card from Comp giving the specs but no instruction.I have the how to modify your datsun book witch gives instruction on degreeing a cam it is a little vauge but I think I can do it. Just wondering if the cam is retarded will alot of ignition timing smooth it out at idel? Quote Link to comment Share on other sites More sharing options...
NewZed Posted September 9, 2015 Share Posted September 9, 2015 The engine will hardly idle with the base timing at 16* won't idle with it at 10* idles fine at around 20* or more . Did you try turning up the idle speed screw? Don't know what carbs you're using but most have an idle speed adjustment. More ignition advance typically increases idle speed. Could be that all you're really doing with your timing adjustment is increasing idle speed. Gotta start somewhere. On the cam - can you see anything like that shown in the attached picture? With the straight side of the chain tight. Quote Link to comment Share on other sites More sharing options...
madkaw Posted September 9, 2015 Share Posted September 9, 2015 I'd say if the cam is installed correctly it is NOT causing your idling issue alone. I can idle at 10 as well as 20 with not much change of idle. 10 thou off the head will not change valve timing enough to cause issues as you describe. Most cam profiles have a bit of advance machined in them just so they can be installed 'straight up' Quote Link to comment Share on other sites More sharing options...
Datsun#1 Posted October 2, 2015 Share Posted October 2, 2015 Try your idle adjustment skrew.also if your running a SINGLE CARB like a holley, check your idle mixture skrew to see if there set properly. Set for highest vacuum at idle.if there multiple carbs,get a Unisin and make sure your carbs are pulling equal amouts of air.do a search on this.if all else fails,check to mske sure your firing order is correct on dizzy and head.let us know. Quote Link to comment Share on other sites More sharing options...
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