Rickie B Posted April 18, 2016 Report Share Posted April 18, 2016 I gave my 720 a complete tune up,new plugs" NGK specified by manual",NGK plug wires,new distributor cap and rotor ,adjusted valves "hot" .012,set timing per Nissan specs 3 DEG. BTDC ,Carburetor is a Weber 32/36 that i installed several months ago "purchased brand new".Truck runs perfect.After a couple weeks of driving i wanted to check the spark plugs to see how they were burning,the exhaust side were a nice light brown,the intake side are White except #2 light brown.Any suggestions why #1,3&4 on intake side are so White?,have aprox. 1000mi after tune up,truck does not run hot. Quote Link to comment
datzenmike Posted April 18, 2016 Report Share Posted April 18, 2016 The NAPS dual plug design will run well on closer to stoichiometric air fuel ratios than a single plug set ups. So this may be just fine. BPR6ES for intake and one heat range cooler for the exhaust BPR5ES. I'll check 1 Quote Link to comment
Rickie B Posted April 18, 2016 Author Report Share Posted April 18, 2016 Mike ,You are absolutly correct on the plugs ,these are the plugs i used,so if i understand you, a very lean looking plug on the intake side and a light brown normal looking plug on the exhaust side is normal for this Z24 motor,so theres nothing to worry about ?? Quote Link to comment
datzenmike Posted April 19, 2016 Report Share Posted April 19, 2016 I wouldn't say normal, only that a dual plug can tolerate a lean mixture better than a single plug head. Running near 14.7 to 1 is good for mileage but only so so for power. A white plug usualy indicates lean. Maybe you might richen the mixture up slightly. Quote Link to comment
Rickie B Posted April 19, 2016 Author Report Share Posted April 19, 2016 Thanks Mike i appreciate the feedback,dont know how i would richen it up as the Weber 32/36 only has the best idle mixture screw,i do have a new Weber 38/38 ,maby this would be a better choice? What do you think? Quote Link to comment
datzenmike Posted April 20, 2016 Report Share Posted April 20, 2016 About half way down. The jet can be changed to increase or decrease the mixture. Best to read everything and check everything to eliminate some problem I'm not aware of. Once you are sure you are running lean you can make changes. Generally slightly rich give the best performance. http://www.classicinlines.com/WeberTune.asp A couple more.... http://www.carburetion.com/Weber/adjust.htm http://www.webercarbsdirect.com/v/vspfiles/images/Weber%20Trouble%20Shooting%20Guide.pdf I think the 38/38 is wrong. It's too big and made for a six or small V8. In addition it is a synchronous carb where the two barrels open together. If it was a vacuum secondary, maybe. Some people like them and yes it will work but works best when really revved up. Yes you can almost eliminate the huge bog when suddenly floored but no 38/38 gives reasonable mileage. Never, never, never over carb or over cam your engine. Better to be slightly small and want larger that to be slightly too big and wish it was smaller. 1 Quote Link to comment
Rickie B Posted April 20, 2016 Author Report Share Posted April 20, 2016 Thanks Mike i value your opinion ,sounds good to me,i will definatly check out the links,have a good one Quote Link to comment
datzenmike Posted April 20, 2016 Report Share Posted April 20, 2016 It's just that, an opinion. Others will differ. Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.