Laecaon Posted September 6, 2011 Report Share Posted September 6, 2011 yeh you can go with a bigger gap if you have Elect. ignition like Petronix, but that's a lot of gapping. Pertronix said not more than .005 so that would be like .0325,I also checked one of my Datsun books and gap is .028 - .032., looks like the bigger the gap the later the years.. Yea, I only see the large gap on the 78-79 620s. Which have matchboxes and of course have L20b's... Quote Link to comment
datzenmike Posted September 6, 2011 Report Share Posted September 6, 2011 Light throttle needs less spark to fire the plug. Full throttle offers more resistance so more voltage is needed. If you have an EI dizzy they will easily run a larger gap whether you drive full throttle or not. Many Pertronix don't use a higher output coil so the output is the same and the gap should not be increased. A wider gap offers a longer spark for lighting the fuel/air. Quote Link to comment
Ron1200 Posted September 6, 2011 Author Report Share Posted September 6, 2011 This is what I have in my 79 620: L16 W58 closed chamber head 260 cam SSS 38mm SU's electronic ignition (matchbox) with MSD coil header I think I remember the Old Datsun site had the gap for a 79 at .041. Is that what I should run? Quote Link to comment
datzenmike Posted September 6, 2011 Report Share Posted September 6, 2011 My '78 FSM says 0.038" to 0.041" andit has the remote EI system. It should run fine at whatever you gap it, at but to take advantage of the extra voltage you can open it up more. If you do be sure the rest of the ignition system is in good shape.... wires,cap,rotor. Quote Link to comment
ggzilla Posted September 6, 2011 Report Share Posted September 6, 2011 stock 1978 has EI with remote ignitor Ron has a matchbox (1979-up) unit Matchbox does a 0.042 inch gap, but requires a matchbox coil. Since you have an MSD coil, probably not. The MSD Blaster coil is replacement for the stock (points) type coil. Quote Link to comment
racerx Posted September 6, 2011 Report Share Posted September 6, 2011 I have a petronix electronic ignition system and installed a hi output coil...which means I can go hire but not .042, mybe .036, will try to see which one responds better. Quote Link to comment
racerx Posted September 6, 2011 Report Share Posted September 6, 2011 So I called NGK about the spark plugs and, although the BP6ES is not a "hot" plug, it does run hotter like 50 degrees hotter, this makes sense since the porcelain is protruding more... Quote Link to comment
ggzilla Posted September 6, 2011 Report Share Posted September 6, 2011 Here's Nissan's own parts, all NGK OEM plugs: standard: NGK BP5ES optional, depending on spark plug inspection: * BP4E * BP5ES * BP6ES * BP6E * BP7ES * BP7E No mention of B6ES, so perhaps Schuck's made a mistake. Quote Link to comment
racerx Posted September 6, 2011 Report Share Posted September 6, 2011 I have L18 those plugs should work, too, right. Yeh funny, I go to Autozone, they wanted $4.99 for BP6es and I went to Winchester Auto, like a NAPA store, and they wanted like $2.99 ea.... Quote Link to comment
racerx Posted September 6, 2011 Report Share Posted September 6, 2011 NGK tech. dept. said B6es but they said I can use BP6es as well... Quote Link to comment
ggzilla Posted September 6, 2011 Report Share Posted September 6, 2011 NGK tech. dept. said B6es For which engine? Ron was asking about an L16 out of a 1971 510. Quote Link to comment
datzenmike Posted September 6, 2011 Report Share Posted September 6, 2011 stock 1978 has EI with remote ignitor Ron has a matchbox (1979-up) unit Same thing really, other than size and location of the box. Quote Link to comment
ggzilla Posted September 6, 2011 Report Share Posted September 6, 2011 Same thing except for the spark plug gap... Quote Link to comment
racerx Posted September 6, 2011 Report Share Posted September 6, 2011 Yeh noticed that too with sprak plug types are all the same except of gap..perhaps as later years like 78 and later, smog was the main issue...my wife's Honda is like .044 Quote Link to comment
ggzilla Posted September 7, 2011 Report Share Posted September 7, 2011 The reason the gap is larger is because they moved to high-energy transistorized ignition systems which allowed a larger gap. It's a win all around with better performance and increased reliability. Quote Link to comment
datzenmike Posted September 7, 2011 Report Share Posted September 7, 2011 My '78 FSM says 0.038" to 0.041" andit has the remote EI system. This is the Nissan factory shop manual that lists this. Coil is 0.84 to 1.00 ohms resistance. Remote or matchbox... same spark output. Quote Link to comment
ggzilla Posted September 7, 2011 Report Share Posted September 7, 2011 Interesting. The 1977 B210 FSM says .039 to .043 (remote ignitor, the big aluminum one) The 1978 B210 FSM says .039 to .043 (remote ignitor), or .043 to .051 for FU models Both are for A14 engine. Conclusion: * the 1978 remote or matchbox unit can work with BIG gaps * the specific gap depends on the engine Apparently the L-series needed a slightly smaller gap. The A14 FU engine could handle a larger gap -- it had the mixture closer to stoich due to a better carburetor and better combustion with closed-chamber heads. They also used special 4-anode spark plugs. Quote Link to comment
racerx Posted September 7, 2011 Report Share Posted September 7, 2011 For L16 you can use same spark plugs and the gap is just a tad different except for 1977 and up then gap gets wider.. 1 Quote Link to comment
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