Donki Posted May 2, 2019 Report Share Posted May 2, 2019 80 Datsun 720 idles up an down backfires out exhaust 1 Quote Link to comment
datzenmike Posted May 3, 2019 Report Share Posted May 3, 2019 A vacuum leak will cause fluctuating idle speed. Check carburetor bolts are snug. Check all hoses going to carburetor and intake. Pinch closed with pliers, see if changes. Clean or replace as needed the plugs, wires, cap and/or rotor. Set valve lash at 0.010 intake and 0.012" exhaust when HOT. Timing at 12 BTDC. 2 Quote Link to comment
captain720 Posted May 3, 2019 Report Share Posted May 3, 2019 My FSM says 0.012 if an inch for intake and exhaust, Mike is the difference here maybe for an 80 model year? Otherwise I would assume he should go with 0.012. 1 Quote Link to comment
datzenmike Posted May 3, 2019 Report Share Posted May 3, 2019 It may be for an '80 so always go with the FSM. All other years of L series are 10 and 12 thou. All '78 '79 and '80 L20Bs use the W58 head so I don't see any difference. 2 Quote Link to comment
Charlie69 Posted May 4, 2019 Report Share Posted May 4, 2019 Captain is your manual for the 1980 720. Quote Link to comment
datzenmike Posted May 4, 2019 Report Share Posted May 4, 2019 The Z20 and Z24 is 0.012" for both. Presumably the Z22 is also. 1 Quote Link to comment
Donki Posted May 4, 2019 Author Report Share Posted May 4, 2019 The truck sat for 3 years new plugs wires cap rotor ignition coil coil starter fuel filter cleaned carb runs good at high revs let off gas it pops out of exhaust smells bad then dies 1 Quote Link to comment
Stoffregen Motorsports Posted May 5, 2019 Report Share Posted May 5, 2019 Clogged exhaust? Rodents get in a make nests, which can smell awful and can cause what you've described. 1 Quote Link to comment
datzenmike Posted May 5, 2019 Report Share Posted May 5, 2019 20 hours ago, Donki said: The truck sat for 3 years new plugs wires cap rotor ignition coil coil starter fuel filter cleaned carb runs good at high revs let off gas it pops out of exhaust smells bad then dies High revs under load, like when driving it? or just revving it up??? Big difference if under a load. 2 Quote Link to comment
tr8er Posted May 6, 2019 Report Share Posted May 6, 2019 Warped head? My z smelt when it burnt coolant. And idled like shit. 2 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.