HRH Posted October 15, 2013 Report Share Posted October 15, 2013 Yeah, that's not good. Quote Link to comment
jacobryandavidson Posted October 15, 2013 Author Report Share Posted October 15, 2013 I didnt think so Quote Link to comment
Stoffregen Motorsports Posted October 15, 2013 Report Share Posted October 15, 2013 It's kind of hard to make heads or tails out of the pics. Are you trying to figure out what happened? I would, so it doesn't happen again. But as far as helping you figure it out, I can't see much in the pics. Quote Link to comment
jacobryandavidson Posted October 15, 2013 Author Report Share Posted October 15, 2013 I'm assuming it a hairline crack and finally blew out I'm changing to a whole new rebuilt head so I won't worry about it anymore I was just trying to get some tips to keep from blowing another head gasket in a hundred thousand mile Quote Link to comment
EricJB Posted October 15, 2013 Report Share Posted October 15, 2013 I think the point Stoffregen was trying to make is, if the hole was caused by a lean condition, (visualize blowtorch) what's to stop it from doing it again? Cause and effect. BTW,I cant see shit either. Quote Link to comment
datzenmike Posted October 15, 2013 Report Share Posted October 15, 2013 Replace the head, repair isn't worth it. Hard to be lean in only one cylinder... cause is likely a tight valve that was never adjusted that burnt. Quote Link to comment
jacobryandavidson Posted October 15, 2013 Author Report Share Posted October 15, 2013 So adjust valves correctly and rebuild carb? Quote Link to comment
Stoffregen Motorsports Posted October 15, 2013 Report Share Posted October 15, 2013 Replace the head, repair isn't worth it. Hard to be lean in only one cylinder... cause is likely a tight valve that was never adjusted that burnt. I think the point Stoffregen was trying to make is, if the hole was caused by a lean condition, (visualize blowtorch) what's to stop it from doing it again? Cause and effect. BTW,I cant see shit either. Replace the head, repair isn't worth it. Hard to be lean in only one cylinder... cause is likely a tight valve that was never adjusted that burnt. Exactly. Assume it blew up for a reason and fix that reason, be aware of that reason's potential for causing problems, otherwise you'll be in the same situation before long. Quote Link to comment
Stoffregen Motorsports Posted October 15, 2013 Report Share Posted October 15, 2013 So adjust valves correctly and rebuild carb? Double check your method of valve adjustment (like at the tip of the rocker and not at the cam). Check them at every oil change until you have verified that they don't move. And check simple things like your fuel filter, make sure you're running the right plugs, and definitely drop your oil pan to clean out all that mess. Quote Link to comment
jacobryandavidson Posted October 15, 2013 Author Report Share Posted October 15, 2013 Right on .... So where do i get a weber carb ?? Quote Link to comment
jacobryandavidson Posted October 15, 2013 Author Report Share Posted October 15, 2013 U know it may be coincidence but the guy at auto zone told me the intake / exhaust plugs were bolth same and he gave me all 8 of the same part number i wonder if he was wrong bkuz thats when it started acting up Quote Link to comment
Stoffregen Motorsports Posted October 15, 2013 Report Share Posted October 15, 2013 Right on .... So where do i get a weber carb ?? http://www.webercarbsdirect.com/Nissan_Replacement_Carburetors_s/37.htm I can't advise you on plugs. Maybe someone here can. Sometimes the parts guy is just wrong. Quote Link to comment
Z-train Posted October 15, 2013 Report Share Posted October 15, 2013 Sometimes the parts guy is just wrong. Now that is FUNNY!!! Quote Link to comment
jacobryandavidson Posted October 15, 2013 Author Report Share Posted October 15, 2013 ;/ Quote Link to comment
jacobryandavidson Posted October 17, 2013 Author Report Share Posted October 17, 2013 So should i rebuild this carb get a weber or is a 2 to 4bbl adapter possible on this like other 4cyls? Quote Link to comment
Z-train Posted October 17, 2013 Report Share Posted October 17, 2013 No four barrel belongs on these engines.Fix one issue at a time.Once a 32/36 is dialed in,they are a really good piece. Quote Link to comment
jacobryandavidson Posted October 17, 2013 Author Report Share Posted October 17, 2013 okay so rebuild kit for this is what ill do thanks guys Quote Link to comment
Sealik Posted October 17, 2013 Report Share Posted October 17, 2013 U know it may be coincidence but the guy at auto zone told me the intake / exhaust plugs were bolth same and he gave me all 8 of the same part number i wonder if he was wrong bkuz thats when it started acting up Different plugs... NGKs Intake.......BPR6ES Exhaust....BRP5ES So should i rebuild this carb get a weber or is a 2 to 4bbl adapter possible on this like other 4cyls? Buy a new Weber 38/38 kit for the Z24 Comes with an air filter assembly and intake/carb adapter plates etc..... Quote Link to comment
datzenmike Posted October 17, 2013 Report Share Posted October 17, 2013 Parts counter guys are idiots. It's up to you to learn and know what goes on your Datsun. We're here to help with that. The exhaust plug runs hotter than the intake so it is a colder heat range. Quote Link to comment
jacobryandavidson Posted October 17, 2013 Author Report Share Posted October 17, 2013 so could that have been what caused my head to burn? Quote Link to comment
jacobryandavidson Posted October 18, 2013 Author Report Share Posted October 18, 2013 Also whats the head tq / and the intake/exhaust clearance? Quote Link to comment
datzenmike Posted October 18, 2013 Report Share Posted October 18, 2013 Valves especially the exhaust get very hot. The only time they can cool is when they are closed and in direct contact with the valve seat. If you do not have proper valve clearance the valve may not close, it over heats and the exhaust 'burns' a path past them and the seat. Now the compression goes down on that cylinder, it doesn't fire properly and all kinds of things can go wrong. The valve seat can even fall out. Quote Link to comment
jacobryandavidson Posted October 18, 2013 Author Report Share Posted October 18, 2013 so what's the proper settings and the head bolt torque Quote Link to comment
datzenmike Posted October 18, 2013 Report Share Posted October 18, 2013 If you have a new head gasket on then every tune up loosen one bolt at a time and tighten to 60 ft lbs. Do this on a cold motor. Valve clearance, or lash, is 0.013" on both sides. Do this on a hot motor. Quote Link to comment
Stoffregen Motorsports Posted October 18, 2013 Report Share Posted October 18, 2013 I'm going to clarify what Mike said. Adjust the valves on a hot motor. Hot = anything over 100 degrees F. And that's .013" at the valve, not the cam. NEVER torque the head bolts hot. A- they stretch when hot so the torque value would not be the same. B- they can break very easily when hot. C- you can pull threads out of the block when hot. I always recommend a cold valve adjustment on an L series. Why hot on a NAPS Z motor, Mike? Quote Link to comment
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