Fellas,
I need your experienced heads on pls. My z has been pretty good at starting from cold but recently over the last two to three months she needs a LOT of cranking but eventually catches. In fact so much cranking that by the time she catches, the oil pressure is half way up on he gauge!!!
When she eventually gets going it sounds like firing on half or four cycls for a few seconds until the rest come to life and she misses a little for about a minute until warm.
I suspected electrical, so have replaced plugs, cap and rotar arm on the 280zx dizzy.
The coil is really not that old. I may try to replace that with a spare one but somehow I have this feeling it won't make much of a difference given the rest of the time it works impeccably. Except for checking resistance, any tips on checking coil health which does not involve my tongue and HT leads!?
I've checked the timing and it's still at 10 degrees.
My next suspect is fuelling. I changed the fuel filter pre Japfest (with a clear one to see any rust etc in the future) and she revs out perfectly, so I'm not convinced it's lack of supply. Could it be too lean that causes this? In which case why would it deteriorate over time?
Compressions range anywhere from 160 - 172 which is still consistent with what I had the day after the head build. Bizarrely before Fourways rebuild the head the compression was in the mid 170s to 180s (see the pic), doesn't make sense why it's dropped post rebuild but that's a different discussion. (FYI Cyl 1 was found to have a completely loose valve seat)
So any thoughts? Anyone seen this before?
I need your experienced heads on pls. My z has been pretty good at starting from cold but recently over the last two to three months she needs a LOT of cranking but eventually catches. In fact so much cranking that by the time she catches, the oil pressure is half way up on he gauge!!!
When she eventually gets going it sounds like firing on half or four cycls for a few seconds until the rest come to life and she misses a little for about a minute until warm.
I suspected electrical, so have replaced plugs, cap and rotar arm on the 280zx dizzy.
The coil is really not that old. I may try to replace that with a spare one but somehow I have this feeling it won't make much of a difference given the rest of the time it works impeccably. Except for checking resistance, any tips on checking coil health which does not involve my tongue and HT leads!?
I've checked the timing and it's still at 10 degrees.
My next suspect is fuelling. I changed the fuel filter pre Japfest (with a clear one to see any rust etc in the future) and she revs out perfectly, so I'm not convinced it's lack of supply. Could it be too lean that causes this? In which case why would it deteriorate over time?
Compressions range anywhere from 160 - 172 which is still consistent with what I had the day after the head build. Bizarrely before Fourways rebuild the head the compression was in the mid 170s to 180s (see the pic), doesn't make sense why it's dropped post rebuild but that's a different discussion. (FYI Cyl 1 was found to have a completely loose valve seat)
So any thoughts? Anyone seen this before?
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