jalexquijano

you mean .035 gap??? NGK BP5ES???

so it does not do any effect if i gap them at .031 instead of .035?

ill try this once again! i thought if i used a pertronix 1761 ignitor module, i should gap them at .035 instead of .031??

Next time you come to Panama i will get you a VIP Tour at the New Locks and let you test my 240z!

I have not stated anyone is wrong here! I am not an expert nor a mechanical engineer! Just trying to understand the deceleration popping at the tailpipe when going down hill or realeasing the gas pedal at 2nd or 3rd gear. I cannot hear it when the car is in neutral and i let the gas pedal go.

so installing the 280zx injector cooling blower will not dissipate the heat produced by the manifold which causes the fuel percolation at the bowls? WHich electric fuel pumps are recommeded? I have an airtex 8012s rated 5 to 9 psi but its really pushing only 3 psi installed at the rear besides the gas tank. I cant believe i can only use my car when there is no traffic at nights or on sunday!! There must be a solution to this percolation!

Dat2Kman, Okay. I found a broken stud which i will replace this weekend including a new manifold to downpipe gasket. Hope it solves the deceleration backfire (popping when releasing the gas pedal) at the tailpipe. I am also enclosing a picture of the new exhaust. Cant stand the popping and not interested on going back to the Steel rail. How much horsepower could i have gained with this new exhaust? I will try and richen the mixture a Little bit more and lower the btdc from 16 to 14 btdc.

I need your advice. Should i swap to ngk bp6es and gap at .031 or at .035? I have a petronix 1761 ignitor module installed at the distributor and not points.

Needles? Both carbs were fully refurbished my ztherapy in 2015 including new needles. I dont think the needles are worn.

Why NGK BP6ES instead of BP5ES? My engine has a Schneider 274F Camshaft which is hotter than stock! I need to compensate and avoid the plugs from getting carbón fouled at idle: http://schneidercams.com/274FL6.aspx I have them gapped at .031

My 1972 240z is suffering from fuel percolation during traffic jams and traffic lights. In addition to the stock heat shield which was installed in the car by the Factory originally, i have mounted a two Stainless Steel heat shield extension that reaches the bottom of both 3 screws SU Carburetor float bowls. However, the fuel percolation is still present. The gasoline in my country, Panama, has no ethanol so this should not be happening. The heat comes directly from the manifold and thus there must be away of lowering that amount of heat so it does not affect the fuel that is inside the float valves and that will evaporize and consequently shut the engine down. Other owners only throw out ideas such as swapping metal fuel rail with 5 inch rubber hoses, i have already done this and the percolation is still present. how do i avoid the car idle becoming lumpy at traffic jams which leads to a sudden shut down of the engine? WOuld installing a 280zx injector cooling blower solve this? The heat in my country is 32°C and lots of traffic.

Spark plug 3 and spark plug 4 at 2.75 turns clockwise. I am still lean? My car suffer from a fuel percolation problem and if i richen them more they get carbón fouled at idle.