Rollover_Red Posted May 14, 2010 Report Share Posted May 14, 2010 so im kinda new to the datsun world(just got it yesterday).... i have been working on the car alot and it runs great...... im not exactly sure what block is in it but i think its a L4???? forgive me on what i call these things and what they are really called...... but it also has a 3/4 inch cam? a closed chamber jdm head? and a weber 32/36 carb. so the car runs great, but there is a hesitation that irritates the hell out of me when i full throttle it........ i have tried turning down the screw and its still there, i have tried turning up the screw and its still there....... any ideas???? my buddy said something about the jets being incorrect, but what gets me, is that the carb was on his l4? and the carb was fine....... he has everything i have, minus the jdm head...... Quote Link to comment
RoadRace Posted May 14, 2010 Report Share Posted May 14, 2010 1) L16, L18, L20? these are the L series motors. what is stamped on the block - pass side at top. what car? 2) auto or Standard 3)3/4" cam - if the guy that sold you the car said that it has a "3/4 inch cam" or he said is has a "3/4 race cam" either way he didn't put it in or doesn't know what it is - if anything at all. the term is a carry-over from the old days - i have a 'tribal knowledge' answer to what that actually means, but that can not be substantiated with any actual proof, so it will stay with me. when it comes to cams, I deal with real numbers, not fractions and heresay. 4) the bog/hesitation can be caused by several things. get the tune up on target first. then you have a baseline to work from. 5) Jetting in the 32/36 is generally not a big deal. but how the motor reacts throughout the entire rpm and load range is what you should be looking at. specifically the transfer zones. ex: idle to part throttle transfer at low speed, off idle to 25% throttle transfer at mid speed and hi speed - all in different gears. part to half throttle transfer and so on up to full throttle. what do the spark plugs look like? 6) JDM Head - does it say A87, 219 or V912 on the side? casting number is on the pass side, bottom of the head, in between the spark plugs, sometimes at the front near the inspection cover plate - although this is more than likely is a secondary issue - if its an issue at all. Quote Link to comment
Rollover_Red Posted May 14, 2010 Author Report Share Posted May 14, 2010 1) L16, L18, L20? these are the L series motors. what is stamped on the block - pass side at top. what car? 2) auto or Standard 3)3/4" cam - if the guy that sold you the car said that it has a "3/4 inch cam" or he said is has a "3/4 race cam" either way he didn't put it in or doesn't know what it is - if anything at all. the term is a carry-over from the old days - i have a 'tribal knowledge' answer to what that actually means, but that can not be substantiated with any actual proof, so it will stay with me. when it comes to cams, I deal with real numbers, not fractions and heresay. 4) the bog/hesitation can be caused by several things. get the tune up on target first. then you have a baseline to work from. 5) Jetting in the 32/36 is generally not a big deal. but how the motor reacts throughout the entire rpm and load range is what you should be looking at. specifically the transfer zones. ex: idle to part throttle transfer at low speed, off idle to 25% throttle transfer at mid speed and hi speed - all in different gears. part to half throttle transfer and so on up to full throttle. what do the spark plugs look like? 6) JDM Head - does it say A87, 219 or V912 on the side? casting number is on the pass side, bottom of the head, in between the spark plugs, sometimes at the front near the inspection cover plate - although this is more than likely is a secondary issue - if its an issue at all. 1) l16 2) 4 speed 3)ill ask about the cams. it was a buddy of mine who owned the car before me and he told me the lobe(for example 272) but i can remember it...... 4)im getting a tune up later today..... 5)in all gears, its about 35% throttle to full. it will get a bog for about 1/2 a second, then it will go...... it seems like it just needs to be tuned but i looked all over to find something about tuning a weber carb, but no luck. i just gotta tune it by ear...... 6) it says something like w53 or ws5, i cant really tell, there is blue paint on the head and block....... it makes it kinda hard to tell...... Quote Link to comment
metalmonkey47 Posted May 14, 2010 Report Share Posted May 14, 2010 http://community.ratsun.net/topic/6117-weber-tuning-guide/ Give that a shot Quote Link to comment
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