arsonist63086

hi I'm fairly new to this Max.org even though I've been a member for a while i just haven't logged on since i lost my 1985 max to the inpound. lol. so i stopped logging on now i have a 77 810 datsun wag ( http://www.cardomain.com/ride/3327973 ) which im working on, to get to the point i have a question / problem with the car wich i cant quite put my finger on. the problem is when i step on the gas the care seems a bit sluggish ( it doesn't bog, stutter, or knock/ping) but its only like that from idle to like 2500 rpm after that she just pulls hard and normal it use to run harder when it was automatic to the point where it will cheep the tiers at time at a hard start. all i did was up grade the distributor to 280zx internal ignition one and set the timing at 10 btc, oh i forgot to mention i have a 1980 280zx ecu with o2 sensor running my car . all i want to know whether its my timing or something, or just me being nit picky...... if you guys can give me any idea of Wat it might be that would be appreciated...........

BlackTopVitz

Awsone datsun! Congrads on the purhase.

Have you done new plugs, wires, cap and rotor? Also running a few
of your grounds straight to the battery usually helps eliminate a bad grounding issue which is sometimes attributed to sluggish engine performance.

arsonist63086

yep new plugs, cap, rotor and i em runing the ground wiers to the batt. wich i up graded to an optima batt. i also instaled to capasitors to the M.S.D. box to keep it a constent voltage and to eliminate most of the radio noise. so my idle is smooth at 800 rpm.

82maxtx

I found this guy's site, has a few informative facts about our motors... check this read VVV

http://www.biopatent.com/l28.html

arsonist63086

thanx 82maxtx for the info

82maxtx

ah ha! I think I might know what is causing your problem.... I think it might be your ecu. here's why : A while back, a man VERY famialar with all things datsun asked me what my plans for the car were, I explained I wanted this and that, blah blah, vg30 ecu, blah blah blah. he stopped me and said it wasn't a good idea because our L24E intake manifold has some thing like 2 " throttle bodies " in the intake manifold. only ONE of them opens until the motor is up to tempature, and when you get on the gas lightly, it only opens up the first one, not both, and the second one opens up later, at a higher rpm, per the demand for air increases w/ rpms going up. all this is controlled by the stock MAXIMA / 810 ecu. the z cars' ecu doesn't do this, all of them, even the l24 z's, allow BOTH of these open AT ALL TIMES. so, I think that maybe making your " sceondary " stick or something, or maybe it's linkage to it maybe broke, or bent or something... maybe try an L28E intake manifold.... it could be alot of things, just reading your thread more closely and remembering what I've heard made me think of these things.. hope it helps! I love to see ANY j-tin being fixed up / maintained! keep it alive and strong!

also, are you on the JNC board?

arsonist63086

thanx for the help, but i think they fed you wrong info in the progresive stile throttel body (2butterfly) because all the l24e-l28e had 1 butterfly throtrel bodies, whitch wher 50mm in diamiter and all the l24e - l28et have the same basic intake manifold some just have egr's, pop charg cap for turbod and none egr ones.. dont get me wrong i aprisiat your help its just the info they gave u was wrong about the l24e throttel bodies.. but i was thinking it might be my ecu fule mix at low rpm so i got to fiddeling with the l28e air flow metter it worked a bit, i just wowned up the tention coil up a bit to cut a bit of fule (it worked ok) know it les slugish.
but i got to thinking do you guys think that the waights inside the distrbuter might be a broblem with the timeing map since im useing a l28e distributer insted of the l24e?

ps. i have been thinking about progesive throttel bodies for economic perpeses and for performence at full throttel. ive herd that some progresive throttel bodies go as big as 70mm -80mm (meaning the valume of bothe the butterflys open) insted of the 60mm of the 240sx. would it work or will the problem like wat 82maxtx said will happen with the ecu..

82maxtx

yeah, I was just going off what this fellow told me... glad your actually digging for the source of your problem...

I posted the link above^^ to this other guys site where he give information about his l28e Z... answer to your question from the guys' page? hope this helps, sounds relative to your question :

"I found a receipt indicating the previous owner had paid the Z Specialist to rebuild the distributor. When I took the distributor apart, I found the main distributor shaft had been reassembled 180 degrees out of position and one of the retention springs for the centrifugal advance weights was gone. These errors allowed the timing to jump ahead to a very high advance at low rpms. Assembled properly, most of the knocking at low rpms under load went away. Later, I replaced the entire ignition system with a MSD capacitor discharge, high voltage coil and 280Z electronic distributor. To delay and reduce the maximum centripetal timing advance of the ignition, I filled the bottom end of the centrifugal advance weight slide slots with JB Weld. I ground out the slots enough to allow 10 degrees of centrifugal advance instead of the stock 20 degree advance. Timing was set to 10 degrees advance at idle and 20 degrees at speed. This new ignition system gives the high voltage necessary to fire under high compression, easier cold starting, longer time between tune ups and reliable timing at high rpms. Knocking was reduced by having advance start at higher rpms and ending with less total advance. "

keep in mind, he's running a completely different beast of a motor than we are, but his insight on fixing his distributor may shed some light on your question...

hope this helps you out man, I may not know everything about our motors... but I'll damn sure try to help!


-and another thing.

I wanna say I think the L28 has a longer overlap duration (I know they use different cams) , which your L24 has a shorter overlap duration, which means, by putting an l28 distributor on an l24, the distributor's timing is gonna " run long " over the what your l24's valve train is moving. by how much, i'm not sure, maybe even enough to " roll it over " into the next timing / firing cycle which might weaken the actual spark at low rpms....... I may even be wrong, but it makes sense to me.