oinojo Posted March 5, 2006 Share Posted March 5, 2006 alright i figured out my ignition problems....but now its something else. When setting my distributor, my carbs backfire...but when i advance it the engine raises in RPM but drastically... i find myself retarding it in fear or over revving the motor. This is getting rediculous and very tedious. Some ppl tell me it could be my cam timing but that still wouldnt explain the overreving. Also when it is overreving, i am not getting any backfiring problems. Quote Link to comment Share on other sites More sharing options...
AK-Z Posted March 5, 2006 Share Posted March 5, 2006 Don't know the carb setup to well but with experiences with my 280, advance it forward until its starts stumble, from there back the advance a degree or so and then ajust by the throttle body. Don't know if this will help Quote Link to comment Share on other sites More sharing options...
fastzcars Posted March 5, 2006 Share Posted March 5, 2006 It sounds like timing to me. Try what AK-Z suggested, advance the dist just enough to smooth out the idle, then back off on the throtle stop on the carbs to get the idle speed back down. Did you reove the distributer? You might be of a tooth. Quote Link to comment Share on other sites More sharing options...
z_cars_rule Posted March 5, 2006 Share Posted March 5, 2006 or the distributer is on 180* the wrong way. Quote Link to comment Share on other sites More sharing options...
AK-Z Posted March 5, 2006 Share Posted March 5, 2006 or the distributer is on 180* the wrong way. I thought that with having the dizzy 180 out, it won't even start. the dizzy won't even fit properly with the dizzy "shaft" 180ed. only way would be to from putting the plug wires in the wrong order, you can't even put the cap on backwards (rotated 180). Quote Link to comment Share on other sites More sharing options...
katman Posted March 5, 2006 Share Posted March 5, 2006 Gee, how about using a timing light and putting it where it belongs, then idle the carbs down and reset the idle mixture? Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 5, 2006 Author Share Posted March 5, 2006 thats the thing i am using a timing light, but whenever im advancing the distributor the engine starts to race VERY high. Almost as if i am WOT. I would think i might have a pretty big vacumm leak somewhere on the manifold. Im going to remove the carb assembly today and retighten everything on the motor to make sure that isnt the case. Quote Link to comment Share on other sites More sharing options...
z_cars_rule Posted March 5, 2006 Share Posted March 5, 2006 I thought that with having the dizzy 180 out, it won't even start. the dizzy won't even fit properly with the dizzy "shaft" 180ed. only way would be to from putting the plug wires in the wrong order, you can't even put the cap on backwards (rotated 180). can you tell i have never pulled down a L series yet? heheh last motor i rebuilt did run with it 180ed, but ran like a dog. the shaft on that thing was shaped (|) , or a Y shape from side on. oh well. i am more of an RB person anyway. Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 5, 2006 Author Share Posted March 5, 2006 BUMP... does anyone have any theories about what might be happening? As i advance the timing, the engine races. I even tried messing with the throttle shaft and when i give it gas nothing happens. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 5, 2006 Share Posted March 5, 2006 Something is F'ed up on your linkage to the SU's or you have a piston stuck open on the SU's or something. Advancing timing WILL NOT cause the engine to go from 800 to 7000 rpm on a normally running engine. This convinces me that the two situations are not related. Figure out what is wrong with the carbs, fix that, turn the idle down if you need to, and set the timing. Quote Link to comment Share on other sites More sharing options...
AK-Z Posted March 5, 2006 Share Posted March 5, 2006 Something is F'ed up on your linkage to the SU's or you have a piston stuck open on the SU's or something. Advancing timing WILL NOT cause the engine to go from 800 to 7000 rpm on a normally running engine. This convinces me that the two situations are not related. Figure out what is wrong with the carbs, fix that, turn the idle down if you need to, and set the timing. I figured it would prbably be somthing wiht the carbs but didn't want to give any bad advice since I have never messed with SU carbs before. Quote Link to comment Share on other sites More sharing options...
2126 Posted March 6, 2006 Share Posted March 6, 2006 Another thought! Is your distributor working properly? I had an experience with a single magnetic pick-up 280Z distributor I transplanted in my Z. Had similar issues, as you described, and what it turned out to be was....the centrifigul advance was just worn out. I had even replaced the advance plate that usually goes south, the shaft bushing were good, and I thought heck, this thing should be good! Wrong, the advance mechanism was flat worn out. I finally bit the bullet and installed a Mallory Uni-Lite.....engine has been running perfectly ever since! Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 15, 2006 Author Share Posted March 15, 2006 alright well my timing is pretty much dead on and im still having overrev problems... my guess is there is a vacumm leak somewhere between the carbs and manifold. I know my fuel pressure is right and the float bowl isnt full. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted March 15, 2006 Share Posted March 15, 2006 Listen to Jmortensen. Your engine cannot be revving that high without a lot of manifold pressure. That has nothing to do with the ignition timing, fuel pressure, or your float chamber, except that when the timing is retarded far enough, the engine slows down in spite of the high manifold pressure. You could have a stuck throttle / something stuck open inside of your carbs, not restricting airflow at idle like it should be, as mentioned before. Track down this issue before worrying anymore about the timing. Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 15, 2006 Author Share Posted March 15, 2006 Listen to Jmortensen. Your engine cannot be revving that high without a lot of manifold pressure. That has nothing to do with the ignition timing, fuel pressure, or your float chamber, except that when the timing is retarded far enough, the engine slows down in spite of the high manifold pressure. You could have a stuck throttle / something stuck open inside of your carbs, not restricting airflow at idle like it should be, as mentioned before. Track down this issue before worrying anymore about the timing. sorry if im coming off as a newb... and i feel retarded because of what i found out. I checked my linkage again and it was way off. My the linkage was too short and so it caused my carbs to be 1/4-1/2 throttle. I lengthened the rod and so far has fixed my problem. Thank you guys for you information. It was very informative and made some of my work painless. Im sorry to those who were fed up by my stubborness. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted March 15, 2006 Share Posted March 15, 2006 Glad to hear you got it worked out. Quote Link to comment Share on other sites More sharing options...
katman Posted March 16, 2006 Share Posted March 16, 2006 "You can see a lot just by looking." -Yogi Berra Quote Link to comment Share on other sites More sharing options...
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