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Reverend

It Ain't Running Right!

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So, first of all, i've been gone from the car circles for a long time for certain reasons. Have forgot most what i learned about carbs and timing.

 

Problem: last summer, i broke my distributor. Yes, it went broken. The collar that holds dizzy on place (with 2 10mm screws) was bent and eventually dizzy started to wiggle, so forth destroying all screw threads that were holding it to place. SO. I replaced it with similar kind of oem 240z distributor (no-points, custom made) and i just CANT make it run nicely.

 

I have 3 SK/OER dual sidedrafts that were tuned last summer. Havent touched them since. I dont remember the basics of timing, but i have timing gun with igniton advance setting.

 

Tell me what are the correct numbers for proper timing on 3 carbs. We tried every combo. It sometimes idled super smooth, then when rpms raised, ran like $^!#.

 

In two weeks we have major car event here, i just need it to be done with before the show.

 

Thanks in advance

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Try 15 degrees initial timing with no vacuum advance. Don't go over 38 at max.

Do you know what the mechanical advance is on your distributor?

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I havent got a slightest idea. By initial timing you mean ..? Sorry for my non-professionality on this matter. I've just had so much stuff on the platter and i've forgot all this.

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Carbs are set up and synced by the tuner last summer when i had the previous dizzy operational. I tried with 18 degrees initial. It idled okay but as soon as i raised rpms, its started to poppoppoppoppopp on the exhaust. 

Edited by Reverend

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Exhaust popping is usually too rich or retarded timing.

First verify timing marks: Check piston 1 top dead centre with the mark on the damper pulley.

Also have a look at exhaust and see if it is spitting soot or stinky like rich fuel burn.

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SO. I replaced it with similar kind of oem 240z distributor (no-points, custom made)

 

Uhm and how does that look ? Petronix ? No points ?

 

Timing with vacuum unhooked, I would try something like 5 BTDC, hook up the vacuum and blip the throttle, should go no further than max 15 to 17 BTDC on the timing mark on the pulley ( use timing light ).

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I have no vacuum advance as im running triples. The dizzy is modified by one old geezer who does these things. Its basic 240z dizzy, no-points with a small box outside. Nothing fancy. And yeah, i can smell fuel. Actually even my neighbour from 100 feet away can smell the fuel... haha. Wich is weird cause the dyno guy said its "okay". Is it normal that my whole rear area goes super BLACK after driving for some time? It looks like im driving a diesel... haha.

Edited by Reverend

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Have you checked timing at 3000 rpm? This would tell you if the mechanical advance is working.

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The carbs seem to have an issue.

If you could take a photo of all plugs together, we could see if it is just one carb or all 3.

Check fuel levels in carbs too.

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a8ca0fe0-c644-46f5-92ea-c457a513ef2b_zps

 

From right to left 1-6. Brand new plugs, all somewhat black, nr1 is the blackest. I tried to set the timing, but my 2 day old timing lamp went mute... :(

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Your problem seems to be too much fuel.

4 & 5 seem less rich.

post-6852-0-15161400-1428714708.jpg

Do you or a friend have an air-fuel measuring device?

Quick and dirty first step would be to lower fuel level if you do not have leaner jets.

You could also get hotter plugs (5) rather than (6) heat rating.

post-6852-0-15161400-1428714708_thumb.jp

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Don't count timing until it's verified since an 'old geezer ' has messed with the curve. You might be just running on initial timing:)

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If I have read all the posts in this thread correctly. The car ran properly and had been tuned last summer. Dizzy broke and got replaced and problem showed up. If that is the case, then start at the dizzy and don't move on until you are 100% sure that timing, advance and spark are totally correct.

Charles

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Yes. I'd do that but my brand new timing light wont work >:I Well i gotta get refund and get another one. And yes, i agree its gettin too much fuel. Those sparkplug holes were soaking wet.. Should i lean out the idle jets or try to tinker with floats? I do not have any float gauge or whatsoever.

Edited by Reverend

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You can dial back the idle enrichment screws to get a good a/f at idle and have clean plugs when idling.

But if the fuel level is too high or the jets are too big then once off idle, the car will still be rich.

Try a few plug cuts at different loads to see what plugs (a/f) is off idle:

1. Cruising

2. Accelerating up a long hill at WOT.

As the guys mentioned above, if your distributor is not advancing, the fuel will burn later as it is leaving the exhaust. I don't think this will blacken the plugs though... but your exhaust will be very hot and may glow at night.

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Haha. Btw nearest hill is few hundred km away, so i'll just try WOT on straight road. Of course i need to inspect it before i can do it. Damn laws.

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I managed to get my timing gun back on track and set up the initial to 15 and max is about 37-38. Something is wrong. It does not run on all six cylinders on idle. Is it normal that you get fuel dripping from the ram pipes/float breathe hole?

 

Edit. I made few test drives and it stutters on steady speed. Plugs are black-ish so its most certain it is getting too much fuel. Was there DYI fuel level gauge instructions somewhere here?

Edited by Reverend

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Your timing seems ok.

For SK's there is a screw for lowering the fuel.

There is a gauge like an eye dropper you can experiment with.

A pipette may do the trick.

You could probably dip a stick or the end of a caliper to measure fuel depth.

The carbs should not leak.

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I drank the Kool aid and wasted a lot of time because of following his guessing.

I expected more based on his writing and credentials but was let down and had to dig out of the hole I jumped in.

Edited by Blue

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I drank the Kool aid and wasted a lot of time because of following his guessing.I expected more based on his writing and credentials but was let down and had to dig out of the hole I jumped in.

I wondered if it was just me.

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So basically all you need for fuel level measurement is a small plastic pipe, slim enough to fit in to main jet hole, put it in and close the other end. It "should" hold the fuel inside..right? Like pipet. OER fuel level was 29mm right?

Edited by Reverend

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I think the oer gauge registers from the ledge where the main jet assembly screws in. For a tube/straw alternate method, you may wish to put a mark or ring on the straw so that it registers from the ledge......or just bottom it out and ensure all three are the same level.

The fuel level from the ledge should be 31mm to 27mm down. It is something you can adjust to tune. Just make sure all 3 carbs have the same level. Repeat the measurement a few times so that the straw measurement is accurate enough for your liking. Take pics to make a tach tip for all when you nail it.

12.305.2.GIF

Edited by Blue

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