Distributor/Timing woes...

[Spades]

I have one of the few NAPS motors with 4 spark plugs, its a NAPS Z20S from a '80 510 wagon...with my last exhaust upgrade, I removed the EGR tube that connected the exhaust manifold to the EGR valve and the intake manifold. The EGR system was not hooked up, but the EGR valve was stuck in the full open position.

 

With full time EGR, the motor handled the huge timing bump provided from the ported vacuum on my 32/36, but without the EGR, the vacuum advance on the distributor is WAY too much.

 

I have been fiddling with it for days, and there has not been a happy medium. Right now, I am running no vacuum advance at all, with the timing advanced quite a bit(I don't have a timing light, I will barrow my dad's this weekend). Currently, the motor bogs pretty bad under 1800RPM, and doesn't have much power after 3800rpm. I am pretty sure this distributor had some mechanical advance, but I don't think it is much. I will know after I can get my paws on a timing light. I can advance the timing more, which I will most likely do tomorrow.

 

I have tried both ported and manifold vacuum sources. If I hook the vacuum advance to manifold vacuum, it's far too much advance at idle, so the timing has to be retarded all the way so it doesn't ping, then when you step on the throttle the massive advance goes away so it tries to die. On ported vacuum, its still too much advance, I can back the timing off as far as possible, then it idles very poorly, and it still pings bad when you crack the throttle.

 

I am wondering, does anyone know anything about these distributors? is there any mechanical advance in them? anyone ever come across this problem? Has anyone used the newer electronic distributors of the 80's on a L20B or L16, ect. and found a way to resolve this issue? The engine I have now is basically a L20B with a different head.

 

P.S. I am running good quality 92 octane, so I can run quite a bit of advance, but nothing like what the current vacuum advance is demanding, I even changed the secondary linkage on my 32/36 so that the secondary opens sooner. That removed the lean sag and lean back fires on throttle, but it did nothing with the core issue of too much vacuum advance.

[datzenmike]

I have one of the few NAPS motors with 4 spark plugs, its a NAPS Z20S from a '80 510 wagon...with my last exhaust upgrade, I removed the EGR tube that connected the exhaust manifold to the EGR valve and the intake manifold. The EGR system was not hooked up, but the EGR valve was stuck in the full open position.

 

With full time EGR, the motor handled the huge timing bump provided from the ported vacuum on my 32/36, but without the EGR, the vacuum advance on the distributor is WAY too much.

 

I have been fiddling with it for days, and there has not been a happy medium. Right now, I am running no vacuum advance at all, with the timing advanced quite a bit(I don't have a timing light, I will barrow my dad's this weekend). Currently, the motor bogs pretty bad under 1800RPM, and doesn't have much power after 3800rpm. I am pretty sure this distributor had some mechanical advance, but I don't think it is much. I will know after I can get my paws on a timing light. I can advance the timing more, which I will most likely do tomorrow.

 

I have tried both ported and manifold vacuum sources. If I hook the vacuum advance to manifold vacuum, it's far too much advance at idle, so the timing has to be retarded all the way so it doesn't ping, then when you step on the throttle the massive advance goes away so it tries to die. On ported vacuum, its still too much advance, I can back the timing off as far as possible, then it idles very poorly, and it still pings bad when you crack the throttle.

 

I am wondering, does anyone know anything about these distributors? is there any mechanical advance in them? anyone ever come across this problem? Has anyone used the newer electronic distributors of the 80's on a L20B or L16, ect. and found a way to resolve this issue? The engine I have now is basically a L20B with a different head.

 

P.S. I am running good quality 92 octane, so I can run quite a bit of advance, but nothing like what the current vacuum advance is demanding.

 

First, if you are not using the EGR close it or seal the tube going to it completely. If there is an air leak you will have endless problems later so make sure it is sealed air tight. If the EGR was stuck partly open then timing and idle mixture must have been radically changed in order for it to rum. If fully open I can't see it even running as this would be a massive vacuum leak at idle.

 

Second, now that you have a secure EGR that is sealed, make sure your valves are adjusted to proper lash as this can have a huge effect on manifold vacuum.

 

Third, set your idle speed and mixture. Turn mixture screw in until idle quality worsens and then turn screw out to get as smooth an idle as possible. Keep turning out until idle quality worsens and select a point about half way. Now adjust idle speed down and perform the mixture adjustment again. Re-adjust the idle speed down toward 700 to 750 RPM or what ever the factory setting is. Keep adjusting the mixture and idle speed until the idle quality cannot be improved upon.

 

Forth test distributor vacuum advance by removing the cap the rubber hose and sucking on the end. You should observe that the rotor turns clockwise slightly and holds until you release the vacuum. If it fails to turn or won't hold position there may be a leak in the vacuum canister on the dizzy or the hose.

 

Fifth, while cap is off gently twist the rotor. It should rotate slightly clockwise and return when released. Though not a perfect test this might reveal seized or sticking mechanical advance weights.

 

Sixth get a good timing light and set the proper static timing for the Z20S. (probably similar to the L20B) You should not have to remove the vacuum advance hose from the carb but it wouldn't hurt to check that there is NO vacuum on this hose at idle. If there is then this may not be the vacuum advance hose or idle isn't set low enough. Once timing is set, the idle speed may need adjusting again.

 

 

 

Static timing is set at idle with a timing light and does not change. All other forms of advance is added on top of the static timing. If you static timing is 12 degrees and there is 20 degrees of vacuum advance then you have a total of 32 degrees advance.

 

There cannot be too much vacuum advance on the distributor. Distributor vacuum advance is set at the factory and can reach a maximum of 20 degrees (approx). The vacuum for this comes from a port just above the primary throttle plate so there should be NO advance at idle. When throttle is applied the plate rises and manifold vacuum is slowly applied to the port and to the distributor. No advance at idle is strictly an emissions thing. Just above idle, vacuum advances the timing to give a longer time for the partially filled cylinder to completely burn and reach peak pressure just past TDC to push down on the piston. As the throttle is opened wider more gas and air enters which requires less and less advance to burn properly. The manifold vacuum also drops as the throttle opens wider so this is a perfect method of providing just the correct amount of advance. At wide open throttle there is little vacuum so no advance and with full cylinder filling none is needed. Vacuum advance to totally load dependant (throttle position)

 

Mechanical advance is a third form of advance and is RPM dependent. As the motor speeds up there is less time for the gas and air to burn and reach maximum pressure at that 'sweet spot' about 17 degrees after TDC so it needs to started sooner. Mechanical advance usually begins to happen around 1,000 to 1,200 RPM and is 'all in' by 3,000. (approx) Mechanical advance is about 20 degrees +-.

 

Off idle, light throttle: 12 degrees static timing plus vacuum advance of 12-18 degrees (no mechanicall advance yet) equals about 24-30 degrees total advance which is just right for maximum performance form a lightly filled cylinder.

 

RPMs increase to 2,000, light throttle. 10 degrees static timing plus a slightly lower (8 degrees) vacuum advance (throttle open wider cylinder more full) but mechanical advance kicking in, of say 10 degrees for a total of 28 degrees.

 

Full throttle at 2,000 RPMs: 12 degrees static plus ZERO vacuum (cylinder full) advance plus 10 mechanical for a total of 22 degrees.

 

Full throttle at 3,000 RPMs: 12 degrees static plus ZERO vacuum (cylinder full) advance plus total mechanical advance of 20 degrees for a total of 32 degrees advance which continues for the rest of the RPM range.

 

Close throttle above 3,000 RPMs and slow down: 10 degrees static plus max vacuum advance of 20 degrees plus max mechanical advance of 20 for a total of 52 degrees advance. Remember the cylinder is very weakly filled and at high RPMs so lots of advance is needed.

[Spades]

Whew, ok, I will try to reply to the suggestions...

 

1. I made a steel plate to cover the open port on the intake manifold. It is sealed with a new gasket. No vacuum leaks anywhere in the system. The EGR was VERY clogged, so while it was stuck open, it wasn't getting as much as it would have if it was clean. Yes, the timing and fuel mixtures were way different.

 

2. Valves are adjusted properly, I have had others double and triple check for me (I am not a well experienced mechanic yet, but where I work has several experienced mechanics, and my dad has been wrenching for 30+ years, he and some of his friends who have also looked the car over).

 

3. I have messed with idle air a bit, but I obviously have to change it every time I adjust the timing.

 

4. It is a brand new distributor(well, a couple months old now). The vacuum advance is working properly, and I can engage it with a vacuum hand pump, and I can watch it activate in accordance with the vacuum gauge on the hand pump. I have also used a vacuum gauge to watch my ported and manifold vacuum.

 

 

So, where I am is that the electronic distributor for a 4 plug naps z motor advances the timing very quickly as soon as the throttle is stabbed. When engine speed is over 2500 RPM with the vacuum advance connected to the ported vacuum on the base of my Weber 32/36, I get pinging and detonation. This happens at higher RPM at partial or full throttle. If I do not use the vacuum advance, I do not have such problems. Gauges tell me I don't have a vacuum leak, I can watch the vacuum advance and all of the other components and everything seems to be working properly. I have even used small amounts of propane around the intake and hoses to try and figure out if I have a leak, so far, I have not found any leaks.

[datzenmike]

At 2,500-3,000 RPM's if you suddenly apply full throttle, the vacuum advance should be almost zero. You are left with static and mechanical, and these should add up to 33-35 degrees. Datsun L series (and most other engines) run best around here. I guess if you connect the timing light at rev carefully to about 3,000 and suddenly open the throttle, the timing light should show the timing drop suddenly to just over 30 degrees if everything is working properly.

 

Are you sure you have the ported vacuum advance on the Weber and not something else? I don't know Webers so can't help you there.

[dimedriver]

If you can get the number off the side of your dizzy you can look up its specs on this page.

 

http://web.archive.org/web/20050308055504/home.att.net/~jason510/dizzy_specs.htm

Unless it has been re-curved or messed with.

-Dime

[Spades]

Thanks, tomorrow I am going to block off any extra vacuum ports on the manifold, go through and completely seal everything off to eliminate the chance of a vacuum leak and see where that gets me.

 

The Weber 32/36 has a port right at the bottom, and according to Weber, it is ported vacuum, and from what I have read, it is doing what a ported vacuum source should when I hook a vacuum gauge to it.

 

If I have time tomorrow, I will also stop at my dads and I will use his timing light and see what I come up with.

 

Thanks for the help and info Mike and Dime!

[datzenmike]

Hope it works.

[Spades]

well, i think the cam timing is off...when I replaced the distributor, I re-installed it in the same position, with #1 at TDC.

 

according to the timing light, without vacuum advance hooked up, according to the timing light, I am at 20 degrees with the distributor advanced as far as it will go just to get it to idle properly. From what the mechanics here have said, it sounds more like I am at around 3 or 4 degrees, not 20 at idle.

 

the symptom I have now, is that it bogs until it gets between 1500 to 3k RPM, then it pulls hard, and after 3k it pops out of the exhaust...

 

so, with the info you have provided mike, I know whats going on. Timing is too far retarded, so when the mechanical advance starts to kick in, it runs ok, then as throttle increases, my vacuum advance goes away, and it reverts to more retarded timing, and it pops out of the exhaust at 3k+ rpm.

 

so, now I need to double check that the distributor is in the right place, and if it is, I am guessing the cam is off a tooth or two.

 

 

Life Lesson #1,386,923: Do not buy a car with a "Overhauled motor" from a shop you don't know...regardless of how reputable the place is or how many years they have been in business. A carburetor, distributor, waterpump, fuel pump,and several seals/gaskets later, I am down to only having a timing problem, a noisy lifter, and crank seal left to be fixed on this engine. So much for "All it needs is a carburetor rebuild"...I guess I get what I deserve for buying a donor car that was having idle problems and paid as though the motor had been completely rebuilt.

[hang_510]

cam timing: what dowel# is the top gear on?

 

 

 

Life Lesson #1,386,923: Do not buy a car with a "Overhauled motor" from a shop you don't know...regardless of how reputable the place is or how many years they have been in business. A carburetor, distributor, waterpump, fuel pump,and several seals/gaskets later, I am down to only having a timing problem, a noisy lifter, and crank seal left to be fixed on this engine. So much for "All it needs is a carburetor rebuild"...I guess I get what I deserve for buying a donor car that was having idle problems and paid as though the motor had been completely rebuilt.

isnt #5 "never trust the seller"

especially when its family? :lol:

[Spades]

cam timing: what dowel# is the top gear on?

 

 

 

 

isnt #5 "never trust the seller"

especially when its family? :lol:

 

I will have to look and see, I didn't bother to check any of that when I resealed the valve cover. I will tear into that after I double-check the distributor.

 

Yeah, it wasn't family. I bought the '80 wagon donor car from Bill's Datsun...Jock told me all it needed was a carburetor rebuild and a new u-joint. *shrug* it was my own fault...if I had looked closer at the carburetor, I would have seen all the stripped screws and realised they had been into it many, many times. Basically, I paid for that car as though it had a completely overhauled motor, and all they had done to it was a re-ring it and shave the head. The motor isn't junk, it just needed many more things than it was sold as. Oh well, a fool and his money are soon parted :)

 

hopefully tonight I can get a better look at the distributor and figure out if I need to move the timing chain.

[banzai510(hainz)]

figure out if I need to move the timing chain?????

 

maybe ur oil spindal dist drive is off a tooth?

 

 

dial crank up to zero mark then look at the sprocket and see if the marks lone up. I know nothing about the Z series head but assume there is a timming mark on cam sprocket and a ref mark to go by. If its lines up then the chain is OK.

[hang_510]

doesnt sound 'they' ever got it to run correctly, :angry: sell it to the next sucker...

 

time to start back @ TDC...

[racerx]

Just curious if these NAPZ engines are like L16-20 where oil pump spindle has to be at 11.28 for TDC?

[dimedriver]

They should be exactly the same. The block and cranks are the same. The heads are nearly bolt on interchangeable. The major difference is the oil pump spindle is shorter so you may have to use a flash light to see it.

 

You can find FSM's for the trucks and cars that had Z series engines on the nicoclub.com site.

 

-Dime

[datzenmike]

Set at TDC using the timing mark on the crank pulley and the timing scale bolted to the right side of the timing chain cover. Turn the crank up to the 0 (zero) in a clockwise direction only. If you overshoot turn back well before TDC and do again as many times as needed to get it right. This will prevent any slack from getting onto the tension side of the chain and give a much more accurate reading or chain stretch or cam sprocket timing.

 

Just like the L series look through the top most hole in the cam sprocket. Use a flash light and look down on the back of the sprocket. There will be either a VEE or a U shapped notch on it, like this:

 

 

On Z series motors there is a faint vertical casting mark between the two rocker shaft towers. Here I'm pointing to the mark:

 

 

Just like the L20B the Z series are set on the #2 adjustment hole. the V or U notch should be just under or very slightly to the right for proper cam timing.

 

While the motor is at TDC remove the distributor and look at the drive spindle position. It should be just like the L series.

 

 

If not, drop the oil pump and spindle and re-position it so that it is like this.

 

..

[Spades]

thanks so much for all the info everyone! I put the engine to TDC tonight and pulled the valve cover off...instead of the lighter colored link being on the cam mark, it was way off and there was a link marked with a drop of paint in the area "close" to the cam mark...

 

I think I am pretty much screwed, because tonight i moved the baseplate the distributor was on and advanced the timing so far it was difficult to start it, and it still lags like hell.

 

something tells me billy-bob got his paint mark off by a bit when he took it apart...either that, or the reason they re ringed the motor was because with all the oil leaks, and with the timing and cam/crank being off made it run poorly with no grunt, they assumed it was burning oil and the rings were tired, and that was what the re-ring was supposed to fix, so when it was all done and it still ran like crap the customer wouldn't pay.

 

Who knows, its all speculation. Right now what I will have to do is pull my radiator out again, and get to the bottom end so that I can take off the lower cover, and then re-align everything properly, and put in a new cam seal while I am there. Thanks for the help folks, and I guess I will know what happened when I can find the time to tear it all apart.

[datzenmike]

The marks on the links are only useful when assembling when the timing cover is off. Once the motor is started, the bright link moves off the setting and becomes randomly placed. If you keep rotating the motor they will eventually line up but why bother? Set TDC and check the U or V notch against the casting mark like in my pictures. If it lines up, the cam is properly timed.

 

Id be more interested in where the dizzy drive spindle is set at.

[Spades]

The marks on the links are only useful when assembling when the timing cover is off. Once the motor is started, the bright link moves off the setting and becomes randomly placed. If you keep rotating the motor they will eventually line up but why bother? Set TDC and check the U or V notch against the casting mark like in my pictures. If it lines up, the cam is properly timed.

 

Id be more interested in where the dizzy drive spindle is set at.

 

heh, looked at your above post AFTER I had already posted,lol.

 

I am back at home now, I will have a look at it either tomorrow morning before work, or tomorrow night after work. Thank you for all your input Mike, you have been a huge help...I wish I woulda left work a little later, I checked this post one last time before I put everything back together and left work at 6pm,lol.

[datzenmike]

You may have a good runner that is simply put together wrong. I got a '78 620 for a cord of wood because the PO couldn't get it to run properly and had had enough. He got close to one and a half cords and I stuck a twig in the carb to hold the choke open and drove it home.

[hang_510]

I stuck a twig in the carb to hold the choke open and drove it home.

:lol: pic!!!

 

i envision you in the cab with the hood on the saftely latch leaning out the window with a big branch jammed under the hood, all the leaves flapping in the wind, as you round another corner...

[Spades]

I am on lunch, pulled off the valve cover and found the problem.

 

The cam marks and distributor are fine...however, the tensioner and guides are toast, maybe more...

 

THERE IS OVER 10 DEGREES OF SLOP BETWEEN CRANK ROTATION AND CAM/DISTRIBUTOR ROTATION....

 

So, if anyone deals with Bill's Datsun in Clackamas, just be carefull...He told me he went through the whole motor...not looking like it at this point. I was an idiot and paid $1400 for the donor car thinking that he had rebuilt the motor. Like I said, a fool and his money are soon parted.

[racerx]

Let me see, if I got this correctly...you bought the car, I am assuming, it's a truck or 510 and he said that it had a rebuilt motor? Is the body of the vehicle, at least in good shape? I would talk to Bill and let him know what's up...

[Spades]

I have never talked to Bill before, the only person I have dealt with is Jock...I bought a blue 1980 510 wagon from their shop. The pictures of it are in my build thread on the projects forum.

 

The wagon i bought from him had a hashed interior, and the outside wasn't pretty, but I only wanted the drivetrain to swap into my 72 wagon.

 

I have had to replace many parts on the motor. I bought it under the claim that the engine had already been gone through, re-ringed, and everything taken care of while they were in there. If he lied to me when he sold it, do you really think he is going to do anything about this?

 

I am so pissed I don't want to talk to him right now, cause I will not be civil. I am into it for the cost of the car, over $500 in parts(gaskets,distributor,carburetor,tune up parts, seals, the list goes on), not to mention now I will have to spend at least $120 just on gaskets, seals, and a timing chain/tensioner/guide kit. Whats more, I am not yanking the motor and putting a new chain on it without completely going through the motor at this point, cause I don't even know that they did shit to it.

 

I doubt they will do anything, if he straight up lied to my face to get me to spend $1400 on a shitty car, you really think they will make it right? I kind of doubt it.

 

I guess I either need to poney up and go through this z20s or drive it as is and wait for the timing chain to skip, and build a z24 in the mean time.

[hang_510]

be sure the guides are installed correctly.

there is a slotted bolt on the tension??? side guide that could cause the issue, and/or the tensioner may have popped out.

 

on an L20 i had, it still ran well w/the tensioner in the oil pan and a broken guide, noisy too.

 

 

and build a z24 in the mean time.

lemme know if you need a Z24 short block. if the old(current) is still in good cond (pulling in 2 weekends) itll be avail for cheap.

the crank may need turning.

[Spades]

The problem is, that you can move the crank without the distributor turning, which, if I am correct, means the crank sprocket and key are worn out or messed up too...cause slop in the chain wont make the rotor not turn when the crank is moved, correct? which means I have a seriously tired motor that literally only got just a re-ring, if they even did that.