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NA distributor in a TUBRO


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Today while doing some basic maintenance i noticed that my car has what appears to be a NA l28e distributor. Now I have a 1977 280Z with a l28et swap in it running Megasquirt 1 v3. The previous owner somehow connected the distributor to megasquirt. How big of a deal that is? The car runs but not that good. Since its a NA do I adjust the timing by twisting it. Should I replace it with a Turbo distributor? 

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Today while doing some basic maintenance i noticed that my car has what appears to be a NA l28e distributor. Now I have a 1977 280Z with a l28et swap in it running Megasquirt 1 v3. The previous owner somehow connected the distributor to megasquirt. How big of a deal that is? The car runs but not that good. Since its a NA do I adjust the timing by twisting it. Should I replace it with a Turbo distributor? 

 

Are you sure its actually wired to megasquirt?

 

If not, yes, you will need to turn it manually. However, you want the timing to be locked, that is to say having no advance.

 

But yeah if you can get a turbo distributor, do that instead. 

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Well there is a guy that might have one for sale on here for 75. I know that the negative from the distributor is connected to pin 7 on megasquirt. I didnt check the + but its probably wires in to. I think all this might explain why the car is running so rough  BTW why would I want the timing to be locked? 

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You want the timing to be locked so the engine doesn't detonate and blow the headgasket, due to excessive timing. The advance inside that N/A distributor/centrifical advance, moves with increased rpm, advancing the timing. You can lock the n/a distributors internal advance by welding up the advance slots. Jb welding, or even using a good silicone sealant.

 

Now the distributor may alreay be locked internally but you may have to take it apart to be positive. Or maybe ask the previous owner if it is. You should be able to also check it with a timing light.

 

There can be many reasons why your engine is running rough. You may want to spend some time diagnosing what is causing the rough run.

I added a turbo to my N/A L28 engine, with a locked n/a distributor and it idled and ran very smooth.  

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well its a turbo engine but the distributor is NA for some reason. I found few problems with the wiring the tuning. Anyways how easy would it be to swap in the turbo distributor? easier that just working with this one? what would be the benefits?

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 Anyways how easy would it be to swap in the turbo distributor?

 

Fairly simple, but you'd need a turbo distributor and a turbo drive spindle.  The end of the shaft is different between the N/A and turbo distributor and their spindles.  (I'm taking about the shaft that runs between the oil pump and the distributor and drives them both...)

 

Go to the Megasquirt part of this Forum and find out if there's a reason to change. 

 

Better to know why it is the way it is.  Those parts will be $$ unless you can find them at a yard or from someone who doesn't know what they are and how many people are looking for them...

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i checked my wiring and found out that there are two wires coming from the dizzy. one is red the other is green. Green is connected to ms1 v3 pin 7(ground i think) and the red one is connected to pin 24. it seems like the dizzy is already welded up but when i rev it i can hear some kind of mechanical noise

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Dude, you need to spend a lot of time reading about MS and other ECUs. The fact that you can "rev it up" means it's connected and working in harmony with MS. There's no reason to change your distributor. I can see fresh weld beads under the reluctor, so it looks like the PO did the correct thing by welding the arms of the mechanical advance.

 

You change your timing by connecting to MS with a laptop and a serial cable. Install Tunerstudio and check your ECU's version, settings, and then once you know what you're working with and have a basic understanding of MS, come back here and we'll help you out with any questions.

 

http://www.tunerstudio.com/

http://www.msextra.com/doc/index.html

Edited by Metro
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I have basic understanding of tunerstudio. I just wanted confirmation that it was done before. I want to know how to adjust the timing adjustment. Do i do it just in TS or also by twisting the distributor? I just got a timing light and from what I read up I should lock the timing in TS to 10 and adjust the distributor and trigger angle. Is that correct? Do I adjust the trigger angle with the car off? 

Edited by konradlip
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It looks like it is locked to me, the weld in the third picture would be pointless otherwise.

 

You can easily check that it's locked out by simply grabbing the rotor and attempting to twist the rotor one way and the other. If the rotor moves a significant amount and you can actually see the mechanicals moving in the dizzy, then it's not locked. If the mechanicals do not move, then it is locked. Back when I was running a dizzy on my car, I found the stock (replacement) rotors had significant play in them. I mention the play just to forewarn you about it and not think it's the mechanical advance not locked out. Don't take offense to me mentioning small things like this, I don't know your skill level when it comes to stuff like this, so I assume people know (next to) nothing about it when I try to explain some things. ;)

 

You don't need a turbo dizzy. The reason there is a "turbo dizzy" is because Nissan changed the control of the engine when they went to the turbo version. They decided to add or change the way the ECM/ICM was triggered. 

 

Since your MS is capable of using pretty much any ignition input signal as an RPM reference, the NA dizzy is fine. I ran my turbo L28 with an NA dizzy (locked) for the first few months it was turbocharged, then switched to DIS. I actually couldn't  use a turbo dizzy due to the ECM I am using anyway.

 

As far as adjusting timing, you do that through a combination of mechanical manipulation and through the SA tables of the MS. You need to set "base timing" using the dizzy itself. Depending on the application this is usually between 0 and 10 degrees BTDC (Before Top Dead Center). You then adjust overall timing through the SA tables in the MS. I can't help you on setting the base timing, I use a different ECM than an MS, that allows for easy adjustment of base timing by disconnecting one wire temporarily (similar in concept to disconnecting the vacuum advance of a carb set-up. You will have to do some research there, I'm sure the MegaManual and MS forums will be of help there.

 

So in short, don't be worried that it's an N/A dizzy, just be sure that it is locked out, and that base timing is set correctly, along with MS doing what it should be doing. If you don't have a timing light, get one, learn how to use it, correctly set timing can solve a multitude of problems.

 

I'm only mentioning this last part as an FYI, but a non-locked out N/A dizzy could be used in conjunction with EFI, provided that the SA tables are set correctly in the ECM to account for such a method. This is a sort of advanced topic, and has no real benefit in doing so, but I mention it, because it could be done and with such a universal ECM as the MS, it could be set up a multitude of ways, along with the actual mechanicals that it is attached to.

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