Timing chain help

[RMin280]

Sorry I didn’t know there was a difference. I have a 280z but it has a l28 from a s130, f54/n42 with flat tops. I could go back to the stock zx damper but I don’t have ac so I don’t really need the second belt. I don’t know much about the damper on the car right now but I think it’s fine 🤷. 
 

I don’t know why I didn’t think about this earlier but I have ms2 and I have the tuning software to monitor different sensors and such. One of the things I can see is timing. Could I potentially use a timing gun and see which mark is being used? This way I could also see if the damper has spun, if I don’t see any mark or if it’s at the wrong degree.

[jonbill]

There should be either:

a) a single mark on the damper and an array on the timing cover, or

b) a single pointer on the timing cover and an array on the damper. 

You've got a mix of both and I don't think you can trust it to tell you where TDC is. Nor can you trust the MS2 - it only knows what it was told by whoever tuned it. 

you need something like this to find TDC : https://www.ebay.co.uk/itm/331342952716 

and then make your own marks to show where TDC is. I'd replace the serated doofer on the timing cover with a pointer that points at the last of those marks on the damper at TDC. 

[Racer X]

4 hours ago, RMin280 said:

Sorry I didn’t know there was a difference. I have a 280z but it has a l28 from a s130, f54/n42 with flat tops. I could go back to the stock zx damper but I don’t have ac so I don’t really need the second belt. I don’t know much about the damper on the car right now but I think it’s fine 🤷. 
 

I don’t know why I didn’t think about this earlier but I have ms2 and I have the tuning software to monitor different sensors and such. One of the things I can see is timing. Could I potentially use a timing gun and see which mark is being used? This way I could also see if the damper has spun, if I don’t see any mark or if it’s at the wrong degree.

I asked earlier how many miles on the engine. It looks like it has quite a bit of time on it. 

You mention the PO used the car for racing, and that it has flat tops (carbs?). Most people ditch the flat tops, as they are emissions carbs that were so troublesome and difficult to tune.

You also mentioned MS, which I assume is Mega Squirt. 
 

So I’m a bit confused. What does the Mega Squirt do if the engine has carburetors?

One last comment.

The L series six has a very long crankshaft, subject to torsional twisting. Even with the rotating assembly (crank, flywheel, clutch, damper) fully balanced, a vibration damper is absolutely required.

 

 

[RMin280]

What do you mean by a serrated doofer? I’ve never heard that term before.

Sorry I forgot about flat top carbs. It has flat top pistons instead of the dishes pistons that originally came in the engine. 
I’m a little confused, you and captain obvious have both said I need a damper, do I not have one? I don’t have much experience working on engines so I thought I did.

[Zed Head]

13 hours ago, RMin280 said:

As for why the po put it on, the car doesn’t have ac and was and will be raced somewhat frequently so having a harmonic damper helps. It doesn’t matter too much on an in-line 6 but still, and less rotational mass. 

It's because you said this earlier.  

[Zed Head]

The doofer is the timing tab with the serrated edge.

And, my comment about pulley size might be more important than it seems if you're planning to use this as  a daily driver.  The Z's are known for having low charging current at idle speed.  A smaller pulley makes that problem even worse.

One thing at a time though.  

On the Megasquirt question I'd guess that it's being used for ignition control only.  It's possible.  Have you looked under your distributor cap?  There might be other odd things on that engine.

[RMin280]

Ohh yea I just mean in-line 6’s are naturally balanced so they don’t have as much harmonics as an i4 or v8. 

I don’t plan to daily drive the car, really just more of a fun weekend car and some autox or road course. 

The mega squirt has to use a zxt distributor for timing advance. I’m not sure exactly how it works. Again, new to engine stuff. I do know however that there are some odd things with the engine and car.

[Zed Head]

44 minutes ago, RMin280 said:

I don’t have much experience working on engines so I thought I did.

 

6 minutes ago, RMin280 said:

Ohh yea I just mean in-line 6’s are naturally balanced so they don’t have as much harmonics as an i4 or v8. 

The mega squirt has to use a zxt distributor for timing advance. I’m not sure exactly how it works. Again, new to engine stuff.

Nothing wrong with not knowing but you really shouldn't double-down on the wrongness.  It puts people off.  No offense.

So the turbo distributor is what you'd expect for a Megasquirt application.  If the guy set it up correctly you might be able to find zero through the Megasquirt program.  But, you won't really be confident in it.

Anyway, sounds like it runs but has a noise.  Try running it without the fan belt on and see if the noise goes away.  It won't hurt it for a short while, especially if the engine is cold.

[RMin280]

I don't mean to double down, it was just my understanding and what I've been told by several people who know a lot more than me.

What do you mean by the fan belt? Is that the belt that spins the alternator and water pump?

[Zed Head]

Yes, if you have a loose pulley removing the belt should remove that as the possible cause of the noise.  But, the downside is you'll have to loosen the alternator adjustment, which can be difficult if you haven't done much engine work.

You're in that danger zone of learning as you go.  You're probably going to break some things.  Really, I wonder now about your lash adjustment if you don't know what a fan belt is.  Again, no offense intended.  Find those youtube videos and watch many.  

Have you looked at your ignition timing on Megasquirt software?

[RMin280]

I am nothing if not prepared lol. I have only ever heard referred to as a serpentine or accessory belt but that would be on my daily so could be different for the z's so I wanted to make sure. I'll pull the belt and run the car for a minute to see if that helps any. I think I can manage 1 bolt but I guess we'll see.

I have looked at the timing through the software and if I remember correctly it is at 12 degrees at idle. 

[Reptoid Overlords]

So I know you're still working at verifying TDC due to the unknown accuracy of the damper, and I'm not trying to distract from that, but I couldn't find anything about whether you are running the stock cam or a bigger one.  I saw aftermarket EFI, flat top pistons,F54 bottom/N42 head, but nothing else about how its built. More cam seems to typically equal more valve train noise. 

I questioned mine and asked the community here in this thread:

https://www.classiczcars.com/forums/topic/67497-l28-normal-noise-excessive-valvetrain-noise-or-exhaust-leak-tick/