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Harmonic balancer for a naps z?


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So the NAPS Z motor I originally swapped into my wagon did not come with a balancer (just a standard crank pulley), and the Z24 long block that I later bought did not either.  I just swapped all the pullys from the Z20 to the Z24 block when I built it (I had just bought all new stuff to stick on the z20 before it tanked about 60 miles later...go Bill's Datsun "remanufactured" engines).

 

I have read in several places that when the balancers go bad it can cause all kinds of chaos, and none of my naps z's have had them, just the standard crank pulley.  I have not been able to find anywhere that sells a new balancer.

 

I am wondering if anyone knows where I can buy a new one (I am sure I can find a used one somewhere, but then the question is how well is that 30 year old rubber going to dampen vibration).  If the worst I am going to be dealing with is the lack of refinement without the balancer, I could care less, but I really don't want to damage an engine with only a few hundred miles on it...so any input or suggestions are welcome.

 

Thanks in advance!

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So the NAPS Z motor I originally swapped into my wagon did not come with a balancer (just a standard crank pulley), and the Z24 long block that I later bought did not either.  I just swapped all the pullys from the Z20 to the Z24 block when I built it (I had just bought all new stuff to stick on the z20 before it tanked about 60 miles later...go Bill's Datsun "remanufactured" engines).

 

I have read in several places that when the balancers go bad it can cause all kinds of chaos, and none of my naps z's have had them, just the standard crank pulley.  I have not been able to find anywhere that sells a new balancer.

 

I am wondering if anyone knows where I can buy a new one (I am sure I can find a used one somewhere, but then the question is how well is that 30 year old rubber going to dampen vibration).  If the worst I am going to be dealing with is the lack of refinement without the balancer, I could care less, but I really don't want to damage an engine with only a few hundred miles on it...so any input or suggestions are welcome.

 

Thanks in advance!

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News to me that there is a harmonic balancer on the Z series engines. I think the KAs have them.

 

That's what I thought, but several people on forums had mentioned some issues with "welded on" flywheels and sheered crank noses that they blamed on a lack of harmonic balancers.  The engine I have is not very smooth, and I blame the extreme OCG camshaft that is in it for the majority of the NVH, but I plan on ditching that cam for a Comp cams CCA-88-123-6.

 

Anyway, Doc510 says he has a couple...I am guessing these things are the unicorn of NapsZ parts...not sure that 30+ year old rubber is going to do alot of dampening anyway.

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Cams won't affect anything. For one they turn half speed. Nissan balances every internal part before assembly. I wonder why the Z series would need a harmonic balancer? longer stroke?

 

 

Someone should post a picture of this harmonic balancer.

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Cams won't affect anything. For one they turn half speed. Nissan balances every internal part before assembly. I wonder why the Z series would need a harmonic balancer? longer stroke?

 

 

Someone should post a picture of this harmonic balancer.

 

I have had interesting experiences tuning and setting the cam timing on this engine due to the mystery cam.  When ignition and cam timing aren't dialed in perfectly, I have found the engine likes to have mid RPM partial throttle misfires, and after tracing the ignition system many times and putting the engine on a labscope, it appears to be from the grind of the "custom" OCG camshaft...so I always figured due to the extreme idle "lope" and the thing not wanting to run out of steam at 5500+ rpm, I figured the overlap and lift on this thing must be as crazy as they could go without the valves touching.

 

All that being said, I figured that had a bit to do with the roughness of the engine, so I never worried about a balancer, but some people on other forums have mentioned that the NVH is possibly due to the lack of a harmonic balancer.  At any rate, Doc510 said he had a used one, and I have seen oics of them on the internet.  Right now I am not making it a huge priority cause it sounds like most didn't have them from the factory...and in my time working as a mechanic for 7 years I never saw a single one...

 

EDIT: I still want to replace the mystery grind camshaft though...I never run the car hard, so it never sees the RPM this cam appears to be ground for.  I also might see if I can re-jet the secondary on the 32/36 (or go bigger, though I hate to loose the fuel economy), the gas analyzer on the lab scope showed it would run slightly lean at WOT thru higher RPM ranges.

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It's a progressive carb so as long as you don't push it past the 'tip in' point, gas mileage won't change if you go larger secondary jet.

 

Part throttle misfires? The NAPS dual plugs allow much more EGR to be run than a single plug engine. Pull the small hose off the ERG valve to deactivate it. See if it helps. There is no EGR when engine is not warmed up, idling or full throttle.

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It's a progressive carb so as long as you don't push it past the 'tip in' point, gas mileage won't change if you go larger secondary jet.

 

Part throttle misfires? The NAPS dual plugs allow much more EGR to be run than a single plug engine. Pull the small hose off the ERG valve to deactivate it. See if it helps. There is no EGR when engine is not warmed up, idling or full throttle.

 

Yeah, if I go over 55 it dips into the secondary with the 4 speed...I haven't had the time to swap in the 240sx 5 speed i have sitting around...I don't even know if it will bolt up to the pickup naps z24 engine I have.

 

As far as the partial throttle misfires, there is no EGR on this engine, it was never installed...the engine is a bored and balanced with forged pistons and rods (as well as the head ported and polished, and I did a mediocre/fair job at port matching the intake and exhaust manifolds) as the guy I bought it from was planning on adding a turbo to it someday.  The partial throttle misfire was a random miss at 1/2 - 3/4 throttle at 3k-4k RPM under medium load...after mucking around with the cam and distributor timing, I dialed it out...but due to the insane amount of timing the engine likes and looking at all of the data I collected when first installing this engine, this cam is set up for either for boost or a high RPM oval track racer.

 

At any rate, after looking at the labscope and gas analyzer readings at the shop I used to work at, I suspect that this engine would make more power and have better drivability with a different camshaft and a richer secondary jet (or an otherwise larger carburetor, I haven't seen the flow ratings, but I suspect the 32/36 might be a little undercarbed for a mildly built z24).

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You should be able it go 55 without being in the secondary. Cruise speed does not require much throttle, just enough to push through the air.

 

What insane timing? The Z24 timing is about 3 degrees. A modified Z24 will not run less, maybe less but not more Make sure both sets of plugs are firing.  BPR6ES for intake side and BPR5ES for exhaust. Use only NGK. If using any other make I'm not surprised there is a miss. Be sure the cap and rotor are good, Nissan stuffed 8 wires on a small cap so good insulation is needed.

 

The 240sx 5 speed has the same bolt pattern but will be longer that the 720 5 speed.

 

 

On a side note I have never seen a harmonic balancer on the Z series engines, ever. Not aware that they are needed either.

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I do remember there being two different types of harmonic balancers. One had a cast-in hub and the other had a separate hub that bolted to the crank and then the balancer/pulley bolted to it with 6 6mm or 8mm bolts.

 

I think the L28D had the same balancer.

 

Sorry. Not solid information, but maybe a direction to get you going in your search.

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You should be able it go 55 without being in the secondary. Cruise speed does not require much throttle, just enough to push through the air.

 

What insane timing? The Z24 timing is about 3 degrees. A modified Z24 will not run less, maybe less but not more Make sure both sets of plugs are firing.  BPR6ES for intake side and BPR5ES for exhaust. Use only NGK. If using any other make I'm not surprised there is a miss. Be sure the cap and rotor are good, Nissan stuffed 8 wires on a small cap so good insulation is needed.

 

The 240sx 5 speed has the same bolt pattern but will be longer that the 720 5 speed.

 

 

On a side note I have never seen a harmonic balancer on the Z series engines, ever. Not aware that they are needed either.

 

The engine wants WAY more than 3 degrees timing.  Already running the right plugs, both sets are firing, and this was all covered in a thread from a few years back (you and I hashed it over in great detail).   http://community.ratsun.net/topic/33328-naps-z24-camshaft-issues/

 

Basically, after a ton of messing around, the cam gear was off time, but even with that reset, the engine ran the best at about 12 degrees advanced...15 degrees would give me more power (no predetonation or knock) but the engine would diesel if ambient air temps exceeded 90 degrees Fahrenheit.  Both coils are functional and all plugs firing.

 

I have swapped dizzys and control modules, checked mechanical and vacuum advance, cam timing, etc...and after tons of effort and placing it on the labscope and gas analyzer, it looks like it is the cam.  Unlike most Naps engines, this one is still pulling strong at 5500 RPM...I haven't run her past 6k ever, but up to that point the power doesn't fall off.

 

All of that brought be to believe the mystery grind cam from Oregon Cam Grinding is set up for high RPM dirt tracks or something, because this engine doesn't act like any other naps motor I have dealt with.

 

EDIT: As far as the balancer, I am not really worried about it after doing a bit more research.

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12 degrees advanced would seem to me that the measuring method could be wrong, such as the timing mark is incorrect or off.

 

Another is that the dual plugs are not firing together. Both plugs must fire together in the same cylinder. Try the timing light on the exhaust side plug as well. A single plug will need much more advance than a dual plug set up.

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12 degrees of cam advance does sound really high. Do you have a cam card or any way to find installation specs? Have you tried the split overlap method of cam timing?

 

I was talking 3 vs. 12 degrees ignition timing advance....

 

 

 

What insane timing? The Z24 timing is about 3 degrees. A modified Z24 will not run less, maybe less but not more Make sure both sets of plugs are firing.  BPR6ES for intake side and BPR5ES for exhaust. Use only NGK. If using any other make I'm not surprised there is a miss. Be sure the cap and rotor are good, Nissan stuffed 8 wires on a small cap so good insulation is needed.

 

 

The engine wants WAY more than 3 degrees timing.  Already running the right plugs, both sets are firing, and this was all covered in a thread from a few years back (you and I hashed it over in great detail).   http://community.ratsun.net/topic/33328-naps-z24-camshaft-issues/

 

Basically, after a ton of messing around, the cam gear was off time, but even with that reset, the engine ran the best at about 12 degrees advanced...15 degrees would give me more power (no predetonation or knock) but the engine would diesel if ambient air temps exceeded 90 degrees Fahrenheit.  Both coils are functional and all plugs firing.

 

 

 

 

 

I had a discussion many many years ago on another forum about the NAPS dual plugs. He was running the wiring as a wasted spark set up. The #1 intake wire was correct but the #1 exhaust wire was plugged into the #4 exhaust side plug firing on the #4 cylinder near the end of the exhaust stroke. His timing was advanced also because he was basically running a single plug engine with the second plug totally wasted.

 

720timing002Large.jpg

 

 

If your cam is way off, your cylinders will not be nearly as filled as they should be.  Say the intake open extremely late and thus will close later on the piston up swing. This will push air back out into the intake. A weakly filled cylinder will need way more ignition advance because it will be weakly packed and burn slower.

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Cams won't affect anything. For one they turn half speed. Nissan balances every internal part before assembly. I wonder why the Z series would need a harmonic balancer? longer stroke?

 

 

Someone should post a picture of this harmonic balancer.

My Z22 balancer:

7301A913-4086-415B-8ED3-275F6D52E4AA-110

 

ADEE24C7-CA90-49BB-A34C-10B4101759A9-145

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If your cam is way off, your cylinders will not be nearly as filled as they should be.  Say the intake open extremely late and thus will close later on the piston up swing. This will push air back out into the intake. A weakly filled cylinder will need way more ignition advance because it will be weakly packed and burn slower.

 

This is what I suspect is happening.  I am wondering if it is the way the cam was ground, because even adjusting the cam gear doesn't make it run "right"...and after exhausting any potential ignition issues (including testing for faulty distributors, coils, and plug wires (or running the wrong wire to the wrong cylinder)) what was left was the mystery grind cam.

 

It does run good now, but again, the timing is advanced high for what these motors normally run.

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