Im pretty sure I have a rod knock

[PsychoNaut04]

I installed a 38/38 carb. I made a few mistakes along the way, like throttle sticking open and revving the rpm up to 7k. A few days later im noticing loud ticking noises when putting it in gear and accelerating. It’s loud! Im sure the engine is done for. I’ll dismantle it and learn along the way, but it stalls on me when trying to go on reverse or trying to change gears. 
 

ps. The plugs came loose and melted the distributor cap. I attached a picture of the damage still present. Sure it’s bad but I have a feeling the bad engine vibration and loud ticking noise is the worst outcome. I since placed a new distributor cap but these melted wires are still there 
 

https://imgur.com/a/LVVCVAk

[datzenmike]

 

Only see two wires to the module. Should be 4? One power, 2 for the coils and one for turning the exhaust side off and on. If it runs it's only on one coil so without the second coil firing the engine will act like the timing is retarded. That module and those wires need fixing/replacing. The stalling is almost certainly from running on single plugs. Turning the timing up 8-12 degrees will fix that stalling and probably the vibration but it needs that module fixed.

 

If you over revved the engine and damaged a bearing or connecting rod or a piston it would make noises right away not a few days later. Making funny noises and vibration after severe revving could also be the head gasket. The Z24 is known for blowing the head gasket every 100k unless you re-torque the head bolts every year. 

 

So don't tear it apart just yet. At the least a new module and at worst a new module and maybe the head gasket needs changing.

[ggzilla]

The L16 could rev to 7000 without damage. I would be surprised if that would damage a Z24

1 hour ago, PsychoNaut04 said:

hrottle sticking open and revving the rpm up to 7k. A few days later im noticing loud ticking noises

 

[ggzilla]

1 hour ago, PsychoNaut04 said:

https://imgur.com/a/

 

The module and wires look partially melted to me ...

 

[ggzilla]

A new module is $59 at RockAuto. You can make new wires using crimp-on female spade connectors

 

RockAuto also has the whole distributor for $135 which includes a new module and a new vacuum can, but not the wires

[PsychoNaut04]

1 hour ago, datzenmike said:

 

Only see two wires to the module. Should be 4? One power, 2 for the coils and one for turning the exhaust side off and on. If it runs it's only on one coil so without the second coil firing the engine will act like the timing is retarded. That module and those wires need fixing/replacing. The stalling is almost certainly from running on single plugs. Turning the timing up 8-12 degrees will fix that stalling and probably the vibration but it needs that module fixed.

 

If you over revved the engine and damaged a bearing or connecting rod or a piston it would make noises right away not a few days later. Making funny noises and vibration after severe revving could also be the head gasket. The Z24 is known for blowing the head gasket every 100k unless you re-torque the head bolts every year. 

 

So don't tear it apart just yet. At the least a new module and at worst a new module and maybe the head gasket needs changing.

I was really, really trying to make time this past weekend to retoque the bolts because of the know head gasket issue.

 

i will place an order for the module and see what happens 

[PsychoNaut04]

50 minutes ago, ggzilla said:

The L16 could rev to 7000 without damage. I would be surprised if that would damage a Z24

 

Thank you. It ticks loud when putting it into gear and going for a drive. Ill try recording it. For sure ill work on replacing the damaged module. I really hope it’s nothing serious inside the engine. It doesnt make this ticking noise when on idle. It only vibrates. It’s only when placing it on gear that it ticks loud. 

[datzenmike]

Theoretical red line for shorter stroke L16 is about 8,250 while the much longer stroke Z24 is limited to just under 6,500 RPMs. The 'red line' is the point below which an engine in good condition can maintain constant RPMs without damaging itself. Above this point rods begin to stretch from g forces. It's a theoretical point based on stroke length and piston speeds. I quick buzz above this can be survived. 

 

Ticking could be the gasket is blown between cylinders. I would check the valve lash on all is 0.012" first and eliminate that as the cause. Valve lash would tick at all times so if only ticking under load then not this. (it it is this is a cheap fix)

[PsychoNaut04]

1 hour ago, datzenmike said:

Theoretical red line for shorter stroke L16 is about 8,250 while the much longer stroke Z24 is limited to just under 6,500 RPMs. The 'red line' is the point below which an engine in good condition can maintain constant RPMs without damaging itself. Above this point rods begin to stretch from g forces. It's a theoretical point based on stroke length and piston speeds. I quick buzz above this can be survived. 

 

Ticking could be the gasket is blown between cylinders. I would check the valve lash on all is 0.012" first and eliminate that as the cause. Valve lash would tick at all times so if only ticking under load then not this. (it it is this is a cheap fix)

There’s loud ticking and then it’ll stall on me. At this point im wondering if it’s the clutch or something with the transmission too because it does it when trying to park and fiddling with the gears at low rpm. 

[NC85ST]

11 hours ago, PsychoNaut04 said:

loud ticking noises

Do you hear this when the rpm’s increase? Kind of what it sounds like from what you’ve posted. It’s possible that the exhaust manifold is cracked. They crack on the back side where you can’t see it. You may have two separate problems that you’re dealing with. Like Mike said, take care of the distributor first and go from there.

[PsychoNaut04]

28 minutes ago, NC85ST said:

Do you hear this when the rpm’s increase? Kind of what it sounds like from what you’ve posted. It’s possible that the exhaust manifold is cracked. They crack on the back side where you can’t see it. You may have two separate problems that you’re dealing with. Like Mike said, take care of the distributor first and go from there.

The exhaust is really rusted out but coming out from it sounds like abnormal firing, like it’s choking. 
 

the ticking does increase with the rpm’s. 
when on idle, the engine is shaking around. I’ll get a video today 

[datzenmike]

Listen to the sound. If a lifter it will make the same noise loudness even under load. If it's say an exhaust leak, a rod bearing or perhaps the head gasket the noise level (not frequency) will increase with the load on it.

[PsychoNaut04]

2 hours ago, datzenmike said:

Listen to the sound. If a lifter it will make the same noise loudness even under load. If it's say an exhaust leak, a rod bearing or perhaps the head gasket the noise level (not frequency) will increase with the load on it.

What could be causing the engine to be shaking around though?

 

it idles fine but the engine shakes around. When putting it in gear is when it starts ticking really really loud. 

 

Im leaning towards the engine because it dies on me when driving it. 

[datzenmike]

Blown head gasket would and is often accompanied with altered engine exhaust sounds.

 

Ticking? is more higher pitch, you're sure it's not a deeper knocking sound? Muffled hammer on solid metal?

 

This is an automatic???

 

Also your distributor is obviously buggered and appears to be running on only the intake or exhaust side and as I said previously the timing will in effect act retarded

[ElliotV]

It really sounds like you might have blown the headgasket. Its possible when you went "to the moon" as some would say you might have compromised the headgasket and a few days later it blew out. When my headgasket blew out it started idling even rougher than normal(I was on the stock carb and it always had a slight miss) and would knock especially when revved it up and the firing sounded super uneven and was spark knocking. A quick way to tell if your headgasket is blown is to pull and the spark plugs out the exhaust side and do a compression test on each cylinder, when I hit #3 and my truck blew between #3 and #4 I could head the compression coming out of cylinder 4 cranking over and I only got 30psi of dynamic compression on both those cylinders.

[PsychoNaut04]

4 hours ago, ElliotV said:

It really sounds like you might have blown the headgasket. Its possible when you went "to the moon" as some would say you might have compromised the headgasket and a few days later it blew out. When my headgasket blew out it started idling even rougher than normal(I was on the stock carb and it always had a slight miss) and would knock especially when revved it up and the firing sounded super uneven and was spark knocking. A quick way to tell if your headgasket is blown is to pull and the spark plugs out the exhaust side and do a compression test on each cylinder, when I hit #3 and my truck blew between #3 and #4 I could head the compression coming out of cylinder 4 cranking over and I only got 30psi of dynamic compression on both those cylinders.

I have videos now. i tried to do a glove test to see the head gasket 
 

https://imgur.com/a/LHzH7zQ

[PsychoNaut04]

6 hours ago, datzenmike said:

Blown head gasket would and is often accompanied with altered engine exhaust sounds.

 

Ticking? is more higher pitch, you're sure it's not a deeper knocking sound? Muffled hammer on solid metal?

 

This is an automatic???

 

Also your distributor is obviously buggered and appears to be running on only the intake or exhaust side and as I said previously the timing will in effect act retarded

I’ll definitely take care of the distributor. 
i have videos now. Hopefully the phone picked up the loud ticking after hitting a certain rpm. 

[PsychoNaut04]

https://imgur.com/a/LHzH7zQ

[ElliotV]

yeah I am going to go with a blown headgasket. Truck sounds and acts like its only running on two cylinders and has that distinct knock sound on accelleration. Glove test wont tell you anything because these engines don't often blow into the cooling system but between the cylinders instead. I would start with a compression test and go from there. The other thing it could be is the distributor not firing two cylinders due to the messed up icm but the knocking sound makes me want to say head gasket. Compression test is a easy check though.

[PsychoNaut04]

1 hour ago, ElliotV said:

yeah I am going to go with a blown headgasket. Truck sounds and acts like its only running on two cylinders and has that distinct knock sound on accelleration. Glove test wont tell you anything because these engines don't often blow into the cooling system but between the cylinders instead. I would start with a compression test and go from there. The other thing it could be is the distributor not firing two cylinders due to the messed up icm but the knocking sound makes me want to say head gasket. Compression test is a easy check though.

Ill get a compression kit tomorrow and get back to you with updates. Thank you 🙏 

[NC85ST]

Blown head gasket can be confirmed by a compression test or you can just look at the plugs. If a couple of them look like they have been steam cleaned and the other two don’t, then you’ve got a blown head gasket.

[datzenmike]

Clean plugs would only happen if blown into the coolant jacket. Coolant getting in can steam clean them but between cylinders not much. You would also have unexplained coolant loss and constant top ups, possibly anti freeze smell at the tail pipe.

 

A leak down test would be more definitive for a bad head gasket. The hole in the gasket will be small and the drop in compression not very much. Two adjacent low cylinders might indicate a blown gasket. A leak down test measures the loss of air pressure in a closed combustion chamber. If a valve is leaking you will hear the air getting out at the carburetor or exhaust pipe. If a broken piston you'll hear air escaping at the valve cover fill cap. If gasket is blown into another cylinder you'll hear air at the other cylinder's spark plug hole.

 

 

 

Just to be sure on a distributor with 8 wires, check every wire goes to the correct plug...

 

 

FIX FIRST

I would take care of this obvious problem first. Fixing this could fix other problems. More pictures!! There should be 4? wires to that module I only see three maybe???? maybe a 3 wire Z22 distributor was swapped? Look for the part number on the side of the case. It's 10 digit beginning 22100-????? I can look up what it was used on to confirm it's correct.

 

 

3 wire

 

4 wire

[PsychoNaut04]

3 hours ago, datzenmike said:

Clean plugs would only happen if blown into the coolant jacket. Coolant getting in can steam clean them but between cylinders not much. You would also have unexplained coolant loss and constant top ups, possibly anti freeze smell at the tail pipe.

 

A leak down test would be more definitive for a bad head gasket. The hole in the gasket will be small and the drop in compression not very much. Two adjacent low cylinders might indicate a blown gasket. A leak down test measures the loss of air pressure in a closed combustion chamber. If a valve is leaking you will hear the air getting out at the carburetor or exhaust pipe. If a broken piston you'll hear air escaping at the valve cover fill cap. If gasket is blown into another cylinder you'll hear air at the other cylinder's spark plug hole.

 

 

 

Just to be sure on a distributor with 8 wires, check every wire goes to the correct plug...

 

 

FIX FIRST

I would take care of this obvious problem first. Fixing this could fix other problems. More pictures!! There should be 4? wires to that module I only see three maybe???? maybe a 3 wire Z22 distributor was swapped? Look for the part number on the side of the case. It's 10 digit beginning 22100-????? I can look up what it was used on to confirm it's correct.

 

 

3 wire

 

4 wire

You’re totally right. I see that it’s using the wrong part. Ill grab the part number in a bit but I checked out rockauto and see this one come up with 4 wires.
 

 https://imgur.com/a/VTDsahJ

 

being that it ran on 3 wires, how would it affect the engine?

[datzenmike]

 

The forth wire (shown above as a gray wire with plastic plug on end) is connected to a vacuum switch that tells the when the engine is under heavy load and it turns the exhaust side plugs off. Nissan says it's to reduce engine noise but earlier Z series do not have this so it will run fine with plugs firing at all times. Look around the distributor for the plastic connector that connects to this and the replacement distributor will connect right up.

 

 Before you replace, put an old spark plug in the end of an intake and then an exhaust plug wire and hold against a grounded surface. Start engine and see if you have spark. If you have spark on both intake and exhaust side plugs you really don't need a new distributor.

[PsychoNaut04]

8 minutes ago, datzenmike said:

 

The forth wire (shown above as a gray wire with plastic plug on end) is connected to a vacuum switch that tells the when the engine is under heavy load and it turns the exhaust side plugs off. Nissan says it's to reduce engine noise but earlier Z series do not have this so it will run fine with plugs firing at all times. Look around the distributor for the plastic connector that connects to this and the replacement distributor will connect right up.

 

 Before you replace, put an old spark plug in the end of an intake and then an exhaust plug wire and hold against a grounded surface. Start engine and see if you have spark. If you have spark on both intake and exhaust side plugs you really don't need a new distributor.

I tested the spark plugs against metal contact and was hearing the shock, so i guess it’s workfing fine.