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Discussion Starter · #1 ·
So I've been riding my 1981 280zx around and for the most part, it's good. but there is an issue at weird and spontaneous times. I hear crackling going off when I drive. The best way I can explain it is it sounds like small sparks of electricity/leaves crumbling. I thought it was just debris at first but then I noticed it happens at times when I rev my engine. the engine does not overheat, it stays between 120 and the midpoint (190). Nothing is leaking from the car, I had UV in the coolant and there are no leaks. I check my coolant levels and they seem to be consistent. any idea what this could be?
 

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Maybe it's the timing chain slapping around inside the cover.
 

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if steve is right (and even if its not the TC) you should check the TC chain tight side chain guide. It can wear to the point of exposing metal (the guide is made from plastic) and if that happens you may catch the guide on the tight side going down, ripping the guide off. I had this happen and was lucky the broken metal guide fell in to a harmless spot.
EVERY L engine owner should check the tight side TC chain guide for wear, and replace as needed. I would say if you have 100k on the engine it should be replaced as a wear item. You really don't want this guide to break like it did on me.

 

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Discussion Starter · #4 ·
if steve is right (and even if its not the TC) you should check the TC chain tight side chain guide. It can wear to the point of exposing metal (the guide is made from plastic) and if that happens you may catch the guide on the tight side going down, ripping the guide off. I had this happen and was lucky the broken metal guide fell in to a harmless spot.
EVERY L engine owner should check the tight side TC chain guide for wear, and replace as needed. I would say if you have 100k on the engine it should be replaced as a wear item. You really don't want this guide to break like it did on me.

mine is like 47k and has happens randomly. ngl it sounds like it came from the back right. keep in mind this is a bit random
 

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1983 280ZX Turbo
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What I hear sounds like an exhaust leak or a spark plug jumping the spark to the engine block. But if that happened, it would miss.

I'm thinking tiny exhaust leak. Check the studs on the outer ends of the exhaust manifold.

But to me it doesn't sound like anything that requires action.
 

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Discussion Starter · #7 ·
What I hear sounds like an exhaust leak or a spark plug jumping the spark to the engine block. But if that happened, it would miss.

I'm thinking tiny exhaust leak. Check the studs on the outer ends of the exhaust manifold.

But to me it doesn't sound like anything that requires action.
It might be the suspension too, ill check that too tomorrow. thank you
and no there are no issues with the sparks.
 

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You're 81 280zx only has 47,000 miles? :oops: If that's the case, your car shouldn't be having any of these issues!
 

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Have you checked the exhaust? It's VERY common for Z-cars to break the outer studs on the exhaust manifold and have small leaks. They usually don't sound like the very faint sounds I heard, but that's not definitive.

Again, the very faint sounds I heard don't sound like a real problem. Sometimes you have to just keep driving it and see if it gets worse.
 

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I agree with Pilgrim! Most of the 280zx’s had poor quality studs on the outside corners of exhaust manifolds which sheared off and then warp the manifold.
 

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Discussion Starter · #13 ·
I agree with Pilgrim! Most of the 280zx’s had poor quality studs on the outside corners of exhaust manifolds which sheared off and then warp the manifold.
Have you checked the exhaust? It's VERY common for Z-cars to break the outer studs on the exhaust manifold and have small leaks. They usually don't sound like the very faint sounds I heard, but that's not definitive.

Again, the very faint sounds I heard don't sound like a real problem. Sometimes you have to just keep driving it and see if it gets worse.
Thank you guys! ill look into it :)
 

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The outside of cylinder number 1 is behind the distributor, use a flashlight. The outboard on number 6 is readily seen next to the firewall.
 

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Scott, I'm afraid you've got it backwards. The manifold warps and causes the studs to snap. The back one is more prone to snapping than the front because the back one has an engine lift bracket on it. You should NEVER use an engine lift bracket on an exhaust stud. Better off using a longer bolt on the intake to head to lift and engine and once that is done change back to the original length bolt. NOTE: On the 81-83 non turbo engines there is a heat shield that goes on the exhaust manifold itself and it runs full length. That heat shield is the reason that model warps so many manifolds. That's why they aren't available new anymore. Some 30 years ago I replaced an 83 exhaust manifold because it was warped so badly I couldn't resurface it. I put that heat shield back on the brand new manifold. 8 months later the manifold warped, broke the back stud and sounded like an old tractor when it was cold. I surfaced the manifold, replaced the gasket, and removed the heat shield. 10 years later the customer sold the car and the gasket was still good. Since then I've never had an issue with the 81-83 exhaust manifold unless it had the heat shield on it. I always tell my customer than I'm going to remove the exh man heat shield and I tell them why. If they don't want me to do it then I will write right on the repair order that there is no warranty on the job. So far everyone has trusted me and let me remove the heat shield.
The heat shields on the intake manifold are very necessary so don't remove them.
To help locate a supposed exhaust leak you can take the probe off of a mechanics stethoscope or just use a long piece of hose with one end stuck in your ear. Take the other end and run it all over the suspected areas. Make sure that you keep the hose pointed away from the cooling fan or it may blow out your ear drums. Z man of Washington
 

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So you are saying the actual silver pot metal shield (4 bolts) shouldn’t be reinstalled? That’s easy to not put back on. I’m certainly not an expert on these manifolds, but did talk to a Nissan Japanese engineer years ago (1990ish) who assured me both the exhaust manifold and those two studs weren’t great. He had recommended I use an after market stud kit like PAllnets to replace all the bolts that hold the intake and exhaust top colts and the combo bolts.
Thanks for the suggestion to leave the heat shield off.
Scott
 
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