The X-75? Those had a limited production run of 1200!BSA/Triumph went Bankrupt the next year.I've only ever seen the Prototype in Pickerington, Ohio.On the Nissan? Autozone can plug into the ODB port and see if any trouble codes show and that's free.I worked with my Dad for years in his Garage but when things went to computers? We couldn't afford the equipment so only worked on older stuff.Now days? I have software and hardware and can completely hack my vehicles!
I don't know, but assume that it has hydraulic lifters. I don't know if they can "get weak" or not. I had a hydraulic lifter fail and dropped a needle bearing in a 6.0 liter F250 diesel. Wiped the whole motor starting with the oil pump. Bought a motor at a junkyard and replaced it $6K. If it doesn't have hydraulic lifters could be a valve out of adjustment and slapping.If it made the sound all the time I would suggest picking up a stethoscope at Harbor Freight. But it's really hard to diagnose intermittent problems.
Quote from: Privateer on November 30, 2022, 01:05:23 PMThe X-75? Those had a limited production run of 1200!BSA/Triumph went Bankrupt the next year.I've only ever seen the Prototype in Pickerington, Ohio.On the Nissan? Autozone can plug into the ODB port and see if any trouble codes show and that's free.I worked with my Dad for years in his Garage but when things went to computers? We couldn't afford the equipment so only worked on older stuff.Now days? I have software and hardware and can completely hack my vehicles!The local Autozone near me doesn't have a scan-tool that can read OBD1 codes- they can only do 96-later OBDII; with this being an 87 D-21, it might be a matter of test-light+ paper-clip and count flashes.I'm still leaning toward doing pressure- and leakdown-tests, but they are solid trucks. I owned a D-21 during my Navy days and the only problem it had was a fuel pump relay failed- it did make a ticking noise before it failed completely- contact were crusty and it was only when you stomped the pedal that it happened (like heading up toward Snoqualmie Pass coming out of Federal Way. After replacing the relay, I went through all the ground connectors and replaced several that were nasty, as well as both main terminal lugs. I swear I got about 10-15 horepower back just cleaning up the grounds. It definitely improved drivability.
I am no Nissan mechanic but, you can try this.Disconnect the the cat or drop the exhaust and see if it runs properly.If dropping the cat is too hard, maybe pull the upstream 02 sensor out and run it for a few minutes to see if it works better.Maybe?
Quote from: mobilehomer on November 30, 2022, 12:28:40 PMCheck the exhaust manifold to the pipe bolts. They could be loose or the donut could be missing.Thought of that, but wouldn't the exhaust be kinda loud if it was leaking?
Check the exhaust manifold to the pipe bolts. They could be loose or the donut could be missing.
Quote from: customcutter on November 30, 2022, 10:37:06 AMI don't know, but assume that it has hydraulic lifters. I don't know if they can "get weak" or not. I had a hydraulic lifter fail and dropped a needle bearing in a 6.0 liter F250 diesel. Wiped the whole motor starting with the oil pump. Bought a motor at a junkyard and replaced it $6K. If it doesn't have hydraulic lifters could be a valve out of adjustment and slapping.If it made the sound all the time I would suggest picking up a stethoscope at Harbor Freight. But it's really hard to diagnose intermittent problems. This Z24i engine is a single overheard cam. So no lifters. The ends of the rocker arms are riding on the cam lobes and the other end pushes down on the valve springs and valves. I had actually thought about lifters and was hopeful until I removed the valve cover and saw this setup.ThanksRay
Quote from: avator on November 30, 2022, 06:08:13 PMNot for nothing but I might check universal joints, clutch and throw out bearing. All of these can make pinging and whining noises.I've thought of that. Unfortunately I've never heard one of those when it failing so it would be a guess on my part. I know it shifts fine and it has the small hydraulic cylinder on the side of the bellhousing, not a clutch cable. And all that is working fine. I would guess the bearing would make noise until you clutched the truck? Or visa versa?Thank RayP.S. Bill I thought of you last night when line of storms passed through Ala. Hope all yall are doing well:)
Not for nothing but I might check universal joints, clutch and throw out bearing. All of these can make pinging and whining noises.
My thought, is there a carrier bearing on the driveshaft, they can make intermittent noise under load, when they start to go.
Quote from: ray1377 on November 30, 2022, 07:23:08 PMQuote from: customcutter on November 30, 2022, 10:37:06 AMI don't know, but assume that it has hydraulic lifters. I don't know if they can "get weak" or not. I had a hydraulic lifter fail and dropped a needle bearing in a 6.0 liter F250 diesel. Wiped the whole motor starting with the oil pump. Bought a motor at a junkyard and replaced it $6K. If it doesn't have hydraulic lifters could be a valve out of adjustment and slapping.If it made the sound all the time I would suggest picking up a stethoscope at Harbor Freight. But it's really hard to diagnose intermittent problems. This Z24i engine is a single overheard cam. So no lifters. The ends of the rocker arms are riding on the cam lobes and the other end pushes down on the valve springs and valves. I had actually thought about lifters and was hopeful until I removed the valve cover and saw this setup.ThanksRayHave you checked the valve clearance on the rockers? I'm wondering if one might be a little out of adjustment, or possibly sticking when under a heavier load. Surely if one was slightly bent it would make the noise all the time and show up on a compression test. Worn valve guides would smoke on start-up.
Quote from: ray1377 on November 30, 2022, 07:13:29 PMQuote from: mobilehomer on November 30, 2022, 12:28:40 PMCheck the exhaust manifold to the pipe bolts. They could be loose or the donut could be missing.Thought of that, but wouldn't the exhaust be kinda loud if it was leaking?Not necessarily. A leak that is just beginning will not be heard at low power needs - idling, level road and such. The higher the power outpput(engine strain), the more it will leak. The longer you go, the larger and louder the leak gets. Been there, done that. And yes, it sounds exactly like a valve tick, but it ain't.Think of it like this, PCP limit of 3000 psi. It leaks down to 1250 and holds. Pump it to 2000 and it leaks silently back to 1250. Then pump it to 3000 and you can hear it. Until the o-ring goes, then you can hear it leak down to almost zero.
Didn't the coat hanger melt after awhile? Or do you have some of the 'Gettin Rare' metal ones?
Upload the video and post a link so we can hear it.
Quote from: mobilehomer on November 30, 2022, 09:11:31 PMQuote from: ray1377 on November 30, 2022, 07:13:29 PMQuote from: mobilehomer on November 30, 2022, 12:28:40 PMCheck the exhaust manifold to the pipe bolts. They could be loose or the donut could be missing.Thought of that, but wouldn't the exhaust be kinda loud if it was leaking?Not necessarily. A leak that is just beginning will not be heard at low power needs - idling, level road and such. The higher the power outpput(engine strain), the more it will leak. The longer you go, the larger and louder the leak gets. Been there, done that. And yes, it sounds exactly like a valve tick, but it ain't.Think of it like this, PCP limit of 3000 psi. It leaks down to 1250 and holds. Pump it to 2000 and it leaks silently back to 1250. Then pump it to 3000 and you can hear it. Until the o-ring goes, then you can hear it leak down to almost zero.I actually in a fit of desperation mounted a go-pro camera under the hood and drove the truck trying to pinpoint the sound. And oddly enough the exhaust header didn't sound any different when under load so I'm sorta ruling out exhaust issues at this point. For all practical purposes the engine is smooth and quiet except for the knocking or pinging sound it makes under a load. What I find interesting is how the sound goes away when you push on the gas and accelerate more. Was wondering if low fuel pressure would cause a lean condition thereby making the engine knock under load? Seriously thinking about checking the pressure with a gauge. ThanksRay
Quote from: ray1377 on November 30, 2022, 11:21:28 PMQuote from: mobilehomer on November 30, 2022, 09:11:31 PMQuote from: ray1377 on November 30, 2022, 07:13:29 PMQuote from: mobilehomer on November 30, 2022, 12:28:40 PMCheck the exhaust manifold to the pipe bolts. They could be loose or the donut could be missing.Thought of that, but wouldn't the exhaust be kinda loud if it was leaking?Not necessarily. A leak that is just beginning will not be heard at low power needs - idling, level road and such. The higher the power outpput(engine strain), the more it will leak. The longer you go, the larger and louder the leak gets. Been there, done that. And yes, it sounds exactly like a valve tick, but it ain't.Think of it like this, PCP limit of 3000 psi. It leaks down to 1250 and holds. Pump it to 2000 and it leaks silently back to 1250. Then pump it to 3000 and you can hear it. Until the o-ring goes, then you can hear it leak down to almost zero.I actually in a fit of desperation mounted a go-pro camera under the hood and drove the truck trying to pinpoint the sound. And oddly enough the exhaust header didn't sound any different when under load so I'm sorta ruling out exhaust issues at this point. For all practical purposes the engine is smooth and quiet except for the knocking or pinging sound it makes under a load. What I find interesting is how the sound goes away when you push on the gas and accelerate more. Was wondering if low fuel pressure would cause a lean condition thereby making the engine knock under load? Seriously thinking about checking the pressure with a gauge. ThanksRayYepQuote from: anti-squirrel on November 30, 2022, 01:58:33 PMQuote from: Privateer on November 30, 2022, 01:05:23 PMThe X-75? Those had a limited production run of 1200!BSA/Triumph went Bankrupt the next year.I've only ever seen the Prototype in Pickerington, Ohio.On the Nissan? Autozone can plug into the ODB port and see if any trouble codes show and that's free.I worked with my Dad for years in his Garage but when things went to computers? We couldn't afford the equipment so only worked on older stuff.Now days? I have software and hardware and can completely hack my vehicles!The local Autozone near me doesn't have a scan-tool that can read OBD1 codes- they can only do 96-later OBDII; with this being an 87 D-21, it might be a matter of test-light+ paper-clip and count flashes.I'm still leaning toward doing pressure- and leakdown-tests, but they are solid trucks. I owned a D-21 during my Navy days and the only problem it had was a fuel pump relay failed- it did make a ticking noise before it failed completely- contact were crusty and it was only when you stomped the pedal that it happened (like heading up toward Snoqualmie Pass coming out of Federal Way. After replacing the relay, I went through all the ground connectors and replaced several that were nasty, as well as both main terminal lugs. I swear I got about 10-15 horepower back just cleaning up the grounds. It definitely improved drivability.Worth checking pump/pressure and your fuel pump relay.
... at this point I'm wondering if horse and buggy might be the better option. I'd be good with that, I have no place to be in a hurry.