engine clatter at high rpm?

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M

M151

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I've considered extreme advanced timing or excessive fuel rail pressure? Without a laptop with software we may never know?
 
Semperfi

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I have been a diesel mechanic since 1982 worked on heavy equipment in USMC and post. Has me fooled, my philosophy is, if it aint broke dont fix it! But this does drive me nuts!!!! I still think its in the valves.
 
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I have been a diesel mechanic since 1982 worked on heavy equipment in USMC and post. Has me fooled, my philosophy is, if it aint broke dont fix it! But this does drive me nuts!!!! I still think its in the valves.
That should be easy enough to diagnose with a section of rubber hose and an assistant to slowly bring up the RPM's. I suppose weak springs could cause float at the higher RPM's where these engine seem to like to make the clatter.
 
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I have mentioned this in the past, as my machine makes the clatter sound any time speed is over 40 mph. RPM makes no difference, the key factor is 40 mph and over. I can push in the clutch and coast at or above 40 mph, it will clatter, even at idle.

On the other hand, if I disconnect the speed sensor at the drive shaft, the clatter above 40 mph doesn't happen. Anytime I want to drive
around without the above 40 mph clatter, I disconnect the speed sensor at the front of the rear drive shaft. Nice diesel purr.

My clatter is purely related to the speed of the machine being over 40 mph, and the speed sensor being connected. Why the clatter happens only with the sensor connected is a mystery to me. Nobody has been able to explain it to me either. The best explanation I've been given is diesels make strange noises, "do not worry about it".

Sure seems like we can do better than that?
 
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"On the other hand, if I disconnect the speed sensor at the drive shaft, the clatter above 40 mph doesn't happen."

Interesting? That seems to suggest the speed sensor is somehow affecting engine timing and perhaps rail pressure? I do know this, forget dealer support, at least in my case. I realized that the day I purchased it.
 
Kake America

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I have a stage one tuning done by hardcoretuning.com with the boost valve. The first thing is temp, if the engine is cold it is much louder. For me, it seems more related to throttle position. Under full throttle it is there in pretty much all gears, but if I don't floor it or back off the throttle the sound goes away. Some smoked salmon to the first person to come up with a workable solution!
 
Semperfi

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Man, I wish it was easier than that to get smoked salmon. I mean really, I thought we were friends. ha ha. Keep on a rollin!
 
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I have a stage one tuning done by hardcoretuning.com with the boost valve. The first thing is temp, if the engine is cold it is much louder. For me, it seems more related to throttle position. Under full throttle it is there in pretty much all gears, but if I don't floor it or back off the throttle the sound goes away. Some smoked salmon to the first person to come up with a workable solution!
Again - it's a normal sound on this type of engine. Quit "looking for problems" Worst case scenario is usually a loose nut behind the wheel :unsure:
 
Semperfi

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WOW!!!!! I think I will try to tighten that loose nut behind the wheel. That should resolve the issue with my clatter also, that may or may not be NORMAL!!!! Sounds like he is a pro and he sounds normal too!!! Keep on a rollin and a clattering!!! Issue resolved send him some salmon. If you dont like the issue or want to discuss it then log off!
 
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I thought " unhooking the speed sensor makes the 40+mph clatter go away", would be the key to figuring out the cause. Has anyone else tried it and found this to be true?
 
Kake America

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I think I will have to give it a shot, I mean why not. This nut only plans to get looser by the way!
 
Semperfi

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Tighten it up my friend, and try some Loctite. Good smoked salmon is tough to get here. I think I deserve some! Keep on rollin and a clattering.
 
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I'm with you, just don't want to be accused of being wound too tight.
This nut is shooting for a happy medium. Trying to figure out the clatter.:giggle:
 
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WOW!!!!! I think I will try to tighten that loose nut behind the wheel. That should resolve the issue with my clatter also, that may or may not be NORMAL!!!! Sounds like he is a pro and he sounds normal too!!! Keep on a rollin and a clattering!!! Issue resolved send him some salmon. If you dont like the issue or want to discuss it then log off!
Hmmm.... looks like I hit a nerve. Caps, multi exclamation points - the works. Point is, for those not used to being around diesel engines the noise, clatter or however you want to describe it is normal. Remember this engine is derived from an industrial tractor design, not a modern passenger car. Also noises of all sorts are amplified in an open air vehicle as compared to an enclosed vehicle with all sorts of sound insulation. BTW It's not that I don't like the issue (I assume you meant topic) - just find it interesting that so many owners are trying to come up with a fix to a "problem" that does not really exist.
"the noise is inherent in the design of this power plant" And yes, after 45 years in the industry I guess I could be considered a pro :cool:
 
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"for those not used to being around diesel engines the noise, clatter or however you want to describe it is normal"

Agreed to a certain extent, but this engine does lose its hum, and not in a good way.

"I guess I could be considered a pro"

Pleased to meet you "pro", and you even threw in the cool shades emoji which somewhat negates all (caps and exclamation points) you crowed about.

"the noise is inherent in the design of this power plant"

Was not aware of that? Tell us why?
 
Kake America

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I love the sound of a properly tuned diesel, 8-71's sing when done right. While you bring up some valid points that these are designed for tractors, I still find the roxor rattle which is definitely there at or around 40mph very strange. No smoked salmon for you
 
Semperfi

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Well since I being a diesel mechanic since 1982, I guess your more pro than most. But other than computer controlled, and a few sensors, the diesel really hasn't changed much. I learned complete rebuilds on Detroits, and Cats. All of which were heavy equipment power plants, yes the newer stuff is much more refined with computer management, turbos and sometimes multi turbos, Blowers, or such, it is still air, fuel, timing and compression. So enough of the pissing match, were here to BLOG with each other, not to try to play the coolest and I am better than you. We all have individual opinions. Mahindra has had these in their modern passenger cars in India for years. And if you are as smart as you lead on to be, and I am not denying you of your professionalism, you would know that the diesel was derived basically from a GM 8-71 that originated from a generator. Oh by the way I have the original picture of my grandfather and my great uncle which were the first to put a Diesel on a 1945 McCormick tractor! And it was a GM 8-71- And no, they didn't patent it. But the tractor is in Waverly, Illinois and still runs in tractor and steam shows. I have all the documentation to back up everything I say. So, well maybe you have hit a nerve, but I would say by the responses that its more than one. Have a wonderful day. Keep on a rollin and clattering.
 
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Looking at the number of views shows more than a little interest in the topic. Not much for answers, unfortunately.
For the time being, I will just leave the speed sensor unhooked, so the Rotor purrs like my other diesel vehicles. I just won't know how fast I'm
going unlike my other diesel vehicles.
 
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Using some highly sophisticated diagnostic equipment (an ice scraper and section of 1/2"rubber hose) this noise/clatter appears to be in the overhead. There sure seems to be an inconsistency in the valve lash adjustment?

On the exhaust side seeing as high as .023 and low side .019 Have an intake valve at .021 I can't find anything on the adjustment specs? Typically .010 intake and .020 exhaust is a safe bet.

I would also note these checks were done on a fairly warm engine so cooling will increase lash.

Anyone have lash specs? Knowing where TDC is would also help. I am going to inspect the balancer and timing cover for marks.

Lastly, lack of oil on the overhead is hardly an issue. I did fire the engine with the cover off. It's a gusher.

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