ooooooooooo

engine clatter at high rpm?

Must fight the urge to post a pic of my other daily driver!
 
BSI said:
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?
Click to expand...

I got a 2019 model with 300 miles on it now. Drove it this morning and when I hit 40 mph the noise begun. Sounds like the 40 mph from speedo is tripping a what seems to be like a air valve open. I will jack it up and run it to 40 mph in next few days and see what is happening so we will know. Whatever it is it’s normal due to the 40 mph speed.


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This has been a forever topic in which has almost enough for its own website. I just finished a 20 mile ride and came home and washed it. The clatter always has me wondering as to everyone else. With all of the computer inputs and electrical bullshit that is now running everything , and nothing manufactured today can run without computers. I was wondering if the computer (ecm) is changing the valve settings at the 40 mile per hour mark?????? Possibly for better fuel efficiency. In which is creating the valve clatter? If I am correct with this clattering scenario then somebody had better send me some salmon. Let me know what you think. Keep on a rolling and a clattering.
 
I like your thinking but if that was true the clatter would go away with the speedo disconnected. I have disconnected my speedometer and the clatter was still there. No salmon for you!
 
It's possible there is more than one clatter being heard and discussed here. My 2018 has 3700 miles on it now. The clatter I am hearing is at higher rpm's not higher vehicle speeds. And it is definitely coming from the valve train. My warranty will run out in a couple of months, so sometime after that, I might experiment with different valve clearance adjustments. My guess is a slightly tighter adjustment than what the specs call for will quiet down the clatter. If you stop and think about it for a minute, you'll realize there is always a gap somewhere between the camshaft and valve stem. This would include the cam lobe against the face of the lifter, one end of the pushrod against the lifter, the other end of the pushrod against the rocker arm, and finally the rocker arm against the tip of the valve stem. At low rpms, the lifter might be riding smoothly around the cam. And then at higher rpms, the lifter might stay up in the bore as the valve is closing and cause no gaps from there to the tip of the valve stem but create a clearance between the lifter and the cam. And then as the cam lobe comes around again, it smacks the face of the lifter and causes a noise that wasn't there at lower rpms. Another possibility is the rocker arms might be moving side to side at high rpms but not at low rpms. If that is the case, adjusting the valve lash won't fix the noise. But a tighter valve lash might reduce any slapping sounds that move about between the different points in the valve train parts as the rpm changes.

Just some stuff to think about.
 
I really don't consider it as something abnormal. It's the noise a diesel engine makes at higher RPMs. Anyone remember the 7.3 Powerstroke diesels? My very first thought when I took off down the road on my new Roxor was how the rattle reminded me of that sound. In fact the noises this engine make remind me of a cross between the 7.3 and a little Cummins. Those old rattly PSDs ran FOREVER, clattering all the way. I wouldn't, and don't, think twice about the noises this little 2.5 makes.
 
The noises could also be coming from the injectors. Diesel injectors can be quite noisy. If so, that will simply be normal and nothing can be done about it. It's just a noise that you have to hear and live with. No big deal.
 
Mine has the 40mph rattle ...I dont even have to look at the speedo .When it hits 40 mph every time it starts ..sounds like a change in timing or fuel mixture ,it is not gradual ,it just starts at 40 mph ,I really would like to know what it is . I have 03 dodge diesel ,ford 550 diesel backhoe ,and yes they all rattle ...but this rattle is different, almost like a gear change ..but always at 40 mph. I have stock tires and auto trans .... its not valves ,temp,or sun spots ..wish i knew ....
 
mickeybobs said:
Mine has the 40mph rattle ...I dont even have to look at the speedo .When it hits 40 mph every time it starts ..sounds like a change in timing or fuel mixture ,it is not gradual ,it just starts at 40 mph ,I really would like to know what it is . I have 03 dodge diesel ,ford 550 diesel backhoe ,and yes they all rattle ...but this rattle is different, almost like a gear change ..but always at 40 mph. I have stock tires and auto trans .... its not valves ,temp,or sun spots ..wish i knew ....
Click to expand...
I finally got a roxor and mine seems to rattle when I need to shift gears/ while I'm shifting gears. Maybe different from what you are all experiencing. There's too much gear whine and wind howl at 40mph for me to hear anything but my shivering bones rattling
 
Cloud said:
I finally got a roxor and mine seems to rattle when I need to shift gears/ while I'm shifting gears. Maybe different from what you are all experiencing. There's too much gear whine and wind howl at 40mph for me to hear anything but my shivering bones rattling
Click to expand...

Put a Windsheld on it u will hear the noise at 40mph for sure they all do it no matter what gear. It’s triggered off the speedo.


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M151 said:
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.

View attachment 6151
Click to expand...
Did you ever find some specs for the valve lash, or make any adjustments?
 
I still cant figure out what the 40 mph+ rattle sound is ......believe its the motor not drive line ...went to taller tires ...still starts at 40 .....any ideas as i think all Roxors do this .....?
 
Mine does it as well. Every time I start off it goes from sounding very good and smooth to concerning at the 40 mph mark. My normally completely uninterested wife has even asked me what’s going on. It almost reminds me of when my newer JD tractors go into exhaust regen while I’m using them at high RPMs. I’m not sure how difficult it is to disconnect the speed sensor on mine (2019) because I’ve never needed to, but I may try it, just to provide another testimony here.
 
I wonder if it has to do with the speed limiter that is modified in a reprogramed a engine ECU(stage 1or2), as the factory speed limiter is around 40mph ? Anyone have the 40mph rattle with a stock ECU?....Oh inquiring minds still want to know .....
 
mickeybobs said:
I wonder if it has to do with the speed limiter that is modified in a reprogramed a engine ECU(stage 1or2), as the factory speed limiter is around 40mph ? Anyone have the 40mph rattle with a stock ECU?....Oh inquiring minds still want to know .....
Click to expand...
Yes. Mine would start right at 40. Same after the tune.
 
Mine does it too.
 
Ridem32 said:
Any updates on this 40mph clatter?


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Click to expand...
Call me crazy, I remembered having that same "clatter" but after a electric fan conversion that clattering went away
 
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