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Topic: Vibration, how much is to much? (Read 865 times) previous topic - next topic

Vibration, how much is to much?

Just got back from a trip where I had another driver so I could check things out in back going down the road.  First thing I noticed, the engine noise in the bedroom with the new resonator is LOUD.  But then, I don't know what it sounded like before.  What concerned me though was the amount of vibration in the floor at the foot of the bed.  I would not have expected that.  Anybody have any suggestions?
1996 U270
Build #4846

Re: Vibration, how much is to much?

Reply #1 –
Our coach has stock exhaust, engine, insulation, and decoration. There is carpet on the floor and lots of fabric in the bedroom. It is NOT a pleasant place to be when the engine is running. When the coach is rolling at 65 mph, there is a lot of noise and vibration in the room.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Vibration, how much is to much?

Reply #2 –
When I first got my coach it had the original tires on it and there was lots of vibration over the wheels.  Put on new tires and it went away.  I think you could sleep just fine when running down the road.  I would look at the tires first.  Tks DAN
Dan & Shirley Stansel
2002 U295 4020 AGDS Build#6054
Towing Buick Enclave & M &  G Braking
Emerald Bay, Lake Palestine, Texas
MC# 16650

Re: Vibration, how much is to much?

Reply #3 –
Hi Gayland,
  I can sleep well in the bedroom going down the road. It is louder than the front. It is warmer than the front. I found it so easy to catch a quick nap. I must like the sound the red head Cummins makes. 1997 U 320.
Raymond
Raymond & Babette Jordan
1997 U 320
1998 Ford Explorer XLT

Re: Vibration, how much is to much?

Reply #4 –
check tires then look at mountings for exhaust, do you have solid ones or with vibration damping on them--important
John
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Vibration, how much is to much?

Reply #5 –
Tires are new, exhaust is loosely hung.  I have notices a slight vibration in the steering wheel when pulling a grade, goes away as soon as the road levels out.  I'll check the u-joints but can't imagine they'd go bad after only 130,000 miles.
1996 U270
Build #4846

Re: Vibration, how much is to much?

Reply #6 –
Did the vibration suddenly start? When you installed new tires? Vibration at idle? John has a good point about the mounts. Also should check that no part of the exhaust/resonator touches the body. That will make lots of vibration and noise. Fiberglas panels can act like a piano sound board with the exhaust pipe touching them. Engine torque can sometime make the exhaust shift enough to touch the body.

Other possibilities are, damaged fan blade on hydraulic fans, vibration dampener at end of crankshaft, U-joint, Allison transmission or retarder problem.

If you crawl under the rig, you may be able to spot a problem. U-joint if dry could be failing. Check for red rust dust around the joint caps. Would indicate a dry joint. Well lubricated joints should last longer than 130K.

You can rule out tires if it goes away while pulling hard at lower speed on hills. Vibration in steering wheel that stops when you level out could be a clue.

Very difficult to describe (and diagnose) vibration/noise intensity with words on the forum.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Vibration, how much is to much?

Reply #7 –
You may wont to check the Torque on the Roloks. Gam
joseph gambaro
1999 U295 36'

Re: Vibration, how much is to much?

Reply #8 –
I don't think anyone mentioned checking the shock mounts.

I can nap very comfortably with my Detroit running down the road. It's a little loud in the bedroom but no appreciable vibration.
The selected media item is not currently available.Kent Speers
Locust Grove, OK
1993 U300 SSE 40' (Restored at FOT 2009) Build 4323
720 watts Solar
6V92TA DDEC Silver Engine
2014 Subaru Outback

Re: Vibration, how much is to much?

Reply #9 –
Quote from: Kent Speers –
I don't think anyone mentioned checking the shock mounts.

I can nap very comfortably with my Detroit running down the road. It's a little loud in the bedroom but no appreciable vibration.

Yes, any place on the rig where there are rubber mounts to isolate vibration are good spots to check. Found a new one to me on the vehicle front of the Allison.

Like a sewing machine. 2 cycle so the 6V-92 fires each time the piston comes up plus no additional minor pulse to cause vibration from the scavenge stroke that 4 cycles have. Even smoother than a 12 cylinder 4 cycle.

Imagine a Fairbanks-Morse submarine opposed piston 2 cycle diesel from WWII. Two opposing crankshafts, no cylinder head, no valves. Combustion takes place between the two pistons as they come almost together. See: Tugboat Enthusiasts Society for great photos, cutaways. 

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Vibration, how much is to much?

Reply #10 –
I'm with the folks who think a trip under (after installing safety blocks) is in order.  Might want to check the wheel lug nuts, look for broken welds, missing or loose nuts on the suspension, leaking shocks, bolts and mounts.  If you can't find anything, maybe the tires need balancing.
Jerry Whiteaker former owner 96 U270  36' #4831 Austin,TX-Owner Mods LCD TV w/front cabinet rebuild - LCD TV bedroom - Dual Central AC, either can cool coach w 30 amp - Skylights at roof AC openings - Drop ceiling for ducting of AC - Shower skylight white gelcoat/wood/epoxy frame - Air Springs/Shocks replaced - 2014 CRV - 8K Home Solar - Chevy Volt

Re: Vibration, how much is to much?

Reply #11 –
Having used "the facilities" while underway, I have not noticed an increase in vibration or noise at the back of our coach since changing out the OEM exhaust for the Aero 5050XL muffler/resonator.

-M
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Vibration, how much is to much?

Reply #12 –
Thanks for the thoughts.  As Pierce said, hard to describe a vibration in words.  Since the only detectable vibration I'm talking about here is felt in the floor and not the whole coach shaking I'm going to move some of the ideas to the bottom of the list for now.  Will get under and check the drive shaft first and go from there.  I have no idea when it started, only when I began to notice it, so have no base line to compare to.
1996 U270
Build #4846