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Heavy front vibration problem - Torsion Bars
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Author:  Daveinet [ Mon May 09, 2022 4:53 am ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

Austro-Revconeer wrote:
"Slantmobile" - because my Revcon has got an Oldsmobile engine? :lol:

I have asked Nick about the settings, let' s see what he writes back. ;)

Why are the specs different? Because of the smaller Olds engine - less front weight?


OK, so there is the flat nose Revcon, which is Olds. The slant nose was custom drivetrain with a 454 engine. The new body style was made to accommodate the new drivetrain, however they were not able to make the switch for a few years, so '78 is the new body, with the older drievtrain. So we have chosen to affectionately identify your coach as a Slantmobiile. I don't remember who coined that term, but it works, so it stuck.

As far as the difference, the drivetrain is quite different. Yes, the suspension is conceptually the same, but is much bigger and heavier. The drivetrain is very different, as the engine has the transmission behind it and uses a transfercase with a driveshaft running forward to a Dana 70 running in reverse. The axle tubes are cut off, so there are still half shafts and independent front suspension, but everything was custom built. They used wear parts common to other vehicles, but the A frames are custom welded assemblies. Because of the conventional orientation of the engine and trans configuration, I was able to swap out to a 502 and switch to a 4 speed trans.

Author:  Austro-Revconeer [ Mon May 09, 2022 6:18 pm ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

Thank you very much for your information.

My 1979 seems to be one of the last produced Revcons with the Oldsmobile UPP, which contains a wide roller chain drive and a final drive connected directly to the
transmission. Nice detail: The former owner of my Revcon ordered new drive axles for a 1978 Oldsmobile Toronado from Rock Auto and changed them twice in 20 years - they fit. Amazing, because they look so small an tiny. :lol:

Manufacturing date of my Revcon: April 1979.

They introduced the new drivetrain in March 1979 and it was available from July 1979 for the 30-foot Revcons.

I am just curious: Did Revcon also use stronger torsion bars for the Slant Noses in comparison to my Slantmobile?

Author:  Daveinet [ Tue May 10, 2022 11:53 pm ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

Everything is heavier in the later drivetrain. The front suspension is rated for 5000 lbs, so the torsion bars are bigger. There is a GMC shop here that has worked on a few Revcons. He was amazed when he saw the size of the front C-V joints. Apparently they are much larger than the Toro/GMC one he was use to seeing.
Most '79 year coaches were still Slantmobiles. Maybe 1/3rd of the '80 year coaches are still Slantmobiles. Pretty much by '81, those were all the later drivetrain. So the conversion took several years. The front suspension was designed by Peter Bryant - vise president of engineering for Revcon. He was an interesting guy. You can search his name along with Legends of Riverside on you tube to see some videos about him.

Author:  Austro-Revconeer [ Wed May 11, 2022 7:34 am ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

Thank you for the valuable information. I' m going to be at my mechanic's repair shop in about 3 weeks. Let' s see how the torsion bar exchange will work out.
BR
Matt

Author:  Austro-Revconeer [ Sun Jun 12, 2022 12:50 pm ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

Unfortunately, my mechanic was ill during May - probably Corona. He never sees a doctor, he always tries to recover with the help of home remedies...63 years old. From the old beat. Anyway, he was not able to work on the Torsion Bars. I' m going to be in Germany by the middle of July again. We have the plan to drive 2500 km with our Revcon this August. The time is running...

Author:  Austro-Revconeer [ Fri Jul 01, 2022 3:05 pm ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

Bad news from my mechanic concerning the GMC Motorhome Torsion Bars:

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Bar unloader in action R. Forum.jpg
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They DON' T FIT in my Revcon, because they are TOO LONG. All my research and caution was useless and I was not able to measure the length in advance. Just didn' t have the opportunity for doing it. Spent 2070,-- USD for the bars, freight to Germany and customs duty included. :oops:

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Torsion bars GMC and Revcon R. Forum.jpg
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But there is still hope...my mechanic from Eastern Germany - anybody else would have already given up this project a long time ago - wants to transfer the retainer of the torsion bars. If this works, the "good old used" GMC Motorhome torsion bars from Applied GMC will fit.

I wonder why Revcon used shorter ones. I think that maybe longer Torsion Bars are stiffer, this could be a reason for using them in GMC Motorhomes.

Well...let' s see how we can solve this problem. I still love my Motorhome. ;)

Have a nice weekend!
Matt

Author:  Austro-Revconeer [ Mon Jul 04, 2022 8:08 am ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

About 2 inches forward and the bars fit.

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Loosen two screws on each side.

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Must be modified.

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Author:  Austro-Revconeer [ Tue Jul 05, 2022 12:41 pm ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

Reinforced.

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Reinforced frame July R. Forum.jpg
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Adjusted.

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Torsion Bar project July R. Forum.jpg
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New pork chops. Now the GMC Motorhome Torsion Bars fit.

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Blue P. C. R. Forum July.jpg
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Author:  Austro-Revconeer [ Tue Jul 05, 2022 12:45 pm ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

What could be the correct ride height and how is it measured?

The 1982 Revcon manual says below:

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Front Suspension Manual July R. Forum.jpg
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But this is the past 1980 construction with the heavier front suspension, not the Oldsmobile Toronado FWD.

Can I use it?

The correct ride height for GMC Motorhomes is 26 Inch from the ground to the top edge of the front bumper,
but I don't know if the mounting height of the front bumper of a Revcon compared to a GMC Motorhome bumper is equal.

Author:  Austro-Revconeer [ Thu Jul 07, 2022 8:04 am ]
Post subject:  Re: Heavy front vibration problem - Torsion Bars

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