Engine Mount Question

[JSutton1]

Hello everyone. New Member to the forum and RVing.

I have been restoring a 1985 Vouge 37' RV for the past two years. Things are coming together and we have begun camping close to home while I work out more issues.

The Vouge has a 8.2L Detroit Diesel pusher engine and a Allison transmission.

Here is my question:

When going up hills, placing a load on the engine, I expirience a "shaking" in the steering wheel. I am trying to locate where that is coming from and am now wondering if it could not bad engine mounts. Here is more info:

1. I dont think it has to do with the wheels or front end as it only shakes when engine is under load.
2. The steering is hydraulic and the lines are 37' long. I thought it could be possible that this was the cause, but have examined pump (ok), and plenty of fluid. I thought maybe the overpressure valve in the pump could be oscillating. Also fan runs off hydraulic.
3. My girl friend did say last time that she could feel the shaking under her feet. Thats why I thought it could be related to the engine.

I attached some pics of the RV and one of the engine mounts. The rubber of the mount is pretty squished. Also under normal load I really dont feel any noticable engine vibration.

These mounts look flimsy to me. Any recommendations?

Thanks for any help.

Jim

[TQ60]

Mounts are somewhat simple to test.

Place park brake on and have helper press on brake pedal.

You observe mounts as helper places in drive and applies pedal then reverse.

About the amount you would press in a parking lot.

If a mount is failing it will allow engine to lift.

Could also be poor cylendar performance under load but check mounts first.

[JSutton1]

I'll try that.

Considering performance, are you suggesting that placing the engine under heavy load would expose a weak cylinder that would unbalance the engine and cause it to vibrate?

I have looked at the engine, and I am looking to get some more power out of it. It runs pretty well, typical dd smoke on cold start, but nothing noticable while driving it.

[TQ60]

Yes a load will expose weak things.

Back in 70s had a 67 f100 with 300 six.

Ran great on flats but up the grapevine the trucks were passing us.

Bad spark plug wires fixed that and it ran much better.

Gas mpg did not change much...just the reserve power.

If you have something that is causing a loss of available hp it is only going to raise its ugly head when that hp is needed.

Checking mounts is easy and takes little time and not much engine...gentle on the pedal.

Seek advise of the dd folks as many folks here have past lives with these engines and there are likely to be some tips and suggestions.

Turbo boost and air filter and a handfull of other common things to check.

Maybe describe your power plant...

Engine is dd something cant remember...

Turbo?

CAC intercooler?

[Skip426]

Those mount cushions are oil soaked , and I'd say probably the least expensive and easiest fix to try first.

[JSutton1]

Where would I look for cushions like that?

[Engineman3rd]

I would check the Belt tension for the Hydraulic pump. It may be slipping under heavy load.