Here's a question for you. If you have an engine with a rough shake and the cowling is rotating left to right ( 9 to 3 oclock) a bit but still running smooth rather than up and down (12 to 6 oclock) what possible problem do you have and why?

The last time my cowling vibrated abnormally, a cylinder had sepated from the crankcase and a forced landing followed. That took place a few minutes after takeoff. The engine was running smooth despite its major dammage. I would take it seriously...

Reading this can not hurt as well:
http://www.tc.gc.ca/civilaviation/certi ... 007-02.htm

Get the prop balenced

Plug.

West Coast Swell wrote:Here's a question for you. If you have an engine with a rough shake and the cowling is rotating left to right ( 9 to 3 oclock) a bit but still running smooth rather than up and down (12 to 6 oclock) what possible problem do you have and why?

Seen this before on a Beaver.

It's like all of a sudden at a certain RPM right? I had one that did it at between 950 and 1000 rpm.

Tried everything to stop it, engine was smooth and prop was balanced.

The shake went away with a new engine and fresh engine mounts.

My advice, just keep it out of the RPM range where it shakes at all costs. It WILL start cracking cowling parts if left there a shakin' and scares the hell out of passengers.

Matt.

Check the engine mounts.. Might be time for some new ones...

Here's a different one for you - do all you radial drivers know what it means if your oil pressure drops from its normal level to a reading a few pounds lower and stabilises there? What is going on?

It's bypassing your screen that is full of chunks of engine so big you can read part numbers.

is that why it shakes? i don't think so.

buster79 wrote:is that why it shakes? i don't think so.

Reading the post above mine and maybe it will all make sense to you.... PAY ATTENTION CLASS!

xsbank wrote:Here's a different one for you - do all you radial drivers know what it means if your oil pressure drops from its normal level to a reading a few pounds lower and stabilises there? What is going on?

A lot of times it's just indication. But it's a good reason to stay near lakes if it isn't.

A lot of radials have seals and gaskets on oil galleries inside the engine that can begin to leak internally and cause a pressure drop. You'll never know because it won't leak on the outside.

Make sure there isn't a bird or something stuck in the oil cooler too.

Matt.

We replaced the engine at 850 hours T.T. ..... it doesn't shake any more!! Better safe than sorry.

I'm glad the problem was solved even though in a pretty expensive way. Do you have any hint of what the problem was by now?

Quite comen on the dhc2, Use the engine mount numbers from the otter andb your problem is solved. been doing this for thirty years and no more shakes. Try it. Dr.

Dr. Mcillicuddy wrote:Quite comen on the dhc2, Use the engine mount numbers from the otter andb your problem is solved. been doing this for thirty years and no more shakes. Try it. Dr.

Crap. I'm loosing my mind........ We also changed to Otter mounts in the DHC-2 when we changed the engine. I forgot about that That seems to solve it too.

Maybe it was you Dr. who suggested it