syn oil not good for older engines

gsxr1100 · Aug 5, 2004

that is weird. I design parts of aircraft engines and we always use "race track" seals. This is just a groove around the housing to cover and it is like a 0.100 width & deep with small rads in the corners to prevent maring of the seal.

The o-ring material is cut to length and pushing into groove. It compresses like 20% of it when it is mates and torqued. Since the o-ring seal is very large you can have a larger profile when maching. When the machines today I do not think it is because of tolerances. More a crappy design if you have problems. Our designs go through a lot more testing then cars or diesel engines. O-rings are the way to go if you select the correct material from the start.

slowrev · Aug 5, 2004

Another question on Synthetic oil. Does anyone make straight weight synthetic oil ? I make no claims to being an oil expert, however I think I am talking about the base viscosity. ie 30 w 30 /forums/images/graemlins/smile.gif
The multi viscosity oil requires additives that change the viscosity with temperature changes. However these additives seem to wear out before the rest of the synthetic oil.

slowrev · Aug 5, 2004

Mike,
"O-rings are the way to go if you select the correct material from the start. "

You are probably right, For most applications O rings will work fine if they are correct for the application. As I stated before the O rings coming from Japan and the eastern areas seem to be substandard.

However don't aircraft engines require more inspections and routine maintenance than tractors and auto's ? Are there scheduled replacement of the O rings is I guess what I am trying to say ?

Ben

gsxr1100 · Aug 5, 2004

No inspections or routine maintenance on the parts I make. I design only the "computer" with all the boards assemblies that control fuel, and avics. They do have fuel running throught to cool and must ahear to vib, thermal, salt spray, nuclear testing, etc. They only get new seals when the parts or assemblies inside get changed. Other then that, they could sit there for thousand of hours.

Now some parts of the turbine do go in for inspection. What gets me is that people think jet engines do not break or break less often because of better designs etc. I would not say that. The kicker is after so many hours some parts are replaced no matter what. If working or not. They have to when moving people onboard. The best is that military planes have more backups then commercial planes. ...go figure.

slowrev · Aug 5, 2004

Mike,
So the O rings you deal with are not subjected to hot oil or 200 degree F temps for all of their life ? Just dust and water type of seal ?

The O rings in the engines might be changed on a routine basis ?

Ben

gsxr1100 · Aug 5, 2004

Oil, not really unless an oil/hyd line breaks. They are tested to pass though. These units can come in contact with very high temp (way over 200), water, fuel, and pressure at 35K feet.

As far as o-rings in the engine. I would have to ask the engine side. Mostly if something is leaking internal, they will replace the main assembly of the leaking parts. They really do not replace every little part. There are maintenance hogs in this way.

Soundguy · Aug 5, 2004

( true, does it have some, yes..all product do )

Yep.. marketing is reraching every corner of our life.

( Also I would also look at more then copper and chrome in oil tests on the big guys )

We get the full work up.. moisture included. Right now, for the purpose of this sub though I was mentioning copper and chrome for our mains... but yes.. there are tons of other wear-metals between the diff and the tran and the engine.

( I do not think some petro oils can handle the higher temps. )

I agree.. That is one of the more valid arguments 'FOR" synthetics... better pour point when cold, and more resistant to thermal breakdown .

The big trucks get away with alot of this due to the huge sumps you point out. Our mack haeld 10-12 gallons of oil...

Soundguy

Soundguy · Aug 5, 2004

( Soundguy, My earlier post was not meant to be sarcastic )

Cool.

( ut rather a cheap shot at Mobil for their disclaimer. )

I imagine it is their legal dept. standing in the way of product development / usage info provided by the 'hands on people'... reminds me of product liability laws.. and how scared of them most companies are...

( As for the guy with the old Ford, I would think that the oil he uses would be the least of this problems! Oops..there I go again )

One things for certain.. even jiffy store 88 cent a quart plain 30wt oil from today has got to be better than the routinely used oils back in 1939 when the first ford N's rolled off the line.

Soundguy

dass · Aug 5, 2004

You got it ! Most of the big corps. have more staff in the legal dept. than they do in R & D.

slowrev · Aug 5, 2004

"I agree.. That is one of the more valid arguments 'FOR" synthetics... better pour point when cold, and more resistant to thermal breakdown ."

With the synthetics ie 5 w 40 , the base viscosity is 5 right ? So if the additives give out that cause the viscosity to increase as the temp gets hotter then you only have 5 W oil at high temps too or something less than 40w. Is this correct ? If so this is a very valid argument for not extending the oil change intervals because you are using synthetic.

Also are the viscosity modifying additives the same in synthetic and non synthetic oil ?

Just trying to get past the hype and down to reality on synthetic oil.

Ben