radiator hoses and there role in engine movement 2

[nickirby]

hello all, I'm new to the forums

my question is does the movement of a engine affect the rubber radiator hoses by bending or moving them?

 

[MintJulep]

Yes.

 

[SomptingGuy]

In more than one way...

- They can be broken.

- They can transmit vibration from the engine to the body.


- Steve

 

[ivymike]

and vice-versa, in some cases. The movement of a raw water pump may be affected by the mass of the hoses hanging from it.

 

[nickirby]

thanks for all the help, ive been kicking around the thought of making some custom mendel-bent metal tubes to replace my rubber ones but, i havent quite worked out all the bugs.

 

[SomptingGuy]

If you have access to a rolling road, take a look at what the engine is doing during a drive-cycle. The amount of movement is a real eye-openner.

- Steve

 

[MacGyverS2000]

Replace those rubber hoses with mandrel-bent metal ones and you're going to see a lot of fluids behind you in short order.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[ivymike]

just open the hood, get someone to hold the brake and load & unload the engine a bit as though trying to drive away. you'll see the engine shake back and forth under the hood...

 

[SomptingGuy]

... I forgot, automatic. You'd need three feet to do that with a proper car , hence my rolling road suggestion.

- Steve

 

[ivymike]

Steve, you forgot to suggest driving around with the bonnet removed.

 

[GregLocock]

If you want to get fancy, tape some paper to the rocker cover and set up a pen held on a frame that bolts to the body. BTDT

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[DanEE]

When copper radiators (or copper tank tops) were used, the inlet and outlet pipes were soldered in.. at the pipe entry on one side and very importantly, to the opposite wall... (obviously with a slot cut in the pipe for the water to enter/exit)..

The vibration transmitted through a regular, factory rubber hose was enough to break loose the entry solder joint, if the back wall solder joint failed and no longer supported the pipe. Learned this through experience..

Trailer towing is another example that can dramaticly change the dynamics of how the drive train moves in relation to the frame/body.

The additional mass of a trailer attached via the frame/body hitch changes the natural frequencies that the body tends to respond to over rough roads. Have seen a few cases where the difference resulted in engine/drive train developing a rather severe harmonic, bouncing totally out of phase with the altered (by the trailer) body movement, causing some rather dramatic excursions to the extreme allowed by the motor mounts.

 

[patprimmer]

It is so obvious I can't believe we are still discussing this. Rubber engine mounts are designed to allow the engine to move. They typically allow up to a few inches movement at the thermostat housing at the extremes.

A metal pipe will obviously break, or it will break what it is attached to unless the pipe and everything attached to it is as strong as the engine mount or unless a flexable section is included to cover the movement and expansion.

Even without engine movement relative to the chassis thermal expansion will cause a problem.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[MacGyverS2000]

Pat, I guess this is what you get when non-engineering-related questions are allowed... ;-)

Dan - Owner

http://www.Hi-TecDesigns.com

 

[MintJulep]

I thought that my original reply said all that needed to be said.

 

[patprimmer]

Mint, I expected your perfectly correct and appropriate answer to be the end of it.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Rob45]

As an interesting side-light, I recently completed a powertrain transfer path analysis (source-path contribution analysis, as some call it) on a heavy truck, U.S. Class 8,
One unexpected finding was that our radiator stay rods, connecting the top of the radiator to the frame, are a major path for powertrain vibration into the frame, and thence to the driver's ear.

Few expected this, and some of the uninvolved still refuse to accept it (data notwithstanding) because there don't "appear" to be any connections between the engine and radiator - except for the radiator and intercooler hoses...

 

[evelrod]

Rob, I agree, you would think that radiator stay rods would have no part in audible body vibration and you would be wrong. Case in point: My 1930 Model A Ford Std. Coupe. When I first restored it in '89 it would shake like crazy and had a very loud 'buzz' ( a better term, anybody?) that was intrusive on the driver. First, new aftermarket rubber isolators at the bell housing and rear trans mt...No change in the buzz.---To shorten the story, several years later I forgot to hook up the radiator stays (bonnet was holding the rad) and, voila...NO buzz. When I found out what had happened, I used several common electrical grommets and, to date, no buzz. Fancy that.

Rod