Warning RE Turbo Charged Vehicles

[robin craig]

I think this is the best place to post this, but correct me if I am wrong.

 

My mind was jogged by reading another thread here and hope that this post might save someone grief if they are a newbie to turbo charged vehicles.

 

This was some information that I already knew but thought that others should be aware of.

 

When transporting a turbo charged vehicle one should always ensure that the exhaust is EITHER facing backwards or that the exhaust is covered ie with a glove or rag and tapped in place.

 

The reason if you have not figured it out, hence you have got this far, is that because some of your valves will be open the is a good chance that the pressure of air forced through the exhaust pipe will start the turbo spinning and without the engine running there will be no oil supplied to the turbo bearings leading to premature failure of the said turbo.

 

Hope this helps someone

 

R

[Topdog]

I would be surprised if the airflow would turn the vanes at all, let alone resulting in any speed which would cause damage. Bearing in mind that the oil is needed when they are turning at many tens of thousand rpm and at high temp.

The flow has got to work its way through the exhaust baffles, up the manifold, through a max of a couple of small valve openings, through the inlet manifold, turn the turbo vanes and presumably out through the air filter.

If folkes have experience of it - then ok - but I would be surprised.

Dave

[robin craig]

Well sir, I beg to differ. The Canadian Forces had an issue early on the service life of the AVGP fleet that was traced to exactly this issue. Bear in mind during long distance transport a we have over here there is a real risk.

 

Even when such mundane items such as our turbo charged TS 90 tractor goes an hour and a half off site for major repair they always cover the exhaust for that reason.

 

An ounce of prevention is better than a pound of cure.

 

Any of the reccy mechs care to chime in on this?

 

R

[gritineye]

I saw a long discussion on a wrecker forum a while ago about this, especially when recovering trucks with high exhaust stacks, covering them was an insurance requirement I seem to remember.

[Ed Batchelor]

When I worked at JCB this was always a consideration although I never thought you would get much vane spin as there ought to be a lot of back pressure, on a diesel engine there isnt much valve overlap like on a wild race spec engine so always wondered where the air was supposed to be going to allow vanes to keep spinning. When inlet valves would be open, surely exhaust would be closed and vice versa, so no throughput of air possible due to ram effect.

[Topdog]

Well sir, I beg to differ. The Canadian Forces had an issue early on the service life of the AVGP fleet that was traced to exactly this issue. Bear in mind during long distance transport a we have over here there is a real risk.

 

Even when such mundane items such as our turbo charged TS 90 tractor goes an hour and a half off site for major repair they always cover the exhaust for that reason.

 

An ounce of prevention is better than a pound of cure.

 

Any of the reccy mechs care to chime in on this?

 

R

 

Robin,

I bow to your knowledge.

 

Regards

 

Dave

[phil munga]

This happened to a large cat loading shovel on delivery , on a lot of turbo charged vehicles the exhausts don't need baffles because the turbo muffles quite a bit to start with , they tend to need strait through pipes so the exhaust is just a drilled pipe with a larger surrounding pipe ( Like the one that was made for the early Dennis on here ) then take into consideration valve overlap , exhaust and inlet can be open together ,

then if you think how a venturi works or small hand held sand blaster , or under seal gun , it does not always need to have flow through just turbulence

[rambo1969]

Another thing to remember is to let the turbo slow down before swiching off.

[Tony B]

I was told treat an engine like a horse, warm up slowly cool down slowly. Classic lesson for me was the Dodge, at Iperes. Back up to coast at full chat about two hours in hot summer. Oil pressure at idle down to about 20lb, temprature up. Fortunatley I had the sense to allow her to idle. After three or four minutes, oil back up to 40lb Temp to normal.

[phil munga]

Can still remember the squeal from the neighbors large ford ( think it was TW series ) ran out of diesel at nearly full throttle whilst ploughing , the turbo squealed to a stop ,the neighbor new from the sound that it weren't good , when he restarted to move on with a few revs you could clearly hear the turbo screaming ,,

by the time he got back to the yard about 1/2 mile it was bellowing out clouds of smoke and he had to stall the engine as it was running on the oil being pumped up to the turbo ,,,

I had one go through not changing the oil ( famous words I'll do it next week ) strange thing is it was making a great sound before it went , when it did go it sounded and felt as though someone had hooked a large chain onto the tow bar

[Tony B]

Memories of whack the govenor open on a cold morning, start it up and let it roar! Oh what's the bang! :-D