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General => The garage => Topic started by: Agreeable Slick on 12 November 2010, 08:50

Title: Interesting Question...
Post by: Agreeable Slick on 12 November 2010, 08:50
Now, then,

I got a question I would like answering. I have my theories, but I'm just interested to see what you guys come up with. So here it is, go crazy...

Q) What is the most critical, highly stressed component in an engine and why?

Title: Re: Interesting Question...
Post by: Wayne on 12 November 2010, 08:56
Cambelt

Think what happens when it breaks  :smiley:
Title: Re: Interesting Question...
Post by: raferackstraw on 12 November 2010, 09:05
i would have thought big end bearings

rotational stress and they are not a roller bearing  :undecided:  plus the stress from the moving the conrod n piston
Title: Re: Interesting Question...
Post by: cняis on 12 November 2010, 18:15
Flux Capacitor for obvious reasons.
Title: Re: Interesting Question...
Post by: sharki786 on 12 November 2010, 20:59
Flux Capacitor for obvious reasons.


 :grin:
Title: Re: Interesting Question...
Post by: tech1889 on 13 November 2010, 18:22
pistons for the temp they go through day in day out sometimes for like 6 hours none stop ??

failing that i would say fuse ??  :laugh:

Cambelt is a good contender but not in a non interference engine  :evil:
Title: Re: Interesting Question...
Post by: danny_p on 13 November 2010, 21:43
intresting question,   

if it can be counteds as critical i would say the accsesory drive belt . on some engines those belts have to drive a lot of ancillaries and transmit a lot of power.

or 2nd guess would be the turbo if in a turbocharged application
Title: Re: Interesting Question...
Post by: Diamond Hell on 14 November 2010, 12:26
The oil.
Title: Re: Interesting Question...
Post by: RTechUK on 14 November 2010, 15:14
Piston crowns, small end then big ends
Title: Re: Interesting Question...
Post by: Agreeable Slick on 14 November 2010, 20:16
The oil.

I'm kind of on this page as well.

Originally I thought possibly the crankshaft. Then maybe the valve springs due to heat and movement.

Then I thought cooling/lubricant system as it has so much to deal with. Heat, movement, forming a barrier between bearings (big ends) as a hydrofilm coating etc etc.

I am not sure on turbo's obviously there is a huge strain on them, but surely the oil is under even more strain then.
Title: Re: Interesting Question...
Post by: danny_p on 14 November 2010, 20:40
turbos run at etreemly high rpm so  there for the centripedal force trying to rip the inpellers apart must be really something and the exhaust side gets quite toasty.   and even the shaft between the inpellers has to transmit quite an amazing amount of power,  id don't think they stress the oil that much as the rotating parts arn't heavy and the core is often water cooled as well. so i would say the exhaust inpeller of a turbo is most stressed but there again there made of some fandango alloys so are they actualy that stressed compared to what they will take.

apparently the cams, tappets give oil the most stick in a modern high outpute diesel due to the shear forces it experiances when the cams trying to open the valve's against the pressure in the cylinder ( on a vag diesle anyway )

the most stressed part may well be engine dependant, on a rover fourum i bet the general consencus would be the headgasket was most stressed
Title: Re: Interesting Question...
Post by: Diamond Hell on 14 November 2010, 21:11
I'm kind of on this page as well.

And there I am - playin' to the crowd....
Title: Re: Interesting Question...
Post by: clipperjay on 14 November 2010, 22:02
The balance crank shaft, oposite rotational forces means alot of stress
Could be talking Bo*locks though...  :grin:
Title: Re: Interesting Question...
Post by: Agreeable Slick on 15 November 2010, 09:22
turbos run at etreemly high rpm so  there for the centripedal force trying to rip the inpellers apart must be really something and the exhaust side gets quite toasty.   and even the shaft between the inpellers has to transmit quite an amazing amount of power,  id don't think they stress the oil that much as the rotating parts arn't heavy and the core is often water cooled as well. so i would say the exhaust inpeller of a turbo is most stressed but there again there made of some fandango alloys so are they actualy that stressed compared to what they will take.

apparently the cams, tappets give oil the most stick in a modern high outpute diesel due to the shear forces it experiances when the cams trying to open the valve's against the pressure in the cylinder ( on a vag diesle anyway )

the most stressed part may well be engine dependant, on a rover fourum i bet the general consencus would be the headgasket was most stressed

This is what I mean. It doesn't state that there is a turbo present, but then there could be. It's quite a nice open question, so technically if you can justify what you are saying about each component mentioned in this thread then you could argue that you are not wrong.

Turbo speed ranges are quite rightly massive, 70,000-300,000rpm last time I checked. They are also made of very exotic alloys as you mention, i.e. titanium, and alloys of that. Even ceramics in some cases.