Old engines vs new

Why does an older enginr(class 8 diesel) vibrate more than a new(newer) motor, same manufacturer?

i.e. what changes are happening as an engine ages/wears that increases vibration/shake?

thanks gary

Reply to
gary556
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Better motor mounts - and truck shock absorbers?

If nothing else, less wear on the rings and better valve adjustment.

Reply to
RAM³

Ignition might be less effective on older engine (missing "bangs" leading to more shakes)? Something out of balance? I had a blade come off the fan at speed on a truck once - the resulting vibration was astonishing.

Reply to
Jordan

I would first investigate everything that surrounds the engine, for poor damping and resonance.

i
Reply to
Ignoramus8092

Probably several things , like motor mounts, cab mounts and such. The fuel injection system has a lot to do with it. With age the injectors and the fuel pump wear. The cylinder balance changes and you have irregular fuel outputs to each cylinder. New engines which are more stringent emission wise are new and have more exact fuel outputs , thus a smoother engine. Once had a new Mack exhibit right front tire imbalance. Replaced tire and rotor. Nothing helped. Around 45 mph the truck would start vibrating. Pulled injection pump and the fuel balance was off. The engine would rock in it's mounts giving you the sensation the right tire was bad.

Reply to
Mike

Reply to
JR North

Reply to
wayne mak

snipped-for-privacy@hotmail.com wrote in news:nr6l42dk9piggu2iph2vtpks8ofqqjd92q@

4ax.com:

Much tighter tolerances on the parts, including balance influencing issues such as piston and connecting rod weights and clearances. There has been a large jump in injector technology, meaning better atomized fuel. The EPA regulations have required a change to a much higher compression ratio, and this has resulted in basically a brand new design of the engines from the ground up. In order to take the increased loads, all the other parts of the engine have to be beefed up, which damps vibration. Gone are the aluminum pistons with a cast ring insert, replaced by, at first a 2 piece steel/aluminum skirt piston combination, and as the latest round of EPA tightening came into effect, an all steel piston. There is another round of EPA tightening due this year, which will require changes beyond that as the diesel manufacturers again bump compression ratios in order to clean up exhaust emissions.

The side benefit to all of this, is a more powerful engine that uses up to 20% less fuel than it's predecessors.

Reply to
Anthony

Reply to
wayne mak

My dad's 63 190d had (from memory) a cr of 21:1. Are today's diesel engines any higher?

Reply to
jtaylor

Seems rather obscene to say the EPA is driving such improvements(?)

Reply to
Dave

Electronic Fuel Pump instead of mechanical ? New Dodges have that and are quiter than their older counterparts,

Reply to
Mike

Totally different fuel system: High Pressure Common Rail - the same basic system used on the Navistar [Ford] and Isuzu [GM] light diesels and not applicable to the engines used in a Class 8 [Peterbilt, Kenworth, Volvo, Freightliner] truck.

Carbon buildup, ring wear [non-uniform compression loss], uneven rod bearing wear, bad valve timing from extended Jake-brake use ... any/all could be factors in addition to motor-mounts and, even, front shocks.

Reply to
RAM³

"Dave" wrote in news:1145795896.721699.324220 @u72g2000cwu.googlegroups.com: to 20% less fuel than it's predecessors.

Nope..tis the fact of the matter.

Reply to
Anthony

"jtaylor" wrote in news:IHJ2g.19222$ snipped-for-privacy@nnrp.ca.mci.com!nnrp1.uunet.ca:

Yup. But, I am not sure of the exact number. The change to a special steel alloy was to prevent melting of the piston at the much increased compression ratios.

Reply to
Anthony

diesel

Steel pistons ? - that's a new one for me !

AWEM

Reply to
Andrew Mawson

Looking at the caterpillar site their engines seem to have around 17-18:1 but they're also turbocharged.

Reply to
J. Clarke

"J. Clarke" wrote in news: snipped-for-privacy@news2.newsguy.com:

Yup...been that way for a few years. Like I said, at first it was a 2 pc steel crown with an aluminum skirt. Now they are 1 pc steel.

Yes, and they run quite a bit of boost.

Reply to
Anthony

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