Obsure Engine

[Drew Dowdell]

There is an engine out there with 5 camshafts. It is a somewhat common engine, two or three may have even passed you on the road today. Sadly, it has mostly been ignored even though it produces large amounts of power compaired to other engines of this vintage. The 5th camshaft is somewhat vestigial and no longer serves it's original purpose, yet is still vital for the operation of the engine. What engine am I refering to? What is the purpose of the 5th camshaft?

[Drew Dowdell]

20 views and not a single guess?

[capriceman]

A Internation Diesiel 6.0 . the 5th cam is for the "Jake" brake or Motor Brake......... Its a guess

[Nick]

I was gonna guess the engine on a semi truck...

[Drew Dowdell]

No, much more "everyman" then that. It's a car engine. The cams on the 5th camshaft aren't there anymore. This engine was a major evolution on a previous engine design.

[Flybrian]

Eh. Why not? The 3800.

[Drew Dowdell]

Oh come on now. Does the 3800 have 5 camshafts.... or even more then one? Think about it.... why would a car have more then one cam shaft?

[Flybrian]

Oh come on now. Does the 3800 have 5 camshafts.... or even more then one?

Think about it.... why would a car have more then one cam shaft?

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But isn't 'the 3800' pretty much a universal answer to any engine question? :P

[ToniCipriani]

Honda VTEC? They use i-VTEC now so the 5th cam is gone? I don't know. Just an uneducated guess. I ain't no mechanic :P

[Drew Dowdell]

not even close.... The engine I'm refering to is a DOHC engine..... yet has 5 camshafts.... one of which no longer has any cams on it. Edited November 24, 2005 by Oldsmoboi

[capriceman]

A motorcycle engine with DOHC and the 5th cam is for The Oil pump...... Edited November 25, 2005 by capriceman

[Drew Dowdell]

Getting sooooo much closer. You are correct that the 5th camshaft is for the oil pump. This is definately a car engine. The 5th camshaft had cams on it in previous variations of this block, but in that configuration, the 5th camshaft wasn't the fifth, it was the first.

[Jamie]

It's pretty common for an engine that started out on the drawing board as a pushrod OHV engine and was subsequently re-engineered into a SOHC/DOHC engine to have a vestigial camshaft that is only used for driving the oil pump and/or distributor. For this trivia question, the GM 3.4L DOHC V6 would most likely be the engine that you are thinking about, but it's not the only DOHC V type engine with a vestigial camshaft.