Thread: Solid Crank Pulley ....

4 cyl = pulse every 90deg
6 cyl = pulse every 60deg
8 cyl = pulse every 45deg

5 cyl = pulse every 72deg
A 5 cyl engine should be smoother than a 4 or 6

I don't know Kev, the M57 Diesel inline 6 in the L322 is smooooooooth....

Originally Posted by Tombie

And the less cylinders usually the worse it is....

4 large pulses vs 8 smaller ones per rotation

Just to expand on this, as Mike says, 4 cylinders are harsher than 8, add to that the Isuzu is close enough to 1L per cylinder. Which really increases its appetite.
Life's little ironies: The low down torque of the 4BD1, which makes it an exceptional motor for its applications, is what munches gearboxes.

Originally Posted by Fluids

4 cyl = pulse every 90deg 6 cyl = pulse every 60deg 8 cyl = pulse every 45deg 5 cyl = pulse every 72deg A 5 cyl engine should be smoother than a 4 or 6

Why is a 5 cyl smoother, and is the 60 degree v6 configuration help? Thanks.

Originally Posted by Tombie

And the less cylinders usually the worse it is....

4 large pulses vs 8 smaller ones per rotation

2 versus 4, unless it's a 2 stroke....

Hello,
Well it makes some sense of what everybody is saying that it absorbs the vibration of everything else. I was just cures I seem to have my answer thanks everybody for the replies......looks like a Ross HB is the go then.
Iain

A 4 cylinder engine pulses (fires) every 180deg of rotation assuming its a four stroke engine

I am still wishing I could shoehorn a 6v53T GM into a defender............ smooth,v6 grunt!!! The sound would just be an added bonus
"6v53 Detroit , turning diesel into noise since '56"

Originally Posted by Mick_Marsh

Nup.
Wouldn't a balanced harmonic balancer help prevent engine pulses? I'm sure it would for a petrol engine. What is different for a diesel?
I've not heard the term "`engine pulses" before. Is it a diesel thing?

smashing a gearbox bearing (7 bigish off site images)

The harmonic balancer isnt there to stop engine pulses (it can help though), thats the job of the flywheel, The harmonic balancer is there to absorb the vibrations and prevent harmonics from developing that can crack the crank and the bearings. initialy it wasnt needed due to the low speeds ad high mass of the crank and block but as engines lightened up it became a required evil. lts less of an issue now with modern design abilities but one of its second advantages of prolonging belt life keep it around.

Where you might be able to convince me to replace a dual mass flywheel in some circumstances unless you oly want a short duration high power high rev only engine you wont convince me to fit a solid pully in place of the harmonic balancer.