4LW heartbeat

[andyb116]

Have seen these Big Bang engines where 2 cylinders fire @ once, both petrol, and in race cars. One was a vauxhall 16V the other was a Suzuki hyabusa. Both had a very strange and unique sound. Was done by having specially made cam shafts done.

[mark99]

There's a fiesta on Utube modded - sounds great!.

 

http://www.youtube.com/watch?v=7BSKTooB4TY

 

Back to Gardners - 2LW = 1 crank rev per bang taking into account there are two cylinders - I'll need to check the manual to see timing diagram to be sure.

Edited March 5, 2014 by mark99

[MtB]

Thanks for the link Mark. Fascinating.

 

I guess the firing order becomes 1+4, 2+3, and yes they must sound really weird!

 

Not sure I fancy one in a narrowboat though

 

MtB

There's a fiesta on Utube modded - sounds great!.

 

http://www.youtube.com/watch?v=7BSKTooB4TY

 

Back to Gardners - 2LW = 1 crank rev per bang taking into account there are two cylinders - I'll need to check the manual to see timing diagram to be sure.

 

 

Yes on a 2LW there will be to bangs on crank revolution 1, then two absences of a bang on crank revolution 2. So an average of one bang per crank rev.

 

On the OP's 4LW the two 'absences of a bang' will be filled with two bangs from the other pair of cylinders so two bangs per crank rev.

 

That big bang Fiesta sounds like my Scooby. Being a Boxer format engine I've never thought through the firing order but it strikes me there must be a problem with balance just like on a twin cylinder, hence the distinctive noise.

 

 

MtB

[Timleech]

 

 

Yes on a 2LW there will be to bangs on crank revolution 1, then two absences of a bang on crank revolution 2. So an average of one bang per crank rev.

 

 

 

MtB

 

Correct, but it sounds like one bang every other revolution because the two 'bangs', or at least the exhaust pulses, blend into one except at very low speeds.

 

Tim

Edited March 5, 2014 by Timleech

[alan_fincher]

I feel I am detached from this thread.

 

When cruising our engine revs at something like 1100 revs.

 

Martyn

 

It's a bugger counting the bangs on those, even at tick-over, isn't it!

[David Mack]

 

Correct, but it sounds like one bang every other revolution because the two 'bangs', or at least the exhaust pulses, blend into one except at very low speeds.

 

Tim

Which is why slow-running 2 pot engines go b-bang b-bang b-bang b-bang

[mark99]

How many revs then here - 2lw on tickover

 

 

http://s844.photobucket.com/user/mark99_2010_01/media/VIDEO0073_zps7e62dc14.mp4.html

 

NB you should not count the valve movements as the camera phone can create a frame lag and bunches them up or misses one.

Edited March 6, 2014 by mark99

[Timleech]

about 350 rpm.

[MtB]

I reckon I can hear about three pairs of bangs a second. Twin cylinder engine so 180rpm

 

MtB

[mark99]

I counted 180 (30 in 10 seconds) so that's 2 revs per bang but there are two cylinders so thats actually 1 rev per bang = 180 revs per minute.

Edited March 6, 2014 by mark99

[Timleech]

I counted 180 (30 in 10 seconds) so that's 2 revs per bang but there are two cylinders so thats actually 1 rev per bang = 180 revs per minute.

 

No, as per my earlier post, you only hear one 'bang' every other revolution because the two are close together, with a long gap before the next, so 180 x 2 = 360.

 

Besides, a 2LW would not be happy at 180 rpm

 

Tim

[mark99]

 

No, as per my earlier post, you only hear one 'bang' every other revolution because the two are close together, with a long gap before the next, so 180 x 2 = 360.

 

Besides, a 2LW would not be happy at 180 rpm

 

Tim

 

 

No, as per my earlier post, you only hear one 'bang' every other revolution because the two are close together, with a long gap before the next, so 180 x 2 = 360.

 

Besides, a 2LW would not be happy at 180 rpm

 

Tim

 

 

Thanks for that Tim.

 

Vid is not good enough, otherwise count a valves opening movements in 10 seconds and *6 (gives per min) and then *2 (as 2 revs per 4 stroke cycle.

[jenevers]

What's all this talk about "bangs"? It's a Gardner not a Bolinder!

My 4LW does 110 "DUMS" per minute (at the exhaust), so thats 440 RPM, so the cranks rotates 4 times per DUM.

[RLWP]

so the cranks rotates 4 times per DUM.

 

In which case, you need a visit from an engineer, there must be something very wrong with your engine

 

Richard

[cereal tiller]

 

In which case, you need a visit from an engineer, there must be something very wrong with your engine

 

Richard

Must be an 8 stroke engine?

[RLWP]

Must be an 8 stroke engine?

 

With three cylinders not working

 

Richard

[mark99]

 

No, as per my earlier post, you only hear one 'bang' every other revolution because the two are close together, with a long gap before the next, so 180 x 2 = 360.

 

Besides, a 2LW would not be happy at 180 rpm

 

Tim

 

NB

 

If the first cylinder bang is at crankshaft position 0 degrees, when is the second cylinder bang if not at 360 degrees? ta

Edited March 6, 2014 by mark99

[RLWP]

 

NB

 

If the first cylinder bang is at crankshaft position 0 degrees, when is the second cylinder bang if not at 360 degrees? ta

 

180 degrees (how many cylinders do you have, and what shape is your crankshaft?)

 

Lister Petter:

 

 

Triumph twin

 

 

Richard

Edited March 6, 2014 by RLWP

[mark99]

 

180 degrees (how many cylinders do you have, and what shape is your crankshaft?)

 

 

 

 

Gardner 2LW - if one bang creates 720 degrees crank rotation before next bang on that cylinder (2 revs of crank) when does second cylinder bang occour - if it's 180 then that makes what Tim say logical - ie two quick bangs then a long pause (540 degrees).

[RLWP]

 

 

Gardner 2LW - if one bang creates 720 degrees crank rotation before next bang on that cylinder (2 revs of crank) when does second cylinder bang occour - if it's 180 then that makes what Tim say logical - ie two quick bangs then a long pause (540 degrees).

 

Like the first crankshaft picture. Cylinder 1 fires (BANG) while 2 compresses, 1 exhausts while 2 fires (BANG) , [end of first revolution] 1 draws (SUCK) while 2 exhausts, 1 compresses while 2 draws (SUCK), [end of second revolution] and repeat

 

Richard

 

MORE strictly speaking, you hear the bangs when the exhaust opens, but you get the idea

Edited March 6, 2014 by RLWP

[MtB]

 

Like the first crankshaft picture. Cylinder 1 fires (BANG) while 2 compresses, 1 exhausts while 2 fires (BANG) , [end of first revolution] 1 draws (SUCK) while 2 exhausts, 1 compresses while 2 draws (SUCK), [end of second revolution] and repeat

 

Richard

 

MORE strictly speaking, you hear the bangs when the exhaust opens, but you get the idea

 

On my Kelvin, you can clearly hear the 'donk' of compression ignition, out of phase with the 'dum' from the exhaust pipe.

 

Even so, each 'dum' on the 4LW must be an exhaust stroke so 4 dums per two revolutions of the crank.

 

I always fancied a three stroke engine, or possibly a nine stroke....

 

 

MtB

[RLWP]

Lenoir's engine of 1860 was a half stroke

 

Richard

[MtB]

Lenoir's engine of 1860 was a half stroke

 

Richard

 

I WANT ONE!!!

 

 

 

MtB

[Proper Job]

What you need is a straight 3

[MtB]

What you need is a straight 3

 

Or a single cylinder V engine....

 

 

MtB