Inline VS Bent engines

Few differing opinions seem to have surfaced, not only here but on other auto forums.

From what I've gleaned, ideal layout seems to be 6 cylinder-5 main bearing crank?
As far as internal balance etc seem to be concerned.
When you get into the 'Vee' engines, the bent 8's -12's - even the V16's get a nod.
Yet early days, the V16 Caddy's and Duesenburgs had troubles with vibrations.
Maybe they were simply better if kept as a lower revving engine?
Look at a lot of the V16-V20 locomotive or ship engines, ticking over at low revs, seem to be reliable with few problems.
Pointed out here on this forum, just how smooth the V12 Jaguar motor is.
Could be mistaken, but wasnt that the engine you could place a coin on the air cleaner, give her full noise and the coin didnt move?
The V12 ( as well as the V16) screamers have been around for ever it seems, maybe not the most economical, but high up on longevity.
Incedentally, and someone would be able to correct me here, I reckon I read somewhere that a 12V71 road truck application running N55 squirters, compared to an 8V71 with the biggest injectors available, were pretty comparable economy-wise, dont know what HP the 12v was set at- 8v probably 318??
Huge difference in torque output of course, plus front axle weights.
But, I'm digressing, was just thinking more about the best balanced engine/ main bearing layouts??
Dave_64

Dave for me, I'd want 7 mains in an in line 6

Dave_64 wrote:

Few differing opinions seem to have surfaced, not only here but on other auto forums.

From what I've gleaned, ideal layout seems to be 6 cylinder-5 main bearing crank?
As far as internal balance etc seem to be concerned.
When you get into the 'Vee' engines, the bent 8's -12's - even the V16's get a nod.
Yet early days, the V16 Caddy's and Duesenburgs had troubles with vibrations.
Maybe they were simply better if kept as a lower revving engine?
Look at a lot of the V16-V20 locomotive or ship engines, ticking over at low revs, seem to be reliable with few problems.
Pointed out here on this forum, just how smooth the V12 Jaguar motor is.
Could be mistaken, but wasnt that the engine you could place a coin on the air cleaner, give her full noise and the coin didnt move?
The V12 ( as well as the V16) screamers have been around for ever it seems, maybe not the most economical, but high up on longevity.
Incedentally, and someone would be able to correct me here, I reckon I read somewhere that a 12V71 road truck application running N55 squirters, compared to an 8V71 with the biggest injectors available, were pretty comparable economy-wise, dont know what HP the 12v was set at- 8v probably 318??
Huge difference in torque output of course, plus front axle weights.
But, I'm digressing, was just thinking more about the best balanced engine/ main bearing layouts??
Dave_64

I think the coin trick was a Rolls Royce and the coin was a wooden thrupence, on its edge.

.
.Yep, i would go for the 7 mains for the straight 6 job,.............

Talking about engine vibrations ..........the most interesting one for me was a hot Mini we bought for my son many moons ago....
Before the 1275 Cooper s period .......this was a Cooper and the donk was a 1220 Mini.....
This was a Deluxe block,(i think).. staggered bored to accept Hillman Imp pistons, an 1100 crank. not sure what the head was ,
but had been fitted with that later extra head bolt like the Cooper S. a tube was fitted in the head, and a stud in the block.
Larger valves of corse .........Compression ratio was a bit over 10-to one..........
Sonig extracters , and a twin throat 45 mm side draft Webber and a BIG cam..............
We pulled the donk apart to have a look ,not realising what the hell it was at the time..........
My son was insistent that we get it fully balanced . And so we did..........
The before and after balancing was remarkable, at full noise or anything between the donk was so smooth , not a tremble at all............
Soooo, when engine makers assemble their donks there is a compromise between really good balancing and the cost involved.........
That is just one reason why a lot of engines seem to run rougher than they should.........
.................Billy................

Can remember the CRB at Syndal with new Louisvilles, 350 Cummins.
Whilst the 903 V8 sounded great and went well, IMO the Cummins 6
would have given better overall service. Better torque for a start.
Just an opinion, Paul.

In an automotive application if its an inline 6 is just taking up the space where a V8 or V12 should be but on two wheels theyre great, I love my Z13 and I certainly wouldn't kick a CBX out of my shed. As for the V12 GMs it seems that they were somewhat unreliable and prone to crankshaft breakage, on one of cunningstunts recent podcast a bloke that has owned a V12 from new said that the GM had been out of the vehicle for most of its life due to breakages and non availability of parts.
I would guess that the inline 6 being the predominant configuration in road transport possibly has more to do with packaging benefits that inherent design benefits.

Soooo, when engine makers assemble their donks there is a compromise between really good balancing and the cost involved.........
That is just one reason why a lot of engines seem to run rougher than they should.........

Billy, I've had the flywheel and pressure plate balanced on the bus (Isuzu 6BG1) and the tractor (Kubota 1.7l from memory). The differences are amazing as you said. When ever an engine is separated I would always suggest having the flywheel and pressure plate balanced. It's only about $200-$250

600 Dodge,
Have worked with a lot of 12V7's and only seen one crank break.
Happens when you let the clutch out at full revs on a large compressor.
Never had any parts supply issues for GM's
Cheers Steve

The most unusual Ive seen is the Packard V12 which has just 3 main bearings......if you ever watched the Addams Family on telly,they had a Packard "Twin Six" of around 1920.......Packard called the V12 a Twin Six.

Blackduck59 wrote:

600 Dodge,
Have worked with a lot of 12V7's and only seen one crank break.
Happens when you let the clutch out at full revs on a large compressor.
Never had any parts supply issues for GM's
Cheers Steve

Have a listen to Bruces podcast with Paddy Ward, number 29 I think, he talks about about the V12 and its reliability problems. Ive worked for several drilling companies over the years that had piles of broken V12s, probably why most of the gear had been repowered with V8s at some stage.