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Engine mating.
morcus - 4/5/11 at 03:43 AM

This is theoretical but how difficult is it to put two engines together to make a bigger engine and whats actually involved? I'm not planning on doing this but I'm curious about it and was wondering if anyone could enlighten me? also what kind of effect does it have on power? would putting to of the same engine offer Double, or less, or maybe more? any ideas?

snapper - 4/5/11 at 05:02 AM

There has to be some physical attraction, engines don't normally mate in public, just put them together in a warm garage with fresh oil and some high octain fuel and let nature take it's course.

MakeEverything - 4/5/11 at 06:31 AM

quote:
Originally posted by morcus
This is theoretical but how difficult is it to put two engines together to make a bigger engine and whats actually involved? I'm not planning on doing this but I'm curious about it and was wondering if anyone could enlighten me? also what kind of effect does it have on power? would putting to of the same engine offer Double, or less, or maybe more? any ideas?


I would imagine that two engines sharing the same crankshaft would have the same HP but twice the torque. The difficulty is joining the shafts in such a way that they dont separate again, perhaps with some sort of flanged coupling. They need to be perfectly synchronised though.

britishtrident - 4/5/11 at 06:39 AM

Has been tried many times by many engine manufacturers including Rolls-Royce and BRM always ends in tears.
Usual cause of failure is torsional vibrations, massive can of worms.

britishtrident - 4/5/11 at 06:42 AM

quote:
Originally posted by MakeEverything
quote:
Originally posted by morcus
This is theoretical but how difficult is it to put two engines together to make a bigger engine and whats actually involved? I'm not planning on doing this but I'm curious about it and was wondering if anyone could enlighten me? also what kind of effect does it have on power? would putting to of the same engine offer Double, or less, or maybe more? any ideas?


I would imagine that two engines sharing the same crankshaft would have the same HP but twice the torque. The difficulty is joining the shafts in such a way that they dont separate again, perhaps with some sort of flanged coupling. They need to be perfectly synchronised though.



One of problems with doing it that way is the crankshaft of the engine at the transmission end is subject to twice the torsional loads it was designed for.

snapper - 4/5/11 at 07:01 AM

The twin bike engined Tigers had 2 engines with separate power feeds to a transfer box.
Rolls Royce had a twin 4 cylinder engine setup in a Fire engine that had the engines connected by the crankshafts, the engines were out of phase by 90 degrees this effectively inserted a power stroke between the first engines power stroke that made for a very smooth engine, low revving though.

Dingz - 4/5/11 at 07:44 AM

I remember Vauxhall building a Bedford truck with a widened frame and two 6 cylinder diesels along side each other linked by a morse chain and some sort of freewheel arrangement. The plan was to use 1 engine for light loadings then both for when extra was needed. Nice simple idea but don’t think it worked too successfully.

Liam - 4/5/11 at 09:10 AM

quote:
Originally posted by MakeEverything
quote:
Originally posted by morcus
This is theoretical but how difficult is it to put two engines together to make a bigger engine and whats actually involved? I'm not planning on doing this but I'm curious about it and was wondering if anyone could enlighten me? also what kind of effect does it have on power? would putting to of the same engine offer Double, or less, or maybe more? any ideas?


I would imagine that two engines sharing the same crankshaft would have the same HP but twice the torque. The difficulty is joining the shafts in such a way that they dont separate again, perhaps with some sort of flanged coupling. They need to be perfectly synchronised though.


Twice the torque = twice the HP (for the same RPMs).

As above never practical to just connect them in 'series' as one crankshaft has to handle the torque and torsional vibration of both engines. Better for both engines to drive a transfer box - essentially a diff in reverse. Not sure what they do in tractor pulling where they use several engines - maybe worth looking into.

britishtrident - 4/5/11 at 11:10 AM

Twin engined Tiger most famous for it spectactular self-destruct on Top Gear

daviep - 4/5/11 at 11:17 AM

quote:
Originally posted by britishtrident
Has been tried many times by many engine manufacturers including Rolls-Royce and BRM always ends in tears.
Usual cause of failure is torsional vibrations, massive can of worms.


Bit of a sweeping statement, the Detroit Diesel 16V71 (and many other Detroits) s simply two 8V71's connected together. These seem are both reliable and produced good horsepower for their size when they were current.

Davie

MikeRJ - 4/5/11 at 11:41 AM

quote:
Originally posted by daviep

Bit of a sweeping statement, the Detroit Diesel 16V71 (and many other Detroits) s simply two 8V71's connected together. These seem are both reliable and produced good horsepower for their size when they were current.

Davie


You mean literally two physically separate engines joined together? So it has two separate cranks with some kind of coupler, two separate cooling systems, separate cam shafts, two sets of timing gears etc?

EDIT: These pictures suggest a single common block and crank with what appears to be two cylinder heads. Hardly the same thing as two engines coupled together...

[Edited on 4/5/11 by MikeRJ]

daviep - 4/5/11 at 12:05 PM

quote:
Originally posted by MikeRJ
quote:
Originally posted by daviep

Bit of a sweeping statement, the Detroit Diesel 16V71 (and many other Detroits) s simply two 8V71's connected together. These seem are both reliable and produced good horsepower for their size when they were current.

Davie


You mean literally two physically separate engines joined together? So it has two separate cranks with some kind of coupler, two separate cooling systems, separate cam shafts, two sets of timing gears etc?

EDIT: These pictures suggest a single common block and crank with what appears to be two cylinder heads. Hardly the same thing as two engines coupled together...

[Edited on 4/5/11 by MikeRJ]


It's not a 16 cylinder block it's two 8 cylinder blocks which are joined together in the middle. The crank and camshafts are 1 piece.

The cooling system for each bank (4) is all connected externally

The 20V71 is made up from 2x 6V71's and 1x 8V71 all joined together, again it has a 1 piece crank and cam.

Davie

jacko - 6/5/11 at 07:33 PM

Years ago when i did car grass track racing a mate of mine bolted 2 Essex v6 engines together this car was very successful for about 4 race meetings then it ripped its self to bits l
We think if it had a clutch fitted in between the 2 engines it would have lasted a lot longer
Jacko

chrisxr2 - 6/5/11 at 07:43 PM

Isnt the clio v6 two engines mated together??

SPYDER - 6/5/11 at 07:58 PM

morcus - 6/5/11 at 08:04 PM

Is that a tractor delivering five engines or are they all plumbed in?

turboben - 6/5/11 at 08:45 PM

I think in tractor pulling the engine all run hydraulic pumps which drive a common motor. Might be wrong though...

Ninehigh - 6/5/11 at 08:50 PM

quote:
Originally posted by SPYDER


Find the misfire!

stevebubs - 6/5/11 at 10:41 PM

If separate engines driving a common drive train, look up Z cars....

The VW scene had a number of vehicles with an engine on each axle...