Detroit Diesel 6-71 engined "MG" type Leyland Leopard - ex-CIÉ / Bus Eireann MG210 (1971)

1971 ex-CIE / Bus Eireann Leyland Leopard MG210 recorded in January 2003. Apologies for the lack of picture as I was trying to record the roar of the Detroit Diesel 6-71 engine which made these buses legenedary icons of the 1970's and 1980's. Listen to that inline 2-stroke roar as it shifts through the gears!!

The story behind the "MG" type buses is the stuff of legend amonst vehicle engineers in Ireland and UK, but to cut a long story short, due to failing Leyland engines and transmissions, CIE decided out of sheer desperation to re-fit almost 100 Leyland Leopard PSU5's with big-ass American 2-stroke engines & gearboxes, AKA: The Detroit 6-71 2-stroke inline-6. a gas-guzzling, ultra-loud, ultra-American engine! The GM / DD engines were used in trains and were widely respected as reliable engines by CIE engineers, and as a result, CIE believed that they could reduce their maintenance costs, by buying in bulk for their entire rail and road passenger services.

To perform this conversion of a Leyland Leopard, the CIE engineers would take a Leyland O.680 and semi-automatic gearbox out of a Leopard, throw them in a 1965 Leopard (upgrading an O.600 engine), cut out about 6 to 8 ft of the chassis rails, weld in a modifed chassis rail that would accomodate a MONSTER Detroit 6-71 (which is about twice the size of a Leyland O.680!), mate it to an Allison MT643 transmission, fit modified driveshafts, add in a cable-type gear selector, and after 3 months of work, you'd have a very, VERY different Leyland Leopard to what you'd find in the UK, or anywhere else in the world!

It was without a doubt, "an irish solution to an Irish problem" but despite the butchering of the chassis and a gut-wrenching engine/tranmission change, the MG's lasted on Expressway work until 1994 and on schools until 2001!! I seen the chassis work that was carried out on a scrapped MG type bus a couple of years ago, and seeing with my own eyes, the engineering carried out between the conversion years of 1978 and 1982, was nothing short of incredible

A cousin of the 6-71 as you hear in this video, was fitted to the KD and KE type buses, it was pretty much the same engine displacement, power, and sound, except it was a V6, not an inline 6. the TEC have an excellent video of preserved KE 35, which can be found HERE:
http://www.youtube.com/watch?v=7IBdZoE5H9Y

Category:

Autos & Vehicles

Tags:

• Detroit
• Diesel
• 6-71
• Leyland
• Leopard
• CIE
• Bus
• Eireann

[volker185]

On the introduction of this video it said DUAL EXHAUSTS. Mistake,or were there actually dual manifolds for 671 Detroits, or wre they home made?

[markthebusman]

@volker185 what introduction??! Also how could you have dual exhaust manifolds on an inline engine? Only get dual exhausts on a V engine. Are you sure your looking at the right video, buddy?

[mrspivvy]

That's something different- a leopard with a detroit! possibly the only engine conversion thats guarenteed to use more diesel than the original o.680!

[markthebusman]

Yeah, it might have used more diesel, but it lasted a hell of alot longer than an O.680 engine!

[irishmanufan]

is that something similar to a bomabrdier engine . it sounds it .

[markthebusman]

Yes it sounds and works pretty much the same (2 stroke diesel with a supercharger) but its a different design, KD/KE/MG bus had exactly the same displacement (436cu inch/6.9 litre) except this is an inline-6-71 engine, a Bombardier KD or KE was a V6-71

[chinitalokita21]

@markthebusman actually some of these did have 2 manifolds, one for the front 3 cylinders and one for the back

[markthebusman]

@danpower71 - I havent a clue what you are saying, English please!!

[icenijohn2]

3500 RPM! I don't think so.  71 Detroits can run up to 2300 RPM, but anything more will give them a very short life. My Crown's 6V92 is governed at 2100 RPM, which gives me 67 MPH with a 4.1 axle and 12R22.5 tires. Remember that a 6-71 at 2300 RPM will sound like a 4-stroke at 4600 RPM! Detroits love to run at WOT, and you won't hurt them running at governor all day long. Nothing kills them quicker than lugging them.

[volker185]

Check your videos. Lots of info on BACK DROP MANIFOLDS for Cummins 220 etc. This was a manifold made years ago by the ELLIS company. Allows for dual exhaust on in line Cummins. Also, something I have been trying for some time to find out ''Can you split an exhaust manifold on a non turbo 6-71 Detroit engine for dual exhaust ?''. I refer You to

MANCUB61081. Check his site and ask him this question. ''OLD IRON! GMC DIESEL'' video. Thanks for your reply.

[tpvalley]

I think the railways used the 149 series detroits in railcars and 567 upwards in locomotives, I could be wrong.

Quite narrow rev range detroits evidently, sound good, have a look at checkmate the tractor puller on youtube its insane.

[mrspivvy]

if you see much more than 300,000 miles from a detroit you're doing very well. they need constant revving which knackers them up quickly.