Low turbo on a DD V-6 in an MC5c

[Craig R]

Does anybody know how one set of the hardware for a 12V71TA -- one of the two manifolds connected to one of the two turbo's that is powered by one of the two cylinder banks . I recall having heard that the 12V71 is two 6V71's put together. It seems like, if the intake manifold for the front OR rear 6 cylinders would fit on the Roots, the turbo would end up hanging off the near side and fabricating pipe from the far exhaust manifold would finish the job. 

[chessie4905]

The 12v71 used a one piece block, unlike the 12v92.

[Detroitenginespecialist]

RJ,
American Fleet Inc in Springfield Missouri has 2 cycles cores in stock.  Place a order and the engine usually ships out 3-4 days later ready to just drop in and go.  Give me a call and i can quote you whatever you need.

[Craig R]

... with a low-slung turbo, Detroitenginespecialist ?

So, could one of the two manifolds from a turbocharged 12V92 be used on a 6V71, chessie4905? ... and the 12V71TA still looks like it has two manifolds.

[luvrbus]

The 12v71 does use 4 manifolds or 2 singles either one all turbo models including the 92 series use the same 2-1/2 in ID manifolds not the 3in ID from a N/A engine.

You can buy what ever you want from Diesel Pro new but at a cost.I don't quite figure this out surely you know one just doesn't slap a turbo on a 6v71 and call it good    

[Craig R]

  Tell me more, Luvrbus ! I mean about "one just doesn't slap a turbo on a 6V71 & call it good". I was looking at an industrial 6V71TA for sale (with the turbo on the top, of course). The local mechanic I've been talking to leans toward converting my naturally aspirated engine. Either way, I need to push the turbo down over the side. Can one use a 12V* manifold and/or ducting to move the turbo from the top of a 6V71 to the side? If so, and if you start with a 6V71TA, do you need to replace the manifold ... or just the ducting?   I'll be very grateful for any insight you can offer.

[luvrbus]

Top mounted turbos drain the oil back through the blower you will need a different air horn and plug the oil drain hole then you need the drain adapter for the turbo to drain into the engine , some how I missed the buying of a industrial 6v71T engine. Finding a 2 piece manifold off a 12v71 is going to be nearly impossible there was only a hand full of 4 turbos 12v71 ever made

[eagle19952]

there was only a hand full of 4 turbos 12v71 ever made

We had a few of them on 48" hydro-static test back in 1974-75..iirc 

[Craig R]

Nope, luvrbus. You didn't miss it; I didn't mention it.
The local mechanic wants to start with the N/A that's in the bus now and I was focusing on the locating of the turbo on the side -- whether it was relocating one on a TA or hanging a new one on a former N/A.
I'm gathering from your reaction that trying to convert a naturally aspirated engine into a turbocharged one ain't the way to go.
Do you know how I can identify the stock parts and where I can get the specialized parts needed to relocate the turbo to where it hangs on the 12V71 or 92?
Being on the side, Do the 12V turbos have that drain adaptor you spoke of?
Thanks!

[Craig R]

4-turbo 12V71's sounds like two turbos per bank or one turbo for each three cylinders. The one I saw being fired up on a U-Tube video had one turbo hanging off each side -- one appearing to pressurize the front six cylinders (front three of each bank) and the other appearing to pressurize the back six (back three of each bank). I wonder if a person could bolt one of the air horns from a two-turbo 12V71TA to the intake manifold of a 6V71TA to mount one turbo beside the V6 engine.

[bevans6]

Here is a pic of how I did the manifolds on my 8V-71T to put it in my MC-5C.  You could do the manifolds on your 6V-91 exactly the same if you wanted to.  FWIW the blower intake cover I "cut-and-shut" from the stock one that came with the engine, and Tig welded it together.  I got the height wrong by 1/4" which I discovered when I first tried to install the engine, I had to take it off and take a bit off the top...   

I bought tube bends from a specialty racing supply house that did the tight radius mandrel bent bends (constant diameter in the tube, no wrinkles), I used 16 gauge tube, and I bought the stainless steel vee band clamp fixtures to join the pieces together.  Material cost was around $800 delivered to my shop in Hamilton Ontario at the time.  I added a slip joint in the section that goes across the front of the engine, it wanted to move too much with heat cycles.  I built it to fit together with perfected fit, the first time I took it off after running the engine it had moved a bit and wouldn't go back on!

Cheers, Brian

[bevans6]

The military 8V71t I started with.  Note turbo is hung off the back, where the accessories attach on an MCI engine.  The military engine had no accessory drives at all, just covers over the holes.

Brian

[Craig R]

So, these are before & after pictures, bevans6 ?
Thanks   

[bevans6]

Yes, the first set of pictures are during the conversion process, when I had just finished roughing in the intake and exhaust manifolds.  The second two are when I was picking it up from a farmer's shed, where it had been stored for many years.  It was a NOS rebuild, zero miles on it, originally a NATO engine for a M110 self propelled howitzer or a variant thereof.   The story is here:  http://www.busconversions.com/bbs/index.php?topic=21836.0

Brian

[Craig R]

Well, fellas, a funny thing happened on the way to enlightenment! I took my little flashlight and peered into the engine compartment of my MC5c at what i believed to be a stock naturally aspirated 6V71; staring back at me was an air shut-down housing with an inlet fitting pointing toward the side. A guy recently told me that the shut-down housing on every V71 has the same bolt pattern. Maybe I'm well on my way to hanging the turbo off the side of the 6V71TA I'm trying to replace the NA engine with ... what do you fellas think? What does any of you know about this?