Dont' swap out your 8V-71N

[JohnEd]

TomC,
In a quest for a 8V71 engine to rebuild, how rare is the 8V71"A"?  I would think that that series would be worth looking for but I defer to you.  Also going with the "T" compression ratio?  Is that rare?  Many AT's out there?

Thanks,

John

[msheldon]

TomC,
In a quest for a 8V71 engine to rebuild, how rare is the 8V71"A"?  I would think that that series would be worth looking for but I defer to you.  Also going with the "T" compression ratio?  Is that rare?  Many AT's out there?

Thanks,

John

Hunh?

The T is for Turbocharged
The A is for Aftercooled

No need for aftercooler without the turbo, it cools the air coming from (after) the turbo.

[TomC]

Yes there were 8V-71TA's made straight from the factory, and with 80 injectors were rated at 400hp and 1200lb/ft torque.  I used the air to air intercooler since I didn't want to swap out my block.  It turns out that my engine is a late block that I could have added the aftercooler, but the aftercooler is very small, and can't possibly cool the air as effectively as the air to air intercooler.  That's why vertually all Diesels in vehicles now are not only turbo'ed but also have air to air intercooling since it gets the most cooling possible.  Good Luck, TomC

[JohnEd]

Msheldon,

The 2 cycle Detroit has a blower on top that Super Charges the engine and forces air through the cylinder on the exhaust cycle.  That blower, like any compressor, heats the air.  Hot air, like in humans, creates reduced power.  Detroit puts a "water to air" , read compact here, "AFTER COOLER" after the blower and before the intake manifold.  Because they install the "turbo charger" right up against the inlet to the blower, the stock configuration does not lend itself to adding a conventional "intercooler" to cool the heated turbo compressed air.  Detroit tries to do all the cooling of the inducted air that is heated first by the turbo and then by the blower by using a water to air "after cooler".  Aftercooler is designated by the "A" and I think all 92 series engines have a :A" suffix.  TomC and many others are the experts here and will correct me if I am wrong.  Anyway, they are where I got all this data and if I am wrong it is because I heard them with a crooked ear.  TomC has a modified engine with a "smoke turbo" and he installed an intercooler after the turbo and before the blower. 

Good luck and welcome to the board,

John

KEEP READING and asking questions,

John

[luvrbus]

I for one could never understand how a aftercooler on a DD could work anyway its no bigger than a auto heater core and has 185 degree water trying to cool air thats why i went to the air to air charger just my opinion

[JohnEd]

luver,

Those DD engineers were not fools, honest.  That little aftercooler is small but as a water to air it does better than an air to air.....for its size.  The intercooler does a lot more cause it is bigger but I won't rip out the aftercooler and reduce the overall air cooling out of spite.  They went to a lot of trouble and expense to incorporate that little cooler in the design.

I used to do equipment testing and analysis work for the Navy.  We strung thermocouple wires to every point imaginable in bays of equipment.  Thin little pairs of wire soldered together on the ends.  Stick them anywhere you want and measure the temp in there with a highly precise digital volt meter.  The wire is cheap and the voltmeter can be had these day for less than $30.  Put a union on top of the aftercooler and one below.  Run her up to temp and apply the load and read the heat.  I'm sure everyone would be fascinated with that data.  The same for the intercooler would really round the data picture right out.  I will do this a long while from today so your test results will be verified.

Food for thought?

John

[luvrbus]

John,i know they are not fools because they built a engine thats been around for 60 plus years,But i had a 1991 Bluebird that had a 525 hp 8v92 and it had a air to air not a aftercooler and it was new.I can tell a big difference in mine now with the air to air on it better fuel mileage and more power and a huge difference at night.In the later years of production this was offered on the 8v92 for highway use

[JohnEd]

Luvr,

Maybe that came out harsh.  Sorry if you thought I was talking down.  This print media is what I was told is "flat" and that that made a lot of stuff "sound" rude.   I don't need any more help in that regard and I wasn't being anything but humorious...honest    Of cpurse they were smart cookies

My mind is strictly MCI.  I think the DD that was ordered for their busses had a limited number of configurations.  Those are the only ones I have even the remotest info on and that is hearsay although by experts in their own right.  I have never seen a MCI with a intercooler that was stock.

They, DD, have a config of the 71 and 92 series for all sorts of stuff that I never heard of.  A miletary rebuilt caught my eye the other day and I learned that the thing made 900HP or some such foolishness.  I thought maybe the block could be used for a rebuild and then learned that the ex manifold and headers wrapped around the engine and draped across the back before going down.  I also heard of a version that has a turbo mounted on the side of the engine and that guy has an intercooler.  I was also told that that stuff was not made by DD.  Am I putting money on any of this...not on your life. 

Went sport fishing in San Diego a while back and the engines sounded familiar.  Yep, it was DD with blower and turbos and used the Pac Ocean to cool itself.  The skipper said each engine put out 1000 hp.  Fisherman do lie though, or so I'm told.  I kick myself for not thinking to ask if they were 71 or 92 series.

Are you certain that the Bluebird engine didn't have an aftercooler?

Thanks,

John

[muddog16]

There was a time when Detriot Diesel was having financial problems and about to do the unthinkable, a guy whom we have all heard of stepped in and saved DD with his expertise and money he turned DD around! Part of the deal worked out was for him to have the rights to all of the DD designs and plans. The funny thing was he excluded the 8v92, he didn't want anything to do with it! It was the only engine that did not interest him.  Detriot Diesel like many other companies made some mistakes along the way!  I know DD made tens of 1000's of these engines, shear numbers doesn't make it a great engine!  Oh by the way the guy's name was Roger Penske!

[cidermill]

TOM,

Hi there. A newbie soon to be 8v71T none after cooled owner here. Just wondered where to obtain and what brand air to air after cooler to go after. 
Wouldn't want the old bus to be just another (run of the mill). May as well make it kick and get.
D.

[makemineatwostroke]

Pat,working for DD from 1961 to 2000 the 2 strokes and the parts for them were never offered for sale but sold to Daimler a  couple of years ago as the parts was a 250 million dollar business alone and the 60 series was already out and running before Roger also Daimler owns 48.6 percent of Roger.the 60 series has been replaced now by the DD15 14.8 L just for information

[TomC]

For the air to air intercooler, I used www.sierratechnologies.com.

While the DD15 14.8L is going to be the replacement for the Series 60 14.0L, the Series 60 is still in production and will be until 2010. The Series 60 is just too reliable of an engine to stop production quite yet.  Good Luck, TomC

[makemineatwostroke]

Tom C i should have said being replace by the DD15 but i don't think the 60 will be around till 2010 but who knows for sure the way that Company management is  now

[uncle ned]

tom

   check your link for air to air intercoolers  I am looking for one for "huggy". but I don't need a protocol analyzer. have those

uncle ned

[JohnEd]

Cider,

Northwest salvage has intercoolers stacked in their yard(or did).  They are take outs from Marathon and Country Coach and others.  I don't know their price but their has to be a size in there you could use.  These guys have gotten more spendy lately and you might try making them an offer and waiting it out.  A friend told me they will give you 50% off if you spend a couple grand in there at one time.  They have a boat load of stuff and that wouldn't be hard for a conversion in progress.

I would definitely shop around the internet.  Course, that goes for any purchase.

Good luck,

John