8v71 and 8v72 what is the diffrence???

[HighTechRedneck]

I'm still skeptical.  I tried a few google searches.

For the keywords 8V71 "Detroit Diesel" (a known valid engine) there were 748 results.
For the keywords 8V92 "Detroit Diesel" (another known valid engine) there were 9280 results.
For the keywords 8V72 "Detroit Diesel" (the one in question) there were only 3 results.

There are no references to any 72 series engines on the Detroit Diesel site (google:  8V-72 "Detroit Diesel" site:detroitdiesel.com yields no results)

Diesel parts sites do not list any series 72 engines.

There aren't any 72 series engines in this rather comprehensive list of Detroit Diesel engines.

It wouldn't make sense for one manufacturer to produce and maintain two different engine lines with only a one cubic inch per cylinder difference.

So, while I could be profoundly wrong, I don't believe Detroit Diesel made a series 72.

[DrivingMissLazy]

For the keywords 8V71 "Detroit Diesel" (the one in question) there were only 3 results.

Did you mean 8V72?

Richard

[tekebird]

Yep I call BullSh!t on the 8v72.........would even put a wager on it not existing.  There is no way DD would build an engine with 8ci more........it just doesn't make sense on so many levels.

The Navy used 8v71's and 6-71's which are both common marine engines

[bus05eagle]

the navy used alot of 6v53s the one eagle is talking about 283 hp at 2800rpm sure sounds like a 6v53 i never seen a 8v53 but i know they could get 400hp from the 6v53s and is a common marine engine

[HighTechRedneck]

For the keywords 8V71 "Detroit Diesel" (the one in question) there were only 3 results.

Did you mean 8V72?

Richard

Thanks for pointing that out.  You are right, that line should be pointing out that for the apparently mythical 8V72 there were only three google results, compared to the more typical hundreds or thousands of results for the known valid engines.  I have edited the post to correct it.

[TomC]

Detroit 2 stroke series made- 51 (made for a short time-no valves-just ports, didn't work well, were made in 2 and 4 cylinder), 53 series (2, 3, 4, 6, 8, 12 [2-6V's put together] cylinder), 71 series (1, 2, 3, 4, 6, 8, 12, 16 [2-8V's put together], 24 [2-12V's put together] cylinder), 92 series (6, 8, 12 [2-6V's put together], 16 [2-8V's put together] cylinder), 149 series (8, 12 [2-6V's put together although a 6V was not made], 16 [2-8V's put together}, 20 [2-6V's on the ends with a 8V in the middle-very strange-but worked!] cylinder.  The 283hp @ 2800rpm is a non turbo 8V-53, was used on boats alot-especially Hatteras.  Hard to find parts and had a weak gear train (weaker than the other 53 series that all had weak gear trains).  Would stay away from all 53 series-are loud and for our purposes, do not produce enough torque.  Even though the 6V-53 could put out 400hp, it only had about 650lb/ft of torque.  With that output, a 6-71 would be a whole lot more dependable, and could crank a 6-71 up to 2800rpm where it would put out 300hp.  Good Luck, TomC

[johnjem]

hi guys thanks for all the good info we all learned alot on this 1  i just got a email for the guy with the bus it sounds like a good deal like i said all i what is the motor here is the email u guys tell me if it sounds like a deal
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Hi John without digging out all the paper work and from memory the motor is an 8v71 it was out of frame rebuild about 110 to 120k ago it runs strong and when worm doesn't smoke it doesn't drip oil on a 2400 mi. trip it used 4 qt. of oil. the trans. is auto allsen v730 3 speed that was installed by a dealer in 97. there is a new radiator I installed in 2003 I have the repair manuals for the bus. it has a power teck diesel 6.6k generator a norcold refrigerator model N841.3 3 way 7.5 cu. ft. I just got a recall on the refer and once it gets a 1 year warranty there is a new magic chief stove 3 burner w/oven splendide 2000 washer/dyer 6 gal. hot water heater 2 13.5k roof ac. 90 gal. fresh water tank 90 gal gray/black tank charge wizard power converter this has a prosser in it so you don't over charge your house batteries there is a full size sleep# bed remco power w/heat mirrors peninsula windows all round I still have one in the box and many other parts that I can't think of right now. $8000 firm Russ
That was the email   tell me if it sounds good john

[johnjem]

also keep in mind i will be parting out the bus it is a 1950s gm 4906   ?on the 6

[tekebird]

4903 or 4905.......neither of which are 50's buses but rather 60's/70's/80's

[bus05eagle]

Tom they also made a inline 6 110 it was used in the AC HD20 dozer and for heavy duty trucks

[TomC]

You're right about the 6-110, but forgot about it since it was only an off road engine.  Interestingly, the first series had a gear driven turbo supercharger, then later had the familiar roots blower.  Good Luck, TomC

[RJ]

JohnJem -

Ask this fellow for the VIN on the bus you're considering, that will tell us a whole lot more.

[NJT 5573]

John. Why would you go to all this trouble if your engine just needs a set of rings in one hole? Is this the engine that had a recent rebuild and had a piece of ring in the pan? Why don't you treat this like its a fleet engine? Is it using enough oil to come out of service? Is it missing? Does it have bad blow by? There are places in the 71 where a broken piece of ring can hide from a rebuilder for a long time and fall in the pan when it gets good and ready. I have been told you can rering a 71 from the oil pan if you turn the crankshaft just right, (slide the rod and piston out the bottom). You can do this your self, pull the cylinder inspection covers and determine for sure you have a broken ring and what cylinder, pull the pan, unbolt the rod and bad piston and slide it out. Inspect the piston, if the ring lands are still in spec, rering and reinstall. Pan gasket and rings around $100. I've been told Trailways and Greyhound would put used pistons from one engine into another and put a bus back on the road. If you have a broken compression ring, it does have more than one compression ring. If you have a broken oil ring, it could still be doing a fair job of oil control, depending on how its broken. I hope this unit wasn't out of serviced because a piece of ring was found in the drain oil, because that doesn't prove much. If you pull the pan and roll the engine thru, you can check all the liners for scoring, if you don't find a real bad one, I think you will be happiest with a cheap fix.