6v71 info

[SEmerson]

A freind of mine is looking at a bus with a 671 in it. it is a 83 with a alison. How well do thay last? and what should we look at? Are the alison differnt? Like lock up and over drive stuff?



Thanks for any info

 

[Ray Torresdal]

6-71 or 6v71?

V or inline? The inline will go a long time - turn the rpm up, and let it scream!



Ray

 

[nickleinonen]

bus' usually have the 6v71 engines, the inline is too long for the bus... [but if i could get my hands on one of them 6-71's... ]

 

[SEmerson]

It is a v

 

[MPBerk]

We use twin 6-71 inlines, naturally aspirated in our 52' Motor Lifeboat (MLB) used for extreme heavy wx towing and SAR operations. We call it the "Sea Tractor", its a TORQASOROUS! :--) Easy to maintain and run.



If you can find a newer turbo'd model... . get it... ... .

 

[SEmerson]

Any v info and alison?????

 

[Philip]

From what little I have been around these little V6 "screamers" they last a long time. The one area to think of is how much care was taken in keeping the antifreeze at the correct ph. If it wasn't taken care of then you can have the water in the air box syndrome. This is cavitation induced liner replacment.



The other thing I would suggest is getting the Detroit air shut off to go on top of the supercharger.



Those year model trans didn't have OD's or lockup converters as far as I know.

 

[Speedo]

6V71s

A lot of the 6Vs in buses were low performance, they used 2

valve heads and small injectors. If this was a transverse mount

the Allison was probably a V-730 (700 series, 3 speed) the engine

should also be equipped with a throttle delay which will slow the

throttle response terribly until the oil gets up to temperature. It

will most likely have crosshead pistons and if multi vis oil is used

in these 2 strokes it will take out the slipper bearing. Cavitation

problems with the liners is non existant with a 71 series engine

as they are a dry liner. I remember one of ours had over 400,000

miles on it in transit service which is equal to well over 1,000,000

miles in open road service.



Gus

 

[V6power87]

Gus, what is a slipper brg. ? So that is why you should run straight 40w?

 

[Speedo]

slipper bearing

Sorry, I haven't been back here in a couple of days. On the cross

head pistons the wrist pin doesn't go through the small end of

the rod, the rod is bolted to the wrist pin. the crown and skirt are

held together by the wrist pin and the the crown has a bearing in

the top half of the wrist pin bore and that is known as the slipper

bearing. The crown is cooled by oil going up the center of the rod

through the wrist pin and slipper bearing. If the slipper bearing

goes bad it will move from its location and cover the oil hole. The

crown gets hot and seizes in the liner and often it will pull the

liner in two. The use of multi vis oil will cause a premature failure

of the slipper bearing.



Gus

 

[Blakers]

One thing good about these Detroits is they are cheap to rebuild.

 

[SEmerson]

Well now that I gathered info on the 671 it looks like he will be getting a 8v71 or a 6v92t. 2 differnt bus he is dealing on.

 

[Blakers]

I've heard the 6v92 has lots more torque than the 71 series. They said it actually pulls like a 4 stroker.

 

[QRTRHRS]

Originally posted by Blakers

One thing good about these Detroits is they are cheap to rebuild.

Driving down 301 one day in North Carolina. Two men parked along the side of the road with their GMC crackerbox cab lifted. Got one of the heads off the old 8v right there. Not a shade tree in sight.

 

[HoleshotHolset]

Our very own Deo Read "TheRabbitTree" is very knowlegeable on the Detroits... . he had at one point - 2 of the 6V-71's (one was a 600hp+ race engine... ) and 2 6V-92T's at his house... .



"Diesel" Doug Doring (www.teamdiesel.com) has a lot of insight on the Detroits as well... .



Matt

 

[therabbittree]

close holeset but my smaller 6v's were 53 series. . i sold the race one and i have 1 1/2 of another in pieces at my parents garage ha they were so kind as to let me store the two 6v92 silver turbos in the driveway ha. . heck they even went out and build a small metall shed to cover them and my 545 allison. . so it looks clean and doesn't **** off the town or the neighbors ha. . they sound cool and if you set the rack and govenor up differnrt they have very good throttle response ha... im kinda saving teh two 6v92s to make a 12v92 . . although that is a long ways away. . ha. . or find a older truck ie a single axle b model mack or brock way and drop one of th e6v92s in to it turned up of course with a 10-12' dump on it ... yes sir 400 plus horspower and a jake in a little runabout dump ... smiles

later

Deo

\x/ hillfolk!

 

[MCummings]

Hey,, My Dad has a 6-71 (straight 6, supercharged, non-turbo)



How to turn them up? It is listed as "industrial" on the ID plate, and I think it's ~250HP I'd like to bellow some smoke when throttling up,, and maybe a Few RPM if it's safe.



Anybody have some links,, or a Detroit 101 BOMBing guide?



I'd really appreciate it.

Merrick Cummings Jr

 

[HoleshotHolset]

I've never messed with one... . but I do know if you go to far with the governor/rack you'll wish you hadn't messed with it in the first place.



Guillotine air shut-off valves are VERY important on these things... .



Deo - my bad... . I can never keep the 53/71/92/149 - series straight... .



Matt

 

[Johnboy3]

We have a couple of them. A 6v72 and a 6-71 both have blowers and turbos. I actually like the v way better then the straight 6. It seems to run a bit better although both of them are pretty skeered of big hills.

 

[SEmerson]

Well I test drove 2 busses for him. Both with 8v71's non turbo. What slugs. 1 had low oil pressure and smoked. The other ran good but the trans seemed confused on a 2 gear shift. Both are 1979 city busses and have 600k on them. It looks like the engines had been out. We are going to test a few 6v92 turbos 1980 and up next. I am hoping for a lot more power.