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Author Topic: 6V71 or 8V71 ???  (Read 7696 times)

Offline RL

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6V71 or 8V71 ???
« on: March 14, 2013, 06:32:28 PM »
Newbie here; first post in topics.

A month ago I had never heard of a PD4106 and I had never thought of buying a bus converted into a motorhome. But a neighbor told me his health wasn't up to spending winters in his bus down south anymore and I ended up buying it. So I've been taking him out to Sunday brunches lately to ask questions about what I've purchased. This is the only question so far, and an important one, that we haven't been able to resolve. How many cylinders does the engine have?

He said it was a Detroit Diesel 6V71. I told him that everybody that I've either read or watched that has a 4106 states the engine is a 8V71. I said maybe there was a smudge on the 8 to make it look like a 6, but research has showed both engines were produced. The bus is 1100 miles south of me and I'm not getting the first face to face introduction till July.

Can anyone shed light on this subject?
1962 PD4106-1546, 8V71, Allison V-730
Birch Bay, Washington

Offline luvrbus

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Re: 6V71 or 8V71 ???
« Reply #1 on: March 14, 2013, 06:41:25 PM »
I have saw a 4106 with a 6v71 before the engine came from a transit bus not a factory setup as they were 8v71 8 cylinders
Life is short drink the good wine first

Offline gus

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Re: 6V71 or 8V71 ???
« Reply #2 on: March 14, 2013, 11:03:33 PM »
Sometimes 6V71s are installed in older GMs in order to make installing an Allison AT easier.

This is common when replacing the 671 in a 4104 or earlier.

If it truly is a 6V71 you have lost quite a bit of power from the 8V71.
PD4107-152
PD4104-1274
Ash Flat, AR

Offline HB of CJ

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A Quick Look Will Tell---Also Sound
« Reply #3 on: March 14, 2013, 11:26:19 PM »
Open the rear hatch and count the exhaust pipes coming out of the head.  If you have four per side, then you have a V8.  Also if the engine is running and you take the Bus Conversion out for a test spin, the sound the engine makes will tell you also.

The 6V71 sounds like...well...a six.  The V8 will sound like a V8.  The V8 will also have much more power, but if you have not yet driven a 4106, (fun!) then this may be subjective.  The factory engine in the 4106 was the V8.  A very powerful combo.

Through the years many different types of motors have been squeezed into that location, including Detroit 6V71s, 8V71s, 6V92's (a popular swap) or even, rarely, the 8V92.  Didn't somebody even once squeeze in a 903 Cummins V8?  Dunno.  HB of CJ (old coot)

Offline RL

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Re: 6V71 or 8V71 ???
« Reply #4 on: March 14, 2013, 11:56:20 PM »
It does have an Allison AT. So maybe a 6V71 was installed during the conversion.
1962 PD4106-1546, 8V71, Allison V-730
Birch Bay, Washington

Offline Utahclaimjumper

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Re: 6V71 or 8V71 ???
« Reply #5 on: March 15, 2013, 12:48:07 AM »
 You must really be into drama,, or it sold for a ridiculously low price... To buy a complex machine sight unseen when the owner isn't sure of what he's selling is asking for a major surprise,,,,I hope it's a good one, for you have LOTS to learn.>>>Dan
« Last Edit: March 15, 2013, 01:12:01 AM by Utahclaimjumper »
Utclmjmpr 
 EX 4106 (presently SOB)
Cedar City, Ut.
 72 VW Baja towed

Offline Runcutter

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Re: 6V71 or 8V71 ???
« Reply #6 on: March 15, 2013, 01:36:09 AM »
RL, welcome to the Board.  You'll find a lot of good experience here, and folks at all stages -- some new, some who've forgotten more than most of us will learn.  In fact, I learned something from the answers to your post -- I never knew of a V6 in an 06, but Clifford and Gus have points I never thought of. 

One of the things we often suggest, is to post your location, as well as the type of coach (see my signature as an example).  That way, when you get her home, you might find help nearby.  For example, I'm impressed that another new member just volunteered to help someone with radiator issues -- that's the kind of folks we are. 

If you post the location of the coach in question, there may be another member nearby that can go take a look.

Again, welcome.

Arthur
Arthur Gaudet    Carrollton (Dallas area) Texas 
Former owner of a 1968 PD-4107

Working in the bus industry provides us a great opportunity - to be of service to others

Offline RoyJ

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Re: 6V71 or 8V71 ???
« Reply #7 on: March 15, 2013, 02:02:25 AM »
Don't know if the 4106s ever came with a 6V71 stock, but I won't be scared of a coach (35' that is) with one either.

If you have one with an old conservative Californian transit tune (2V heads, 55 injectors, 2100 rpm) then it'll be pretty slow. But for RV duty, I feel it can be safely tuned up a bit.

Mine has 4V heads, 70 injectors, and I believe a 2400 rpm governor. Probably makes a solid 250+hp at sea level. My 35' Prevost weights 26500 lbs ready to camp, the aluminium 4106 is probably a fair bit lighter.

Offline Ed Hackenbruch

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Re: 6V71 or 8V71 ???
« Reply #8 on: March 15, 2013, 03:23:49 AM »
If it is in Yuma you have a whole bunch of busnuts that could take a look at it!
1968 MCI 5A with 8V71 and Allison MT644 transmission.  Western USA

Offline RL

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Re: 6V71 or 8V71 ???
« Reply #9 on: March 15, 2013, 03:44:37 AM »
It's in Anza, CA
1962 PD4106-1546, 8V71, Allison V-730
Birch Bay, Washington

Offline wg4t50

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Re: 6V71 or 8V71 ???
« Reply #10 on: March 15, 2013, 10:46:57 AM »
For me, the 8V is acceptible, the 6V is not, power just too low unless you have it in a 15k lb what ever. I drove a cracker box tractor with the 6V-71 once, it was very dependable like all the 2 cycle DD engines, just no power. grandmas on bicycles pass you on a hill.
Dave M
MCI7 20+ Yrs
Foretravel w/ISM500
WG4T CW for ever.
Central Virginia

Offline Ed Brenner

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Re: 6V71 or 8V71 ???
« Reply #11 on: March 15, 2013, 01:54:29 PM »
I had a 4106 that had a 6V71 Turbo and a 730 trans. That was a great running hot rod. Knowing how well it ran is why I am putting the 60 series in my Eagle. That 06 would run circles around the Eagle with it's 8V71.
ED
Ed Brenner
77 Eagle 05  Murrells inlet, SC
 " While We're At It " A Busnut's most costly Phrase !!

Offline RL

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Re: 6V71 or 8V71 ???
« Reply #12 on: March 15, 2013, 03:04:16 PM »
It doesn't have a turbo according to the seller. Btw, I really appreciate all the comments. I'm finding tapping your knowledge indispensable. Reminds me that a leading theory to our species advancement was social networking.

For those curious as to what I paid for the 1962 4106, I will be paying approximately the same amount for the 1999-2001 Honda CR-V I'm looking for as a tow vehicle. I emailed my buddy / seller, (oh and by the way for those who suspect my inexperience is being taken advantaged of, he will be joining me in September in Anza for the start-up. Anybody want to come, we could make a party out of it :) ), and asked if the bus could tow a 4000 pound vehicle. He said it could tow a full sized pickup and wouldn't know it. That bit of info gives me hope it's a 8V71.

Soon I'll be asking for your help again as to what I should try to accomplish in the 10 hours I'll have with the bus July 3rd. I'm not going to try to start it as it's been sitting for 3 years. He said it ran perfect at that time.
1962 PD4106-1546, 8V71, Allison V-730
Birch Bay, Washington

Offline TomC

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Re: 6V71 or 8V71 ???
« Reply #13 on: March 15, 2013, 03:54:44 PM »
The 8V-71 with N65 injectors will put out 304hp and 800lb/ft torque. The 6V-71 with N65 injectors will put out 228hp and 600lb/ft torque. Rebuild the 6V-71 into a turbo engine and use N80 injectors and the engine will put out 300hp and 900lb/ft torque-which would make for a great running 4106.

Most all 4106's came standard with 8V-71. Rebuild the 8V-71 into a turbo engine using N80 injectors and you'll have 400hp and 1200lb/ft torque-now that would be a real hot rod!  Good Luck, TomC
Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.

Offline Runcutter

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Re: 6V71 or 8V71 ???
« Reply #14 on: March 15, 2013, 03:55:46 PM »
If you haven't already looked into it, please think about emergency road service before you bring her home.  Before we picked up our coach, I got coverage through CoachNet.  Other people here use other services, search the archives.  I've used CoachNet, happy with the service (other than them sending a toy wrecker the first time).

Make sure you do a good inspection of the tires.  Again, search will tell you how to read the date codes.  Typical for a converted coaches, there may be plenty of tread, but cracked sidewalls from aging rubber.

Arthur
Arthur Gaudet    Carrollton (Dallas area) Texas 
Former owner of a 1968 PD-4107

Working in the bus industry provides us a great opportunity - to be of service to others