8V71N bus - bad decision?

[windtrader]

Three buses on the final short list, all powered by 8V71N. The more comments how slow these are up hills, the more doubt and second thoughts about acquiring a bus with this motor.

I'm sure if asked how many current 8V71N bus owners would swap in a more powerful motor, it'd likely be a universal yes. So, how many feel this motor is severely  underpowered and really strongly feel compelled to repower or get a more powerful coach?

thanks

[Dave5Cs]

Don you will learn that it is about the Journey and not always about the destination, No seriously! If you are looking for power get a Cummins ISM or even a powerful series 60 tuned up to what 400HP. CAT or something newer that will run cooler than a DD 2 stroke. Get a Turbo-ed one though if you like to climb hills. Just sayin........
Dave

[windtrader]

Hi Dave,

"...you will learn that it is about the Journey and not always about the destination".

Yeah, right. This is the mantra of all 8V71N bus owners. Sit back and enjoy the scenery.

Those running 400-500HP buses are saying the journey is nice but sure feels better to get to the destination in half the time. LOL.

All was fine with the enjoy the view crowd but the recent comments about hating the slow ride got me with second thoughts.

The reality is based on my budget for this "hobby", the only practical option is an 8V71N.

Take care , don

[Dave5Cs]

LOL then Let the Journey begin.

By car we can rush to AZ down I-5, 58 40 95 to Quartzite in 1.5 days by car or we take three days in the Bus. We stopped to look at the planes at aero express way in Mojave CA and see friends, help others Tear walls out of their Bus and then went up the hill to a nice RV resort for a week, went over to Laughlin Nevada had some good food. We stop along the way to take pictures of the Dessert and wild flowers everywhere. Then we moseyed into to Quartszite to the rally for 14 days.
We took another route home and did that in 4 days. We were gone a little over a month. We try not to go over our 300 mile a day limit otherwise you miss stuff. We stop and eat along the way generally in the bus... Our days of rushing somewhere just to get there are over...
Dave

[Uncle Augie]

Hi Dave,

"...you will learn that it is about the Journey and not always about the destination".

Yeah, right. This is the mantra of all 8V71N bus owners. Sit back and enjoy the scenery.

Those running 400-500HP buses are saying the journey is nice but sure feels better to get to the destination in half the time. LOL.

All was fine with the enjoy the view crowd but the recent comments about hating the slow ride got me with second thoughts.

The reality is based on my budget for this "hobby", the only practical option is an 8V71N.

Take care , don

Bought my bus from the widow of the previous owner, she showed me 4 speeding tickets he go on the interstate for doing 85-90mph. With the right tires and a well running 8v71n with the 4spd standard you dont have to be caught in the slow lane... Ive only had it a few weeks, but the trip home was 68-70 no issues for 200 miles.

[windtrader]

Augie,

Not concerned about the flats. Living in NorCal means Mountains with a capital M getting out of state. North, South, and East all have some serious climbs. Maybe an extra hour here or there is chump change in the grand scheme of things, ala Dave5C providing the real wisdom of travel by bus. When he says journey he really does spell it with a J. The J is the trip. OK. Back to making a deal.

[Tom Y]

After driving my 5C home to Pa from Az I decided the stick had to go. If the stick was going so was the 8v71 a lot of work but glad I did. The torque on the 4 stroke on the hills is great.

[luvrbus]

The 8v71 is not a race horse but has been getting buses across the USA since 1958,it will get you there and back home.
Most were 260 to 270 hp.It is the hp to weight ratio a 8v71 would be useless in the newer 50,000 lbs buses of today.
Dave and RJ enjoy their buses with the 6v71 and probably  200 hp tops. 2 things affect the N/A 8v71 or any 71 N/A engine that is altitude and extreme desert temperatures the hp and torque drops like a rock so you change gears
 

[kyle4501]

What do you want ?
It is all a compromise.
I wanted higher HP & an automatic - in my price range, that meant an 8V92T with an 740 allison.

With mine, at full power & a properly maintained cooling system, the engine temp is 125 above ambient

[Utahclaimjumper]

 The age old problem,,,"speed costs money,,how fast do you want to go??>>>Dan

[Geoff]

I guess if you don't mind shifting and crawling up mountains and having all the trucks pass you on the way up, a stock 4106 is okay.  When I pass a old bus on a hill I can hear their engine roaring at Max rpm and I'm doing 15-20 mph faster than they are.

I started with 270 HP in my RTS and upgraded​ to 350 HP.  What a huge difference!!

--Geoff

[Geoff]

What do you want ?
It is all a compromise.
I wanted higher HP & an automatic - in my price range, that meant an 8V92T with an 740 allison.

With mine, at full power & a properly maintained cooling system, the engine temp is 125 above ambient

"125 (degrees) above ambient" -- that is something Detroit used to say but it never made any sense to me.  Ambient temperature is defined as the current outside temperature.  So as long as it is no more than 75f outside you can add the 125 degrees and you are at 200f.  If it is 90 degrees outside that formula would put you at 215f, which is far too hot for a Detroit engine.  Am I doing something wrong or is this formula flawed?

--Geoff

[daddysgirl]

NOT a bad decision. I can even provide reasons

The 8V71 is a mechanical motor. IF something breaks...you fix it without having to pay a fortune for someone to read a code.
My speedometer stops at 85mph. I have had it buried more than I should admit. I have had friends behind me call me and ask me if 92mph would get me    
.a ticket on I95 or I64.
I have been up and down mountains...I pass the trucks and some cars.
I have never...not one time...seen any smoke of any color whatsoever...even when towing the Jeep, truck or trailer.
I have never had the temp even close to overheated.
In a MC8...I have room in the engine compartment if I need to reach something.

But most importantly, after all of the research you have done, don't second guess yourself. I would say that regardless of the power plant you choose.

[Geoff]

It looks like your engine is rebuilt and the odds are the timing was advanced and N65 injectors installed.  This would put you at 304 HP vrs. a stock 4106 8V71 with N60 injectors and 277 HP.  Or do you have a turbo with 350 HP?

--Geoff

NOT a bad decision. I can even provide reasons

The 8V71 is a mechanical motor. IF something breaks...you fix it without having to pay a fortune for someone to read a code.
My speedometer stops at 85mph. I have had it buried more than I should admit. I have had friends behind me call me and ask me if 92mph would get me    
.a ticket on I95 or I64.
I have been up and down mountains...I pass the trucks and some cars.
I have never...not one time...seen any smoke of any color whatsoever...even when towing the Jeep, truck or trailer.
I have never had the temp even close to overheated.
In a MC8...I have room in the engine compartment if I need to reach something.

But most importantly, after all of the research you have done, don't second guess yourself. I would say that regardless of the power plant you choose.

[RJ]

Don -

Some perspective for you:  When I was in the charter business back in the late '70s > late '80s, the majority of the fleet were powered by 275 hp 8V71Ns, and the running time from Fresno > Las Vegas was eight hours.  Just before I left the company, we got two MCI 102A3s, both with 400 hp 8V92TAs.  That engine cut the run time to Las Vegas by one hour - seven vs eight.  It only shaved 15 minutes off the run time to Disneyland from Fresno, and just 10 minutes into The City.  No difference in the run time for field trips to Sacratomato since it was all flat the whole way.

We just completed a 12,000 mile round trip to FL from WA with a 6V71 in my MCI, which you've seen.  Sure, we were down to 25-30 mph on some grades as we went east and west, but we still averaged 50mph for the entire trip because the majority of the time we were rolling along in high gear at 60-62 mph, where my coach is happiest (because of it's rear axle gearing.)  Dave's 5C has the same powertrain, so our comments echo each other.

I'd love to have the a 350 hp 6V92T like Geoff has in his RTS, but my engine compartment won't allow it w/o some serious work to both the engine's turbo location and cooling system.  The major bonus, however, would be the ability to change the rear axle ratio from 4.11:1 to the 3.36:1 pumpkin I have in my 2nd MC-5C, thus lower rpm at any given speed = longer engine life.  But in the meantime, it ain't broke, so I ain't gonna fix it!

Dave & Clifford -

While working on the bathroom remodel this week, I opened the engine hatch on the engine hump and found an engine spec sticker on the LH valve cover - something that I didn't see from the engine compartment.  I couldn't see the injector size spec, but the sticker says "ADV. HP 250 AT 2300 RPM." I think that's got to be hp on a dyno, not installed!

Geoff -

The 4106s in our fleet would climb the Grapevine at 45 mph with 40 passengers, but then again, they're pretty light to begin with.  The MCIs, with the exception of the A's, were all sitting on the governor in 2nd gear at 30 mph - but that was the deal back then, wasn't it?

Oh, and while I'm thinking of it, I do hope your back gets better.

FWIW & HTH. . .