I'm still thinking about a re-power....

[Chaz]

Ok guys, to start off, I have no idea how my bus is supposed to run. This is the first DD I ever drove so I have nothing to compare to. I know some have you said in the past that if she will start....RUN IT!!    And to drive it like you're mad at it. (I really like that idea!!  )
But I would just like to know if it might be a good idea to do an in-frame. Is there things I can check for?

Here's what I can tell ya: I seems like it is a bit of a "dog", and I get 6.2 mpg.
I already had the rack run and been adding injector cleaner (and trany fluid). She is also a little tough to start at 50* or so, so I understand there may be some cracked rings. She can kill LOTS of 'skeeters when she starts until she gets a couple blocks down the road. She can run around 70 or so down the highway (but it's a guess- no speedo)

I'm thinking I should have a compression check and I was also told about some sort of inspection covers on the side of the motor that you can look in and see the........ cylinder walls??

Is there anything else I can do or check for??  I understand there is a couple places on the net I could get some info from, but I would rather trust real world info from guys I know.

By the way, reason I am a little concerned is I want and need to take her on about 8 trips this year. Work and play. The work part is important.

So what do you think?? Any help or suggestions??

Thanx,
   Chaz

[Len Silva]

The hard starting and the excessive smoke are indicators that something may be wrong, especially after a tune up.

A compression check is in order and there are several other pressure checks that can be done (air box, exhaust, etc.

As for your speed, my experience is that you are probably going faster than you think.  I know I scared the hell out of myself the first time I hit an off-ramp much faster than I thought I was going.

Len

[bigjohnkub]

My 4903 gets 6.5 mpg at 65mph. Any faster, I start losing. Go to wally world and get a hand held GPS, or better yet borrow one and check your speed and miles. My gps is exactly twice as fast as my speedo, but hub meter was only 1 10th mile off in 500 miles. I get a little smoke on start up , and have been 85 mph when not paying attention . Check your speed.  big john

[Jerry32]

sounds like it's time to look at a little engine work. Mine starts on a 30 degreee day just fine and no smoke after startup. It gets 7 MPG at 65-75 mph with 24.5's on the drive axle. Jerry

[captain ron]

Chaz, Auto or Spicer? My old 4905 got 7.5 to 9.5  flat land or hilly made the difference. 8V71 with 4 speed Spicer. If your gonna do an inframe that would be a good time to do your veg oil conversion also.

[Rick Brown]

Here's what I did while repowering my 4905
http://home.att.net/~intermountainac/BusRepower.html
RickBrown in Reno, NV

[tekebird]

hard start and excessive smoke at 50*.....needs rebuilt.

mileage seems OK, a DD 2 stroke will run well after it is worn out.

[TomC]

Sounds like your engine is on the worn side.  Might be cracked rings-can check through the side inspection air box plates by rotating the engine until you can see the rings in the intake ports-then you can rotate the rings with a sharp ice pick type tool to see if they are cracked.  I realize that the 8V-71N is a very reliable engine, but it is out of production (as of 1998) and it isn't very fuel efficient (it was in its' day) compared to the newer engines now.  Instead of spending the big bucks to overhaul your engine, you might consider installing a Cummins 8.3 or ISC mechanically injected engine with the reverser gear.  Your fuel mileage will increase to around 10 mpg and will be able to have it serviced wherever anyone knows Cummins engins.  These engines will have around the same power as your 8V-71N (what injectors do you have?).  If you want to go electronic, you could use the Cummins ISL that puts out up to 400hp and 1200lb/ft torque-which you would love.  Also, the Cummins L10/M11/ISM can be used with the reverser gear, but is much bigger.  I would stay with the mechanical 8.3 liter for simplicity.  Good Luck, TomC

[tekebird]

with brand new military surplus 8v71's cosyting around 5k I would not do a repower......not even taking into acount the headaches it MAY cause.

worst case is you get an engine that is turing the wrong way and you make it go the correct way.....not that difficult, and swap all the bolt on stuff onto it.....and then slap it in.

[kyle4501]

Reversing the direction would involve at least a partial teardown. Why not just stick with what you have? ~$2K for the parts needed for a rebuild & fewer surprises too.

What is the oil consumption? If not bad, I'd consider running her another year while you line up things to rebuild it later.

Not everyone here believes you have to run new equipment or professional grade.   

[NJT5047]

Yeah, I agree with Kyle.
If your bus idles with any oil pressure, runs on all cylinders when warmed up, and you can add oil faster than it burns (or leaks) out...may I suggest that you run it.
Unless you're a pro-mechanical wizard (one of those things where if you have to ask?), it'll cost much more than the bus is worth to repower.  Estimate $15 to $20K if you pay for a DD dealer to rebuild your 8V71.  You do have an 8V71?  Right? 
Don't expect large gains in fuel mileage or power.  Your engine only makes 2
Install a block heater.   That valuable accessory will enable it to quickly fire up in zero degree weather.  As long as the engine doesn't run out of oil, and isn't allowed to overheat, and is not in a death rattle, it'll run for a long time.  Probably.
Not sure what sort of trips you have planned, or how far you wish to drive?  70 MPH is about what they do, and 6 MPG is sorta what you would expect from an automatic 40' coach with an 8V71.   
Not trying to be cheap (I tend to that end of the continuum),  but you'll have plenty to do with your conversion without adding another year or so of 'repowering' effort.
No doubt your engine is worn out. But it ain't dead....yet. 
Buying a RH engine and reversing it is about as much work as rebuilding yours.  Figure a complete teardown, changing oil orifices, main seals, fuel pump, oil pump, cams, gears...and the list goes on!  Reversing an DD is more comlicated than most realize.  It obviously is possible.
In today's market, you could buy a later coach with a known good engine for considerably less than repowering your bus.   
That's my opinion....keep us updated on the repowering project!   
The possibility exists that our buses could become about useless if the fuel costs continue their upward spiral.  We could (I don't believe so, but?) be witnessing a sea-change in our leisure-time vehicles. 
And lifestyles.  I'd move slowly on the major engine work until the rest of the bus is ready to use and you know that you for sure wish to travel as anticipated.  And can afford and obtain fuel for such purposes. 
Are you aware that there are transverse S-50s with reversers?  Would make a nice item once completed!  There are a good many takeout 6V92TAs around too.  These make great  cheap repowers.  Watch for a LH engine though.
JR

[jackhartjr]

Chaz...I hope I don't get in trouble here with this post but here goes.

It appears it is running now.  The block heater thing JR talked about would take care of the starting when cold.  (He didn't mention the part about some of them can runn the light bill up as high as diesel!LOL  MIght want to plug it in several hours of the night before a trip.)

A lot of these smoke a little before taking off.

So it appears you have a somewhat tired dog?

Like Kyle said, run it a while, then decide on a repower.

Now here is where I might get in trouble;

I see all these guys wanting these big turbo powered, tricked out motors and think about the first time I saw a 'Cigarette' boat.  I didn't know what they were, I just know they were realy long, really loud and rreeaallllyy fast!  I casually turned to by friends wife and said, "What's that?"  She said, "Oh, that's a penis extention!"

Jack

PS...back in my cross country truck driving days, we had a team that ran 60MPH when we ran 80MPH plus.  (I'm not telling what the 'PLUS' part is, I don't think the statute of limitations is over yet!)  That team always beat us to LA...ALWAYS!  They just stayed out of the truck stops and kept on running.

[DrivingMissLazy]

I run my 4104 with 6-71 for at least two years with compression so low that I had to use a small squirt of ether most of the time to start it. Always on the first start of the day, regardless of the outside temperature. I eventually had it re-built with 4 valve heads. I never really saw any difference other than it was much easier to start.

Richard

[Chaz]

Hey Thanx Guys!! I appreciate all the advice and PM's too.
The coach is already converted but I am bringing things up to snuff right now. So I have been using it for about a year and a half. I will keep an eye on the oil consumption on my next trip. I had just been keeping it toppped off until now.

  Oh, and Jack, a Cigarette isn't the only way to get one of those. My friends wife says a Corvette is one too. I guess (hell, who am I kiddin, I KNOW) I need one!! Plus I like both of those modes of transportation!  But sadly, my other 10 vehicles will just have to suffice.

I already have a block heater and it does work well. It's just that all of my starts aren't always planned. But it does work well.

I'm pretty sure I can get into a rebuild for around 4-5K. So my mechanic has said. I'm not really wanting to, but if it would be a good idea, I would do it. Reason being - if I have something I usually hang on to it. Hence the 9 other vehicles.  (I've had my '56 29 years, my '46 Harley 28 years, my '39 truck 26 years, etc. And they are drivers, not dust collectors.) So in that regards, it may be worth it. The Cummins swap sounds interesting, and altho I am only about an hour from where their office and factory is, I doubt I can get any kind of deal on one.    Plus, i have no idea how to do it........or even anyone who would.

Thanx for the info Rick. Interesting setup!

Charley, She's an auto which I know sacrifices some mpg. But..........    Regardless what I do, I won't do both at the same time - in case there is a problem. I know so little about it, I wouldn't know where to start troubleshooting. I learned many times- the HARD way- that it's easier for me to do one thing at a time. (Rick mentioned an air leak in his fuel, on his site, that might have caused him some grief. That would be my luck.)

Looks like I will take her in for a "Check-up". Compression, inspection, etc. If the guy doesn't mind me hanging around, I may stick around for a "School Day". I'll let you al know what I find.

I really appreciate all the help and insight!
  Thankfully,
      Chaz
     

[kyle4501]

Watch your oil level as it drops. From full, does it use the first half gallon fast & then takes a while to drink the next half? If so, you're over filling it & that's easy to fix, just don't put so much in. 


When I got my first bus, it had 2 block heaters & weak coolant. So when the first big cold snap came, instead of buying 13 gallons of coolant, I just plugged her in, Yep, both of 'em. Then the power bill came for 2 weeks of use, HOLY COWS! Yep, more than one!  That was more than the 13 gal of coolant! I learned that you don't leave them plugged in all the time! I also learned that with 2 of 'em going, the radiator was also protected from freezing. 

So, if you had 2, I'm guessing it wouldn't take much time to warm her up. Probably no longer than the pre-trip inspection you are supposed to be doing.