test drove a 4104 today

[Rube]

Bus is nice, a little concerned with the power. It has the 65 injectors. Tha gas pedal was dead until about 1/2 way down. My MCI 5C with a 6v71 and an auto trans would walk all over this one. Don't know if it is a good comparison. Other than the lack of power the bus is 100%. Is it possible the blower seals are worn out causing lact of power? It had no oil leaks, owner claims he never has to add oil. Need you opinions guys. Also - he has a 4 valve head just redone - is this a straight swap with the 2 valve head ? Will this increase performance. Owner also states he always gets 7.8 MPG. Bus tops out at 68 MPH at 2100 RPM. Come on guys speak to me - I want to convert to a GMC guy....

Rube

[Dallas]

Rube,
One question I have is who has done the tuning of the engine?
My '03 with the same setup as most of the 4104's will run circles around our old bus.
Starting out is slow, because I have the 3 5/9ths rear gears, but once I get moving I have lots of acceleration.
I also get close to 13.5 MPG most of the time, (it varies between 11.3 and 14.1).
I would say that engine needs to have a complete tune up, have the air filters cleaned or replaced, and talk nice to it. It will perform!
One interesting note, the inline six has a much better torque curve than the V, even though they are rated the same for power and torque at any given RPM.
Get yourself a GMC and feel what the rest of us already know.
Dallas

[Len Silva]

The first thing I would check is the throttle linkage. The cable gets stretched out and sticky after a few years.

Len Silva

[Rube]

The PO has has the bus for many years. It motor is original to him. It has never had a problem and he states it has always run the same. He has had friends work on the bus. He is in the trucking business so he does have connections. the motor also has the 2 valve heads, he will be giving me a 4 vavle head that was magnafluxed then rebuilt, never installed. Will this help on the power?

Now.. on the other hand, my MCI ran very similar until I had it tuned at a bus shop. It made a hell of a difference. I had my MCI governor set to 2200 which tops out at 73 MPH... it has 4:11's.

[gus]

My 4104 is kind of like a locomotive, the 671 will not do much until it gets wound up. Acceleration is not something I think about now with this engine!

Don't know anything about  the 6V71 but most V engines seem to wind faster than straight.

68 mph is about tops for mine but don't need more than that.

7.8 MPG is an honest figure.

To check for oil consumption it needs to be driven at least 60 mph for a couple of hours to also check for oil being thrown from the engine (Corrosion Control Fluid)!!

Any engine work described is worth nothing unless there are documents to prove it. If he had work done by buddies he should at least have the parts invoices.

I love this bus, have had it since last August and am now almost midway into a 5000 mi trip.