8v92 vs 60 series

[Bryan]

Hey guys, browsing prevosts and noticing most of them either have a 8v92 or 60 series. Is the 60 series also a Detroit? Also what are pros and cons of both of these engines? Thanks!

[PRZNBUS]

60 series is a four stroke Detroit but not near as cool as the two stroke 8V92. I believe in 1987 DD added all the electronic stuff many have problems with.

Bruce

[Bryan]

Oh and one more question. How many miles should these motors last? I guess a better question is, at how many miles should you not purchase one?

[Bryan]

I've been told that it's much easier to find mechanics to work on the 60 series? What about fuel mileage?

[PRZNBUS]

I believe you'll be able to find a mechanic in most areas, they made a lot of them. A 60 series any Detroit Dealer will have parts and expertise. As far as mileage, couldn't say. Mine is pre electronic stuff and on a good day gets up to 7 mpg but most of the time 4 to 6 depending on terrain. Comparable to a truck and a large fifth wheel.

Bruce

[Lostranger]

I'm part of the tiny minority on this forum who are not fans of the 2 stroke DD. One way to think of the difference in the two engines you mention is 1930s technology vs. 1990s technology. A lot changed in this world during those 60 years.

The 2 strokes produce considerable torque for their displacement, but they are among the dirtiest burning engines in existence. The 60 series is one of the cleanest and most fuel efficient engines ever built. Many of the 60s were built before federal EGR mandates, and that is a plus.

I will never fully understand the deep-seated paranoia about "electronic stuff." Hardly anyone on this forum does not depend daily on some vehicle with multiple computers and electronic systems, but I hear no one talking about trading their cars and pickups for 70s models with carburetors and ignition points. Electronic controls and sensors for diesel engines and automatic transmissions represent a major improvement in bus efficiency, reliability and diagnosis. Even the 2 strokes and Allisons made after 1986 have DDEC and ATEC.

Everyone is entitled to their opinion, and you will certainly read many that run opposite of mine. So be it. I lived for nine years with a 6v92TA DD (2 stroke), and I will never own another. Our current bus has a four stroke 40 Series DD (8.7 liter) concerning which I can wax eloquent.

Two stroke lovers carry on about the "sound" and the "feel", and I respect visceral attachment to technology. Everyone should own and use what pleases them. I, on the other hand, am attached to the fact that a 60 series operates so efficiently that over-the-road trucks running 60s usually have to have a separate system to heat the cab. I love the sound of dollars NOT being spent on fuel and the smell of air bearing significantly fewer emissions, but that's just me.

In the end, you pays yer money and takes yer choice.

Best of luck,

Jim

[Jon]

I vote with Jim H. I have had both. I have put about 250,000 miles on my 8V92 before I sold the bus, and I have a similar amount of experience with the Series 60, both a 12.7 and a 14.0.

No engine on the planet sounds as sweet as an 8V92. It is an easy engine to work on when installed in a Prevost. But it is not real economical to own. My lifetime mileage in a DDEC I 8V92 was 5.6 MPG in a 40,000 pound coach. My 12.7L Series 60 in a 46,000 pound coach was an 8.0 MPG engine until the fuel sulfur content was messed with and it went to a 7.5 MPG engine. My 14.0 liter engine in a 53,000 pound coach is a 6.0 MPG coach, but it has an EGR engine.

The Series 60 installations will only allow limited engine access with serious work having to be done on an engine that is removed from the coach. Bot Series 60 engines are excellent. The do not use oil, they have been very reliable, and if they needed work any Detroit shop has the expertise that is not always available for the 8V92.

If you are buying a converter coach that started life as a motorhome it is unlikely you are going to need to think about engine rebuilds or service unless it has a lot more than average use. All bets are off on a seated coach conversion. In fact with the market for older used coaches ad deep in the dumper as it is, it only makes sense to buy an older Prevost professionally converted coach because prices are so low you cannot buy an old seated coach with long engine life, plus all the stuff to make the conversion for what some conversions are now selling. Some that look decent are in the sub $50,000 range in fact. Those are going to be an 8V92.

[belfert]

I like my Series 60 even if does have a computer.  At this point I don't think I would want a 2 stroke bus if you gave it to me.  If it does need service nearly every town has someone who can work on a Series 60.  Not so much with a two stroke.

Cars have been electronically controlled for 20 plus years now.  I doubt many of you drive cars that don't have electronic fuel injection. 

[luvrbus]

LOL electronics are not the only problem with engines but you are lucky if you have a non EGR engine.

Fuel mileage is not that much difference all the 14L DD I have been around are 5 at tops @ 70 mph.Mine coming from OK to AZ was 4.8 mpg a H series with a 515hp 14L Detroit 

I looked at a few H series Prevost with the 11.1 series 60 engine those were a joke the outfit had 10 of the H's with 11.1's they were trying to rid their self of, so you buy what you like they all have problems 

[wg4t50]

Being old and near crazy, I do love the 2 strokes, BUT their time is about over.  Today the ECM (computer) is the way to go, the earlier ones prior to the EGR is good.  I wound up  with the Cummins ISM500, was the ISM450 pre EGR 2001 model, had upgraded to the ISM500 + rating, being a Cummins dealer, some things are possible ,  Point; I now prefer the reliability, smoothness and yes power of the ECM setup along with the Allison 4000R into a 3.91 rear, a happy setup.  Note, the ISM 11L is the smallest engine Cummins rates as Heavy Duty.

Dave M

[Jon]

My current 14L Series 60 is an EGR engine. 515 HP. My first step was to add the Ugly Fix which fools the engine so the EGR will not function. My mileage went from  5.9 to about 6.1. Then the ECM was programmed to change the EGR "on" to 3200 RPM, and the EGR "off" at 3600 RPM. Obviously that means the EGR is not going to function. At the same time I plugged the exhaust path just downstream from the EGR cooler so no exhaust can enter the intake manifold. After doing that the mileage went to 6.2 MPG.

After several thousand miles of driving the mileage started to creep up. Apparently the exhaust gas entering the intake manifold soots up the valves and maybe the cylinders so it appears the engine is cleaning itself up which is now reflected in approximately 6.4 to 6.5 MPG. My next project is to get with one of the members of this forum and strip my engine of the EGR related components, including the V pod, heat exchanger, intake manifold, exhaust manifold and turbo and replace the manifolds with non-EGR manifolds and a larger single speed turbo. I know another owner who has made that mod and his 14L Series 60 has gained about 1 MPG over his previous mileage.

My point is later engines were not designed for mileage or performance. They were designed to meet EPA emission standards and when we rid the engines of the garbage that was hung on to meet the standards and get back to a pure Series 60 we have both power and performance. I won't go back to a two stroke although I really do like their sound.

BTW, I am 53,000 lbs, and typically tow and H2 Hummer at 6700 pounds, but I cannot keep up with Clifford. I drive about 62 MPH.

[luvrbus]

LOL it is either drive 70 to 80 mph on I 10 in west Tx or get run over Jon

[digesterman]

We get 8 MPG with our 60 pre EGR, 65 to 70 MPH 50,000 total including toad. Now in the mountains about 6 MPG. Total miles on coach is 110,000, DDEC 111

[Gary Hatt - Publisher BCM]

I know the feeling.  I have a 6V92 in my MC-9 and a Series 60 in my Eagle.  I definitely like the sound of the 2-stroke much better.  Even more than the 6V92, I liked the sound of the 8V92 I had in my MC-7 even better.  I used to run heavy equipment and one of my favorite sounds was when I started my dad's D4 dozer on gas and after it ran for a minute or so depending on the ambient temperature, and then shutting off the gas supply and pushing the diesel throttle forward as it switched over from gas to diesel.  The sound of that old diesel starting up and watching the smoke rings come out of the exhaust stack was awesome. 

Someday before I take the Eagle on the road much, I plan on finding someone with an 8V92 and putting my tape recorder near the 5" exhaust pipe and have him take off down the road and go up and down the mountains for about a 45 minutes then copy it onto my 8-Track tape player.  Then when I fire up the Series 60 to head out on a trip, rather than playing "On the Road Again" by Willie like I usually do, I will turn on my 8-track player and turn up the volume on the inside and outside speakers in the engine compartment and everyone will think I have an 8V92 in my Eagle and it will be music to my ears.

[Lostranger]

I will turn on my 8-track player and turn up the volume on the inside and outside speakers in the engine compartment and everyone will think I have an 8V92 in my Eagle....

I KNEW 8-track tape was gonna make a comeback! I wonder if I still have Iron Butterfly's In-A-Gadda-Da-Vida. That drum solo sounds like my old two-stroke pulling hard. Or trying to.

Jim