Anybody Ever R/R the Cummins ISB in an FL70?

The Gibster · Mar 21, 2005

I know some of you will consider this foolishness, but has anyone ever completely replaced/upgraded the ISB 250 Cummins in an FL 70?

Our carrier allows 'not-new' trucks with the proper upkeep and maintenance, and it seems more logical ($$) to us to keep our great sleeper and good truck and just replace the ISB junk.

Anyone - have you had it done or know of the swap with the new ISB/ISC's, how much moohlah to get it out the door, and any good shop recommendations? ANY PITFALLS?

So far Frtlnr says a week to build the engine out - it's not a stock/warehouse item. And we've found about $5-7K parts and $5-7K for labor.

Thanks everyone!

The Gibster

Glen Rice · Mar 21, 2005

If you have 15K to put into your old FL70, why don't you just take the plunge and trade your old unit and your available cash and move up to a newer more reliable, more marketable, safer, 1 or 2 year old truck. Just seems a shame to pour more money into a FL70 at this stage of it's life cycle.

rode2rouen · Mar 21, 2005

I tend to agree with Glen....it sounds like time to upgrade to a later model truck. Class 8s are SOOOOOOOOOOO much nicer than an FL70, not to mention that they have a higher level of durability built in!!!

However, if you decide to go the new engine route, I would consider going to a Cummins distributor's shop as opposed to the Freightliner shop. The $5-7K labor guesstimate seems awful high.

Rex

davekc · Mar 21, 2005

If you really like your sleeper and it is not the one piece shell from AB, take the sleeper off, and reinstall on a new chassis.
We have done this several times on different trucks with good results.
Then take your chassis and sell it. Turn it into a flatbed or tow body, and make a few more dollars off of it.
Davekc

NEVERHOME247 · Mar 21, 2005

We tried that approach with our truck. Was not a FL/70. But in anycase. The result was after overhauling the engine. Next was the transmission,the rear,etc. Get the picture. Over a period of time you end up rebuilding the entire truck. I would take the money and invest in a new unit with extended warranties on everything. You get a complete new truck. You start the depreciation process all over. And all in all you will have a new,safe,dependable unit. Dave's suggestion is also great. Buy a new chassis and put your sleeper on it. And sell your old chassis. Good luck in what ever route you take.

LDB · Mar 22, 2005

I had an excellent experience with Cummins Mid-States Power Inc. at 450 W Northtown Rd in Normal, IL 61761. Their phone is 309-452-4454. They are a master dealer for my ProHeat unit and that is what I had serviced there. I can say the shop was clean and well organized. All of the staff I had contact with were polite and professional. They kept me informed and although my situation presented them an opportunity to take advantage of me they did not. They even finished about 15% below the preliminary estimate. I will definitely be returning to them in the future for service and am now more inclined to go Cummins for my next truck engine.

I have to agree with the others you should at least look into the trade value of your truck plus the $15k toward another truck and see where that would put you. If you get a lot better quote on your replacement engine that has to be factored in as well. Take your time to seriously think about all alternatives. Good luck.

Leo
truck 4958

Support the entire Constitution, not just the parts you like.

The Gibster · Apr 4, 2005

Well, we did all the math, talked to Dealers about trade-in and new truck costs. The result - new engine from Cummins, to be installed at Piedmont Peterbilt in Greensboro NC.

The whole deal, out the door is quoted at $12.5K. When we were offered about 10K for the trade, and new to newer being $65-100K, the decision became easy.

No truck note, new engine with extended 5yr/300k warranty, our redone customized walk-thru sleeper (now all cherrywood) it made more sense to be able to afford a repair in the future then have the truck payment exhausting our attempt at reserves. And with the fuel costs and a little slower freight time, we went conservatively.

We have been reading everyones posts about Cummins, Frtlnr, good & bad shops and mechanics and appreciate every one. This is a great forum! We've noticed also that going direct to Cummins, and thru a good shop gives us new faith in Cummins engines (and reaffirms) our problems with Frtlnr.

Thanks for everyone's input, we'll let you know how it goes in a future post.

The Gibster

LDB · Apr 4, 2005

Which engine are you getting as the replacement and what are the specs of it? I'm already weary of only 300hp and thinking of an upgrade so just curious what others are running.

Leo
truck 4958

Support the entire Constitution, not just the parts you like.

davekc · Apr 4, 2005

300hp can be ok depending on transmission and rear gear ratio.
Davekc

LDB · Apr 4, 2005

I've got a 6sp Allison automatic and I think it's about 5.33 gears. Turns about 1600 at 60 in 6th. There isn't enough hp/tq to pull even moderate hills without downshifting to 5th. There's also a very annoying situation that if the cruise control is set it will downshift many times where it doesn't downshift if the cruise is off and I'm pressing the throttle. I presume it gets better fuel economy at lower rpm so I don't run the cruise except in the flats. That way it won't be downshifting and revving high as often.

Leo
truck 4958

Support the entire Constitution, not just the parts you like.

davekc · Apr 4, 2005

You could have the dealer reset the perameters on the computer or drop to a 4.1 rear end. Your rear end ratio sounds high. A standard 6 speed is at 3.9 or 4.1 but can be dropped to a 3.37 or 3.5 without voiding the warranty.
This is on the 2005-2006 models with a Mercedes 260-300
Automatic transmission may limit you to 4.1 because of torque requirements.
You would want them to spread the torque requirements on your final drive so you don't have repeated downshifts on every incline. This is killing your fuel milage.
Davekc
owner
20 years

Larry · Apr 9, 2005

I have been reading this post and am still confused. Please clarify.

What engine was in the FL70? Are you replacing the Cummins engine or was there a Cat or some other engine, initially?

Thanks.

Drive Safe.

The Gibster · Apr 10, 2005

The engine in the FL70 was an ISB 260, we had always been told it was an ISB 250. At Piedmont Peterbilt they tried to ID the tin engine tag, but because it was so beat-up they called Frtlnr with the VIN and found out it was indeed a 260.

This is only important because we had experienced every fuel problem know to these engines. Anf frtlnr had kept hanging 215 HP fuel lift pumps and distribution pumps. We finally discovered the problem with an independent shop, and got a 260 pump installed. We also boosted the injectors to 275. It would flat run!

We decided on the new engine after just a whole series of leaks. All our seals were going, gaskets were needed to be replaced, it happened all at once. Then when in the shop, the cam and tappets looked UGLY! So we decided to just make the decision to R/R the engine, keep the truck, and get back on the road.

The new ISB's have supposidly been re-engineered, with new fuel system and other engineering snafu's addressed. So far we think we're getting the straight scoop from Cummins.

I don't have the specific specs available tonight, they are listed in the cummins brochure and I'll post them tomorrow afternoon, (Sunday). We just got back from a 3377 mile 4.5 days and am bleary-eyed. Our carrier loaned us a truck for the week so we could still make so money. We loaded up and hit the road. Great company, great folks.

Thanks again for all the posts everyone!

The Gibster

simon says · Apr 10, 2005

I think some (or most) of you are talking about an ISC. The 315 hsp./950 torque ISC will get the best fuel economy of them all, if set up correctly. You need to be doing at least 1650 rpm at 65. 4.10 RA, .74 final. 300 hsp similar, but simulation at same gearing and your FE drops to 9.0 mpg. If you go lower, you don't have power over grades. Fuel efficiency will increase if you have aerodynamic aids and take your foot out of it- drive 60-63. I can get up to 9.5 mpg in non-winter months- but I also have been as low as 8.25. Jeff Jones used to set his T-300 HDX with a 315/3.9 RA/.74: that spec would be 1600 @ 65. I think the 4.10 and overdrive is better.

The Gibster · Apr 10, 2005

The ISB 275 shows 660 ft/lbs at 1600 rpm, 2600 rpm top governed.

We've got an Eaton 6 speed, not sure the rear ratio. Stretch FL70 with 96" sleeper, we're every inch of a heavy 40 feet.

We really noticed the 275hp injectors flattening out the hills. The increase in ft/lbs of torque should help. We usually only have to downshift once. Twice only on the steepest grades under gross loads.

Checkout specific powertrain options/specs at
www.powerspec.cummins.com

The Gibster