Bus Conversion: 2007 Engine Replacement Pictures

The story of putting a new engine in the bus is best told by the posts I put on the MAK bulletin board.  Pictures will help finish the story.

January 6th:
Went out this morning and noticed antifreeze had filled up my passenger side slobber tube catch bucket.  What does it mean when antifreeze is coming out of the passenger side slobber tube?  I’ve last run the bus down to Virginia and back for Thanksgiving without issue.  It’s been sitting without running ever since.  So, any ideas as to what is going on and how bad it is?  Thanks!

The problem turned out to be a leaking cylinder liner o-ring to block seal.  The only way to solve the problem is to tear down the engine and rebuild.

January 7th:
I found the leak in the middle cylinder liner on the passenger side of the engine.  I turned over the engine with a wrench last night as well and no water came out of the ports… so no leaks in the injector tube.  I’m now trying to figure out all my options.  I’ve been doing a lot of calling around on different engines to see what is available and what it might cost.  I’m also trying to find a local DD 2 stroke guy willing to do a little moonlighting with me if I decide to tear down this engine.  Lots to look into yet… The biggest thing I’m trying to figure out is if I can swallow putting money into a engine I’d like to just get rid of all together …. I looking at getting a L10e or an M11 right now.  I finally got some dimensions for the motor and the next step is to figure out what automatic transmission options I have are given the length available to me.  After I figure that out I have to crunch some numbers and see where it leaves me.

I tried so many different ways of getting a local Detroit Diesel guy to help me out.  I just couldn’t find anyone.  There are a couple of steps in the rebuild that are extremely critical to get “just” right and if you mess those steps up the rebuild will end up needing to be done again.  I  calculated it would take about $5000 to rebuild the motor correctly.  That was $5000 I did not want to invest in this motor.  Since we had the financial means to consider an engine swap/repower we researched further.

I considered several different motors.  An obvious candidate was the Detroit Diesel S50.  This is a 4 cylinder diesel engine with an excellent reputation for running over 1 million miles without ever being opened up.  This motor is commonly found in 280 hp setup and can be built up to produce 350 hp in “fire truck/RV” trim.  This is a heavy engine at about 2600 lbs.  My next choice was a Cummins ISL engine.  This is a short straight 6 diesel engine capable of 400 hp in “fire truck/RV” trim.  This motor is very popular in many of the late model Diesel pusher S&S RVs.  I tried very hard to find this motor on the used market and never came across one.

The next motor I tried to find was a Cummins L10.  This is a 10 liter motor made in vast quantities and highly available on the used market.  This motor is most often found in mechanical form and capable of 300hp.  A few of these were produced in electronic form and were capable of up to 350hp.  The successor to this motor is the Cummins M11.  This is a 10.8 liter motor capable of 400 hp.  This is an electronic motor and is in EVERYTHING!  It is highly available on the used market.  However, it is most popularly found in 280 hp form.  I did find a few in 300 – 300 hp form.

Following the M11 Cummins released the ISM.  This is a next generation M11 with “next generation” electronic controls and is capable of 450 hp.  I’ve heard of this motor making 550 hp, but was not able to confirm how it was achieved.

Since I couldn’t find an S50 capable of more than 280 hp and never found a single used ISL I decided to put the L10/M11 in if I could find a good one.  As mentioned earlier I was able to find a couple of good used M11 to choose from.  From there I had to decide what kind of transmission to use.  I had wanted to keep my just rebuilt Allison 5 speed automatic transmission.  However, it was simply too long to fit given the additional length of the M11 compared to the V6 6v92 that was coming out.  With a little research I determined an Eaton AutoShift would be the best bet for me.  It was short enough for me to get it to fit and had an overdrive 10th gear of 0.73:1  The AutoShift is a 10 speed transmission with automated gear shifting.  A clutch is used to get rolling.  After the vehicle is rolling the transmission and engine computers cooperate to perform all gear shifts, both up and down, without the use of the clutch.  This transmission is readily available on the used market and have a very good reliability reputation.

After speaking to a friend, Jim Shepherd who has a Detroit Diesel Series 60 and the AutoShift in his bus, I decided the AutoShift was a good transmission for us.  I had wanted to put an Allison World Transmission (B500) in, but couldn’t find one on the used market as it is a very popular transmission.  Jim also told me about a truck salvage yard in Utah he had visited early in 2006.  The owner had just recently purchased a bunch of trucks for salvage from a large trucking firm.  The trucks were all Freightliner Century Class 2000 trucks with the Cummins ISM and Eaton AutoShift powertrain.  I gave them a call and struck a deal on a truck that had 612,000 miles on it with only 78,000 on a recent inframe overhaul.  After the oil analysis came back clean we decided to head out to Utah.

February 21st:
As many of you will remember I posted earlier this year about coolant in my oil.  I decided to not rebuild my 6v92 and am instead putting in a Cummins 410hp ISM and Eaton 10 spd autoshift tranny.  This Friday I will be picking up the entire assembly and hauling it home.  I’m picking it up in Ogden, UT and should hopefully be back home on Saturday evening unless the anticipated snow storm gets bad.  The motor has 78,000 miles on an overhaul and the tranny has 612,000 miles.  Wish me luck as I’m borrowing a friends trailer and hoping I have no trailer issues!  I’ve verified all brakes work, fixed the running lights and am getting the wheels balanced all to try and make sure I have no problems.

I’m leaving work early on Thursday afternoon and going down I35 down to Des Moines, IA and then head straight out to Ogden on I80.  My wife and I will switch off driving during the night and hopefully arrive in Ogden around 1 – 2 pm on Friday.

The motor is actually 400hp, but capable of 450hp with a simple programming change.  I have yet to decide if I’m going to get the power upgrade done.  It may happen next year after the financial pain of this repower this year is “forgotten”.

We negotiated with the salvage yard to buy the entire front clip of the truck.  The purpose was two-fold:  1)  to get the entire engine/transmission wiring harness; and 2) to get all of the little odds and ends used to connect the entire package up and get it running.  I salvaged LOTS of great parts out of this that helped me to do a much higher quality and better job of the re-power.


We test ran the engine before taking it home.  It started and ran good.  However, I was unable to test the transmission, though the company claimed they had made sure it was working the day before.  Everything else they told me has proven to be true, so I assume they really did get it to work as they stated.


Man, what was I thinking!  Oh well, I can’t back out now!  Man, that thing looks HUGE back there behind the Jeep!


Here we are with the truck loaded on a friends trailer.  Thank you SO much Fred for letting me use your trailer.  This was an experience I’m glad I was able to have and you helped to make it possible.


Here was our view February 23rd after driving all night.  This was taken right before we started loading up.  Beautiful!


This was a rest area just 20 miles from the salvage yard.  We stopped to perform a tire/hub check and to make sure all the straps were still tight.  It was towing good so far, but I was definitely nervous at this point.  I figure the truck front clip to be around 5,500 lbs and the trailer to be around 1,500 lbs.  So, that means I was towing 7,000 lbs behind a 4,200 lb tow vehicle!  The Jeep I have is rated for 7,000 lbs and can be had in a setup rated for 8,000 lbs.  So, I wasn’t over taxing the rig, but I was very glad the electric brakes were working!

2007_0223_ism_18February 24th:
Hey Guys,

Yeah, that rain in Nebraska never materialized!  (I had been watching the weather forecasts and the Nebraska route was only predicted to have rain with the snow north and east of our intended route.)  We got the blizzard with lightning instead!  It is something for it to be snowing at 40 degrees and lightning!  We ended up stopping in North Platte and got a hotel room for the day/night.  (Saturday morning I-80 was SO bad there was literally 6-12″ of snow packed on the road.  We decided it was completely un-safe to be driving in those weather conditions with SO much weight and money on the trailer.)  The snow is stopping, but the winds are still terrible and drifting snow is now the problem.  We are hoping the insterstate will be better tomorrow and will try to leave early morning and see how far we can get.  We wanted a blizzard this year, just not on the trip!  🙂  Before we got off I-80 we were encountering white out conditions where the trucks 1000′ in front of us would dissapear.  Then the trucks behind us decided they wanted to go faster than 25mph and decided to reopen the fast lane.  UGH!  The funny thing was is they would get in front of us and then find we had been following a whole line of trucks and they would end up having to pass a line of at least 10 – 15 trucks to go faster.

We are safe and sound, no problems to speak of and really love having all wheel drive!  The  brakes on the trailer have worked great and have had no problems stopping, even on the ice.  We got about 14 mpg heading out to UT and gotten from 8mpg to 12mpg on the way back.  Our first part of the return trip through WY was with a tail wind and that is when we were getting 12mpg.  The Eastern most part of WY and NE has all been with the North wind and doing about 50 is about all we could do at about 8mpg ( before the snow started)!

Oh, and I was not calling Fred *just* to complain about the tires!   Grin  I really wanted Fred to know how much I appreciated him letting me borrow his trailer.  It truly has done a great job.

We also got to meet up with another silent board Bus Nut — Kent.  It was great to meet another Nut and shoot the breeze for awhile.  It was also great to have another set of ears with as we started and ran the motor to help me know what I was and was not hearing.  Thanks a lot Kent for coming down.  It was truly appreciated.

That Cummins is one smooth machine!  I couldn’t believe how there was no vibration from it even when running at governed speed.  I can’t wait to have it in and working.  🙂  This should be one great adventure getting it all to work!

-Brian and Hilary Diehl
Stuck in NE — lovely North Platte.

February 25th:
So, we got up this morning and hit the road by 5am.  The roads were great, but we were the ONLY people on the interstate for about 2 hours.  We learned later that West bound I-80 was still closed and apparently all east bound trucks were getting their Sunday morning rest before hitting the road.  We encountered some bad roads in western NE and eastern IA, but otherwise the driving was just fine.  It was great to not deal with the 50 mph wind gusts from the North today!  We came home to lots of snow, but our neighbor had already run his snowblower over our driveway.  What a blessing to not have to shovel 10″ of snow off the drive.

This was at our hotel in North Platte after the blizzard conditions had slackened off later on Saturday.  We were able to get the last hotel room thanks to Hilary’s Mom calling ahead and finding this hotel on the internet for us!  What did we do before the internet?


Sunday night, home safely … tired, but relieved to be home!

Monday night my friend came over and in 2 hours we were able to  get the truck front off the trailer.  I only had two “normal” engine hoists (2 ton).  With a little careful work and one close call we got it off the trailer.  Thanks Kevin James for your help!  I couldn’t have done the job alone.


March 14th:
I am very happy to report I got the cab off the truck frame tonight.  I am only a few transmission mount bolts away from being able to remove the motor from the frame or the frame from the motor depending upon what works out easier.  I am very happy with how EASY all the bolts have come undone.  Even the big 1 3/16″ bolts have come apart with minor fanfare.  I have been absolutely amazed at how little rust is on this thing.  So, by this weekend I hope to have the motor/tranny in the garage and ready for the next phase.  I also hope to have the cab all cut up with new Dewalt Sawzall by the end of this weekend.

Here is a picture of what it looked like this evening right after I pulled the cab off the frame


I ended up just removing all the frame from around the motor/transmission.  This ended up being easier than trying to lift the engine/tranny out of the frame.


March 23rd:
Well, I had wanted to use a hydraulic system to actuate my clutch.  However, I can’t find any used truck parts and really haven’t looked at what new parts would cost.  Do any of you have your air assist parts left over from converting your manual over to automatic?  I’m thinking I could us an air assist to make using my existing transmission shifter cable as a clutch cable workable.  I.E.  I’m thinking of using my existing automatic tranny shifter cable as the clutch actuator cable.  Then, I would hookup an air assist on the transmission to reduce the actual load placed on the cable and make the leg work easier.  Is this a workable idea?

I never did end up with any help on the old Bus “mouse trap” systems.  Apparently I didn’t connect with anyone who still had their air clutch system left over after they converted over to an automatic transmission.

March 25th:
Well, things went much better this weekend than I expected.  I was able to get the motor/tranny out of the bus by the middle of Saturday!  I used the rest of this weekend to get the engine frame rails cleaned up and ready for reinforcements.  I got the muffler and heat shield removed along with the fiberglass on the passenger side.  Now I just need to make my cardboard templates.  Once I have templates done I can get the metal cut and get the frame rail reinforcements welded on!  I can’t believe how easy it actualy was to get the motor out!

The ISM/AutoShift are now in the garage and the bus is parked where I had put the front clip of the engine after unloading it from the trailer.

2007_0324_removingdetroit01 2007_0324_removingdetroit02

Yep, I got this out with just my wife and I pushing and pulling!  There is one hydraulic engine hoist on the front and the bell housing is resting on a “wheely cart” I made.Yep, I got this out with just my wife and I pushing and pulling!  There is one hydraulic engine hoist on the front and the bell housing is resting on a “wheely cart” I made.


The “hole” ready to be cleaned up, beefed up, and loaded again with the new motor!


I had to fabricate a new alternator mounting bracket.  I purchased a used 270 amp 24v belt driven alternator from Nimco.  I couldn’t use the alternator of the 6v92 because it was gear driven and the ISM does not have any provisions for a gear driven alternator.

2007_0407_140813aa 2007_0407_140825aa

April 15th:
I did my first test fit yesterday of the new powertrain setup.  I was able to validate all my alignments and prove my motor mounts were setup correctly.  However, I also discovered that due to those pesky jake brakes I will need to modify the floor a little bit.  (The jakes make the motor ~ 2″ taller.)  I need to get the motor 3 1/4″ back more.  Oh well, I’m not giving up the jakes, so the floor has to go.  I didn’t see any other clearance issues while I had the engine in.  I was able to get it in and out in one day.  I finished the day by completing the welds on the motor mounts now that I know I don’t need to cut them apart and adjust them.  I’m also including a picture of my alternator mount that I finished last week.

April 16th:
I’d thought of the lowering … but I start to have interference issues with the tag axle crossover tube and I’m not wanting to drop the oil pan that much closer to the pavement.  I also will be able to run a standard MCI blower drive belt if I keep the current engine height (same as the detroit at the crank).  I don’t expect the floor modification to be that bad.  The main structural strength is up further in the flooring system, which means I’m not going to be modifing large load carring structural members.  I’ll need to reinforce around my cut, but I won’t need to worry about handling extremely large loads.


I had only “tack” welded up my motor moutns to the rail so I would be able to make small adjustments if necessary.  No significant adjustments were needed during my test fit.


This picture show how the valve cover intersects the floor.


April 17th:
Jim, (Jim Shepherd) Thanks for the thoughts on the belt alignment.  I did the best I possibly could for alignment and hope I got it right.  Time will tell!  On the tensioner I think it is okay as I used the existing old belt off the truck.  So, the belt has already gone through all its stretching.  Also, the idler is smooth… no ribs so the belt should run true from the alt. back to the crank.

On the blower drive and A/C compressor I have a machine shop helping out.  I’m cutting apart the old detroit pulley and running the blower drive off the crank shaft by welding the old fan drive pulley to the existing alt. pulley.  Then I’m welding the original 2 groves worth of A/C compressor pulleys to the existing Cummins accessory drive pulley.  I think it will work great.  The only thing is I will need to find new belts for the new shorter distance from the accessory drive to the A/C compressor.  I haven’t done this yet ….

May 2nd:
I pulled the Eaton Autoshift off the Cummins ISM tonight.  The clutch looks to be in great condition — maybe very recently replaced.  I was very pleased with how easily it came apart … much easier than I had anticipated and worked myself up for!   Grin

However, it looks like the clutch brake was not replaced when the clutch was.  Before I call and try to get a replacement I thought I would ask for an education on things I should know or ask for.  What say ye … anything I need to know before I call … or do I just call and ask for a replacement?  If it matters, the clutch is an IATCO M-496 — dual plate clutch.

The clutch brake ended up being an $18 part.  One of the cheapest replacement parts I had to buy!


Here I am building out the wiring harness for the front of the bus.  This includes all switches, gauges, connectors to the bus 24v system and transmission gear shifter harness wires.


This is the board where I interface the bus 24v wiring system into the engine 12v control system.  I just used cube relays to perform the interfacing.2007_0506_frontwiringharness4

Here is the 42 wire harness in rough form for running from the engine at the back to the front of the bus.  This is May 28th.


This is my clutch pedal setup ready to be bolted in the front.  This is the second iteration after I learned the first plan of using a cable pull would not work.  This setup is to use a hydraulic connection.


May 29th:
This evening I finished the connection of the main wiring harness from the front to the back by plugging in my new front wiring harness to the “extension” cable I created to run from the front to the engine.  What a FEELING to look at that connector and know I am getting so much closer to S-Day (Start Day)!  The deutsch connectors are really awesome setups and so easy to work with.  I’m really glad I decided to reuse so much of the original wiring harness, which is why the deutsch connectors are getting used.

I also sent out some of my intake manifold parts and turbo outlet parts to get dual 3″ tubing added on to the single inlet and outlet.  So exciting!!!!  I think I’ll be looking at rolling the engine back in to the engine compartment sometime this weekend and if it all fits good it won’t be coming back out!

June 5th:
I got the ISM in the bus last night!  Sorry, no pictures yet ….  Tonight I tested removing the valve cover so I can be sure it is possible given the tight space.  I got the engine cradle bolted down and started hooking up all the wiring, plumbing, etc….

The engine fit good and never did have to come back out!

June 11th:
As many of you remember I’m putting an ISM and Eaton Autoshift in my MCI 96A3.  This weekend I got my clutch linkage, pedal assembly hooked.  Since I could pull the clutch arm myself by arm force alone I was hoping a cable pull setup would work.

Well, actuating the clutch with just a cable pull is not going to work.  It simply takes too much force to be realistic.  So, I need to go hydraulic.  I need a master cylinder and slave cylinder to make this work.  Does anyone have ideas of appropriate parts?  I’m not even sure where to start looking and will appreciate any and all ideas.

After some fairly lengthy discussions on the bus board I came up with my own system.  I purchased a matched master/slave cylinder from Wilwood engineering.  I then pulled a used vacuum booster off a Lincoln towncar.  I hooked up a vacuum pump from Stainless Steel Brakes to “power” the booster.


Here you can see part of the slave cylinder in the bottom center off to the left of this picture.


Here are pictures of the motor going in for the final time.


Yeah, I know, the engine is not shinny clean painted.  I had considered painting the engine.  In the end, I just didn’t want to take the time to pull everything off the motor so I could paint it correctly.  I figured it is in the back of the bus and will continue to get dirty and I really don’t mind it


July 16th:
So, my progress ….

I am completely hydraulic on the clutch now.  I used a matched slave/master cylinder from Wilwood.  I also bought a vacuum pump and a brake booster ($22) out of a 99 Lincoln town car.  The clutch pedal can be fully depressed without vacuum.  With vacuum it is like slicing butter with a hot knife!

The motor is completely in.  I have the drive shaft hooked up now and completed the lower cooling system fabrication this weekend.  I have to fabricate the exhaust from the turbo to the muffler and the intake from the air filter to the inlet on the turbo.  The last part I needed for the intercooler piping arrived today and that finishes the intercooler system.

The drive shaft had to be purchased all new as the shaft I had could not be shortened enough due to its design.  That was a major bummer for me since I had to put a new drive shaft in after I bought the bus due worn out u-joint sockets on the yokes.

I have completed a power on test with amazingly little fan fare.  No blown fuses, no popping breakers, and no smoke let out of any electronics!  My power on test shows good communication between all computers and no warning lights on the tranny shifter tower.  I have no warning lights installed for the engine computer yet, so don’t know any engine computer status.  However, I do know it powers on enough to satisfy the Autoshift as all warning lights go out on the shift tower once the ignition on signal gets to the engine computer.

I’ve got a bunch of work and home stuff going on this week, so don’t expect to get much done this week.  I’m hoping for a start test before the end of the first full week in August.

This shows a better picture of the slave cylinder.  The red is the battery cable to the starter.  The black loom above the slave cylinder is the engine wiring harness.


Here is the vacuum booster connected to the master cylinder and  actuating arms with mounting bracket.


Here is the fully connected master cylinder in the compartment below the drivers floor.


Here is the exhaust system all welded up and ready to go.


Another view showing the exhaust.  The green tube is the oil fill for the engine crankcase


This is the MCI stock air filter housing modified to clear the exhaust pipe.


Here is the final setup after a couple of test drives!


2007_0803_final4 2007_0803_final6 2007_0803_final8

There is an inter-cooler in front of both the driver and passenger side radiators.  The inter-coolers have about 300 cubic inches of additional “core” area compared to the truck inter-cooler.  I’m hoping this is enough to make up for the fact there is no ram air affect.  There was some concern expressed by some of my friends about how well the engine would stay cool with so much of the radiator covered up by the inter-cooler.  So far the hottest day I’ve driven in was 86 degrees.  No cooling problems so far.

The inter-coolers are plumbed using 1/8″ thick wall 3″ aluminum tube.  Given the two inter-coolers and plumbing to each with the 3″ tube I compared this to the original 4″ tubing on the truck.  The cross sectional area of two 3″ tubes is the same as the cross sectional area of the 4″ pipe.  This means I have much greater air flow restriction with this setup than the truck system had with the single 4″ pipe.  I also have lots of 90 degree connectors further causing air flow restriction.  This is not perfect from an ideal efficiency standpoint, but it has worked okay so far.  I think the consequence of my setup is two fold:  1) I probably won’t get the full 400hp from the system; and 2) I won’t get the fuel economy I might have been able to get with a single side mounted inter-cooler.  Time will tell … 2007_0803_radiator1 2007_0809_191646aa

July 25th:
Well, the good news is the motor started right up no problem at all!  So exciting!  The transmission works great …. goes into gear as it should!  Bad news is I can’t get more than 1200 rpms out of the motor.  The check engine light is lit, but the only code in the computer is 319 — real time clock lost power.  So, I’m going to be calling Cummins tomorrow and see if they have any ideas on how to find out why the computer is keeping the check engine light on, but not giving me any codes.

Man am I excited!  I can’t believe it actually started up with no issues!  I’ve had it down to the end of my driveway and back a few times checking out how it works.  1st gear sure is low (walking speed)!  Now my wife wants to know where we are going this weekend!   Grin  I’ve had to remind her we are not quite ready yet for an outing!

July 26th:
I talked to Cummins today and they aren’t sure what could be the problem without any “real” trouble codes to start working from.  They had me “recalibrate” the throttle pedal, but it didn’t make any difference.  The engine responds perfectly to the throttle until 1200 and then it doesn’t matter how much more you push down, it won’t speed up any more.  BTW, it did not work like this before, so I know it should respond all the way up to 2100 without any load.

So, looks like I’ll have to have a tech come out and hookup with the “Insite” tool to figure out what is holding the engine to just 1200 rpms.  I think it will be some simple “protective” measure possibly as a result of having had no power for the past 4 months.  We’ll see….

July 31st:
Well, I had a Cummins mobile tech come out and take a look at the engine computer.  It turns out some of the “features” defaulted to some very bizarre values.  One of the problem values was “Maximum switched engine speed”, which had a value of 1205.  So, the tech simply upped the value and wala, the engine now revs correctly!  I had the tech set some of my other features/parameters as well.  The computer also indicates that the engine has already been reprogrammed to its maximum 450hp setting. (sweet!)

Later I learned he was looking at the wrong thing.  The engine is currently programmed for 400 hp and 1450 lb/ft of torque.

Before the tech left he says “so, you want to take it for a drive so I can make sure no other fault codes come up while we are moving”?  I of course said “Sure!”.  So, I disconnected shore power and took off down the drive way.  Imagine my complete surprise when the tranny (Eaton Autoshift) was already in 3rd by the end of the driveway!  Wow, it works! I can’t believe it did autoshifting like it was supposed to!  I mean, all that work over the past 5 months and my wiring was correct on the very first try.  SWEET!  Man, I’m so excited now I almost forgot to slow down for the end of the driveway to make the turn onto the street!  We went around the short block and the tranny performed flawlessly.  It is in 5th gear before 20mph and all shifts are supper smooth and fast.

We stop in front of the house again and the mobile tech finishes setting some other parameters for me like my diff gears and tire rotations/mile.  Then, he offers to ride again while we make sure all the final changes are okay with no new codes being set in the computer.  So, off we go for a 3 mile loop. We speed up and high range is selected with no fanfare (5-6 gear change).  Then stop for a stop sign.  The next shift from low range to high range “hunts”.  The next stop light and as we accelerate the tranny gets hung up between high and low range and we drift to a stop.  I try all kinds of things to get it out of “no mans” land, but no luck.  Then in a moment of genius (my own delusion!) I decide to pump down the air tanks.  Dumping the air does the trick and after building my air pressure back up again the tranny is happy to go back in 1st.  Start going and it hangs up again between 5th and 6th.  Dump my air pressure and restart….  Then I decide to not allow the tranny to go to high range and stay in 5th all the way back home.  Boy, 5th sure is slow — about 23 mph at 2200rpm!

So, tonight I tear apart the range select valve and cylinder assembly to find out why it is getting hung up.  I have a bad air leak out of the range select valve and I think if I solve that air leak the range split shift should work correctly again.

Of course, after all that I had a hard time going to sleep last night.  What an exciting day after all that hard work to have it run the way it is supposed to.  Those Jake Brakes are cool too!  Grin

Now, due to so many shifts before 20mph it is a little slow off the line.  Each shift is fast, but there are still a lot of shifts.  Get it up into 6th and higher and put the foot into the throttle and you can really feel the engine come alive.  Wow, does it accelerate fast!  I can’t believe how different that 4-stroke behaves from the old 6v92.  It sounds different, accelerates like nothing I’ve ever experienced and cruises along at 1200 rpms!  The one time I had high range without problems I hit 43 mph and the tranny was running in 9th gear with the engine loping along at 1200rpms.  It was not lugging at all and when I put my foot into it just a little you could feel the jolt in the backside as it poured on the power.  Gotta get that high range valve working right so I can get on the freeway and see how it handles the hills!

July 31st:
Turned out to be a simple fix.  I tore apart the range valve and found a bunch of crud in the high range selector air ports.  There was enough rocks in the air ports to completely block the air flow.  A good clean out job and put everything back together was the ticket.  It now shifts smoothly and quickly into and out of high range.  My air leak is even gone as well!   I’ve now got about 40 miles on the repower.  Nice to have the tranny shifting good.  Now I need to deal with my turbo charger …. — in another post.

August 3rd:
Put the reman turbo on last night and then got about 38 miles of mostly interstate driving in.  It ran great with the exception of one of my inter-cooler pipes popping apart.  I’ll have to come up with a permanent fix for that.

So, it runs great!  My inter-coolers work wonderfully and I had no overheating problems.  In fact, in 85 degree weather it takes a long time to get the engine up to operating temperature.  I wonder if my thermostat is hanging up partially open?  I’ll look into replacing that when I drain out the water to replace with coolant.

The thermostat was replaced, but still didn’t make any difference.

The Eaton is shifting great!  I’m very pleased with that 600,000 mile gamble.  It appears to work EXACTLY like it is supposed to.  The shifting program is very intelligent.  Getting on the Interstate I have some rolling hills to go up and down for about 4 miles after hitting the highway.  At about 63 mph I pull my foot out of the throttle and the tranny shifts into over drive.  The engine is then turning over right around 1200 rpms.  When I hit the first hill it drops back into 9th (direct) and stays there even on the backside of the next hill.  It will then stay in 9th until I speed up a little bit on the flat to let the tranny know the load level has gone back down.  Cruising along at 70+ is a quiet experience as the motor is ticking over in the 1300 rpm range and has no problem managing the speed at that rpm even into a head wind.

I’ve got a couple of wiring issues to clear up on the original bus wiring side now.  Gotta get those taken care of next.

I’ll try and get some pictures up this weekend so you can see what it now looks like.

So, far so good!  oh yeah, and love those jakes, especially in the upper rpm range!

August 9th:
Right now I have all the inter-cooler pipes torn off.  I just got them back from a welder who put a pretty good bead all the way around each end of each pipe.  I’m hoping this will allow me to explore the full power of the engine!  I have to get the pipes back on and put a new thermostat on before the next trip.

August 31st:
Looks like our “brand new” reman turbo is on the brink.  We made it about 1/2 hour from home when I noticed it was getting oily looking in the exhaust.  Stopped and took apart an inter-cooler line and sure enough oil in the pipe! 🙁  UGH
So, we had to turn around and come home.    We only had about 400 miles on the turbo and this past weekend when I had the inter-cooler pipes apart there was no oil in them at all.  So this is a new issue …  It really sucks since this is supposed to be a brand new reman turbo.  I guess I’ll pull it off some time this weekend and talk to Cummins on Tuesday to find out if they will honor the warranty.  I expect them to, but …
Man, we are losing out on our 4 days of relaxing up in Northern MN.  🙁 🙁  boo hoo

Okay, enough crying and back to the regularly scheduled programming.  At least we figured it out and are not stuck on the side of the road some where at 0 dark thirty in the morning!

October 13th:
When I designed the rear floor relief for the valve cover of the ISM to slide in far enough I did not leave enough room for the last valve cover bolt to be put on.  When I first started running the bus I didn’t worry about not having that bolt.  However, after a period of time I was getting oil seepage down the back of the valve cover where the bolt was missing.  So, I designed a little bracket to apply the equivalent of the bolt pressure.  This bracket was able to be accessed through the rear floor engine access hatch.  While the bolt down was missing I never had any problems with exhaust smoking during throttle at idle conditions.  However, after I put the bolt down bracket on the valve cover I started having problems with significant quantities of smoke coming out the exhaust during power off conditions like slowing down a freeway exit ramp.  The very first drive after I put the bracket on was our Labor day weekend.  As you might recall we ended up canceling the trip and coming home because it was smoking SO bad I thought the turbo had failed.  We put a new turbo on and a significant portion of the smoke went away.  However, not all of it disappeared.  I even brought it in to Cummins and they could not find anything wrong.  Their theory was possibly an injector hanging up every so often.   However, I had my doubts about that since the smoke would be blue with the jake brakes off and white with the jake brakes on.

Well, over the last 2 months I’ve been trying to figure out what would cause this problem to come on all of a sudden when it wasn’t doing it before.  Finally I put the pieces together and realized that the problem started only after I put the bolt down bracket on the valve cover.  So, I developed a working theory about the problem and decided what might be happening was the valve cover breather was not allowing crank pressure out to atmosphere and therefore on throttle lift off the pressure on the inside of the turbo oil galleries exceeded the pressure on the exhaust side thereby forcing the oil through the oil control rings and out into the exhaust stream.  Today I took the valve cover vent off and found out my theory was correct.  Inside the vent was a bunch of metal mesh designed to catch large “chunks”, etc and to filter the air going out the vent.  This mesh was completely CLOGGED up with 600,000+ miles of GUNCK.  YUCK.  I pulled it all out and put the vent back together.

I am now happy to report a smoke free driving experience.  So, sometimes it is the simple things that are necessary to solve a problem.  I am very glad to be able to come off the freeway and not be embarrassed about the smoke coming out the tail pipe.  After all, part of the benefit I saw in the electronic 4 stroke was the clean exhaust.  The entire time I drove on my 20 mile test trip earlier today I had not a bit of color at any time!  Yeah!  What a relief!

(Middle of October, 2007)
So, I have a couple of thoughts on life with the new powertrain.  The motor is AWESOME!  I simply am addicted to the power and torque available with the ISM.  It truly is amazing what it will do compared to the old 6v92.  I never would have imagined such a difference.  Truly, I can look at a hill and think to myself, how much FASTER do I want to be going when I get to the top.  I used to think, how SLOW will I be going when I crest the top of the hill.

On the tranny I have mixed feelings.  Given my budget I’m very pleased!  However, if I had more money I think a b500 would have been the better tranny.  I am literally in 6th gear as I clear an intersection.  All those shifts make starting off the line very slow.  The tranny is pretty darn fast at shifting, but it still takes time.  I’ve tried the skip shifting method and really don’t think it gets me much additional time savings for the effort.  The transmission itself has worked flawlessly since I got the parts in need of replacing replaced.  It truly is a very slick bit of engineering!  I can run in overdrive at any speed over 60mph.  60mph in 10th is right around 1200 rpms or so.  At any speed over 70 or so the transmission does not automatically downshift to 9th for any hill I’ve yet to encounter.

I’ve put in one tank of diesel so far.  The mileage on the first tank was 8.2 mpg.  This includes all of my testing miles, idling time, tinkering time, Webasto usage since last November when I bought the tank, etc.  I’m hoping this next tank gives me closer to 9.5 or so.  I’ve only got about 260 miles on this tank, so have a long way to go before I can determine what it gives.

So, it was a lot of work, and I’m still working the bugs out of a few things, but I love the combination.  For my money and time it was well worth the work!  I have no more overheating problems.  I have about 1/3 of the air flow out of the blowers blocked off and had no heating issues last weekend when we were in the upper 80s, low 90s.  Set it how fast I want to go and just cruise!

If I could do it over I think there are two things I’d do differently.  I’d put a non-ceramic clutch on and would use a hydro-boost instead of a vacuum pump for the clutch assist.  I figure eventually the vacuum pump will die and at that time I’ll change over to a hydro-boost.  The clutch I hope to have to live with for at least 10 years!  The ceramic clutch is very touchy and is essentially impossible to slip.  It just grabs!  Eventually I hope to get the autoshift reprogrammed so I can start out in 3rd or 4th if the grade is right.  The current program only allows up to 2nd gear starts.  That is okay for now and helps protect my driveline from the clutch “grabbiness”.

(July, 2008)
I discovered I needed a “turbo cut off valve”, or E-Con valve in Cummins parlance.  I’ve been having what I thought was a leak in my intercooler system, but couldn’t find it.  Well, while going up to the parking area at Devil’s Tower National Monume during our Summer 2008 vacation the air system called for air and when it reached the purge cycle I heard the loud sound of air escaping come back.  Unlike the normal purge cycle that should quickly end, this did not and of course my air was not leaking down.  Later on it happened again and I noticed when the purge cycle started it felt like I lost some power.  So, I called my friend at Cummins with my motor serial number and he told me I had a Holset Type-E air compressor.  This air compressor needs some back pressure on the exhaust line at all times even when not compressing air.  Cummins makes the E-Con valve for this purpose.  I bought one out in Boise and installed it while on my trip.  I enjoyed the rest of the trip back without the sound of escaping air and better throttle response.  🙂  I even think I had a little bit more power!  My wife even commented on how she noticed a difference.

During my trip back from Idaho with the E-Con valve I got a tank @ 9.0 mpg and 8.7 mpg.   These are my best mileages and were attained while towing the Grand Cherokee.  I should see a bit better on my shorter trips in MN where I don’t tow Cherokee.

(November, 2009)
Fuel mileage is ranging between 8.2 and 9.3 miles per gallon.  The average mileage for the past 8,800 miles is 8.7.  The worst during this time was 7.9 driving into extremely heavy head winds (estimated at 25+ mph) and the best was 10.0 with a decent tail wind (estimated at 15+ mph).  So, I have not seen the consistent 9+ mpg mileage I was hoping for, but 8.7 over 8800 miles is not bad!  I’m really happy to have cruise control, excess power, and enough gears for any situation.