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dljosephson · 02-24-2009, 12:18 AM

Thanks to Mike Leary and others who answered a bunch of questions last year ... I bought the 310 near Tacoma, Washington, from a fellow who lost coolant going over the mountains near there. He thought he had toasted rings and liner on one cylinder, my hunch was that it was a bit worse. Fortunately it wasn't a *lot* worse than I imagined. An old friend of mine and ex aircraft mechanic near there was looking for a project, so long as I wasn't in a hurry. He thought it would take a month or so, it ended up being almost four, but I think I have a really nice MH with a very meticulously redone engine. The next few months will tell! I thought I'd relate some of the things we learned in the process.

First, this is a stock 310 (on Fred's Airstream Archives as exhibit J) with the 6BD1A engine and aftermarket turbo added by Airstream, THM475 trans, GV overdrive, Alcoa wheels, near new tires and batteries, just under 100,000 miles. 1800 rpm propane genset running well with few hours. All maintenance records from about 1986 on. There were a lot of improvements made by the two POs including front end upgrades, a bigger fuel tank, marine style fuel totalizer, water spray auxiliary cooling and a pre-oiler pump (which also allows you to change the oil by pumping it out), a fancy stereo and Select Comfort bed. It had been run on synthetic oil and that seems to have limited the damage caused by the overheat.

I picked up the Airstream in late October and drove it ~40 miles to another friend's yard where the work was to be done. Aside from a lot of white smoke at startup it drove very well -- a little underpowered but not bad for 5 cylinders out of 6. That was a good start and gave me confidence to proceed.

We found very little available in the way of manuals. We had the basic engine manual and the AS book. Hamilton Engine in Portland is the distributor for the northwest and they were very helpful. From Helm we found a book for an Isuzu truck with the same motor, which contained all the stuff that was missing from the engine book. Still no parts book, but it turns out that this isn't too relevant anyway because there are *very few* original Isuzu parts left for this vintage of engine. Discussing this with some marine diesel rebuilders confirmed it -- many of these parts are so plentiful in the junk market and from second sources that you can't get them from Isuzu anymore. Eric had worked on a bunch of different diesels in the past but not an Isuzu. He says he's impressed.

Head off, have a look inside. Oops, a little more damage to the rest of the pistons than we might have thought. It got *really* hot in there. The liners actually looked okay, just a slight ridge near the top, but the pistons got so hot that most of the piston ring grooves were galled. According to Hamilton, we got the last complete set of Isuzu factory liners in North America, and the last puller tool for that size.

It is a huge deal to get enough of the front end apart enough (38 bolts?!) that enough space can be made to get the oil pan off. Once up and open, though, things came apart without trouble. Liners are sized with special codes, but this is apparently optional. Eric chose liners for the best fit. The head showed further evidence of heat -- the intake valve springs were compressed far beyond tolerance. There was only a slight warpage though, so a short run on the milling machine was enough.

Lots of preventive inspection and replacements. Everything rubber, of course. Found large leaks in the flexible hoses connecting the intercooler and some dicey hoses in the cooling system. Of course the plastic Y fitting has been replaced with metal, and the cute Prestone cooling system flush fitting removed. Turbo checked out OK, had been replaced by a PO. Injector pump checked out OK. There are remaining minor electrical issues but that's my department.

Things got very hot in the engine compartment, but some things seemed to have been hot long before. The appropriate heat shields were there around the really hot bits, but it seemed that a lot of wiring and hoses had melted or degraded from being too close to metal that was too hot. There is a reason to mount hoses and wiring in looms away from these things, not just drape them anywhere! There doesn't seem to be a baffle around the sides of the radiator, allowing a lot of air to simply spill around it rather than going through.

Everything went back together last week and cranked up just fine (I had a voice mail from the mechanic featuring Gene Wilder as Young Frankenstein saying ... "it's alive!") I haven't heard it yet but Eric says it's the smoothest running diesel he has heard in a very long time. We are running on Delo 400 for the break-in period. Next weekend it comes home to California... will report on anything new that we find.

Now I have to take some big trips to get the mileage on the engine that it's supposed to have... anything else I should know?

--
David Josephson
Santa Cruz, CA

overlander63 · 02-24-2009, 07:36 AM

Quote:

Originally Posted by dljosephson

We are running on Delo 400 for the break-in period. Next weekend it comes home to California... will report on anything new that we find.

Now I have to take some big trips to get the mileage on the engine that it's supposed to have... anything else I should know?

--
David Josephson
Santa Cruz, CA

When you drive it home, try to avoid the freeways and Interstates. Vary your speed, and avoid full-throttle acceleration. You will be breaking in some new parts, and should treat it as a new engine. The parts will need to get to know one another before "serious" work.
Good luck.

Mike Leary · 02-24-2009, 08:49 AM

Good for you! Glad to hear she's about ready for a shakedown cruise. I'd putt down the
coast, no climbs of any consequence. The Delo will work fine, I seem to remember you
changed both fuel filters, take a spare or two for the lower, it's easy to change if she
starts "bucking". Check the rear air bags from time to time by draining the accumulator
tank of moisture & adding up to 125 psi at a tire store, buy a good gauge with a short
hose attachment to check, I would not trust the on-board compressor until you've
gone through the sixty-forty switch and wiring. Again, good luck, hopefully we'll see
you on the road. Feel free to contact me through a PM or on the forum.

Diesel Phil · 02-24-2009, 09:38 AM

Great post! Good Luck,have fun. Phil&Sandy

dljosephson · 02-25-2009, 12:14 AM

Yes, good points -- looks like more snow this weekend so will probably head out to the coast (friends in Bandon) and take 101 south instead of 5.

Mike Leary · 02-25-2009, 07:49 AM

You don't want to be down in Southern Oregon on I-5 this time of year. Safe trip, take pics!

jking · 03-02-2009, 07:15 AM

Hey! I want to know what you have for an intercooler and where it came from ... the original 6BD1A didn't have one, and I still don't have one in mine. BTW we have about 160K on the odometer (hard to be accurate after three changes of speedo/odo).
Jamie

cooperhawk · 03-02-2009, 07:51 AM

An inter cooler is used to cool the air going into the engine from the turbo_charger. As it is the turbo-charger gets its power to turn from hot exhaust gases, which in turn build up the heat in the turbo itself, which are then transferred to the air as it is pumped through it into the engine. The inter-cooler cools the gases before the enter the engine.

Mike Leary · 03-02-2009, 09:53 AM

Quote:

Originally Posted by jking

Hey! I want to know what you have for an intercooler and where it came from ... the original 6BD1A didn't have one, and I still don't have one in mine. Jamie

Ditto here, though I've always heard that would be the way to go. I'd like to
know where it came from too, though I'm still crusin', burn no oil, have only
replaced the turbo, had the injectors done and valves adjusted.

jking · 03-03-2009, 07:09 AM

Cooperhawk - that's a good description but it doesn't help me find one that will fit on my 6BD1A, which is what I'm after. Any ideas? Jamie

Minnie's Mate · 03-03-2009, 07:18 AM

Congratulations on your motor home acquisition and rebuild on the engine. A diesel Classic Airstream motor home is a prize worth saving.

When you get her home, post lots of pictures. We love pictures!

overlander63 · 03-03-2009, 07:24 AM

Quote:

Originally Posted by jking

Cooperhawk - that's a good description but it doesn't help me find one that will fit on my 6BD1A, which is what I'm after. Any ideas? Jamie

Try a salvage yard that specializes in big trucks. We had a fleet of Isuzu FSR trucks with this engine, and they all had intercoolers. It would be a good idea to take measurements of the area the intercooler would go in to confirm the FSR intercooler will fit.

cooperhawk · 03-03-2009, 07:26 AM

Quote:

Originally Posted by jking

Cooperhawk - that's a good description but it doesn't help me find one that will fit on my 6BD1A, which is what I'm after. Any ideas? Jamie

I don't have one either, but if I wanted to go to the trouble I would find a used Isuzu truck that is junked out and see if it had one. If it did I would salvage it and try to re trofit it. Remember, takes another cooling core. that means radiator, ac, trans cooler, and then the inter cooler. Lot of radiators.

dljosephson · 03-17-2009, 12:03 AM

The intercooler in this 310 was definitely an aftermarket affair. I have all the docs for it however and will post. Y'all like pictures, will do some of this

They clearly had a challenge getting the air out to the cooler and back, a lot of cutting and brazing of the induction piping. But it works fine and we located some spiffy molded silicone rubber hoses that replace some dodgy cloth/rubber duct that was in there originally.

dljosephson · 03-19-2009, 02:05 PM

Apparently Eric didn't take his camera very often, but there is one set of photos he sent, which I have cropped and posted in the gallery under "why you don't want to run it out of water" #1 and #2 were worst, but three of the others were pretty bad too. But, the engine still ran, in fact made 60 mph on the highway from Tacoma to Gig Harbor (with about 2 pounds of turbo boost due to leaks, and 1050 degrees on the pyro). All fixed now

blacksheep · 03-19-2009, 03:56 PM

It's a diesel, no need to be concerned about break in procedures like a gas engine (unless the Isuzu manual calls for it of course!). Just get in it and GO!

Godspeed,
Trent

jjhypnotist · 04-21-2009, 10:52 PM

Hi Guys I have an 82 280 turbo deisel that runs well however my boost gauge does not work and It crawls up hills... I am wondering if my turbo is gone and need some direction here...

Also anyone who has those missing manuals I.E.. cross reference to other Isuzu parts I would greatly appreciate...

On another note I put a gear vendors in along with a a new tranny and I cruise at 75 with out blinking till i hit a hill.......

Justin

Mike Leary · 04-28-2009, 02:06 PM

Quote:

Originally Posted by jjhypnotist

till i hit a hill.......

Get the boost gage replaced, you should be showing 5-10 psi when climbing. The diesel should have had a Allison transmission, 40 mph is the norm.

When you blow the turbo, you'll smoke like mad! Watch the tach, 75 seems a little much since 3200 rpm is max for the diesel. We've got a o.d. also and 65 is our crusing speed.

dljosephson · 04-28-2009, 11:05 PM

Just what Mike said, get that boost gage replaced. But, one other thing to check before assuming that the turbo is blown, check the whole air system around the turbo. Normally you'll hear if the hot side of the turbo has a leak, but you can just as easily have major leaks in the cool(er) side, especially if you have an intercooler. At least some, if not all, of these were installed aftermarket and the ducting to them can be quite flaky. We had many inch-long slits in the flex tubing connecting the intercooler to the induction system, so while the turbo was producing boost, it wasn't doing the engine any good.

jjhypnotist · 05-03-2009, 11:55 AM

I will be home this week and inspecting it.. as for the Gear vendors I am running 75 at under 2500 rpm.. the 82 came with a turbo 400 ... Not the Allison also the turbo 400 was of special make with flat cut gears... quite a pain.....

I had it replaced with a shift kit and Allison converter cost close to 2k ... The only thing I don't like about the GV overdrive is that you have to change fluids every 5000 miles...

Now on the turbo... how is that boost gauge connected? Is it vacuum or solenoid??

What else should I be looking at?

Honestly If I need to replace that gauge I have a few others that fit the bill...( for replacement that is...)

Also where do I find replacement hose for that turbo..?

Thanks guys,

Justin