Big Diesel, MPG increase ideas?

[Piotrsko]

I was the only male driver for the district and was known to ask difficult questions. The lad boss said don't lug the handshaker bus and I asked how do you know it's lugging. That's the answer I got. Fair enough.

Not sure on a split tank if there are humps that hold extra fuel, but that full forever until it isn't, is caused by the float not reaching the tank top. No easy fix for that since the float arm is too short. They are also famous for needing a burp during a fueling. Mine will add 4 gallons to the fill if I burp it.

The Zf6 is much tougher than the Zf5 except for the ford version in 2000 had a known issue with torque eating the input bearing on chipped trucks at low rpm and high load (trailer towing) Although it is supposedly the same trannie, the Zf6 in a chevy is rated for much higher torque inputs. I'm unsure if they are direct swappable. You'll want to lose the dual mass flywheel when you convert.

I am learning the transition years from flat hood to bump hood are full of one-offs. Found the warm up controller in the turbo, but mine is controlled by a heat rod like old chevy carb choke. Can't alter that, so im thinking of wiring it open.

I like your new relay. Mine is a Cali truck so I have a harness and controller that is EPA compliant and cost $200 to replace since it sets a CEL/sel warning light if even one glow plug is not working

[ps2fixer]

Yea I read the CA trucks have a shunt to read the amps that each glow plug bank uses and if it's too low it sets the CEL. I think I read something like 29 amps or less sets it off which I think would be more than one glow plug since people say combined they draw something like 190 amps.

It does seem that ford makes a lot of one off years, actually there's a bunch of 1/2 year things too. Like early 1999 has the older style 7.3L turbo setup (2in spider) but they designed it with an intercooler so it has the correct setup for the 93.5 (I think that's the starting year) to 98 trucks to convert them. The later trucks, 99.5+ have 3in spiders.

I haven't nailed the year down exactly, but 95 is 100% 7.3L PSD/OBS, either 93 or 94 was the turn over year from IDI to PDS/OBS. The IDI either had the option for a turbo, or they all were turbo for about a year, again another one off thing because the IDI's before that were NA. Of my understanding 95 and 96 are effectively identical, 97 had changes, 98, 99, and you mentioned a 2000 change xD. I think it was 2003/2003.5 for the turn over from 7.3l to 6.0l. It's almost sounding as bad as my dad's old 89 Mazda B2600i, every electrical thing on that truck was like $100(relays etc) and fitment was one year only.

I also found in the manual that what I read wasn't wrong on the tank sizes, but they were not for my truck, 155in wheel base is the "long wheel base" version of the truck with the extended cab. Front tank 19 gal, rear was like 18.2 gal. Did the quick math on what my tanks read before I filled the truck up and it seems like they were quite accurate, within 1-2 gal just doing the math based on 1/4 tank accuracy lol.

I'm looking at replacing all the fluids so I have a solid starting point in knowing when it was last done. Redline makes good stuff, but the price is nice and high too. Not sure what other options are solid for synthetic fluids. For the engine I'm planning on either Rotella synthetic for turbo diesels, or Mobile 1, the rest of the drive line I'm not sure on. The trans/transfer case calls for Synthetic ATF, front is 80w90 (don't remember if it specs for synthetic or not), and rear 75w140 synthetic. Goal is to get a bit lower rolling resistance in the fluids, easier shifts in winter (it's already slow to shift when it's ~20f for whatever fluid is in it now).

Here's the product list for reference for the redline stuff. Before I know it I'll have $1500 in fixing this truck up. Planning to keep it a long time, so the up front cost shouldn't be too big of a deal. Maybe there's just a better place to buy the fluids locally for cheaper, I'm cheap, but I also know oils are critical for longevity, same story with filters.

[cRiPpLe_rOoStEr]

Originally Posted by Isaac Zachary

One time I accidentally dumped the clutch at a stop and quickly stepped on the clutch again. The engine kept running, but as I tried to pull away the bus started backing up. I had changed the rotational direction of the engine and it was now running backwards!

Was it a 2-stroke Detroit Diesel? AFAIK only a 2-stroke engine can rotate to the opposite side quite easily.

[Isaac Zachary]

Originally Posted by cRiPpLe_rOoStEr

Was it a 2-stroke Detroit Diesel? AFAIK only a 2-stroke engine can rotate to the opposite side quite easily.

No, it was a 4 stroke inline 6 International. And yes, it was pushing the exhaust out the intake.

AFAIK, any mechanically injected diesel can do this since it injects at TDC regardless of direction.

[cRiPpLe_rOoStEr]

Originally Posted by Isaac Zachary

No, it was a 4 stroke inline 6 International. And yes, it was pushing the exhaust out the intake.

Exhaust leaking at the intake during valve overlap is not unheard of.

AFAIK, any mechanically injected diesel can do this since it injects at TDC regardless of direction.

Valve and injection timing would also need to revert, which is unlikely to happen, unless for some marine engines which have their valvetrain reversible due to some design features.

[Isaac Zachary]

Originally Posted by cRiPpLe_rOoStEr

Exhaust leaking at the intake during valve overlap is not unheard of.




Valve and injection timing would also need to revert, which is unlikely to happen, unless for some marine engines which have their valvetrain reversible due to some design features.

I don't think that valve and injection timing are that far off in either direction at idle speeds in a low RPM high torque diesel engine. Of course that would likely change as engine speed increases since the injection timing won't advance but would rather retard ATDC.

I'm sure I reversed the direction of the engine. It sounded different, strongly smelled like exhaust up at the front of the full sized (40ft?) school bus and 1st made it go backwards and R made it go forwards. I shut off the engine and started it again and everything went back to normal.

[cRiPpLe_rOoStEr]

Turning on the opposite side, there wouldn't be enough compression, as the charge air would be wasted since the exhaust stroke would happen right after the intake stroke, while the power stroke would generate vacuum.

[Isaac Zachary]

Originally Posted by cRiPpLe_rOoStEr

Turning on the opposite side, there wouldn't be enough compression, as the charge air would be wasted since the exhaust stroke would happen right after the intake stroke, while the power stroke would generate vacuum.

No. The exhaust stroke becomes the intake stroke sucking in air through the exhaust tubbing. The combustion stroke becomes the compression stroke. The injector is cam driven and fires what used to be just before top dead center, but now fires just after top dead center (and retards from there with more RPM's since timing is centrifugally driven.) The compression stroke is now the combustion stroke. The intake valve opens at the end of the what is now combustion stroke and becomes the exhaust valve. Now starts what used to be the intake stroke but it's now the exhaust stroke as it pushes exhaust through the intake manifold.

[cRiPpLe_rOoStEr]

That would be something interesting to look at, even though it's quite easy to understand why it would be so detrimental to performance.

[Piotrsko]

The issue that has been sitting in the back of my head: there's 25ish foot of "intake manifold" (muffler system) which should be full of exhaust that needs to get sucked back through the engine before it should run unless there was so much unreacted air left in the exhaust. Since I have a COX .049 engine that only runs backwards to the prop flip, I am good with everything else.