My Official OM617 Toyota Pickup Repower Thread

[JB3]

Originally Posted by t walgamuth

Did I miss where you spoke of the gear ratios in your rear end and so forth? Tire size too? If the gears are too tall for your engine you will have sluggish performance on hills and so forth. Is it a stick or automatic? OD?

Haven't read every word so sorry if I missed it.

Wouldn't the 90 v6 truck have a 4.11 rear end? He might of mentioned it too, I might have missed it, but if its a 4.11, should be pretty well matched? What tires are being run? I'm on my phone at the moment, but funola posted over in my astro thread a great gearing calculator vs rpm. Ill link it over later when I'm at a computer, very useful for nailing down just what works perfect for rpm vs gear for best power.

For power loss though id be checking the fuel filter, adjusting the valves, ect. Clogged stock fuel filter could cause major bogging.

[Stretch]

If you need help calculating expected rpms and road speeds I can help there - though I think JB3 and funola (?) found a site that does that for you. (Might be linked in JB3's astro build thread - started by whunter - confused yet?)

Anyway back to the suspected fuel problem - you need to refresh my memory too...

...have you checked

1) the lift pump
2) the filters
3) the IP timing
4) the camshaft timing

?

[OM617YOTA]

Howdy folks - thanks for all the replies and advice!

First, the gearing:

Rear end gears (ASSuming they're stock, ahem, to be verified) are 4.55's, according to the code on the door tag. Stock tires were 225/75r15's(diameter ~28"), current tires are 31x10.50's, for a difference in diameter of ~10 percent. Plenty enough to make a difference. 4.88's were available stock, and that's probably what I'll wind up converting to, especially if I can find a set used on CL. The truck has not been lifted.

I'm solid on the calculations to figure engine RPM from tire speed and rear end/trans ratios. Online calculators are also easy enough to find.

I also discovered that I was just plain not revving it enough. I gritted my teeth and left my foot down and by golly she spun third gear clear to 50mph before I chickened out. I need to remind myself that this isn't an 8.3l Cummins w/ a 2500 rpm redline. She's just fine revving to 4k+ rpms.

This thing will be getting a muffler. Currently straight piped, sounds like a banshee when wound out, barely moves. Noise : HP ratio just ain't there.

Fuel/Tuning:

Cam timing is perfect. Injection timing is as close to dead-on as I could get it with my homebrew equipment - within 1*. If anyone knows of a good MBZ mechanic in the Salem, Oregon area, I'd love to have someone who does this every day double check my work.

Fuel filters were replaced when the engine was installed. Once I had the power problem, I checked and the primary filter has visible garbage in the bottom of it now. I have spares of both primary and spin on filters, I'll change the primary out and see if I notice any improvement. If no improvement is evident, I'll change the spin on. Based on the advice of everyone who's ever looked at a diesel engine before, I carry spare filters and the tools to change them out in the truck with me at all times.

The transmission is making expensive sounding noises. She clatters at idle, sounds like a terrible knock until I put in the clutch and stop spinning the transmission, then all that's evident is the diesel purring. It's also making a clattery sound when backing up. I checked the trans fluid level before I drove it, I'll do so again. Used trans, $200 ish. I will NEVER add up what this conversion has cost me.

New suspicious oil leak. Appears to be the front main seal. Easy to see what the oil is dripping off of, hard to see where it's coming from. I'll have to wipe down everything and then take her for a spin and then see where fresh oil is.

Fuel mileage appears to be quite good, mid 20's. Diesel is still less expensive than premium gas, which is what all my other vehicles require.

Edit: Valve clearance was also checked + adjusted.

Danged stock alternator just isn't keeping up, either.

[OM617YOTA]

Just tossed some gear ratios into an online calculator. My 40mph 4th gear crawl up the mountain w/ 31" tires and 4.55 gears was turning that poor engine at ~2000rpms. Poor little diesel, no wonder she was struggling.

If that was only 2k rpms and she's SUPPOSED to spin faster than that normally, this thing is going to need a muffler. The noise gets pretty ridiculous.

[Stretch]

Well the oil leak might just be a valve cover gasket - check that first they do leak and nobody changes them.

(I forget) which transmission do you have fitted? If it is Mercedes I might be able to help.

[t walgamuth]

If you are short of fuel start by dosing the tank with biocide.

Yes, it will have to be wound up a bit to get everything rolling.

Do you have an estimate of total weight with the engine?

[Walkenvol]

Originally Posted by t walgamuth

If you are short of fuel start by dosing the tank with biocide.

Is this likely to be a problem since the tank was holding RUG until the recent diesel repower?

[Simpler=Better]

Once you're up to temp, it's safe to rev it to the govenor limit. If the IP hasn't been tweaked internally it should rev to aorund 5,500 and stay there. Obviously, downshifting into 2nd on the highway will overspin it and break something, etc. For me, 70mph was ~4,000rpm in 3rd gear and that made for a very responsive pedal.

I ran my 300D with a straight pipe with both the stock garrett and a small VNT. She was loud, but not motorcycle loud(unless I was winding it up). Are you getting resonance inside the cabin? Does your exhaust make it past the body?

The transmission sound like a friction plate spring broke or your throwout bearing detonated.

Glad you carry fuel filters & tools. It only takes one tank of crappy fuel to strand you. Might want to pick up a jerry can & some power service stuff

I bet your conversion cost less than importing a diesel yota from across the pond, or buying a fullsize diesel rig

[t walgamuth]

Originally Posted by Walkenvol

Is this likely to be a problem since the tank was holding RUG until the recent diesel repower?

Good point. Probably not unless he got some contaminated fuel, which is the usual way of getting bacteria problems. Bacteria usually looks like black dots in the first filter.

[t walgamuth]

The Mercedes trannies and others are known to rattle in neutral with the clutch out. Its not a problem if mild.

[JB3]

Originally Posted by OM617YOTA

Just tossed some gear ratios into an online calculator. My 40mph 4th gear crawl up the mountain w/ 31" tires and 4.55 gears was turning that poor engine at ~2000rpms. Poor little diesel, no wonder she was struggling.

If that was only 2k rpms and she's SUPPOSED to spin faster than that normally, this thing is going to need a muffler. The noise gets pretty ridiculous.

do you still have the gas V6 muffler system laying around?

I used my stock muffler in my swap, and just put in a straight pipe where the catalytic converter was. Saved a bunch of money on exhaust work.

[OM617YOTA]

In order asked:

Stretch-
I just replaced the valve cover gasket. I'll double check it and make sure I didn't booger up the install.

Transmission is the stock Toyota R150F that was behind the V6.

t walgamuth-
The junk in the fuel filter looks more like remnants of sealant or similar that I used on the surge tank. There's a filter leading into the surge tank from the main tank, and that filter looks clear. The filter between the surge tank and the MBZ lift pump is where the garbage is.

Total weight around 3800lbs, weighed at the local grain elevator's scale.

The tranny rattle is not mild. People have asked me if my motor is knocking.

Simpler=Better-
Thanks for the info on the RPMs this motor will handle. I took my dad(ex semi driver) for a spin, he started yelling whoa whoa whoa whoa whoa! You can't rev a diesel like that! Had to explain the difference to him.

Exhaust pipe is 10 feet of 2 1/4" flexi pipe, no muffler or resonator or anything, that dumps right in front of the back wheel. It does exit the body, and I don't get any resonance inside the cab. Every time another car passes me I hear the noise loudly reflected back at me. Muffler is a low priority.

Entire clutch pack and throwout bearing is brand new. If my throwout bearing had detonated, it would be making noise when I have the clutch pedal pressed, not when I have the clutch pedal released. Quiets right down as soon as I push on the clutch pedal and stop any of the transmission internals from spinning. I would love to get this thing apart and find it's just a spring on a friction disc. Right now I source a replacement and probably run the current one until it blows up.

Purely dollars spent, I might break even on buying a diesel pickup. If I include my time and labor, no way. I should have bought a diesel F250 and been done with it. It wouldn't get well over 20mpg though......

JB3-
Stock exhaust departed long ago. I have several car buddies and CL is full of interesting options for mufflers. Low priority at this moment.

Thanks all. Long day at work, and still got more to do. Please keep the ideas and suggestions coming.

[Stretch]

Well before you write off the gearbox and drive it till it dies I'd at least check the shifter linkages and the oil level.

[OM617YOTA]

For sure, Stretch. The shifter is solid(manual trans), will definitely verify fluid level.

I need to re-mount the radiator cooling fan, build the in-cab shutoff, locate/fix the oil leak, modify the fuel filler to accept diesel nozzles, replace a fuel filter, revise the oil cooler lines, and about a million other things.

It's 90 degrees outside, which means none of this is getting done right now.

[ROLLGUY]

For your power (lack thereof) problem, you may want to check and see if the boost line signal is getting to the ALDA. If you remove the banjo bolt from the ALDA and lightly hold the banjo (not the bolt) between your fingers while revving it up, you will feel a little suction at idle, and increasing pressure as the RPM's increase. If no pressure, you have found the problem. If there is pressure, another test is as follows: Holding the banjo with a finger sealing one side, rev the engine up to about a steady 2,000 RPM and hold the open side of the banjo against the ALDA, thereby temporarily giving it the boost signal. The engine RPM should increase. Remove and replace the banjo several times in this fashion, and every time the results should be the same: RPM increase. That will tell you if more fuel is being added to the air from the turbo. If the RPM stays the same with a good signal (pressure) from the banjo, then your problem is inside the IP. I have tested many this way, and have always found either a clogged banjo bolt in the intake manifold, a bad hose, or a rubber connection. You will be amazed what a difference a working turbo boost signal will make!