gerg i have to say you hit the nail on the head with that one. also probably one of the reasons for going to efi.
3B Rebuild and Performance Notes (1 Viewer)
- Thread starter yotahed
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- diesel engine rebuild
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At part load you don't need the advance you do at full load, mainly because the fuel injected is much less so it occurs in a shorter time. The end of injection is typically fixed, start of injection varies with load. So as load goes up and injected quantity increases, so does advance. But advance needs to increase with load as it takes longer to vapourise and burn larger quantities of fuel.
So I say don't worry about it too much. Just don't go cranking up the timing advance for more power on high compression IDI engines. You have to run slightly retarded to lower the peak pressures and stresses on everything.
GTSSportCoupe
2LTE abuser
I'm generally not a fan of the early EFI diesels (2LTE), but I must admit, the computers ability to change the injection timing with engine temperature is pretty good. I've sort of taken it for granted until thinking about the last few posts in this thread. Also, on the 2LTE it's the end of the injection event that varies as more or less fuel is injected. But this thread is about 3B, so I digress...sorry.
Next engine will definitely have a more conservative tune, but I really have to get one of those injection line timing gadgets for diesels. I hate taking my stuff to a shop.
I don't think the 2LT will have anything sophisticated for timing vs temp. My 2000 Nissan EFI diesel doesn't, it just alters timing based on speed and engine load.
My VAG tdi does have a different injection timing map for every 10 degrees of water temperature. It's a lot smoother throughout the temp range than the above Nissan is.
My VAG tdi does have a different injection timing map for every 10 degrees of water temperature. It's a lot smoother throughout the temp range than the above Nissan is.
GTSSportCoupe
2LTE abuser
Maybe not sophisticated, but it definitely does it (I've observed it first hand). It's not just a cold advance either, as it continues to retard even after the thermostat has opened. Here is the flow chart for injection advance from the 2LTE EFI manual. Anyhow, really, I should stop typing as this is a 3B thread.
Just pulled the crank this morning. Fortunately the bearings are in great shape considering what happened, and no damage to anything else. Glad I shut it off right away. Now for for a good clean up, new crank and bearings and reassembly. If your wondering, the shaded areas on the bearings are what's left of the moly coating I had applied.
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Here was the worst of it, not a surprise it was on the thrust bearing.
Course I couldn't forget the crank. Amazing that stayed keyed together. Praise the Lord!
GTSSportCoupe
2LTE abuser
That is a miracle indeed! How could you tell it broke? Loss of oil pressure? Are the 3B cranks forged? Hard to tell from your pics? I was trying to comprehend how you broke a crank but did not completely destroy your engine, and now I understand.
Well while climbing a gentle hill one click from my house, there was a huge bang! And my clutch pedal was pumping in and out a lot. Before I glanced to shut it off I made a note that it had normal pressure. I then shut it off and pondered a while. Then started it and watched the oil pressure build, but was too disturbed by the pedal movement so I got a tow home. About 10 seconds run time.
Would cryo treating the next crank toughen it up? Maybe some balancing
Nah, needs a stronger crank and/or lower compression ratio. Cryotreating is the hocus pocus of heat-treatment.
Kinda like ceramic coatings in my books.
Well next motors head had some extensive chamber porting as well as pre cup work, so I guess the compression has dropped a bit, but timing will be retarded more. The crank took that for 5 years mind you, so it's not exactly an overnight failure. And it started it with 400k on it. Id say shot peening would yeld more bennifit than cryogenic treatment. Cryo is pretty specific to types of metals and how they are cast and stuff.
Ceramic coatings do work, but the every day guy can't exactly have several mm worth applied easily. It's extremely expensive. The 5 thou you can commonly apply would really make a difference on aluminum, but not as much on steel. I think it's more of a bennifit to prevent hot spots and detonation in gas engines. I'm a bit cheesed at myself for not coating this last head, but I had to draw a line somewhere. I really wanted to do the pre chamber.
Ceramic coatings do work, but the every day guy can't exactly have several mm worth applied easily. It's extremely expensive. The 5 thou you can commonly apply would really make a difference on aluminum, but not as much on steel. I think it's more of a bennifit to prevent hot spots and detonation in gas engines. I'm a bit cheesed at myself for not coating this last head, but I had to draw a line somewhere. I really wanted to do the pre chamber.
that is a serious chunk of broken steel.
yotahed
Diesel Head
- Thread starter
- #298
So,
Had a look at a 13BT and 3B pump side by side today.
Sad to say it wont work out. The camshaft nose on the 13BT is about 20mm and the 3B is around 17mm. Also the flange seal is flush on the 3B whereas the flange seal/oring area on the 13BT pump protrudes out about 1/4"
So extensive mods to the 13BT pump would be needed, and IMHO, not worth it.
I may be fitting up a mechanical RSV governor with boost fuel control to a customers 3B pump over the next month.
Much easier mod and very simple to tune.
Might do up my spare 2H pump in the same way just for fun.
Updates on this when it happens.
Had a look at a 13BT and 3B pump side by side today.
Sad to say it wont work out. The camshaft nose on the 13BT is about 20mm and the 3B is around 17mm. Also the flange seal is flush on the 3B whereas the flange seal/oring area on the 13BT pump protrudes out about 1/4"
So extensive mods to the 13BT pump would be needed, and IMHO, not worth it.
I may be fitting up a mechanical RSV governor with boost fuel control to a customers 3B pump over the next month.
Much easier mod and very simple to tune.
Might do up my spare 2H pump in the same way just for fun.
Updates on this when it happens.
Slightly off topic but this thread seems to have some VERY cluey people in it so I figured I'd post here before attempting any of the mods in this thread.
Backstory: purchased this motor sight unseen, supposedly had a rebuild 80K (km) ago and judging by how it starts and runs generally and a few other factors, I have no reason to disbelieve it.
It's out of a 1985 BJ73.
It had the turbo fitted about 60K ago along with an injector pump rebuild and overhauled injectors. Both injectors and pump have had "extensive work/mods" but the PO didn't specify what had been done.
I have no compression figures for it.
She starts and runs but is quite lumpy at tickover and when out on the road it's a push to get her to 110.
In the first three gears it'll rev through but in fourth and fifth it just seems like it has no torque. Others with the same turbo and engine say 120 up hills in 5th is easily done so I know something is amiss somewhere.
New to diesels and turbos and I know the 3B is a rattly old girl but it appears to be running hard on one cylinder. It's not a knock in the classic sense of the word. This "knock" also appears to coincide with a slight chirp out of the pipe.
I did the valve clearances last night, they were a bit tight and I bled the high side this morning. Not sure if this is relevant in any way but the front two injector lines I could easily feel the "pumps" through them whereas the back two I couldn't.
Motor was sat for approximately 18 months before I got it.
Any help or insights would be greatly appreciated.
Backstory: purchased this motor sight unseen, supposedly had a rebuild 80K (km) ago and judging by how it starts and runs generally and a few other factors, I have no reason to disbelieve it.
It's out of a 1985 BJ73.
It had the turbo fitted about 60K ago along with an injector pump rebuild and overhauled injectors. Both injectors and pump have had "extensive work/mods" but the PO didn't specify what had been done.
I have no compression figures for it.
She starts and runs but is quite lumpy at tickover and when out on the road it's a push to get her to 110.
In the first three gears it'll rev through but in fourth and fifth it just seems like it has no torque. Others with the same turbo and engine say 120 up hills in 5th is easily done so I know something is amiss somewhere.
New to diesels and turbos and I know the 3B is a rattly old girl but it appears to be running hard on one cylinder. It's not a knock in the classic sense of the word. This "knock" also appears to coincide with a slight chirp out of the pipe.
I did the valve clearances last night, they were a bit tight and I bled the high side this morning. Not sure if this is relevant in any way but the front two injector lines I could easily feel the "pumps" through them whereas the back two I couldn't.
Motor was sat for approximately 18 months before I got it.
Any help or insights would be greatly appreciated.
I might have found some more potential in these pumps.
I've got a 3B inline pump on the bench in bits at the moment and the diaphragm doesn't travel far enough for the rack to reach full fuel. The rack has 19mm of travel and the diaphragm approximately 14mm. I can't say how much travel the daiphragm was giving up on the max fuel end, but it felt like a few mm. I busted the centre out of the leather whilst trying to figure it out, it was already quite torn.
It's probably dependent on who made your diaphragm but this one would have been original. It would be quite easy to check. Remove the diaphragm cap, remove fuel screw and see if you can push the diaphragm in far enough to max out the rack which will bottom with a nice "click". If it does bottom out you should tell us what brand diaphragm you are running so we can buy one too.
I've got a 3B inline pump on the bench in bits at the moment and the diaphragm doesn't travel far enough for the rack to reach full fuel. The rack has 19mm of travel and the diaphragm approximately 14mm. I can't say how much travel the daiphragm was giving up on the max fuel end, but it felt like a few mm. I busted the centre out of the leather whilst trying to figure it out, it was already quite torn.
It's probably dependent on who made your diaphragm but this one would have been original. It would be quite easy to check. Remove the diaphragm cap, remove fuel screw and see if you can push the diaphragm in far enough to max out the rack which will bottom with a nice "click". If it does bottom out you should tell us what brand diaphragm you are running so we can buy one too.
