is the 2 lt engine reliable???

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expat said:
Hmmm. Good question, Greg. It sure makes sense that there is a higher thermal stress. From what I understand, the precup even increases the compression temperature due to the friction of the small neck of the precup itself.

But now let me say:
I ain't no expert and...
I've never seen the inside of a B or L series diesel.

I cut my diesel teeth on a fairly large marine diesel, a Fairbanks-Morse ND81/8, two-stroke, scavanged, opposed piston (no head). Not much in common with automotive diesels. The first time a saw a precombustion chamber, it was on a Rabbit diesel. I had no idea what it was, so I had to do some research. So now that the disclaimer is out, I can opine freely! :)

Mike
Click to expand...

Sounds like an interesting engine...

I am not sure if it is the precup increasing the compression temp, or simply the precup soaking up more of the heat from compression. My reading indicates the increased compression used by IDI engines over DI engines is to make up for the precup taking up the heat; so increase the compression ratio, increase temp of the air, so there is enough heat of compression left for ignition after going through the precup. Whichever way it is, it makes sense it acts as a heat sink into the head.

Opine away...please :D

gb
 
Greg_B said:
How is/was the Dyna line marketed in terms of L series, B series, or H series motors? Load capacity, axle size, truck size? gb
Click to expand...

Anyone?

gb
 
Greg_B said:
Opine away...please :D

gb
Click to expand...

Theres a simple shape consideration as well. The machined hole for the precup adds some angles and stress risers to the casting, or at least makes the shape more torturous than a comparable DI head, which makes for an even more uneven heat distribution and thermal deformation.
 
I haven't heard of much head cracking in the 2L or NA market 2LTs. Seems to happen mostly in Australia, esp. when it's 35 degrees and 90 percent humidity! The 2LTE has the most problems, due IMO to people revving them far too high for too long and probably not checking fluids. A lot Surf owners think they're driving gassers apparently. Because the redline is at 5500 doesn't mean you can wind it out to 3500 and not pay a price (other than at the pump:D ). Anyone listening to the motor should be able to tell that it is not happy beyond 3000rpm....IMO.

The Dyna, Elf etc. are all built for different 'duty' levels with different engines & trannies.
 
one thing i have definately noticed is that the pyro can peak very easily in a 2LT and a 2LTE which could explain some of the problems when "putting your foot down"
cheers
 
2L engines don't seem to have the same problems, only the 2LT and 2LTE.

Seems that there is a couple of things that cause the problems.

1. The original heads were approx 75 thou thinner on the face than the redesigned ones which meant there was insufficient meat between the valve seats and the waterways.

2. The Turbo caused a more uneven heat characteristic across the combustion chamber.

A couple of know modifications that seem to help on top of fitting the newer heads.

1. Increase the size of the turbo dump pipe (exhaust front pipe) to 3 inches and the rest of the exhaust to 2.5 inches. This allows the exhaust gasses to escape more quickly reducing the head temp on the exhaust side.

2. Remove the EGR valve or block it. The EGR valve causes reduced burn temperature on the inlet side which seems to make the problem worse - inlet side is cooler than exhaust side causing uneven stresses on the head - a big cause of cracking on cast Iron heads.

Also the stock cooling system is at best marginal and often is not working 100%. The Viscous fans oftne are not working properly, the radiator is oftne partially blocked etc.

The 2LT/2LTE cooling system has some compplicated pipe runs which make it renowned for getting partial blockages due to all the bends in the pipework and internal waterways. Also it's a real bad engine for getting airlocks.

However on the plus side, the 2L series engines even with the turbo are so overspeced on the bottom end that it is pretty difficult to break. The overall engine design is very good, torque curve is a little narrow however removing the EGR and increasing the dump pipe diameter really helps in that respect giveing really good mid range for a small engine. The engine generally doesn't need to be reved much above 3500 rpm whatever the power curve says, the maximum torque is pretty low down. With a bit of work you get a really goo engine.

My 2LTE that I had in a Hilux Surf was a great engine after I changed the head on it, enough grunt to do most hings although it struggled to maintain 70mph up shallow hills on the motorways however the Surf was a pretty heavy motor.

You can really make these engines work well with a bit of thought and not too much money, they take intercooling well, the exhaust mod shouldn't be too expensive and the EGR mod will cost you a cable tie and give you quite a marked difference.
 
harveya said:
You can really make these engines work well with a bit of thought and not too much money, they take intercooling well, the exhaust mod shouldn't be too expensive and the EGR mod will cost you a cable tie and give you quite a marked difference.
Click to expand...
some good info there.
i recommend the 2 1/2" exhaust on all the 2LT and 2LTE trucks i sell as well as a pyro. i never thought of the 3"-2 1/2" exhaust... i did notice a definate difference in power and exhaust gas temps after instalation.
what is this EGR mod? as in block it off completely?
 
Bloody good post Andy.

I thought the EGR raised inlet temps by feeding some exhaust gasses into to the inlet manifold? IF that is the case, based on what you said about uneven temps causing cracking, perhaps blocking it is not such a good idea...?

I know it feeds in soot with the exhaust gasses which then sticks to the oil usually found in the inlet causing heavy buildups if the engine is run on short, cold trips.

I put a ball bearing in the vacuum hose - is that a reliable way to block it in your experience?

Given the cooling problems you mentioned it might be a good idea to let the engine idle for five minutes or so after high speed runs before shutting down. Many of the cracking incidents seem to follow people doing 120Kmh at 3500 rpm for hours at a time.
 
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Previa Diesel said:
Bloody good post Andy.

I thought the EGR raised inlet temps by feeding some exhaust gasses into to the inlet manifold? IF that is the case, based on what you said about uneven temps causing cracking, perhaps blocking it is not such a good idea...?

I know it feeds in soot with the exhaust gasses which then sticks to the oil usually found in the inlet causing heavy buildups if the engine is run on short, cold trips.

I put a ball bearing in the vacuum hose - is that a reliable way to block it in your experience?

Given the cooling problems you mentioned it might be a good idea to let the engine idle for five minutes or so after high speed runs before shutting down. Many of the cracking incidents seem to follow people doing 120Kmh at 3500 rpm for hours at a time.
Click to expand...

The EGR reduces temp in the head (although it may slightly raise the temp in the inlet manifold however the amount is pretty small.

It reduces the combustion temp because the CO2 injected is inert and therfore doesn't burn. This reduces the overall burn efficiency and the temperatire of burn to below 600 degrees which is when Nitrogen Oxides are producesd - the sole purpose of an EGR is to reduce NOx however it can actually increase CO2 levels in the exhaust and also heavy particulate emissions due to it making the burn less efficient and some of the particulates don't get burnt off - EGR working often makes the engine more smokey.

Personally when I did mine I removed the pipe feeding the EGR and turned it double and tied with a quick tie. Ball Bearing works but a quick tie is easier and les prone to falling out.

As you said, oil life also reduces on engines fitted with the EGR (certainly the earlier non electronic vacuum activated ones. The Soot fed back in the engine finds its way into the oil and reduces the life.

You should always let the engine cool at idle after a fast run as shutting the engine off straight away removes the oil flow from the turbo. The remnant oil in the turbo can then cook and glaze the inside of the turbo - eventually ruining it completely. This is the prupose of a turbo timer. However in some places (certainly the UK) it is illegal to leave an engine running in a vehicle that is not manned, so a turbo timer means you still have to sit in the vehicle so you might as well dispense with the expense and just sit there with the engine idling for a coupl eof minutes.
 
crushers said:
some good info there.
i recommend the 2 1/2" exhaust on all the 2LT and 2LTE trucks i sell as well as a pyro. i never thought of the 3"-2 1/2" exhaust... i did notice a definate difference in power and exhaust gas temps after instalation.
what is this EGR mod? as in block it off completely?
Click to expand...

Best thing to do is to remove the pipe from around the back of the head, make up a plate and fit it to block off the path from the exhaust manifold. However that is a PITA and the easiest way is to just block off the small rubber feed tube that goes into the top of the EGR unit, turning it over and using a quick tie is the most reliable method.
 
harveya said:
Best thing to do is to remove the pipe from around the back of the head, make up a plate and fit it to block off the path from the exhaust manifold. However that is a PITA and the easiest way is to just block off the small rubber feed tube that goes into the top of the EGR unit, turning it over and using a quick tie is the most reliable method.
Click to expand...

Just to clarify: you're talking about blocking the thin rubber tube that runs into what looks like a vacuum unit on top of the EGR assembly? Does the EGR open up at a certain RPM, then, to start returning exhaust gasses to the intake manifold?

I gather that tying off this rubber hose prevents the EGR from ever opening...is that right?

Just making sure before I go crazy tying stuff off willy nilly...not that I can drive my truck anyway, but this gives me something to do while I wait for my brake pads to arrive...

BTW, anybody looking for a set of rear brake shoes for their BJ60/70? Who woulda guessed that *some* LJ78s have 4 wheel discs? :doh:

Robin
 
light_duty said:
Just to clarify: you're talking about blocking the thin rubber tube that runs into what looks like a vacuum unit on top of the EGR assembly? Does the EGR open up at a certain RPM, then, to start returning exhaust gasses to the intake manifold?

I gather that tying off this rubber hose prevents the EGR from ever opening...is that right?

Just making sure before I go crazy tying stuff off willy nilly...not that I can drive my truck anyway, but this gives me something to do while I wait for my brake pads to arrive...

BTW, anybody looking for a set of rear brake shoes for their BJ60/70? Who woulda guessed that *some* LJ78s have 4 wheel discs? :doh:

Robin
Click to expand...
Robin.

Yes you got it right. Only way this won't work is if the EGR has already failed in the open position which they sometimes do. Only getout then is to block the pipe round the back of the head with the previously mentioned blanking plate. You will know if the tieing off the vacuum pipe has worked, you shoul feel quite a bit of extra pickup from about 1800 rpm. you should also see a reduction in smoke under acceleration.
 
Excellent information on the 2LT and 2LT-E.

Thanks

gb
 
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