TD42 compound turbo

[slidenyo]

why rush it sounds expensive?
how does the factory oil pump handle feeding two turbo's i wonder.
a hand held temp gun might tell you a few story's I reckon that little turbo's exhaust side is going to get firken hot

[bombaybasher]

Got a couple of oil restrictors in the oil feeds , as for the poor wee turbo I've got these ball bearing t28's glowing red hot, so much that it melted my welds On a waste gate I had mounted directly on the exhaust snail and it still didn't blow on a 2 litre petrol , be interesting to see what huge exhaust flow is gonna do.

[IcedJohnno]

My thoughts on crank breakage would be due to the typical harmonic resonances that a straight 6 cyl crank sets up. Obviously the factory harmonic crank dampener/balancer is designed to reduce this, but they are design-tuned to factory spec. Higher torque outputs or greater max power outputs will change the characteristics needed in the dampner. Thus fatigue crank breakages occur at a much higher pace.

Best method I have found to combat this is the Silicoln fluid dampeners available for aftermarket competition engines, or from truck engines like the Scania/ Holset one that I have, ex Europe. These work at any resonance frequency that is required, rather than being tuned for one particular range of frequencies.
Highly likely this would make a big difference in fatigue life.

[Twodiffs]

Not that I'm aware of, but I know of 4 in AU over the last 18 months. Most are high psi setups (I.e. 35-40psi), with 13mm or 14mm pumps, so the forces involved are ridiculous!

200kw seems to be a consistent figure where reliability just goes out the window, unless you're prepared to spend big dollars to make it hold together...billet crank etc.

I disagree mate, UFI and one or two other experimenters are discovering crank issues with 12mm pumps and fairly modified td05 18/20g's, usually within 25-30psi.

This is nothing against the stability or quality of the std td42 crank...it's purely the output of the turbo and pump mods that are being realised.

[GQTROL]

Not that I'm aware of, but I know of 4 in AU over the last 18 months. Most are high psi setups (I.e. 35-40psi), with 13mm or 14mm pumps, so the forces involved are ridiculous!

200kw seems to be a consistent figure where reliability just goes out the window, unless you're prepared to spend big dollars to make it hold together...billet crank etc.

I disagree mate, UFI and one or two other experimenters are discovering crank issues with 12mm pumps and fairly modified td05 18/20g's, usually within 25-30psi.

This is nothing against the stability or quality of the std td42 crank...it's purely the output of the turbo and pump mods that are being realised.

I'm a little surprised you're having issues at that level of boost, but wonder if it's more of a symptom of higher milage engines? Without a doubt, the stresses at these higher levels is having an impact.....the failures in AU I've refered to above are on completely fresh and rebuilt engines.

There is alot to be said for a modest 170kw, using 11mm plunger and td05-18g!

[Twodiffs]

Not that I'm aware of, but I know of 4 in AU over the last 18 months. Most are high psi setups (I.e. 35-40psi), with 13mm or 14mm pumps, so the forces involved are ridiculous!

200kw seems to be a consistent figure where reliability just goes out the window, unless you're prepared to spend big dollars to make it hold together...billet crank etc.

I disagree mate, UFI and one or two other experimenters are discovering crank issues with 12mm pumps and fairly modified td05 18/20g's, usually within 25-30psi.

This is nothing against the stability or quality of the std td42 crank...it's purely the output of the turbo and pump mods that are being realised.

I'm a little surprised you're having issues at that level of boost, but wonder if it's more of a symptom of higher milage engines? Without a doubt, the stresses at these higher levels is having an impact.....the failures in AU I've refered to above are on completely fresh and rebuilt engines.

There is alot to be said for a modest 170kw, using 11mm plunger and td05-18g!

You've lost me...I'm not having boost issues or any other issue and haven't said so, what I have said is that some outfits are pushing the boundaries on standard engines with turbo's and pumps that are constantly being improved. Cranks are strong but as I mentioned it's only taking a highly tuned 12mm pump and turbo to do the damage.

I've gone back through some forum stuff and I think what you said above is correct, the few breakages have occurred up above 30psi and where they have pushed the boundaries to 300rwhp. It's considered that between 200-250rwhp is ok for cranks but it's random they have found....some cranks handle 250rwhp ok and the odd one out fails.

Having said that there are heaps of guys running 11 & 12mm pumps and 18-20g's at up to 28psi boost and not having engine or crank issues either.
Just goes to show I guess how far the 'developers' are pushing their testing.

[GQTROL]

I disagree mate, UFI and one or two other experimenters are discovering crank issues with 12mm pumps and fairly modified td05 18/20g's, usually within 25-30psi.

This is nothing against the stability or quality of the std td42 crank...it's purely the output of the turbo and pump mods that are being realised.

I'm a little surprised you're having issues at that level of boost, but wonder if it's more of a symptom of higher milage engines? Without a doubt, the stresses at these higher levels is having an impact.....the failures in AU I've refered to above are on completely fresh and rebuilt engines.

There is alot to be said for a modest 170kw, using 11mm plunger and td05-18g!

You've lost me...I'm not having boost issues or any other issue and haven't said so, what I have said is that some outfits are pushing the boundaries on standard engines with turbo's and pumps that are constantly being improved. Cranks are strong but as I mentioned it's only taking a highly tuned 12mm pump and turbo to do the damage.

I've gone back through some forum stuff and I think what you said above is correct, the few breakages have occurred up above 30psi and where they have pushed the boundaries to 300rwhp. It's considered that between 200-250rwhp is ok for cranks but it's random they have found....some cranks handle 250rwhp ok and the odd one out fails.

Having said that there are heaps of guys running 11 & 12mm pumps and 18-20g's at up to 28psi boost and not having engine or crank issues either.
Just goes to show I guess how far the 'developers' are pushing their testing.

I thought you were suggesting you were having issues too, obviously you're not.

Agree with your comments regarding people pushing the envelope beyond 200rwkw. The reliability will eventually be improved, but it will be at the expense of more engines until the issues are resolved.

[Cameron]

do they stay together over that limit when used in applications other than fairly serious 4x4 work?
if you're going to go to the effort of pushing 200kw out of a td42 in an offroad vehicle, you're not exactly going to be gentle on the thing. would be interesting to see if a vehicle modified like this put into the same kind of use as the equivalent 'performance car' held together vs. the shockloading, clogged cooling systems and potential oil starvation due to angles etc that they're subjected to in fairly extreme 4x4 use.

[Twodiffs]

Yep...once you get into that area ya might as well start ceramic coating pistons as well lol.

[Twodiffs]

mispost.

[bombaybasher]

edit information.

[Twodiffs]

What exactly is blue printing? I know it used to be done years ago with 1500cc Cortina's etc. I had a 308 rebuilt by Dons Speed Centre years ago obviously....as far as running in went they said take it for a good blat up the hills to the Hilltop pub and back, change the oil afterwards and that was it.

[bombaybasher]

edit information.

[GQTROL]

I didn't think anyone had advocated the use of aftermarket parts when rebuilding TD42's? I'd say it's fairly common knowledge that Nissan OEM components are quality and are more than adequate if things are kept sensible. It's just a shame the OEM parts are so damn expensive!

I recall one TD42 rebuild where the internals were sent off to be balanced. Very little work was necessary to do so.

[Dumbass]

GQTROL knows first hand what factory and aftermarket parts can endure . but when any boost let alone 28psi was added to a non turbo engine (and that includes new and well seasoned engines) or even factory turbos OEM flew out the window. They can take a fair bit of abuse yes but not as much as some people like to tell you. Please do not fall victim to the pub legends like I myself have.. The best one I have been told lately is "you are wasting your time intercooling a turbo diesel" should I believe this person?

[bombaybasher]

the only reason i could think of a snapped crank would be from high ks, too much timing,hammered bearings and lots of heat causing excessive knock-pretty much everything that my motor is going to get this weekend.

can't wait for vids!

https://www.youtube.com/watch?v=FBdlP4G ... vDYYTWYelA

there is a couple of vids

patrol went really good

[jA-]

so how did it go????

[Crash bandicoot]

Anyone in NZ broken a crank in a TD42 yet?

yep.

[churchill]

I wonder if a dual mass flywheel woukd help in solving the broken crank issues. Most modern diesels run these now and they reduce the cyclic stresses from the power stroke thus redicing the fatigue load on the crank. Ive even seen automatic gearboxes with these on them. Might be worth a shot?

[zed]

Are the failure points the same on silver top td42's vs black tops? I remember the black top turbo motors being lighter and more free revving than silver top turbos but wonder if the cranks were the same? Anyone know? Factory turbo motors not +t's

[bombaybasher]

Just like to reply that it's still going hard with no oil consumption , managed to crank 40psi out of it and it was almost doing wheelies, only probs so far us it keeps wrecking water pumps, I think mud might be getting in it and stuffing the bearings , I get warranty on them but I'll try block up the hole with a bit of silicon.

[Swamped]

Do you mean block the little tell hole on the pump?? That lets you know when a seal has begun to let go.

[Crash bandicoot]

From what i have read, and from a personal case of TD42 crank failure, seems to happen once cylinder pressures reach in excess of 5-600 psi.

taking into account volumetric efficiency, (or the ability for your head and valve design to flow air along with any residual gases left in the cylinder from the last stroke )your average actual cylinder consumption would be around 85% of any given calculation.

What we have to remember is that this is a truck engine, it was designed with the intention of going anywhere and everywhere at 2500 rpm all day long up hill down hill mud snow road, under load.
And since it is a truck engine it didn't have a main bearing cradle like nissan's high performance engines, the block although strong.. is long. longer then a mitzi, toyota, jeep, its even longer then the straight six that comes in an Isuzu FSR 12 tonner.
Given this, it does suffer crank twist and i wouldn't be surprised if the block flexes as well, considering static compression is 22 to 1 the aussie trucks suffering failure are getting cylinder pressures anywhere up to and exceeding 1000 psi.

the most common point appears to between number 5 and 6, and would make sense when you consider the firing order of a inline six engine
1 – 4 – 2 – 6 – 3 – 5

5-1 and 2-6 have the longest span between loading pistons allowing for the most flex and twist in the crank. and since the load is on the back of the crank this is the point most likely to break