oil consumption

datsun_nugget · May 21, 2010

gday all

d21 with td27t terano motor

symtoms = power is extremly sluggish, has a huge vapour trail of blue smoke where ever i drive, in a trip of about 80kms it will use all the oil.

would this mean the rings are rooted. would a new set of rings and bearings fix the problem and return power.

people have also said that the oil return line to the turbo is to small and the little oil that is getting thru the line is just burning up. but being a factory turbo engine i would have thought it would been a sufficiant line. the engine has had a gigger garet turbo put on it tho.

any ideas and input would be great

cheers

tweak'e · May 21, 2010

if its rings there should be large amounts of blowby which should be noticeable out of the breather or oil filler cap. also do a compression test.
check there is not large amounts of oil in the intake after the turbo. while it could be from breather (put the breather tube into a container) or you could have stuffed turbo seals.

is the new turbo a ball bearing turbo? if so is a restrictor fitted?

Old.Tony · May 21, 2010

First thing I'd do is fill the crankcase up and leave the cap off and start the thing. If there's lots of gas coming out of the filler hole, your rings are probably shot.

If not, you could have badly worn inlet valve guides - they're not as easy to diagnose, as the oil pours down the valve stem and gets drawn into the combustion chamber and once the valve closes, there's nothing to indicate a problem.

I'd guess it's bad rings, given the horsepower loss. If a large portion of the combustion is being blasted past the pistons, then they aren't going to be pushed down as hard = less power to the wheels.

Dion · May 21, 2010

datsun_nugget,

You've probably mentioned, but how many KMs on the engine?

tweak'e said:
also do a compression test.

Also if you do get a compression test done, take the following into consideration.

- If you are DIYing it, chances are your/your dad's/your brother's/brother-in-law's compression tester can't handle a diesel. It needs to be a diesel compression tester.

- Whether you're DIYing it or getting it done by a mechanic, take note of the length of the fitting which attaches the gauge to the glow plug port. Even shortish connectors change the volume of the cylinder, and will result in lower than real pressure readings. If your mechanic says "yeah mate she's buggered eh you'll need a rebuild" then ask to see his gauge and the fitting he used, and take note of the length. Even dealerships' service departments misdiagnose low compression and ask the manufacturer for a new engine, under warranty, from time to time.

- General rules of thumb - if you're DIYing it, and you come across one cylinder that is low, poor a small amount of oil in the glow plug port, and test again. If the compression improves, the rings are shot. If not, it's likely a buggered valve. If you come across two cylinders that are low and the oil doesn't make a difference, you're most likely looking at a buggered head gasket.

- Gauges, depending largely on purchase price, can be only of indicative accuracy. Perhaps their best purpose is diagnosing a difference in compression between cylinders, and/or an overall, notional condition of the compression, however comparing the values you get to the book values will sometimes be useless.

Anything you can do to avoid a rebuild based on a misdiagnosis is a Good Thing.

Aido · May 21, 2010

Pro-Nav2.7TDi said:
datsun_nugget,

You've probably mentioned, but how many KMs on the engine?

Also if you do get a compression test done, take the following into consideration.

- If you are DIYing it, chances are your/your dad's/your brother's/brother-in-law's compression tester can't handle a diesel. It needs to be a diesel compression tester.

- Whether you're DIYing it or getting it done by a mechanic, take note of the length of the fitting which attaches the gauge to the glow plug port. Even shortish connectors change the volume of the cylinder, and will result in lower than real pressure readings. If your mechanic says "yeah mate she's buggered eh you'll need a rebuild" then ask to see his gauge and the fitting he used, and take note of the length. Even dealerships' service departments misdiagnose low compression and ask the manufacturer for a new engine, under warranty, from time to time.

- General rules of thumb - if you're DIYing it, and you come across one cylinder that is low, poor a small amount of oil in the glow plug port, and test again. If the compression improves, the rings are shot. If not, it's likely a buggered valve. If you come across two cylinders that are low and the oil doesn't make a difference, you're most likely looking at a buggered head gasket.

- Gauges, depending largely on purchase price, can be only of indicative accuracy. Perhaps their best purpose is diagnosing a difference in compression between cylinders, and/or an overall, notional condition of the compression, however comparing the values you get to the book values will sometimes be useless.

Anything you can do to avoid a rebuild based on a misdiagnosis is a Good Thing.

Once again punching well above your weight for age D.
Good advice but my advice is no matter what it's rooted
Pull it out and chuck another at it.

Dion · May 21, 2010

Aido said:
Once again punching well above your weight for age D.
Good advice but my advice is no matter what it's rooted
Pull it out and chuck another at it.

Thanks Aido.

Haha. I have a vested interest here. The more TD27s get bought up as replacements for misdiagnosed engines, the more expensive they are when mine reaches 500,000+ and I need a new one! :big_smile:

Conflict of interest?

Anyway, the key points are A) roughly how many kilometres on the motor?, and B) when you had your boost wound out to 18psi (!), were you monitoring exhaust gas temperatures on the fly?

Krankin · May 21, 2010

has a huge vapour trail of blue smoke where ever i drive, in a trip of about 80kms it will use all the oil.

Blue smoke = REBUILD!

Oh, probably not much use doing a comp test as by the amount of oil the engine's using the cylinders will be quite saturated with oil and you wont be able to get (no oil and with oil) results.

and as mentioned before,
(though not for the reason you mentioned)
check the inlet side after the turbo to rule out oil contamination from that as thats simpler than taking down the engine,

but if I were a betting man I'd put my 2 bob on worn cylinders/rings.

would a new set of rings
fix the problem

Depends on the condition of the cylinders & pistons

crossy · May 21, 2010

to use 5 litres of oil in 8o kms is massive mate im surprised you cant smell the oil burning, i'd be pulling the donk out if i was you and replacing those rings. if ur not a 100% sure do a few quick tests. take your radiator cap off and run your engine look to see if you have bubbles in your coolant( if no it rules out a blown head gasket which could also cause you having excess oil consumption). check for blow bye which is combustion gases passing the piston rings and into the crankcase, you can chech it by simply removing the oil cap and running the engine and see if there is gas coming out. to check if its a turbo seal remove the pipe from your turbo to your intake manifold check for oil an ever quicker way to check is check your air filter if your using that much oil its gonna be everywhere

Dion · May 21, 2010

If you DO buy a TD27 and move your turbo gear across, move the fuel pump too. I believe it has an aneroid (boost compensator) and this is worth transferring across. Once you do the swap, get it tuned and get reco'd injectors.

datsun_nugget · May 23, 2010

the donk has only done 230 000kms but its had a hard life offroad by the previous owner. whichever way i look at it, its going to be a expensive job. i brought the old girl for $7000 because it was in ok order, had lots already spent on it, had a reco gearbox worth $2700 in it with 3000kms on it and the motor had low kms for age. ive spent around $ 4000 on it so i would prefer not to have to put a new motor in it. also i got a couple quotes on a full rebuild and it was $3000 to rebuild long motor and $2000 to rebuild injecters and injecter pump. but ive spent to much on it to sell it because in the state thats it in now blind freddy could tell the motor is rooted therefore id get shit all for it.

Dave · May 23, 2010

Those TD series motor's injector pumps dont give much trouble, but in saying that the rest of the motor has had it hard so the pump probably would have to.

Dave.

crossy · May 23, 2010

personally id never trust rebuilt injectors the price u pay for new injectors compared to rebuilt isnt worth the possible injector failure u could have with rebuilt injectors, $3000 is a reasonable price cheaper diy

datsun_nugget · May 23, 2010

yea im thinking of just putting new rings, bearings and injecters in it. on ebay a td27 full rebuild kit is 1800. would they be good quality parts or cheap shit.

Krankin · May 23, 2010

Check your cylinder condition before you go buying rings

Old.Tony · May 24, 2010

If your rings are that badly worn your pistons may have started to wear the sides of the cylinders rather badly. You may also need to budget for either larger pistons (honing the cylinders) or a resleeve. Also pay attention to the pistons as they may have some bad wearing as well.

Not everything you get off ebay is bad, but with a big-name store you know that you have a chance of getting stuff replaced under warranty. With the ebay seller you don't get the same confidence.

I won't apologise to the ebay sellers for this, this is just the way I am wired: I'd rather pay $1500 for an object, than pay $1000 for it through ebay and have it break with no recourse. If the ebay one breaks, I'm up for either another $1000 to take the same risk again, or spend the $1500 that I should have the first time.

datsun_nugget · May 24, 2010

yea you are certainly right old. tony. i found a navara td27 engine near where i live. non turbo engine without altinator and water pump. the add said good running order and low ks, but they cant tell me what they consider low ks. for an engine that could do 600 000 +ks whats low. also with the warrenty they may want the motor to be put in by a professional to retain warrenty where as it would be a DIY project. the motor was 1850 i didnt no wether that seemed to cheap. i dont want to buy it only to find its warn and needs work on it aswell. also could the water pump and altinator be transported from my terrano td27t to the td27, i no the turbo running gear can be.

anyone have any ideas where i could get a good quality second hand or rebuilt motor from

crossy · May 24, 2010

ive also had a look on ebay at the rebuild kits i reckon there not bad but theres no big name backing it up but nissan being japenese it all comes out of the one factory. they also say u can order oversized rings and bearings if needed which could be the option ur after. worn rings means worn bores but nothing a light hone and oversized rings cant fix. these kits come with pistons and con rods so pretty much all ur internals would be brand new, the gasket kit that comes with it is excellent everything u need really. really the choice is $1800 for a kit which will get everything running sweet and have piece of mind knowing its all good or $1800 for a second hand engine which takes out the diy hassles but not knowing if or when it could blow up

Krankin · May 24, 2010

crossy said:
worn rings means worn bores but nothing a light hone and oversized rings cant fix.

Mate, if only it was that easy.

crossy · May 24, 2010

yeah it is only 200 odd thousand kms and hes not complaning about a knocking or slapping noise associated with the oil consumption, u can get .060" oversized rings which is a fair bit over 1.5mm if the was that much wear it would just be a puff of smoke he would be worrying about. a hone and rige removal would be all u need to see ur block being good enough to go again. i tend to think a new block or resleving is a bit extreme for worn rings the rings are designed to wear not the block. each to there own really depends how much work is intended out of the engine and all that sorta thing its a quick low cost option which is just as realiable, if it wasnt they wouldnt make oversized rings

Krankin · May 24, 2010

Ok..........

oil consumption

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