My Diesel Let me down!

[smithy010]

Hi All,

I was on my way 600km to Narrandera from sydney, when my old girl let me down last night.

I got 100km down the road, and she started running on, and overheating.

I stopped at pheasants nest, topped up the oil, let her cool down, checked the air filter (the manifold had a lot of oil in it, as expected).

I carried on for 20k's (after calling aydan), and she started doing it again. I tried taking the air filter out, but that only created a ****load of smoke because the air filter housing was leaking oil onto the exhaust manifold. So i stopped, rang the old man and said i wouldn't be home that night.
I decide i would limp her home, so i made a catch can (may as well not have).

My car went through 4L of oil (poured it on the ground) on the way back home.

Now i'm trying to diagnose what's wrong. What i don't understand is, why all of a sudden am i having all this blowby?
Have i cracked a ring or something?

Or have i done a valve seal or something like that?

[smithy010]

Oh, and for everyone's information, once it stopped running on, by the catch-can method, the temperature behaved itself quite well, and it ran very well. Smooth as ever.
It also starts very easily.

I don't really believe that there would be anything wrong with the piston/rings, because it would surely be running rougher than before.

The sudden-ness of it all is what confuses me.

But there is definitely some serious positive pressure coming from the tappet cover.

I have the blowby stopper, but with this amount of oil, it didn't help at all.

Please tell me it's something i can fix without taking the head off!

[Greg Roles]

I'm afraid my vote is for a leaking valve seat. Explains the increase in pressure from combustion into oil jacket, thus pumping oil out the crancase vent. Fraid that means the head off mate...

I'm not a diesel guru, so how the heck do you check combustion pressures without sparkplug holes? Pull the injectors?? Anyone??

[cetane]

Compression tests are done through the glow plug hole with the fuel solenoid disconnected and at full throttle.
Sorry, Smithy...It doesn't look good. For that much oil going into the air box it has to be more than just rings. Do you have the VW modified breather?

[gregozedobe]

Compression tests are done through the glow plug hole with the fuel solenoid disconnected and at full throttle.
Just curious - why full throttle on a diesel ? (on a petrol engine yes, but from my understanding of a diesel the accelerator pedal only controls the amount of fuel injected)

[cetane]

Ooops..Been thinking of my Nissan SD33 a bit too much lately! :n: (It has a multi-element injection pump with a butterfly to control inlet air). No...full throttle isn't necessary with a distributor type pump such as the VE.

[gregozedobe]

Well there you go, keep your eyes open, your ears connected, your brain connected and you can always learn something new :)

[gldgti]

hey smithy,

this is an old time issue that comes up again and again.

i know it seems to be "all of a sudden" but this type of thing occurs when you get the oil really nice and hot - on the highway - and under sustained high rev conditions - highway. unless you have both of these its hard to get to a runaway condition.

the continued high reving allows good buildup of oil fumes to occur, since you have low load conditions and high revs, a nice production of oil vapours will occur and then you know the rest.

get rid of the 10W-40 for some heavier oil, and get ready for an engine pull-down.

basically mate you need to pull her down and do the rings. seriously.

good luck,
aydan

[smithy010]

Well...

It actually does seem sudden, because just last weekend i took it on a hard run up the blue mountains- Got the oil nice and hot up the mountain, then on the relative flats and downs of the bells line, i had her at high revs and there was not even a hint of anything wrong. Up there and back, and 110 on the great western highway and nothing. Then this just a week later. I think something must've happened suddenly.

What i also don't understand, which i took for granted before, was that i am now getting high tappet cover pressure.. Wouldn't bad rings cause high crankcase pressure, and not high tappet cover pressure? Can someone explain to me how the pressure is getting to the tappet cover?

Oh, and i'm sure the high pressure is coming from the top of the engine.

Another theory is that i've done a head gasket, and the pressure is coming up through an oil gallery.

Ok. Next question.

If it turns out i need to re-ring her.. Then assuming it is so bad that i need pistons as well, how much will i be up for, and am i better off hitting loon up for one of those 1Z engines that he's got coming?

[Preen59]

Well...

It actually does seem sudden, because just last weekend i took it on a hard run up the blue mountains- Got the oil nice and hot up the mountain, then on the relative flats and downs of the bells line, i had her at high revs and there was not even a hint of anything wrong. Up there and back, and 110 on the great western highway and nothing. Then this just a week later. I think something must've happened suddenly.

What i also don't understand, which i took for granted before, was that i am now getting high tappet cover pressure.. Wouldn't bad rings cause high crankcase pressure, and not high tappet cover pressure? Can someone explain to me how the pressure is getting to the tappet cover?

Oh, and i'm sure the high pressure is coming from the top of the engine.

Another theory is that i've done a head gasket, and the pressure is coming up through an oil gallery.

Ok. Next question.

If it turns out i need to re-ring her.. Then assuming it is so bad that i need pistons as well, how much will i be up for, and am i better off hitting loon up for one of those 1Z engines that he's got coming?

Crank case pressure is only vented through the cam cover breather. But it mainly comes from the crank case. You have ventilation around the cylinders that vents back up into the head (this is how some of the oil gets from the head back to the sump, too).

On some high performance engines you will see vents on both the crank case and the cam cover, but that is mainly to alleviate the additional pressure (the better you vent it, the less hp you lose). Whether the vent is in the block or the cam/tappet cover is mainly due to the application the engine will be used for and the components fitted.

[Golf Loon]

If it turns out i need to re-ring her.. Then assuming it is so bad that i need pistons as well, how much will i be up for, and am i better off hitting loon up for one of those 1Z engines that he's got coming?

I only have one left and its 8 weeks away :(

I dunno about the problem you have, I know bugger all about diesels.
Good Luck getting it sorted.

[smithy010]

Crank case pressure is only vented through the cam cover breather. But it mainly comes from the crank case. You have ventilation around the cylinders that vents back up into the head (this is how some of the oil gets from the head back to the sump, too).

On some high performance engines you will see vents on both the crank case and the cam cover, but that is mainly to alleviate the additional pressure (the better you vent it, the less hp you lose). Whether the vent is in the block or the cam/tappet cover is mainly due to the application the engine will be used for and the components fitted.

Thanks. That answers my question.

[gldgti]

probably cracked a ring or two mate, that would account for the suddenness.

remember that once the rings are worn, they get thinner in x section so o become weaker..... well you know that... :-)

[smithy010]

Yeah, that's reasonable...

It looks like i'm on shanks' pony for a while, while i pull her down and work out what's going on..

[smithy010]

Question:

If i got one of loon's 1Z's, would it hurt to run it turboless for a bit while i save up for a turbo?

Would i get issues with glazing or anything because of the lack of boost?

[jets]

Compression tests are done through the glow plug hole with the fuel solenoid disconnected and at full throttle.
Sorry, Smithy...It doesn't look good. For that much oil going into the air box it has to be more than just rings. Do you have the VW modified breather?


Just to clarify a point, compression tests are also done through the injector holes.If you remove the injectors you will need to replace the sealing washers. You will probably need to remove the pipes to get access to the glowplug holes anyway. The kit I have just bought has adapters for both.

[cetane]

Your kit sounds good. Where did you get it? How universal is it and will it test motors other than VW, Merc?
(Either way, the fuel rail has to come off, however if you test compression through the injector holes at least you don't need to take off the glow plug rail. But you will need to renew the heat shields.)

[jets]

I bought my kit from this guy. I paid $49.50 as a Christmas special. I finished up buying two [One for a friend] & halved my postage cost.

http://www.toolaus.com.au/catalog/product_info.php/cPath/3/products_id/116?osCsid=0d7254d3c21f81b5581a783a00f58ad5

It's possible to buy cheaper kits from the States but the freight is too expensive. I don't know what other engines the kit fits but it fits the VW.
If you have a special purpose you will have to give me the thread details.
If you take out the injectors, you can watch the glow plugs heat up to check them. The heat shields cost $2.50 ea.

Here are some more details for the same kit from a different seller.

http://cgi.ebay.com.au/Brand-New-Diesel-Compression-Tester_W0QQitemZ170204930748QQihZ007QQcategoryZ356 25QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l12 62

[gldgti]

you wouldn't have a problem running a 1z without a turbo - infact that engine was sold (under different code) in some mk3's as SDi - non turbo direct injection diesel..... why? who knows? the same reasons vw brought out mk3's with 13" wheels, why my car came out with solid rotors on the front and drums on the back, the same reason i had a doughnut spare..... some marketing guy thought it was a good idea i suppose...

...

winge over.... cheers ;-)

[smithy010]

I guess it will already be worn in, being second hand, so i won't need to bed the rings like a new motor... The bores are probably already glazed from being babied in the UK...

Does anyone have any ideas on how these puppies perform? What's the output? what sort of fuel economy? are they reliable? I would assume there would be less blowby problems due to the lower compression ratio, although probably not the case because with turbo, pressures are as high anyway..

Aydan, i'm guessing you can shed some light on this, seeing you own one and you're an engineer, or at least should be by now ;)


Smithy

[smithy010]

Ok, so i think i've decided not to buy one of Loon's TDI's.. The reason for this, is i think it will be too much rooting around, especially for my daily driver. If i had a functional engine, and could work on the tdi at my own pace, then i'd probably do it.

Just an aside, i think if i were to go TDI, i would try to keep the Electronic engine management..

Anyway, unless someone has a spare AAZ laying around, i'll be keeping the 1.5.

So i started it for the first time since i had to limp it home from pheasants nest. It was not really a surprise, but it ran quite rough (on 2 or 3 cylinders) for about 5 minutes after starting, then it started running fine. I think this is probably that the cylinder temperature came up and then it began to fire on all cylinders. Would this be feasible?

I'm trying to decide what to do next. Seeing i pretty much know it's buggered, do i dig up a compression tester before i pull the head off, or do i just bite the bullet and pull it down and have a look see?

Next question is where should i buy parts from? I guess i'll check out tooleys importers and see what sort of price they can do for me. Any overseas place that i should check out?

Getting sick of public transport.. want my car back!

[gldgti]

between tooleys and HSY imports you can get pretty much everything you need. prices arent bad.

[smithy010]

Well, in case you all want to know, i will be taking the head off the diesel probably tonight. Will send pics of what i find inside!

I'm guessing it will be interesting.

[smithy010]

Well, the head's off, but the pistons aren't out yet.

I reckon the head looks to be in pretty good nick. No cracks between the valves. There is quite a bit of soot buildup on no. 3 exhaust valve. Maybe this is the one that has issues.
The bores look ok. They are fairly glazed, but i guess this is to be expected. There is a little step at the top of the bore, but that's to be expected as well.

I'll take the pistons out soon, so i can see what's really wrong. I'm expecting cracked rings in one pot at least. Photos when it's light.

[smithy010]

Hmmmm..

Well, one thing's for sure, the rings are quite worn. The gap on them is about 2mm. Some more, some less. The bores are fairly glazed as well. The pistons look in pretty good shape though, and there are no cracked rings. But that's not all.

It's got some major wear on the no.3 big end bearing, which is disconcerting. It also appears to have spun. The thing that makes me think that's it's not my shoddy big end bearing job is that when i bought the engine, it had a spun no. 3 big end bearing as well! But then, it could well be a shoddy job on my part.

So my theory about why i suddenly got a stack of run-on and blowby issues is that it spun this bearing, and then started overheating as a result (due to the extra bearing drag). This could have brought on the blowby. Anyone think that's plausible?

So, where to now, a new set of rings and big end bearings and off i go again?

Also a question while it's on my mind, when i hone the bores (i haven't measured them yet, but we'll see), should i be dropping the crank out to stop filings getting into the main bearings, or is there a trick to keeping the filings out?

Ok. Well, i guess the only way to learn is to fiddle, and if anything, this is some of the cheapest fiddling i could be doing.

[Blitzen]

Hmmmm..

Well, one thing's for sure, the rings are quite worn. The gap on them is about 2mm. Some more, some less. The bores are fairly glazed as well. The pistons look in pretty good shape though, and there are no cracked rings. But that's not all.

It's got some major wear on the no.3 big end bearing, which is disconcerting. It also appears to have spun. The thing that makes me think that's it's not my shoddy big end bearing job is that when i bought the engine, it had a spun no. 3 big end bearing as well! But then, it could well be a shoddy job on my part.

So my theory about why i suddenly got a stack of run-on and blowby issues is that it spun this bearing, and then started overheating as a result (due to the extra bearing drag). This could have brought on the blowby. Anyone think that's plausible?

So, where to now, a new set of rings and big end bearings and off i go again?

Also a question while it's on my mind, when i hone the bores (i haven't measured them yet, but we'll see), should i be dropping the crank out to stop filings getting into the main bearings, or is there a trick to keeping the filings out?

Ok. Well, i guess the only way to learn is to fiddle, and if anything, this is some of the cheapest fiddling i could be doing.

While you have the engine out and apart you should drop out the crank and inspect your main bearings and crank while you are at it. The spun bearing could have damaged your crank in some way, so have a good look at it and get it crack tested. Depending on how many km the engine has done, you may as well throw in new main bearings too.

[cetane]

Smithy... is the motor still in situ? You'd have to pull it to remove the crank. It sounds as though the runaway has done a fair bit of damage and the safest way is to pull the motor, remove the crank and get it reground. It costs time and money but it's better than replacing the shells and reassembling then finding you've wasted your time. If you decide not to, inspect the journals for scoring and mic them to sure they're within limits then to be sure get some "Plastiguage" or equivalent and check for bearing crush. As for filings from honing, just get some kero and wash everything thoroughly after you've done it. I'd also remove the ridge and make sure the honing left a nice "cross hatched" finish. If it was my motor and I wanted to preserve the car (and I could afford it ;)) I'd get the crank done.

[smithy010]

Thanks for the words of advice cetane. I'm not sold on pulling the crank out yet.. It seems like it could make some sense though. The crank was replaced with a good second hand one 12 months ago. I know it was good then, and i plastigauged it then as well.. So it has had new main bearings about 10 000k's ago. Then, considering it did this to the big end bearing in that time, it may have done it to a main as well..

What would cause a big end bearing to spin on the same pot twice in a row? Just a fluke?

[VW Convert]

Thanks for the words of advice cetane. I'm not sold on pulling the crank out yet.. It seems like it could make some sense though. The crank was replaced with a good second hand one 12 months ago. I know it was good then, and i plastigauged it then as well.. So it has had new main bearings about 10 000k's ago. Then, considering it did this to the big end bearing in that time, it may have done it to a main as well..

What would cause a big end bearing to spin on the same pot twice in a row? Just a fluke?

I'd be checking the conrod out to make sure it is to tolerance. Can't really understand how the crank could be re-useable as is if it has spun the bearing, surely it would need to be mic'd and at least linished if not reground.

Cheers

George

[cetane]

It's usually caused by lack of lubrication, although if the big end cap wasn't torqued to the correct setting or replaced back to front there'd be the same result. Whenever I rebuild an engine I check each journal by tourquing it and then slackening off one nut. You should be able to get a 5 thou feeler in between the cap and the conrod. If the gap is too big, then the bearing will fail. If it's too small than it won't get enough lubrication with the same result. The 1.5D conrod is the same as the 1.5 petrol's so they can be swapped, so if there's any doubt I'd do it. Also, check the oil galleries in the crankshaft for blockages.

[smithy010]

I haven't examined the big end journals carefully yet, but assuming the journal is ok, is it a bad idea, instead of removing the crank, to just remove each main bearing cap one by one and examine each main bearing? I don't really want to pull the engine.

Also, anyone in sydney got an internal micrometer they'd be willing to loan me for a week?

[smithy010]

Update.

I've been too lazy to take photos as yet.. The interesting thing is that i have measured the top ring gaps, and it is 0.7-0.75mm, which is certainly worn, but by no stretch of the imagination is it "out of spec"..

I have examined the crank, and there is a tiny scratch on it, about 1/3 of the way around, and on the left hand side of the journal. I reckon i'll be able to polish it out with a bit of wet and dry.

So, to stop it spinning bearings again, i'm going to measure up the no.3 conrod to check, and possibly replace the rods.. Does anyone think it could be troublesome replacing rods with other second hand ones? I guess if they are the right size for the little ends, they should be ok, right?

I'm waiting for a set of mics to finish on ebay, and then i'll be able to measure her up. :)

I have a little newfound enthusiasm since the petrol price has risen, and also since i went to the nats and had a yarn to the diesel boys (including aydan's old man in his GLD with light truck tyres on it). Sick!

All good

Smithy

[cetane]

OK to mix and match conrods, mate. Petrol ones are OK. Just make sure you check for bearing crush when reassembling.

[smithy010]

Cool. Cheers Cetane.

Yep, i'll plastigauge them all. Shouldn't be a problem.