300 Tdi Rebuild

Al2O3 · Jun 28, 2017

Saint.V8 said:
Oil amount is similar from memory, will have another look - but may not be until the weekend before I get the chance....will report back.

No hurry, mate.
I'm not sure if my 'I/C pipe off' experiment proved anything. It still smoked. JM suspects piston ring to bore seal.

I'm hoping it's valve guides. I reckon guides will be easier to solve. Either way, dreading it.

Al2O3 · Jun 29, 2017

Right, gents. I was going to wait until Saturday to do the compression tests, probably because I was frightened for the results.

Anyway, grown a pair tonight and in a gap in the rain decided to give it a go. Here are the results.
I used the heater plug hole.
Here is cylinder No1

440psi
The end of the heater plug was a little sooty in one part and grey over the rest. I rubbed it with my finger - too late to take a picture then!
But, I took pictures of the others! Here's heater plug No2

Here's the compression on cylinder No2

440psi
The heater and compression on No3

432psi (Tester had an extra elbow in it to get in behind air filter)
Finally No4

432psi approx Again with the extra elbow on the tester compared to cylinder 1 and 2.

I thought 300Tdi compression was in the region of 348psi so mine seem to be very high! Is that a problem? Gauge carped?
Do the heater plugs look as though they are getting too hot? I'm a bit nervous about that as the piston crown in cylinder No4 was melting when the engine knacked.

What do you all reckon?

jamesmartin · Jun 29, 2017

gauges vary ,bores could be oily,compression test wont necessarily show a bore surface hat burns oil

Al2O3 · Jun 29, 2017

jamesmartin said:
gauges vary ,bores could be oily,compression test wont necessarily show a bore surface hat burns oil

Cheers, James. I'm struggling to get my head around this. How does the oil get past brand new scraper rings?

jamesmartin · Jun 29, 2017

Al2O3 said:
Cheers, James. I'm struggling to get my head around this. How does the oil get past brand new scraper rings?

its held in hone or boring grooves
if your burning oil its either the bores or oil entering through manifold

Al2O3 · Jun 29, 2017

But if the honing is not deep enough, how are they holding oil?

jamesmartin · Jun 29, 2017

Al2O3 said:
But if the honing is not deep enough, how are they holding oil?

depends on the angle and whether theres not enough honing to remove boring tool grooves

Al2O3 · Jun 29, 2017

jamesmartin said:
its held in hone or boring grooves
if your burning oil its either the bores or oil entering through manifold

So via manifold you're thinking turbo seals or breather? Hmm............I'll have to clean the air pipe to turbo and then the other I/C pipes and see if oil appears before and after the turbo or just after!

jamesmartin said:
depends on the angle and whether theres not enough honing to remove boring tool grooves

Are boring tool grooves microscopic, cos I can't remember seeing any. Just honing marks!

jamesmartin · Jun 29, 2017

Al2O3 said:
So via manifold you're thinking turbo seals or breather? Hmm............I'll have to clean the air pipe to turbo and then the other I/C pipes and see if oil appears before and after the turbo or just after!

Are boring tool grooves microscopic, cos I can't remember seeing any. Just honing marks!

very small too small to see the surface looks smooth but its like a thread on a bolt

Al2O3 · Jun 29, 2017

jamesmartin said:
very small too small to see the surface looks smooth but its like a thread on a bolt

Al2O3 · Jun 29, 2017

James, if I was to go down the home honing route. What do you think of the idea of honing the bores with engine still in? I could wrap the crank up to keep metal particles off it and fabricate a catcher to go over the bottom of each bore. I don't fancy taking the crank out again!

jamesmartin · Jun 29, 2017

yes i do often do them with engine in situ you just need to cover crank etc with a rag with journal at lowest point, you need to remove oil squirts though

Al2O3 · Jun 29, 2017

jamesmartin said:
yes i do often do them with engine in situ you just need to cover crank etc with a rag with journal at lowest point, you need to remove oil squirts though

That's good news

I presume you use a honer with the three arms on, like the one you pictured, rather than one of those with all the beads?

jamesmartin · Jun 29, 2017

Al2O3 said:
That's good news
I presume you use a honer with the three arms on, like the one you pictured, rather than one of those with all the beads?

yes with medium stones 280 grit, your putting grooves on at the correct angle 22 degrees to horizontal or 45 degrees to each other,you then use a fine hone 400 grit or whats called a plateau hone for a few strokes 15 or so ,which flattens the peaks which is what running in does as well

Al2O3 · Jun 29, 2017

jamesmartin said:
yes with medium stones 280 grit, your putting grooves on at the correct angle 22 degrees to horizontal or 45 degrees to each other,you then use a fine hone 400 grit or whats called a plateau hone for a few strokes 15 or so ,which flattens the peaks which is what running in does as well

Ok, sounds good. I'm not ruling the turbo out yet though. Obviously I'm hoping it is the turbo cos it'll be a lot easier.

I've got a boost gauge to go in at some point. If the seals are iffy, will it show if I temporarily fit the boost gauge up in to the cab?

jamesmartin · Jun 29, 2017

Al2O3 said:
Ok, sounds good. I'm not ruling the turbo out yet though. Obviously I'm hoping it is the turbo cos it'll be a lot easier. I've got a boost gauge to go in at some point. If the seals are iffy, will it show if I temporarily fit the boost gauge up in to the cab?

yes check everything first ,sometimes the oddest thing shows up, no just knowing oil is passing will do that, id isolate any sources of oil too the turbo ie breather hose and run engine with out let hose off and place a catch sheet to see what amount if any oil passes fro turbo

Al2O3 · Jun 29, 2017

jamesmartin said:
yes check everything first ,sometimes the oddest thing shows up, no just knowing oil is passing will do that, id isolate any sources of oil too the turbo ie breather hose and run engine with out let hose off and place a catch sheet to see what amount if any oil passes fro turbo

I did a brief, similar test, the other night. I looked primarily at the amount of smoke coming from the exhaust. It still smoked, but I was thinking that might be fuel smoke if it wasn't breathing properly.
How long would you do the test you describe for? Which outlet hose do you mean, out of turbo or out of I/C?

jamesmartin · Jun 29, 2017

out of the turbo 5 to 10 mins,are you getting litle oil spots on the rear window etc

Al2O3 · Jun 29, 2017

jamesmartin said:
out of the turbo 5 to 10 mins,are you getting litle oil spots on the rear window etc

Rear window!

Never thought to look. Will the oil not be being burned? Do you think it could make it out of the exhaust??

jamesmartin · Jun 29, 2017

it can depending on how much and were its coming from, ie it can pass straight in to exhaust from the hot side of the turbo

300 Tdi Rebuild

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