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Engine Specific Info and Questions => IDI Engine => Topic started by: regcheeseman on March 14, 2011, 08:12:44 am

Title: Diesel knock? - NOW FIXED!!!!!!!
Post by: regcheeseman on March 14, 2011, 08:12:44 am
I sold an engine to a friend for his caddy and gave him help setting it up.

It knocks quite heavily  ::)

I changed the pump timing and still the knock remained, I even swung the pump across it's timing limits while the engine was running - no real change.

He swapped the injectors for known good ones - still knocking.

Fearing the worst I missed out on Sunday lie in and was down at his garage early, I pulled the head - very clean, slight carbon build up on number 3 but as expected.

Now pulled the sump, nothing in the oil, dropped the connecting rod caps and pulled the pistons out to check

Still nothing  ???

It's not lifters as it's not 'that' type of ticky noise, it's more clack.


Any ideas people? It starts and runs fine. Just noisy.

It can only be pump now surely?

Title: Re: Diesel knock?
Post by: 8v-of-fury on March 14, 2011, 08:38:15 am
Diesels do have a particular knock to them all the time, to the tune of an explosion happening in the piston at 23.5:1 compression. :p

however, if you say it is louder than normal, and you have checked everything.... I dunno what is left. I had a set of dirty injectors run all stupid.. and loud. ATF fixed the knock.  you have swapped the injectors so maybe there is something in the pump.. Do you have it back together in running order? I'd get it back together and run it off a bottle of Auto Trans Fluid.. let it fill the pump and let it sit over night (in a heated garage, atf doesnt like to start cold) and then run the piss out of it the next day, and see if it helps! 
Title: Re: Diesel knock?
Post by: Bugsy_malone 666 on March 14, 2011, 08:48:37 am
I noticed when my diesel was cold the other day it has a much more industrial clatter/knocking noise, but I know full well its just the sound of the diesel engine when cold.

Did you warm it right up first?
Title: Re: Diesel knock?
Post by: regcheeseman on March 14, 2011, 09:02:48 am
It's not normal knock - it's pretty damn loud. I do appreciate a normal cold IDI diesel engine is noisy but this is +30% extra.

It 'seems' to be coming from the engine rather than the pump - as if a pump setting/problem is causing the knock rather than anything physical within the pump. Hard to tell though.

I just wanted to be sure I'd eliminated the possibilites before I fit the head back on.

I did notice that the owner is running a single central speaker with a 6x4 speaker - maybe this needs to be upgraded?
Title: Re: Diesel knock?
Post by: Bugsy_malone 666 on March 14, 2011, 09:39:38 am
I did notice that the owner is running a single central speaker with a 6x4 speaker - maybe this needs to be upgraded?

Ah theres your problem right there, bigger speakers = less ability to hear the engine :lol:

I honestly dont know why it could be knocking, its not something like the brake vacuum pump or something related to the intermediat shaft is it? How about clutch/flywheel? If they werent fitted tight enough might do it.

I think really you should probably get an oil pressure gauge hooked up and try to determine if theres a problem with oil pressure as to why it could be knocking.

Title: Re: Diesel knock?
Post by: regcheeseman on March 14, 2011, 10:29:44 am
Funny you mention clutch/flywheel and somehow the TDC mark is about 45 degrees away from actual TDC.  ???

Yes it IS a diesel flywheel and clutch.
Title: Re: Diesel knock?
Post by: Bugsy_malone 666 on March 14, 2011, 10:53:50 am
Well the reason I mention about the flywheel/clutch is because of a problem I had when I was fitting a new engine to a T25 working for my Mechanic mate, basically we got the new engine and stock the old flywheel and bolts in, after a few hundred miles apparently it started knocking really bad and we were a bit worried as it was a Vega Recon with the temperature guarentee sticker on it, turns out when you fit the flywheel your supposed to use new bolts! Now I know why this is and when I did the diesel in my Camper I used the same bolts, but used lock tight on them and did them up to book spec. After several thousand miles I have had no trouble, but I know when you take the old ones out they have some blue lock tight on them which is why they say 'new' bolts when refitting the flywheel.

The other thing I found with the clutch arrangement is that you can fit the flywheel 1 way only if its the flywheel that bolts to the crank, in which case the clutch pressure plate has the markings on and I think it can be fitted atl east 1 of 3 ways, when you have the pressure plate that bolts to the engine, that only fits one way round, but I think you have the make on the flywheel that can be fitted one of 3 or 6 ways round (which would account for it being maybe 45deg out.)

Depending on if the engine already had the clutch fitted or not I guess that would have been the first thing I would have checked before ripping the rest of the engine apart.
Title: Re: Diesel knock?
Post by: clarkrep on March 14, 2011, 05:22:12 pm
X2 on the flywheel bolts being loose.
Didnt put loctite on them one time, I did torque them though. I was 15 at the time an had just did a full engine rebuilt(my first Vw diesel) in my dad's caddy and after maybe a 100 miles they worked loose. I was VERY relived to find it being just that  :)
Title: Re: Diesel knock?
Post by: Vitwagen on March 14, 2011, 07:03:55 pm
I had an AAZ that had a phenominal knock:

http://www.youtube.com/watch?v=uL3zUyLKwyU

Just found out this weekend what it was - does it sound anything like that?

I assume this is an AAZ fitted to a Caddy? originally a 1.6D?...
Title: Re: Diesel knock?
Post by: blackdogvan on March 14, 2011, 07:23:35 pm
I've found the best way to differentiate knock from a fuel related clatter is a long hill, some speed & a downshift. With little to no fuel injected all you're hearing is the engine rotating & if its fuel related it'll be gone & if its some other nasty issue it will likely still be there.
Title: Re: Diesel knock?
Post by: regcheeseman on March 14, 2011, 08:05:21 pm
Quote
Depending on if the engine already had the clutch fitted or not I guess that would have been the first thing I would have checked before ripping the rest of the engine apart.

The engine is still fitted, ripped apart in situ. I can get to the back of the fly and 'shake' test it.
It did start the knock straight after fitting motor, so not sure the flywheel bolts could have worked loose instantly?


Vitwagen - it sounds a lot like that.....a replacement pump would be good ;)

It's a 1.6 TD fitted into a caddy mk1 that was 1.6D

The owner has noticed machining marks that look like a block skim - I've asked him to measure protrusion, it was running a 3 notch - could this potentially make it knock? There is no physical interference.
Title: Re: Diesel knock?
Post by: Vitwagen on March 15, 2011, 02:21:03 pm
Vitwagen - it sounds a lot like that.....a replacement pump would be good ;)

It's a 1.6 TD fitted into a caddy mk1 that was 1.6D


Ah, 1.6? My noise was an AAZ conrod cap hitting the 1.6 oil pickup pipe flange (!). The problem came about due to the longer stroke of the 1.9.

Pump needed eh? I expect demand on them may push the price up?  ;)
Title: Re: Diesel knock?
Post by: 79rabbit4dr on March 15, 2011, 11:01:01 pm
http://www.google.com/#q=mechanics+stethoscope&hl=en&prmd=ivns&source=univ&tbs=shop:1&tbo=u&sa=X&ei=0yaATaqCKIaosAP4k-z5BQ&sqi=2&ved=0CCwQrQQ&biw=1366&bih=575&bav=on.2,or.r_gc.r_pw.&fp=d57722a22572de1d (http://www.google.com/#q=mechanics+stethoscope&hl=en&prmd=ivns&source=univ&tbs=shop:1&tbo=u&sa=X&ei=0yaATaqCKIaosAP4k-z5BQ&sqi=2&ved=0CCwQrQQ&biw=1366&bih=575&bav=on.2,or.r_gc.r_pw.&fp=d57722a22572de1d)
I've had good luck narrowing down knocks (especially in extra noisy engine compartments with these) with one of these. Cheap for how useful it is. Just thinking outside the box.
Title: Re: Diesel knock?
Post by: regcheeseman on March 16, 2011, 06:19:01 am
I've got a long screwdriver. ;)
Title: Re: Diesel knock?
Post by: carrizog60 on March 16, 2011, 09:16:21 am
on my gtd when the bushing on the accelarator shaft on pump went bad the engine will know badly... ???
Title: Re: Diesel knock?
Post by: Mark(The Miser)UK on March 16, 2011, 08:18:58 pm
I sold an engine to a friend for his caddy and gave him help setting it up.

It knocks quite heavily  ::)

I changed the pump timing and still the knock remained, I even swung the pump across it's timing limits while the engine was running - no real change.

He swapped the injectors for known good ones - still knocking.

Fearing the worst I missed out on Sunday lie in and was down at his garage early, I pulled the head - very clean, slight carbon build up on number 3 but as expected.

Now pulled the sump, nothing in the oil, dropped the connecting rod caps and pulled the pistons out to check

Still nothing  ???

It's not lifters as it's not 'that' type of ticky noise, it's more clack.


Any ideas people? It starts and runs fine. Just noisy.

It can only be pump now surely?

It could be the valves kissing the pistons, or getting very close to them.
Nearest point is not TDC  but a little either side, as the piston chases the exhaust valve before it closes BTDC and as the inlet chases the piston ATDC.

The sound echoes out the manifolds. Worsened  by skimming of head, naturally...

My engine has been doing it for 30,000miles :-[
Title: Re: Diesel knock?
Post by: fatmobile on March 17, 2011, 12:52:47 am
Rod pins feel sloppy in the pistons?
Title: Re: Diesel knock?
Post by: regcheeseman on March 17, 2011, 06:16:09 pm
Gudgeon pins and small ends are fine - that was my no1 suspect after timing and injectors were eliminated.

Quote
It could be the valves kissing the pistons, or getting very close to them.

I'd expect to see some witness marks - there is nothing

No 2 piston has a little dent on one edge, looks like something solid entered the chamber made two dents before being spat out, there's a corresponding mark on the cylinder wall - but no damage, not significant.
Title: Re: Diesel knock?
Post by: maxfax on March 18, 2011, 12:14:26 am
Off the wall question, is this engine hydro or mech lifter???
Title: Re: Diesel knock?
Post by: Mark(The Miser)UK on March 18, 2011, 05:23:11 am
I sold an engine to a friend for his caddy and gave him help setting it up.

It knocks quite heavily  ::)

I changed the pump timing and still the knock remained, I even swung the pump across it's timing limits while the engine was running - no real change.

He swapped the injectors for known good ones - still knocking.

Fearing the worst I missed out on Sunday lie in and was down at his garage early, I pulled the head - very clean, slight carbon build up on number 3 but as expected.

Now pulled the sump, nothing in the oil, dropped the connecting rod caps and pulled the pistons out to check

Still nothing  ???

It's not lifters as it's not 'that' type of ticky noise, it's more clack.


Any ideas people? It starts and runs fine. Just noisy.

It can only be pump now surely?



Reg,
If you can take the vehicle out for a drive, then on a quiet stretch [might still be one in Devon way]with the clacking happening, turn off the engine, whilst still in gear and see if the sound disappears, if it goes, then its fuel, if it doesn't then it's 'mech' ;D
Title: Re: Diesel knock?
Post by: regcheeseman on March 18, 2011, 08:16:52 am
Quote
Off the wall question, is this engine hydro or mech lifter???

hydro


Mark/Blackdogvan

I'll try that test when it's rebuilt, the workshop is right next to the only real dual carriageway in North Devon. A well known test strip.
Title: Re: Diesel knock?
Post by: sdwarf36 on March 18, 2011, 12:21:35 pm
If you crack the fuel lines one at a time, you will take the load off that cylinder( no fuel= no fire=no load) -you can see if the noise changes.
 To check for the flywheel bolts, put the car in gear-have someone stand hard on the brakes-and go back+ forth with the crank bolt. Look to see if the flywheel moves the same amount as the crank bolt.
 Also-are #1+4 piston up the same amount? (just thinking possible prior bent rod)
Title: Re: Diesel knock?
Post by: regcheeseman on March 18, 2011, 06:34:34 pm
Quote
If you crack the fuel lines one at a time, you will take the load off that cylinder( no fuel= no fire=no load) -you can see if the noise changes.
 To check for the flywheel bolts, put the car in gear-have someone stand hard on the brakes-and go back+ forth with the crank bolt. Look to see if the flywheel moves the same amount as the crank bolt.
 Also-are #1+4 piston up the same amount? (just thinking possible prior bent rod)

Rods are fine, already done the injector test before tearing the motor down.

I'll do the flywheel test.
Title: Re: Diesel knock?
Post by: rdezsofi on March 19, 2011, 02:21:38 am
I guess you have it torn apart.....how are this pistons and bore, as far as measurements? I'm thinking severe piston slap maybe??? Did you do a compression check prior to teardown? It might just have extremely high compression. (Head surfaced, etc, etc.)
Title: Re: Diesel knock?
Post by: Mark(The Miser)UK on March 19, 2011, 05:26:50 am
Quote
Off the wall question, is this engine hydro or mech lifter???

hydro


Mark/Blackdogvan

I'll try that test when it's rebuilt, the workshop is right next to the only real dual carriageway in North Devon. A well known test strip.

Hi,
 I'd just like to apologise to Blackdog van , I didn't  spot his [I assume a chap :o] prior post detailing similar technique. ::)
"I must read the threads more closely  I must read...."

In my defence, my technique removes even more fuel ;D
Title: Re: Diesel knock?
Post by: regcheeseman on May 24, 2011, 03:45:25 am
It's got me beat! looks like the turbo seal is giving up the game too.

We're going to fit another engine and this one will get an autopsy at some point.
Title: Re: Diesel knock?
Post by: Mark(The Miser)UK on May 24, 2011, 05:23:39 am
It's got me beat! looks like the turbo seal is giving up the game too.

We're going to fit another engine and this one will get an autopsy at some point.

Don't you hate that.

I'm thinking my only solution in my case is to remove the 'unleaking head' and skim the outer exhaust valves.
I too had bought small end and big end bearings, expecting[hoping] to find a rogue one; but no play detected so the kits remain in reserve.
Did the sound continue with no fuelling?
Title: Re: Diesel knock?
Post by: carrizog60 on May 25, 2011, 08:34:41 am
my aaz(well 1y with turbo) is now making a tim tim tim sound,not clatter...
not to highjack the thread sorry but can anyone help?
timed to 1.00mm,with aaz injectors and 1.6 gtd fuel pump
Title: Re: Diesel knock?
Post by: regcheeseman on May 26, 2011, 05:43:02 am
FIXED IT  ;D

I can't take any credit for doing so, it was only spotted by a mechanic who had a Toyota Hilux doing similar.

Basically despite have the injector lines and pump removed at least four times, no-one noticed that they were wrong.

The previous owner had managed to bend them to fit in a different sequence. They didn't look obviously bent and offered themselves up to the head quite naturally.

A quick switch around and it's running sweet as!

It's surprising that it started, idled and run quite happily in it's mixed up state.
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: macka on May 26, 2011, 06:05:09 am
well its fixed and all is well. That is funny that it ran
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: 745 turbogreasel on May 26, 2011, 02:35:30 pm
Wow, mine always seem to crack after even a slight bend.
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: rabbid79 on May 26, 2011, 07:16:07 pm
Quote
well its fixed and all is well. That is funny that it ran
More like shocking! :o

I wonder about the physics of that.  Which cylinders were switched around?
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: R.O.R-2.0 on May 27, 2011, 09:41:02 am
surprising it didnt break a ring, or blow a head gasket.. theres no way it was running right..
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: macka on May 27, 2011, 09:44:47 am
Quote
well its fixed and all is well. That is funny that it ran
More like shocking! :o

I wonder about the physics of that.  Which cylinders were switched around?

One thing I have learnt is that even though physiques sometimes says no, it happens anyways.
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: regcheeseman on May 27, 2011, 06:07:27 pm
Quote
theres no way it was running right..

now you'd think so wouldn't you, and while it wasn't running right, it ran quite happily!

it started easily, it idled quite smoothly and revved happily

it only made 14 psi, clattered badly and billowed white smoke

I didn't find the fault so I'm unsure which pair were swapped
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: crezz on May 28, 2011, 01:19:35 pm
it is quite shocking how it did run with them wrong but it did, wasnt full of power but its not as tho it had none, but since its back to normal, it goes really well  ;D i suppose we missed the problem as the lines are clamped together in pairs, so came off that way and back on that way, silly really that we didnt check this before hand, but out of all the people that had looked at the motor and had suggested problems, nobody spotted or thought aboutthe firing order. it wasnt like it was missing tho, just an allmighty clatter!
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: Mark(The Miser)UK on May 28, 2011, 02:25:13 pm
Interestingly, the clatter was probably from the lines that were injecting correctly, but needing to do so too far advanced, but one or more of the others  steaming off the diesel from the surfaces relatively quietly... maybe 8)
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: pointynoggin on May 28, 2011, 02:49:18 pm
I would guess the swaped lines were injecting at the bottom of the compression stroke and pre-igniting at the top making the knock, same as leaky nozzles.?
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: rabbid79 on May 28, 2011, 04:05:27 pm
Quote
Interestingly, the clatter was probably from the lines that were injecting correctly, but needing to do so too far advanced, but one or more of the others  steaming off the diesel from the surfaces relatively quietly... maybe
Quote
I would guess the swaped lines were injecting at the bottom of the compression stroke and pre-igniting at the top making the knock, same as leaky nozzles.?
I like both theories.  This is specifically why I was curious which two cylinders were swapped.  I guess we could figure out what would happen if 1&2, 2&3, or 3&4 were mixed.
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: 745 turbogreasel on May 29, 2011, 12:57:05 am
I got my caddy to start with the pump 180 out, and it smoked and knocked like a demon from hell.
Title: Re: Diesel knock? - NOW FIXED!!!!!!!
Post by: wdkingery on May 29, 2011, 09:39:22 pm
I got my caddy to start with the pump 180 out, and it smoked and knocked like a demon from hell.

hahahah love it.

i got my turd to start with the the IP set at .10 mm.. and it smoked and missed like hell but would do 50 mph