Question about tightening the timing belt

[Mark(The Miser)UK]

those air bubbles are some what normal. it happens when fuel is being pulled. its funny that it doesn't leave the pump but more gets sucked in..

Wow. lol since when does pulling a liquid make a gas appear? They go in and don't come out of the pump because your engine is ingesting them. You'll notice your car will run like complete *** when there is bubbles present. The bubbles are there because you have a leak in your fuel line somewhere and air is lighter and less dense than diesel, thus making it get sucked in through the leak and in to the engine. You my friend, have made me entire weekend that much more funny.  :lol:

Bubbles are probably an air leak, however did no-one ever experiment at school and get a flask of water to boil when cool due to the pull of a vacuum? I can get 'air'  or is it voids out of a liquid inside a large syringe by sealing end and pulling on plunger. Maybe a less than perfect fuel filter or partial blockage down at the tank would do this, either way not to be dismissed as foolishness IMO...

[Rabbit TD]

i am curious myself how much the new fuel really hurts the pumps, i've ran 3 cars on it hard with out any issues, my dad runs it, and i know alot of the vw diesel people in my area, and i haven't heard a word about any issues with their pumps, i think if anything the new fuel just killed pumps that were already on their way out.

I pretty much agree with that 100%.  It's kind of like when they say synthetic oil in an engine or trans. will make it leak and most of the time they will leak if the seals already have 150000 miles on them because the synthetic is thinner in the first place.  I'd still like to know though how they could make the insides of the pumps so close tolerance to stand up to the ULSD if nothing was added to the fuel to replace the sulpher lubricating properties when you get it at the pump.  I see you live in York Pa. not a great distance from me here in Hagerstown Md. and maby if it is actually a lack of some companies not putting in the right amount of lubricant causing problems that we just happen to be in an area of the country that gets the right amount.  Other than that I have no idea :roll:

[dieselherb1]

Just wondering when is/was sulphur a lubricant? For a long time the same was claimed about lead in gasoline, but it was used at the refinneries to crack the crude. Sulphur comes naturally in the oil and coal in places around the world.

[arb]

Bubbles are probably an air leak, however did no-one ever experiment at school and get a flask of water to boil when cool due to the pull of a vacuum? I can get 'air'  or is it voids out of a liquid inside a large syringe by sealing end and pulling on plunger. Maybe a less than perfect fuel filter or partial blockage down at the tank would do this, either way not to be dismissed as foolishness IMO...

For a "void" to form in diesel fuel, you would need 30" of mercury in vacuum. That's what we did in school to make warm water boil - full vacuum. You would need nearly a complete blockage and this would form bubbles only on the vacuum side and they would disappear on the pressure side of the pump, so there would not be any issue with the injectors as they will only see fluid, no voids...

That said, these bubbles would need to be air introduced because of a leak between the bottom of the tank and the suction side of the IP.

[Rabbit TD]

Just wondering when is/was sulphur a lubricant? For a long time the same was claimed about lead in gasoline, but it was used at the refinneries to crack the crude. Sulphur comes naturally in the oil and coal in places around the world.

The sulphur was never added to the old fuel as a lubricant, it was just a natural part of it to begin with just like in coal.  When they decided to make the diesel fuel have less emissions they took out the sulphur to the amout the exhaust had no more than 500 PPM {parts per million} with LSD.  They then decided to reduce it further to no more than 15 PPM which is ULSD.  The problem we are talking about is what the problems realy are with pumps going bad with the new fuel.  Are they just leaking or is there actual internal wear happening because of it and not all areas of the country seem to be having trouble with it.

[arb]

They then decided to reduce it further to no more than 15 PPM which is ULSD.

This was required for the new piezoelectric injectors used on Common Rail Diesel systems. These injectors do 5 - 7 injection events per power stoke per cylinder !  The sulfur would attack the piezo materials.

[clbanman]

http://www.cleanairfleets.org/altfuels.html
http://www.cppi.ca/pdf/ULSD_Q&A_e.pdf
http://www.manitoulinfuels.com/content/news/
I am not a chemist, but I believe sulfur has some use in lubrication. I think it is an element of Molybdenum disulfide.http://www.imoa.info/moly_uses/moly_compounds/lubricants.html
I vaguely remember hearing that it increases the pressure capability of lubricants (extreme pressure lubricants) but if overdone can cause corrosion, but can't find anything to back that up.

[Rabbit TD]

Sulfur is also not a lubricant.  I have not seen anything that would indicate that the new ULSD is in any way inferior WRT lubricity.

Andrew

So then what is the problem people are having wih ULSD in older design engines like we have if in fact the fuel is the reason for their problems if it's lubricating properties are the as good or better than the old fuel? Like I said originaly, we don't seem to be having any problems with it around here and if anything I feel it is actualy better than the old stuff and it does seem to smoke a little less.  If the sulphur actualy corrodes parts of the new injectors and ULSD has as good or better lubricating properties than the old stuff then what is supposed to be the problem with it.   That's what we are trying to get at, are all these stories about ULSD and LSD hurting older systems just urban myths or something of that nature?  I have heard others on the forum say that their seals started leaking after they started using ULSD, and with your pump sealing service you would know the reason for that as to how it affects older seals.  Personaly I don't know if there is actualy a problem with it at this point, at least around here anyway, and like it better so far.  

[theman53]

Maybe it is just the junk around here. I know my old Rabbit hated it and my dad's duramax drinks it more than the older stuff. Is it just that it all the vehicles are getting older? I don't know, but with the old flat red rabbit I had it over multiple winters and always did a little less with winter fuel. After the USLD it went even worse and when spring/ summer came around it didn't get much better, and it was usually noticably more better :lol: .
My pump was about shot but it never leaked until the new diesel...maybe it was the timing of my stuff turning junk at the same time all the pumps said 15ppm or less. I guess I will never know now.

[vanbcguy]

A big reason for getting rid of the sulfur was the invention of the Diesel Particulate Filter (DPF).  DPF's trap particulates and then burn them off more completely rather than just emitting them directly into the air.  Sulfur clogs the hell out of a DPF.

Another big thing is when you burn sulfur you end up sulfur oxides (SOx)... When you mix sulfur oxides with H2O you get H2SO4... Another name for that is "Sulfuric Acid".  So when the sulfur oxides mix with water in the air they form sulfuric acid which then turns in to acid rain.  Even better, when you burn any hydrocarbon (like diesel fuel) you end up with CO2 (carbon dioxide) and H2O (water), so you've got that sulfur oxide and the water together with lots of heat in your exhaust, perfect for a chemical reaction!

Well, now we've got EGR systems that circulate exhaust gases back through the engine.  And these exhaust gases are full of sulfuric acid.  So guess how much extra engine wear you get from that!!  Blowby is a problem too, it's another way for the acid to get in to your engine and chew away at everything.

So there's LOTS of good reasons to get rid of the sulfur in diesel fuel - reduces acid rain, makes your engine last longer and it stops your DPF (if you have one) from getting plugged.

OK, so what about lubricity and pump problems?

A lot of people reported pump problems very early on after switching to ULSD.  If you think about it, just how "non lubricating" can an oil-based fuel be to cause people's pumps to die right away?  Answer is it can't... So what happened?

One of the other things that was in older diesel fuel were aromatic hydrocarbons.  The process that came along to remove the sulfur from the fuel also removed most of the aromatics.  These are "long chain" molecules that have some interesting properties.  They get absorbed by all the seals in your pump and cause them to swell up (like power steering fluid does).  This is all fine and good as long as you continue feeding your pump fuel with aromatics in them.  However once you STOP giving all those swollen seals aromatics they shrink back to their original size, or in some cases even smaller.  Guess what happens then?  Your pump starts leaking all over the place!!

If you have a pump that never saw old diesel it won't have a problem with ULSD.  If you took a brand new "modern" pump designed for ULSD and ran it on "old" diesel for 5 or 10 years, then switched it to ULSD it'd probably start to leak (if the old diesel didn't kill it first!).  From what I've read the big deal seems to really be pumps that have run for at least 10 years on "old" diesel and then have switched to "new" diesel without the aromatics.

So really the problem wasn't so much the "new" fuel destroying pumps, it was that the "old" fuel gave your pump an aromatic addiction.  If it doesn't keep huffing aromatics it goes through "withdrawl" and you need to service your pump.  Yeah, the problem wouldn't have happened if the aromatics hadn't been removed from the fuel, but we're actually better off without them and we're DEFINITELY better off without the sulfur.  Once your pump is re-sealed (and it was generally only really old pumps that had the problem in the first place) it won't happen again due to the fuel unless you find a 10 year supply of "old" diesel to run on and then switch back!

BTW, switching from "old" diesel to ANYTHING else has the same potential for problems... Yes, B100 eats some types of rubber but guess what, it doesn't have aromatics in it either!

[Rabbit TD]

Maybe it is just the junk around here. I know my old Rabbit hated it and my dad's duramax drinks it more than the older stuff. Is it just that it all the vehicles are getting older? I don't know, but with the old flat red rabbit I had it over multiple winters and always did a little less with winter fuel. After the USLD it went even worse and when spring/ summer came around it didn't get much better, and it was usually noticably more better :lol: .
My pump was about shot but it never leaked until the new diesel...maybe it was the timing of my stuff turning junk at the same time all the pumps said 15ppm or less. I guess I will never know now.

 The only thing I ever read that makes sense to me is that the new fuels will make an old seal leak sooner than if it was still being run with the old fuel.  Supposedl something in the new fuel has a tendancy to shrink the seals a little and if they were pretty old to begin with they will leak a lot sooner than they were going to otherwise.  I had a shaft seal start leaking 3 years ago, the engine was rebuilt but the pump had over 200,000 on it.  I was running it on fuel oil which at that time was still the older style with the full sulphur content.  I think it was just time for it to go as it certainly wasn't the fuels fault.  One thing that I wonder sometimes though is that I think we can get carried away with some of these injector cleaners and maby use too much of the wrong thing too often too and blame it on the fuel.  I did use a lot of injector cleaners of different types pretty often at that time but still, the seal had over 200,000 on it, the new one has 35,000 on it and is still not leaking.

[vanbcguy]

Oh yeah, one more thing...

ULSD tends to be thinner than the "old" diesel was (lower viscosity).  The VE pump used in our cars depends on internal pump pressure for proper ignition advance, and that pressure is partially regulated by a small orifice in the 'OUT' bolt of the pump.  Thinner fuel slips through that orifice more easily and causes internal pump pressure to be reduced.  This results in less dynamic timing and poor fuel economy and likely power loss at higher RPM ranges.  Fortunately pump internal pressure can be adjusted, so you can calibrate your pump for the new fuel, but of course a pump set up for old thick fuel isn't going to run the same on new thin fuel.

[Rabbit TD]

A big reason for getting rid of the sulfur was the invention of the Diesel Particulate Filter (DPF).  DPF's trap particulates and then burn them off more completely rather than just emitting them directly into the air.  Sulfur clogs the hell out of a DPF.

Another big thing is when you burn sulfur you end up sulfur oxides (SOx)... When you mix sulfur oxides with H2O you get H2SO4... Another name for that is "Sulfuric Acid".  So when the sulfur oxides mix with water in the air they form sulfuric acid which then turns in to acid rain.  Even better, when you burn any hydrocarbon (like diesel fuel) you end up with CO2 (carbon dioxide) and H2O (water), so you've got that sulfur oxide and the water together with lots of heat in your exhaust, perfect for a chemical reaction!

Well, now we've got EGR systems that circulate exhaust gases back through the engine.  And these exhaust gases are full of sulfuric acid.  So guess how much extra engine wear you get from that!!  Blowby is a problem too, it's another way for the acid to get in to your engine and chew away at everything.

So there's LOTS of good reasons to get rid of the sulfur in diesel fuel - reduces acid rain, makes your engine last longer and it stops your DPF (if you have one) from getting plugged.

OK, so what about lubricity and pump problems?

A lot of people reported pump problems very early on after switching to ULSD.  If you think about it, just how "non lubricating" can an oil-based fuel be to cause people's pumps to die right away?  Answer is it can't... So what happened?

One of the other things that was in older diesel fuel were aromatic hydrocarbons.  The process that came along to remove the sulfur from the fuel also removed most of the aromatics.  These are "long chain" molecules that have some interesting properties.  They get absorbed by all the seals in your pump and cause them to swell up (like power steering fluid does).  This is all fine and good as long as you continue feeding your pump fuel with aromatics in them.  However once you STOP giving all those swollen seals aromatics they shrink back to their original size, or in some cases even smaller.  Guess what happens then?  Your pump starts leaking all over the place!!

If you have a pump that never saw old diesel it won't have a problem with ULSD.  If you took a brand new "modern" pump designed for ULSD and ran it on "old" diesel for 5 or 10 years, then switched it to ULSD it'd probably start to leak (if the old diesel didn't kill it first!).  From what I've read the big deal seems to really be pumps that have run for at least 10 years on "old" diesel and then have switched to "new" diesel without the aromatics.

So really the problem wasn't so much the "new" fuel destroying pumps, it was that the "old" fuel gave your pump an aromatic addiction.  If it doesn't keep huffing aromatics it goes through "withdrawl" and you need to service your pump.  Yeah, the problem wouldn't have happened if the aromatics hadn't been removed from the fuel, but we're actually better off without them and we're DEFINITELY better off without the sulfur.  Once your pump is re-sealed (and it was generally only really old pumps that had the problem in the first place) it won't happen again due to the fuel unless you find a 10 year supply of "old" diesel to run on and then switch back!

BTW, switching from "old" diesel to ANYTHING else has the same potential for problems... Yes, B100 eats some types of rubber but guess what, it doesn't have aromatics in it either!

Thank's a lot for your responses on this and I feel they are 100% right on from what I have read also.  I know also that the old fuel will mess up these new particulate traps pretty quick just like leaded fuel will kill a catalytic converter.  As far as the seal shrinkage or lack of being swelled it makes perfect sense too and I read something similar when I ordered my shaft seals a while back that as long as you stayed with the new fuel after you changed the bad seal the new one would last with no problem for the reasons you stated.  As far as mileage and power I haven't done a thing to my timing or fuel screws and my mileage never dropped a bit, has as much if not more power than it ever did.  Probably theoreticaly the differences in viscosity should make a difference but if it has made a difference for the worse It isn't enough for me to even notice, I really feel it is actualy better.  Thanks again for your answers and I hope it makes others out there feel a little more comfortable as well using the new fuel:D

[Golf/Jetta]

ok experiment  time
tools:
water (sink full)
soap (dish soap)
clear syringe  (without niddle)

Procedure
mix soap w/ water
dunk syringe into the sink and get the bubbles out
with syringe in the water suck in 1/4 of the syringe's capacity
put your finger at the end of the syringe to block the flow of fluid going in and out
pull the syringe to create a vacuum

Conculsion
can't compress water but you can pull/rip it apart

[arb]

ok experiment  time
tools:
water (sink full)
soap (dish soap)
clear syringe  (without niddle)

Procedure
mix soap w/ water
dunk syringe into the sink and get the bubbles out
with syringe in the water suck in 1/4 of the syringe's capacity
put your finger at the end of the syringe to block the flow of fluid going in and out
pull the syringe to create a vacuum

Conculsion
can't compress water but you can pull/rip it apart

If you were to put a vacuum gauge at the end of that syringe, you would see 30" of mercury in vacuum. Further, if you hold that syringe under the water when you pull the vacuum, you will be elininating the air that leaks around that little ruber seal in the syringe.

30" vac - Nothing you're going to see on the suction side of the IP unless there is a real problem.