High Noack Oils and Dirty EGR Valves...

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The presence of Lead on the back of inlet valves doesn't surprise me.

Gasoline has an aggregate molecular weight of 145. Tetraethyl Lead (TEL) is much heavier with a molecular weight of 323. I don't know for sure but I suspect that commercial TEL was never 100% pure and that it contained small traces of even heavier stuff liked Tetrapropyl Lead & Tetrabutyl Lead. Now while this stuff was perfectly soluble in liquid gasoline, as soon as you 'pull' it into the intake air in a carburetor, the different species in the gasoline will evaporate at different rates (especially if both the fuel and air are cold). Very light stuff like Butane will always rapidly enter into the gas phase. TEL (and particularly any heavier associated junk) will volatilise more slowly. Should any TEL still be in the liquid phase when it hits the back of a hot inlet valve, it could decompose and leave behind the type of deposit you found.

Nowerdays we don't have lead in gasoline but the same principles apply to any heavy stuff that gets into then intake air in that, relative to the fuel, it's going to be slow to evaporate (and may not evaporate at all). So oil that traverses the PCV system and the heavy additives that get added to gasoline fit this bill and are likely to play a role in deposit formation.
 
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At the time I thought the inlet valve build up on these old pushrod engines was oil dripping down the guide...but then remembered the lead taste, and knew there had to be fuel involved. Haven't seen it for many years, but it is still something that can happen.
 
Originally Posted By: SonofJoe
Originally Posted By: Shannow
EGR was on everything 70s and 80s. It, and the things that went around it typically contributed to 20% more fuel consumption, and a similar power loss. Cat-Cons gave another NOx control mechanism in the 80s, and a lot of Oz's petrol engines regained their power, could again hit 30MPG.

(I had a 1978 V-8 auto, that I got to 30MPG through mucking around. EGR at idle, with porting directing the exhaust gasses directly at the idle fuel ports on the Q-Jet carb. Full vacuum advance at idle. Thermostat to control coolant inlet temperatures rather than outlet. PCV fumes routed through a copper pipe wound around the exhaust manifolds and wrapped in insulating tape, and as a result of all the heat, had to use fuse wire in the transition fuel ports to get the idle screws to adjust enough...it was a finnicky POS to get running, but ran great on the highway...and 30MPG...had to pull the junk off to sell it but)

EGR on consumer diesels (in Oz) is a new Century thing...and it's very high rate compared to the back in the day petrol engines.

Re the Pug test...is my reading of your post correct that the NOACK specification was virtually superfluous when an actual engine test was specced ?



It's strange to think that there was once a time when petrol engined cars DIDN'T come fitted with a catalytic converter to zap nasty NOx! However I sort of remember that back in the seventies, I was less concerned about emissions and more concerned with windscreen wipers that fell off while driving along, sills that rusted through, driving on highly lethal £5 remold tyres, hand brake levers that detached themselves from the floor when you pulled too hard, gaping great holes in the front bulkhead which let water in when it was wet, the horrendous stink inside the car from sodden, mouldy carpets & leaking rear drum brake slave cylinders that made stopping in an emergency a 'brown trousers' moment. And you tell that to kids of today, and they don't believe you!

Yes, the TU5 did limit Noack to well below 13% especially on 10W40s. You could cheat the test with Shellvis VII but as it cost twice as much as OCP, it was always something of a pyrrhic victory. Likewise with the VW TDi, you could beat the test by adding more Ashless Dispersant or you could beat it my using more Group III in a semi-synthetic to reduce the level of VII. Often the latter approach made more sense when you took everything into consideration. If like me, you come from this 'low Noack' normality, the very high, close to 15%, Noacks you see in the US look very abnormal.


You must be a North Yorkshire man!.
 
Originally Posted By: Jetronic
Originally Posted By: SonofJoe
Originally Posted By: Shannow
EGR was on everything 70s and 80s. It, and the things that went around it typically contributed to 20% more fuel consumption, and a similar power loss. Cat-Cons gave another NOx control mechanism in the 80s, and a lot of Oz's petrol engines regained their power, could again hit 30MPG.

(I had a 1978 V-8 auto, that I got to 30MPG through mucking around. EGR at idle, with porting directing the exhaust gasses directly at the idle fuel ports on the Q-Jet carb. Full vacuum advance at idle. Thermostat to control coolant inlet temperatures rather than outlet. PCV fumes routed through a copper pipe wound around the exhaust manifolds and wrapped in insulating tape, and as a result of all the heat, had to use fuse wire in the transition fuel ports to get the idle screws to adjust enough...it was a finnicky POS to get running, but ran great on the highway...and 30MPG...had to pull the junk off to sell it but)

EGR on consumer diesels (in Oz) is a new Century thing...and it's very high rate compared to the back in the day petrol engines.

Re the Pug test...is my reading of your post correct that the NOACK specification was virtually superfluous when an actual engine test was specced ?



It's strange to think that there was once a time when petrol engined cars DIDN'T come fitted with a catalytic converter to zap nasty NOx! However I sort of remember that back in the seventies, I was less concerned about emissions and more concerned with windscreen wipers that fell off while driving along, sills that rusted through, driving on highly lethal £5 remold tyres, hand brake levers that detached themselves from the floor when you pulled too hard, gaping great holes in the front bulkhead which let water in when it was wet, the horrendous stink inside the car from sodden, mouldy carpets & leaking rear drum brake slave cylinders that made stopping in an emergency a 'brown trousers' moment. And you tell that to kids of today, and they don't believe you!

Yes, the TU5 did limit Noack to well below 13% especially on 10W40s. You could cheat the test with Shellvis VII but as it cost twice as much as OCP, it was always something of a pyrrhic victory. Likewise with the VW TDi, you could beat the test by adding more Ashless Dispersant or you could beat it my using more Group III in a semi-synthetic to reduce the level of VII. Often the latter approach made more sense when you took everything into consideration. If like me, you come from this 'low Noack' normality, the very high, close to 15%, Noacks you see in the US look very abnormal.


You must be a North Yorkshire man!.


Tha's not wrong there Obadiah!

When I were a boy, we were so poor, we couldn't afford fancy synthetic lubricants. We had to make do with cold, rancid chip fat with a Noack of 1000%. But we were 'appy!
 
Originally Posted By: SonofJoe
Originally Posted By: Jetronic
Originally Posted By: SonofJoe
Originally Posted By: Shannow
EGR was on everything 70s and 80s. It, and the things that went around it typically contributed to 20% more fuel consumption, and a similar power loss. Cat-Cons gave another NOx control mechanism in the 80s, and a lot of Oz's petrol engines regained their power, could again hit 30MPG.

(I had a 1978 V-8 auto, that I got to 30MPG through mucking around. EGR at idle, with porting directing the exhaust gasses directly at the idle fuel ports on the Q-Jet carb. Full vacuum advance at idle. Thermostat to control coolant inlet temperatures rather than outlet. PCV fumes routed through a copper pipe wound around the exhaust manifolds and wrapped in insulating tape, and as a result of all the heat, had to use fuse wire in the transition fuel ports to get the idle screws to adjust enough...it was a finnicky POS to get running, but ran great on the highway...and 30MPG...had to pull the junk off to sell it but)

EGR on consumer diesels (in Oz) is a new Century thing...and it's very high rate compared to the back in the day petrol engines.

Re the Pug test...is my reading of your post correct that the NOACK specification was virtually superfluous when an actual engine test was specced ?



It's strange to think that there was once a time when petrol engined cars DIDN'T come fitted with a catalytic converter to zap nasty NOx! However I sort of remember that back in the seventies, I was less concerned about emissions and more concerned with windscreen wipers that fell off while driving along, sills that rusted through, driving on highly lethal £5 remold tyres, hand brake levers that detached themselves from the floor when you pulled too hard, gaping great holes in the front bulkhead which let water in when it was wet, the horrendous stink inside the car from sodden, mouldy carpets & leaking rear drum brake slave cylinders that made stopping in an emergency a 'brown trousers' moment. And you tell that to kids of today, and they don't believe you!

Yes, the TU5 did limit Noack to well below 13% especially on 10W40s. You could cheat the test with Shellvis VII but as it cost twice as much as OCP, it was always something of a pyrrhic victory. Likewise with the VW TDi, you could beat the test by adding more Ashless Dispersant or you could beat it my using more Group III in a semi-synthetic to reduce the level of VII. Often the latter approach made more sense when you took everything into consideration. If like me, you come from this 'low Noack' normality, the very high, close to 15%, Noacks you see in the US look very abnormal.


You must be a North Yorkshire man!.


Tha's not wrong there Obadiah!

When I were a boy, we were so poor, we couldn't afford fancy synthetic lubricants. We had to make do with cold, rancid chip fat with a Noack of 1000%. But we were 'appy!



Is that because you were poor?
 
Originally Posted By: SonofJoe


Tha's not wrong there Obadiah!

When I were a boy, we were so poor, we couldn't afford fancy synthetic lubricants. We had to make do with cold, rancid chip fat with a Noack of 1000%. But we were 'appy!



You were lucky! We used to DREAM about cold, rancid chip fat. We used the wax from our ears, and only could afford an oil change when we had collected enough wax. Our dad used to crack the wax with our heads against the wall. But we were 'appy!
 
Originally Posted By: Ducman


Is that because you were poor?


No, mostly because he must show he had it worse than anyone else, but persevered..
 
Cleaning up a bit at work today, and was looking into some old service briefs, in the old shop the service manager was playing the ''I know more than you'' power tripping game, and I never saw this stuff. Now I have it all for myself.

Around 2009 MNZ became aware of the manifold build up, first the MAP sensor port would block up, then there were some manifold changes, and then a 60,000km cleaning suggestion, with them backing out of any warranty on that, being an in service issue. Anyway, there was also a note about there not being any problems with the Thailand spec version. All the Tritons are made in Thailand, but the ones for local service have less EGR, so have less deposits. Certainly ties it in with EGR.
 
In Europe we had problems with diesels with intake manifold flaps. BMW's, FIATs, Opel's and others exhibited the same problems. Soot from EGR in conjunction with oil vapors from crankcase gum the flaps. They start to stick, than after they simply brake. If you're lucky you have aluminium manifold with plastic flaps-no harm for the engine.
Unfortunately most had the opposite- plastic manifold and metal flaps.

IME, if EGR is deleted or it works "lazy" by remap oil by itself won't do nothing for the intake.
Generally, here, engine will have 160-180 tkm before cleaning is necessary. Problems is people often didn't react on time before the damage occurs.
 
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