has anybody got some ideas on engine missing problem

[yaapeet30]

Another thing I forgot to mention. I had a miss a couple of years ago and it turned out to be quite simple. I lifted the bonnet at night and could see an arc from one of the plugs. Whats the condition of the distributor?

I would start simple and slowly eliminate each before you got to the tear the motor down.

Cheers

Rod

[EKUTE]

Thanks again fellow members for your imput,I,ve ruled out electrical because I,ve changed everything,when the head was off I noticed this cylinder had far less carbon than the others indicating water somehow to be a factor in solving the mystery.I,ll let you know once it,s been torn down so stay posted.ie might be awhile before the riddle is solved,I,m working on a suzuki 73 waterbottle right now getting closer to launch day.

[Craig Allardyce]

120,000 miles.............that's 192,000 km. That's pretty good for an engine with a pretty average oil filter system (bypass or nothing) and high rev operation due to low gearing. 100kph on standard running gear is approx. 3600rpm. Not many cars these days put up with all that and last much longer. Wear rate on an engine equates with how much distance the piston and crank has covered over time (and all other components), how much fuel is burnt relative to loading hence why so many cars these days employ overdrives or multispeed gearboxes.
A full flow filter conversion, EFI, synthetic oils, 6 or 7 speed auto/manual, lock up clutch, cruising rpm of 1500-2000 rpm and your old grey would do a whole lot better. Its all relative.

[rosco]

As Craig states - 120k miles is exceptional... but, it depends on what it was doing.
As you are fully aware - the grey only has four mains - if a grey holds good oil pressure at those sort of mileages - whoever has had it has been very kind.
It's a question of balance, as I understand the philosophy of getting longevity from engines.
I often asked people if it was kinder to rev a motor and apply a lighter load than gear up (very poor way we speak of gearing) and wring the daylights out of the mains.
Fuel wise, I don't believe it makes much difference - unless you're running multi carbs and like to feel the toe-board under your foot.
High load, low rpms or light load and lots of rpms... fuel gets sucked in and blown out just the same.
If you can keep off the power valve - that seems to make a lot of difference to single Stromberg carb engines - push down and open that up, and you start to drink.

Piston travel certainly equates to high rpms - and yes, the more distance those rings run in the bores - the more "work" they will peform.

I've always been a mega filtration advocate - if everything which goes into the cylinders is clean - wear can be significantly reduced.
For air intake - I'm not a fan of foam filters and not totally in love with paper ones either. They both have advantages.
The best I ever had was a product called UniFilter... that one was brilliant. Until the element finally failed and I was ever so fortunate to find this happen when the element was getting its periodical wash and re-oil. Not one jot of anything got through that filter into the air cleaner... I could wipe a white cloth around the internal of the air cleaner body and never got anything on it. A bit further down the throat, however - resulted in black staining... probably the "pulsing" of air going up and down in the carby throat - or choke use.

Oil - well, I'd rather change a good quality mineral oil with the usual additives every 1,000 miles at the same expense of using really top class synthetic and holding it in there for 3,000.

I have used synth (Mobil 1) in one of my engines for some 50,000 km's... and everything is still fine - but it is damned expensive to do an oil change on a regular basis at every 3,000 km's as is my practice with that engine.

For my old bus, I usually change it every six months - it seldom ever gets more than 3,000 miles within that period.

I am an advocate for Nulon - this red motor which is in my old bus was run in for 1,000 miles then Nulon E30 was added.
I add E20 at every oil change.
When we pulled down the engine about 5 years back - there was no markings on any of the crank or rod bearings.
There wasn't any "ledge" in the bores and the rings and pistons were just stained - absolutely no carbon on anything in the lower end of the motor.
The head was a mess, though - GEM (Sydney) sent down a replacement head when I told them I had compressions of 220 psi.
The engine would not run in properly, it was extremely lumpy and wouldn't idle below about 800 rpms. It had very high coolant temperatures - even on the mildest of days.
I put up with it for a month and my grizzling finally brought results.
When the replacement came in the found that it had been fitted with a 149 high compression head by mistake... on a 192.... the blasted thing wouldn't shut down without rocking itself to death after turning off the ignition. With the 4 speed box and the little 3:55 diff - I believe you can only appreciate the power this resulted in.

The head they replaced it with after one month's running (1983) defanged the motor.. and it wasn't until I went to have it reconditioned by Ray Layton 5 years ago (who actually threw the blasted thing out because GEM had done so much damage to the guides and seats) that I found out the motor had been maligned so poorly.

This replacement head fitted 5 years back has given back much of the life lost when the second one was fitted... but certainly not of the power of that 149 HC one.

Oil filtration -
I run an additional Frantz oil cleaner - not many people know about these - but they employ what looks like a toilet roll as a by-pass filtration cleaner. They were very big in the late 60's and 70's.. I fitted mine to the second grey in around 1978.

Oil from the sending unit outlet runs through a "T" piece and then via a restrictor into the top of this oil cleaner. It then passes down through the ends of the roll leaves (tightly wound) and comes out the bottom before being strained once again by thick stainless gauze.
After passing through this - it returns into the engine sump through a tapped hole in the sump - above oil level.

I believe you can appreciate the degree to which oil is filtered/cleaned - through some 4 inches of filter - as opposed to maybe 1/16"th with the full flow spin on unit.

The filter element is changed every time I change the engine oil - it holds an additional quart of oil.
This on its own adds to the volume of oil which passes through the engine up to 7 times a minute when at operating temperature.. which is pretty normal for a modern engine.

This Frantz system is of the by-pass type.. but, so too is the full flow system when the oil is cold... the pump pressure simply opens the by-pass valve and unfiltered oil runs through your engine until it warms up sufficiently to pass through the thin cardboard like paper element in the spin on filter.

Who knows what percentage of oil, even when hot - actually passes through the full-flow filter... as it goes through the galleries...
I would doubt very much that the full volume of oil, even at some 45 psi - would be able to satisfy the needs of the galleries if it had to run though the spin on filter to get there... even at only 3 times a minute... some 7 pints times 3 ... per minute... through that paper element... hmmmmm.

Originally, Frantz was marketed as a "never change the oil" product - which caused much damage in the long term.
I was never an advocate for doing this - the acids and "big lumps" simply couldn't get through the restrictor.. so had to go back into the engine...

I did prolong oil changes in the grey to around 2,000 miles - plus the Frantz element.

Both my grey motors in this old dear did not live long lives - I thrashed the living daylights out of the first one and it started oozing oil out of every seal... that motor was changed at 78,287 miles... the second grey went in at that mileage and got the Frantz not long after.

This motor lasted until 152,000 miles (even with the Frantz) so that made around 72,000 miles.. it was still in good nick when I pulled it out and got rid of it... lost a bit of compression - but I believe that was valve related. It still ran very smoothly and did not burn any oil.

The very sad decision to modify the dear old thing to a red motor, aussie box and disc brake front end was entirely due to the sub-frame having rusted out in the front left corner (read my thoughts on fitting rubber blanking plugs into the outrigger holes in the stone tray beneath the radiator baffle in subframes - and I continue to note that most still do not do this).

The red went in just before the 152,000 mile mark and it's now just over the 232,000 mile mark and strong as ever.

There is an engine "rattle" under power from around 2,200 rpm to 2,400 rpm which none of us have been able to find (hence the total strip down 5 years back - finding nothing - every piece in the block came out, all pistons were pressure tested with dirty kero).

Compression is still up around the 195 mark on all pots... and all of them within 5 psi.

Oil pressure is a bit odd... typically high when cold, dropping off 10 psi when hot - but I do fully appreciate there is an issue with the electric pressure gauge (VDO) - turning the gauge lights on causes the oil pressure to drop... an earthing issue, which I will attend to shortly.

I fitted the V8 oil pump (high volume, not high pressure) prior to the Hervey Bay nats - and the motor held better pressure on both journeys. It dropped off a bit climbing steep hills.
The big tyres and 3:08 diff made it work very hard at low rpms - and the oil temperature would have climbed considerably - reflected by oil pressure readouts.
On descent, the oil cooled and the oil pressure restored.
This is about a red motor with 7 mains...and what I believe to be the ultimate in oil filtration.

So, to get 120,000 miles out of a grey motor without any filtration, I would consider this extremely long life.

As Craig states - regular oil changes, good oil, air and fuel filtration - and some consideration and respect for those 4 main bearings especially when cold and at low rpms.... would go a very long way to extending the life of a grey motor.

I would further suggest some form of positive filtration to the rocker breather system.
The positive forced,side plate drawn system has worked for ever.. but, if you want to prevent extremely fine grit and debris getting into the top of your motor (and oil)...I'd suggest fitting something.... but ensure it is "positive".... not simply a foam gauze inserted into the breather... as this will reduce airflow through the ventilation system.

I ponder if it is possible to fit a PCV to a grey motor... and add a filtered breather arrangement.
It would certainly remove that well known "blow" of fumes from underneath the car when idling.. and the occasional drip of carried over oil/condensation from it onto the ground.

Holden, with something in the year of the HJ or thereabouts - fitted a sealed rocker system.. but, they stuffed it up... the "filtered" air intake was from the "unfiltered" side of within the air cleaner... a felt pad inside a plastic holder...

The dust and rubbish removed from withdrawn air through the nozzle of the cleaner fell on the very base from where the air drawn into the rocker cover was taken..... why?... I have never worked that one out..

On my little Toyota Corona - it employs the same "filtered" rocker system.. but - the air admitted into the rocker cover is taken from within the air cleaner element - not outside, like the HJ one....

I ran the HJ system in my red for quite a few years - but modified it to admit filtered air.

The external top end of this motor has always been very, very clean... the ports, valves and guides were very poorly machined and set by GEM - this amounted to a useless head for reconditioning.

I am ever hopeful of getting at the very least well over 150,000 miles out of this engine.... it's got 80,000 on it now.. so, with a bit of good fortune - it's now just beyond half life.... not bad for a reconditioned engine.

It is now only ever a cruiser... it won't ever tow again, nor will it be allowed unbridled wide open throttle through the gears.

It floats along the road at the speed limits quite effortlessly, unless there are hills... I make use of the gearbox to short shift and light load where the "rattle" is..
It only ever now goes over 2,400 rpms in top gear - which is well beyond most state speed limits (NT excepted).
It putters along at the 100 km/h mark at around 1,850 rpms... and still well under that dreaded rattle range at 110 km/h.

Oil, air and fuel filters are kept clean - scrupulously clean, in fact... and every care is taken whenever a cover or breather etc is removed for whatever reason.

..... Oops... just read what I've typed.... another novel... apologies (again) to the OP... swamped this one as well.....

frats,
Rosco

[Craig Allardyce]

Rosco,

a few points to add:
in my mind and within the industry, engine wear usually equates to the amount of fuel consumed over time rather than km's done. Overdrive or low gearing is a fine line in reducing rpm before loads are increased too much requiring richer mixtures (as you state re power valve).
Mind you though cylinder filling at light throttle openings is poor and very inefficient. If it were ever possible I think the best operating range would be somewhere around highest torque rating i.e. 1400rpm which equates to about 25mph! haha

I use K&N filters on anything not stock. They don't work how you may think.....vibration filtering.

Nulon is great stuff. I ran a 1300cc Mazda engine for 270,000km before I sold it. Went as good as day one. I have however heard that engine machinists hate the stuff. Apparently the Teflon coating in the bores makes them hard to rebore...........I cant confirm this.

VDO's fail safe engineering if vehicle voltages drop, oil pressure reads low and temp gauges read high. Makes the driver check first. If it was the other way you'd never know before its too late.

Your PCV mystery is answered. Reverse flow under full throttle conditions and low manifold vacuum. Those systems flowed backwards when you worked the engine hard rather than when cruising with higher manifold vacuum drawing fumes in the normal direction. Full throttle would require mass air flow in the air filter housing through that little trumpet inlet causing a depression at the felt pad. This had to be slightly higher than the vacuum sourced at the manifold PCV hose connection. Flow wasn't great, but it's enough.

[rosco]

Thanks, Craig - I agree entirely as to when IC engines are at their most efficient.
Interestingly, in original format - for example, a little 138 grey would probably develop its maximum torque somewhere just over the 2,000 rpm mark. A 149 red HC just about right on the 2,000 mark and my 179 at some 1,600 rpms..
The diff ratio for a grey is 3.89, the 149 more likely suited to a 3.55 and the bigger 179 probably was better suited to a 3.36...
Clearly, this co-relates to all three engines running at their maximum torque at somewhat of a similar speed....

We do know that diesel turbo engines get thirsty the higher the rpms. I find that running our tt V8 at around the 1850 mark in overdrive at higher throttle settings far more efficient than slipping it down to 1:1 and running higher rpms at lighter throttle settings.
Diesels, of course - are a different kettle of fish... but why many people rev them so hard when they are quite capable of pulling an available higher gear is beyond me.
The very same people tell me of simply amazing fuel consumption figures - which I know to be from fairy land.

With an IC petrol engine. Light loads are somewhat compensated for efficiency by vacuum advance - and further compensated at higher rpms by mechanical advance. I don't believe there is any possibility of perfect combustion throughout the entire rpm spectrum.. but I do know of one instance where the parameters can be controlled with the vehicle in running.
Blue Haze - aka Richard, has such an opportunity. I am aware that he was able to twiddle settings with his EFI red motor whilst on the hop.. with someone else at the wheel, of course...

As for wear, yes - it's piston travel, not vehicle travel. Petrol is not a lubricant - in fact quite the opposite of it, it "washes" lubrication away.
I use FlashLube for my valves, which I was told by Ray Layton is directed intended towards exhaust valve.
The inlet valve gets some form of lubrication through the cold/wet air/fuel mix - but this appears a paradox to the belief of petrol causing wear to cylinder walls.

Yes, I was told that engine re-conditioners hate Nulon. I can verify that it does indeed impregnate and fill the cross-hatching of cylinder bores and also coat bearing caps. I'm not convinced that it does much to the hardened steel surfaces of the crank and piston rings - but in combination with the coating of cylinders - I believe it a very suitable option for those who have or are about to rebuild/condition.

The rave at the time (test conducted by Wheels magazine) was the running of a treated Holden 173 engine (after some 3,000 miles) in a Torana which was driven from Mildura to Melbourne without any oil in the sump.
The engine was stripped down after the trip and "there were insignificant signs of engine wear on any of the major components".
This was a very ambiguous statement - I don't know if "major" components are the block, water pump, distributor etc.... but I do know I would not consider even starting an engine without oil in it... let alone run it from Mildura to Melbourne.
Apparently, the greatest concern of the two drivers involved was running along the road against the oil warning light.... arghhhh, tests - I wonder how many engines were ruined when something in the lubrication system failed... and the oil light came on - the drivers believing that Nulon would afford safe running until repairs could be made....

PCV - hmmmm.....
Yes, the system does work both ways. With little vacuum in the manifold - the greater draw of air through the carby and air cleaner would reverse flow direction.
There is probably an "optimal" vacuum level where the PCV "floats" against its spring. I have absolutely no idea where this setting is.
I do observe that by blocking the PCV with my thumb that the idle suffers. Of course, this is most likely because the richer idle mixture setting which compensates for the additional air entering the mixture through the port in the manifold.
This then suggests that a positive extraction of fumes/vapors/condensates is effected at idle and also at higher engine speeds where similar manifold vacuum is retained.
This positive flow would indicate that air flows into the rocker cover through its vent under these conditions.
At low intake vacuum settings I would expect that there would be precious little intake through the system.

The latter HJ (or thereabouts) system was probably more intended to conform with EPA requirements - to reduce emissions from the engine bay.
I believe the "rave" at the time of a sealed ventilation system to promote engine life, was probably one of those "famous" inventive promo's which were played out between manufacturers in those highly competitive years.
Who could ever forget the rave for the belt driven air pump "which affords greater economy"...
This pump was added to purely pump additional clean air into the exhaust... to reduce emission saturation... and had not one jot of effect on economy... in fact, being a belt driven component - reduced it.

The poor old "red/blue/black" engine block had been strangled so much to conform, that Holden, who were in bed with Nissan at the time - opted for the Skyline engine to get a more efficient alternative. Even though it was a great engine, it simply did not belong in the VL Commodore - there were massive issues with air locks in the cooling system (the head sat above the top tank of the radiator) and the clutch was a nightmare for mechanics to keep operating (it was designed to run on the other side in the Nissan).
For just one model, Holden paid significantly for their Nissan venture - if the successive VN Commodore had been released with this engine - these issues would have been resolved and we may very well still be running with a straight six... but ...

When the $Aussie dropped against the Yen - GMH looked around for another alternative... and came up with the V6 Buick engine, which basically has "evolved" in Commodores ever since.

At the time, I can still hear our Fxxd combatants telling us that anything but a V8 would never work.... and Fxxd stuck to the straight six and four for their "smaller" engines..... for heaven's sake - they should know.. who could forget the Transit V4 and the Capri V6... but, I note now that these hecklers seemed to have gone very quiet with the success of this "Buick" engine.. and the trend for modern six cylinder diesel engines having gone to the V configuration.

K&N filters, Craig - I know precious little of them. I have not yet read or studied their application.
I do appreciate that many on our forum use them and have enjoyed great success.

The UniFilter I make mention of employed exactly the same vibration principle. This filter was at it most effective when the outer surface received a coating of dust - this dust acted as a further "wall" on which incoming particles struck the surface and bounced off.
This "wall" was created by the employment of a special filter "fix" - sticky conditioner.
It was always intended for the outer surface of the element to get "dirty"... but deeper into the element it trapped and retained anything which did penetrate the outer surface.

I still have the inner "cage" from the filter - which is the most expensive part. I will probably re-fit the unit when I can locate a replacement element.

The achiles heel of my element was the top and bottom surfaces - where it was mechanically sandwiched between the two halves of the air cleaner body.
Obviously, I was not meant to tighten the wing nut to the point of compressing this part of the element so much that in time, it caused it to fracture.
I can adamantly state that when using this filter - there wasn't ever one occasion where there was anything within the air cleaner body on the filtered side..
The much greater working filter capacity of this type of filter affords increased air volume through the element than that of a paper type filter... and, as with the Frantz oil cleaner element - provides a deeper degree of filtration.

If all of the discussion thus far increases engine life, I'm all for it.

I did, for some time - fit a filter unit to my cooling system. This type of filter was used in motor sport.
Most people who got into trouble with these fitted them on the inlet side of the radiator (top hose). The "V" shaped perforated stainless plate would get blocked by debris and suspended metals from the iron parts of the engine... blocking the top hose is the same as a thermostat which fails to open.

By fitting the filter to the lower hose - coolant is "drawn" through it... I don't yet understand why - but by having it on the outlet side of the radiator hardly ever resulted in an overheating issue.

I removed mine after some 10 years of use with this motor. It was an issue to cut the anti-collapse spring and hose when service replacement of both radiator hoses.
The initial employment of fitting this simple unit paid off - the amount of rubbish which came out of this motor when I first fitted it (again - from GEM) was astounding. I would have been of the belief that they should have been able to deeply clean and flush the cooling system of the block and head during reconditioning.. but obviously - they didn't... I had "lumps" in the top tank of the radiator.
The "fines" continued to get trapped in this little filter for probably the first year. After this, only remnants of silicone sealant breakaways were ever caught... and my decision to remove the filter at some point was probably appropriate.

Another "filter" I initially fitted to this engine was under the carburetor.
The people at Mulla and Jacka suggested that I fit a stainless mesh screen between the lower body of the carburettor and the intake manifold flange.
They suggested I fit two flange gaskets and sandwich the coarse screen mesh between it.
This served two purposes - one, it "smashed" the liquid of fuel into a better vapor as it entered the manifold and two, it provided some protection against anything coming loose or falling down through the carburettor (screws, shards etc).

I did this initially, but later fitted a "fuel miser" centrifugal element - which did not afford the same parts protection - but did effect some violation of raw fuel wash through the intake system.

One question I might ask, for comment - is the employment of the "HR" implemented twin pre-heating arrangement of the intake manifold.
I can fully appreciate that this assists with heating a cold intake system but, once the engine is at operating temperature - is it feasible that this very same permanent heating actually reduces efficiency by heating intake air when it is not required.
Heating intake air to such an engine would, in my thinking - actually reduce efficiency...
Maximum efficiency should be attained by reducing the intake temperature as much as possible... with the view that it can better expand during combustion... as in inter-coolers.

I noted at some point during the progression of development, that GMH might have considered this.. and decided to re-plumb the pre-heating of the inlet manifold by running it in conjunction with the cabin heater... that is, in warmer weather etc... the heating system would be "off" and this would then close off flow of coolant through the intake manifold pre-heater.... any thoughts?

Ok - done it again... kindly remind me, is this my thread......?

Again, apologies to the OP... maybe I should start a "discussion" thread - rather than completely stray from anything pertinent to the subject of the thread....

frats,
Rosco

[Craig Allardyce]

Rosco, the HR twin carb preheating arrangement (pretty much same as all the water cooled manifolds that fed off the thermostat housing) was not a constant flow. If plumbed correctly off the two ports at the thermostat housing it will only have maximum flow when the thermostat is closed and flow reduces as it opens. If you have a look at an old block and head you will see one port goes through the head but feeds down into the block to the water pump bypass port. Something the old grey never had.
You also need to think about fuel atomisation and the cooling/icing effect it has on the manifold walls. Going from cruise to full throttle would see massive temp drops and think it would to some extent start to cool the water in the manifold chambers (open thermostat - less flow).
Of course this all changed when they went to constant water flow through the heaters (HQ I think) and directional flaps and this necessitated and air preheat system on the air cleaner intake not long afterwards. 1975 and ADR 27 after that..............arrgghh EGR

[rosco]

Thanks again, Craig - yes, I can now see that the thermostat would have effect on coolant flow through the twin pre-heat piping from the head/water pump.
The original GEM head which came with the engine (149 HC) - did not have the hole which connected through the block into the water pump - as it wouldn't have.
The second one did - so it was obviously from a 186. The third one also had this tapped hole - so, I believe I have the thermostat controlled system you speak of.

With the alloy manifold, the facing surface of the jacket from the carburetor downdraght - has molding rings - I expect this is probably designed to smash the fuel/air mixture and spread it over the face of the heating surface.

I can appreciate that return coolant to the underside of the thermostat might do something to delay thermostat operation... but have yet to look at my diagrams and get a solid appreciation of operation... bit hard up here at Airlie Beach, Qld - all my books are some 3,500 km's away.

As for EGR systems... grrrrr - my LC TTD V8 has one.. and this is the absolute insult to the very necessity to keep the intake system of a turbo diesel engine as meticulously clean as possible..

Fortunately, my little RT104 Corona - was the last batch which did not get EGR and AI .. all it got was a carbon canister for fuel evaporation and a TP thermo valve to keep idle speed up until the engine reached operating temperature.

The next model got hit with everything - air pump, TP, EGR, thermo controlled distributor vacuum advance and air filter thermo-flap intake air drawn over a "stove" on the exhaust manifold.

That original 1
late 1977 model was well known for backfiring when one of these systems or control check valves malfunctioned.. what a terrible thing to do to just a 1968 cc over-square engine...

Many poor souls tried to circumnavigate much of this... but in reality, unless it was taken on as a job lot - just blanking off one component often resulted in worse fuel economy than leaving the entire system untouched.

Toyota persevered with the 18R engine for some time, but the even later revised (and slightly larger body) Corona got hit with the Holden "Starfire" engine (maligned and slanged as the "never-fire") - basically, a 4 cylinder version of the basic red motor.. something is nagging me that it had overhead cam - but I can't be confident that such was the case.

How we could "leap" from an established reliable, long-life and efficient Toyota motor.. back to a not-so-clever crude basic cut-off Holden red motor, is a little beyond me.

I don't believe, however - that this backward step lasted very long - a further revised version came out of Japan in the form of a dual cam, multi-valve cross flow alternative.... the death of the Starfire engine for Toyota purposes.

My emissions control ire is directed towards the regulators... we had fume belching blasted trucks and buses which oozed out black and blue smoke into the atmosphere which were afforded hugely greater leniency, larger capacity petrol engined cars which pumped out greater quantities of emissions than these poor little engines - which, incidentally were equally seen to be the commute of a single person on our roads in the morning and evening road peaks as prevalent as the larger engined cars also commuting just one person - but the law decreed the need to inject fresh air into the exhaust system of a reasonably efficient small capacity engine...to reach the standards stipulated.

It made little sense to me then, and probably makes less sense now - but what would I know - I hold no formal qualification from which to make any "observed" opinion...

The EGR (exhaust gas reticulation - for those following this discussion) is simply put as returning some of the hot exhaust gas back through the engine intake to raise combustion temperature - and subsequently effecting better combustion efficiency and a more thorough burning of all admitted elements (oil included).

In a perfect world - this was probably fine.. almost... but, carbon from the exhaust usually blocked/restricted the porting which caused hot spots and created issues with enriched mixtures. I can vividly recall one of my father's cars belching out black smoke and backfiring when the EGR became out of whack...

A proportion of any additional elements recirculated, and recirculated... so, if oil was to be carrying over into the intake - it would aid the formation of carbon... and speed up the process of blocking the system.

My humble opinion would be that once these systems became faulty - and owners persevered with them running poorly... so too, did the poor quality emissions result... far worse than those without such systems...

The regulatory authorities would stipulate that such occurrence should not eventuate - because all "responsible" motorists would keep their vehicles in perfect running condition... sadly, such was not the likely outcome.....

We might now have vehicle monitoring which can detect poor emissions from vehicles in running on our roads - but I question the ability to detect one with a partially blocked EGR.. or most modern vehicles would probably be in threat of receiving notice to have the vehicle inspected for fault....

Yes, Craig.. EGR - and it continues to thrive in modern engine design - and requirement.

end of rant.

frats,
Rosco

[Craig Allardyce]

Hi Rosco, the misfire four was a in block cam as per its derivative.
EGR serves to cool the combustion process in the high temp ranges in order to reduce NOx.

[rosco]

Thanks Craig,
so basically - it was a 186 minus two cylinders..?
Thanks for the nitrous oxide info... guess I had that one buttocks up....

Think we've frightened off the OP from his own thread.... any news on the misfire?

frats,
Rosco