how is the V8 engine dirty?

ButterFingers

ButterFingers

Active Member
Hi there,
I have read in this forum that the V8 engine is a dirty engine and it has intrigued me as to what is a dirty engine when this term is referred to? obviously if a 40 + engine has never been rebuilt it is going to have a bit of sludge in the sump and elsewhere in nooks and crannies.
In my modern every day car I always pour in a can of "engine clean", before taking it in for service, which is a 30 min drive to town. So it always has the oil and sludge removed at every oil change.
Would this be a good idea to start doing to my V8 engine?
I had thought of removing the sump prior to starting this new service regime?
Peter
 
Hi Peter,

The term 'dirty' comes from the propensity of the 14 bolt engines for combustion chamber contamination. The outer row of 4 bolts when torqued to the factory specifications delivers uneven pressure across the interface between cylinder head and the block deck. This allows for an imperfect seal providing a mechanism for combustion gases to enter the remainder of the engine. Dry dirt in the flame traps and hoses, on the inside of the rocker covers, over the rockers predominately, along with brown discolouration throughout the rest of the engine. Regular oil changes will diminish the discolouration to a certain degree, so that is all that can really be done in this situation. Removal of the heads, chemical cleaning and refit without the outer row of bolts will prevent any further contamination, over what resulted previously. The later engines with 10 bolt heads, if looked after, will be significantly cleaner on the inside. These V8 engines are not 'dirty' at all, as that term is reserved for the earlier engines.

Ron.
 
Later cylinder heads also have valve sealing which actually works too. The blue valve stem seals on all 16 valves. That too can be retrofitted.

In the 1990s on Range Rovers/Discoveries, running the engine hotter with EFi and semi-synthetic oil would further help due to more complete combustion.
 
After I rebuild any of my engines I always add an engine flush to the oil before changing and change the oil every 3000 miles or annually. I do not flush an engine that is old and dirty as loosening up all the crud is bad news and will block up oilways, lifters etc.
 
Many classic cars will be driven with very low revs around (I must point finger to myself too) which is indeed not good for these engines (for any engine). For "S" drivers it´s easier to rev through the gears, but the auto-drivers have to push the right foot down (DOWN) regularly....
 
I have always thought that too and have a lead foot almost often.
One of my co workers when I was at Repco, never used engine flush (clean) as he was afraid of dislodging some grit/dirt and
it getting into his turbos oil line.
I used it regularly on my Saab which, without a breather mod., was prone to sludging on engines if not regularly serviced. It was a HOT engine and never hurt it.
Was an expensive engine to keep doing full synthetic oil every 5 thou kms, but I liked the cars speed and agility, so put up with it.
I have used a bottle of motorup in my rv8.
I used it on my MK4 zephyr V6 Essex and worked a treat.
You could hear it get quieter as I emptied the bottle as well. A good thing? Well never had a issue before.
 
PeterZRH said:
Later cylinder heads also have valve sealing which actually works too. The blue valve stem seals on all 16 valves. That too can be retrofitted.
Click to expand...

They were originally meant to Peter, but they don't actually work, not according to Rover (Land Rover). In 2007 when my 4.6 was built, I too was of the understanding that the 10 bolt heads would come with seals fitted. The workshop manager though told me that they would come off in use, and all the new heads that they had received from Rover no longer had them fitted. Consequently, the cylinder heads on my Rover have no oil seals fitted, and yet the engine is as clean as a whistle even after 150,000 miles of use on the 4.6 litre engine. No brown stain or dirt as you will find in 3.5 litre P6B engines.

Ron.
 
thamesroverp6 said:
I have always thought that too and have a lead foot almost often.
One of my co workers when I was at Repco, never used engine flush (clean) as he was afraid of dislodging some grit/dirt and
it getting into his turbos oil line.
I used it regularly on my Saab which, without a breather mod., was prone to sludging on engines if not regularly serviced. It was a HOT engine and never hurt it.
Was an expensive engine to keep doing full synthetic oil every 5 thou kms, but I liked the cars speed and agility, so put up with it.
I have used a bottle of motorup in my rv8.
I used it on my MK4 zephyr V6 Essex and worked a treat.
You could hear it get quieter as I emptied the bottle as well. A good thing? Well never had a issue before.
Click to expand...
this could indeed be engine caviar, your car was saying thank you.....:rolleyes:
Peter
 
Most Important thing to keep clean. FLAME TRAPS. When was the last time you cleaned or replaced these unsung heroes? Go do it now !!!
 
If you used a catch tank the emission crankcase system would not work as you would have a air leak/ weak mixture from the carb take off point where the breather pipes fit and a possible cause of engine oil leak due to a non vacuum needed
to draw out crankcase fumes.
Clive.
 
If the catch tank was routed back to the carb take off points, then surely that would work? After all, all you have done is lengthen the lines and add a method of cleaning the suspended oil out of the mixture in order to allow clean air back into the engine rather than oily air.
 
SydneyRoverP6B said:
Hi Peter,

The term 'dirty' comes from the propensity of the 14 bolt engines for combustion chamber contamination. The outer row of 4 bolts when torqued to the factory specifications delivers uneven pressure across the interface between cylinder head and the block deck. This allows for an imperfect seal providing a mechanism for combustion gases to enter the remainder of the engine. Dry dirt in the flame traps and hoses, on the inside of the rocker covers, over the rockers predominately, along with brown discoloration throughout the rest of the engine. Regular oil changes will diminish the discoloration to a certain degree, so that is all that can really be done in this situation. Removal of the heads, chemical cleaning and refit without the outer row of bolts will prevent any further contamination, over what resulted previously. The later engines with 10 bolt heads, if looked after, will be significantly cleaner on the inside. These V8 engines are not 'dirty' at all, as that term is reserved for the earlier engines.

Ron.
Click to expand...
how would I determine which engine I had in the car, is it possible to count the bolts mentioned? 14 or other?
Peter
 
With catch tank I mean the usual canisters used in "sports cars". The catch tank itself has an inlet from the crankcase (pure hoses, flame traps detached) and an outlet (i.e. with a filter) to avoid backpressure to the crankcase. I.e. in literature (Des Hammill) it´s recommended to take away the return hoses from the SU carbs and close these connections. I´ve thought about using a catch tank with twin inlets (the two rocker covers I would link together plus the one from behind the valley), they are not very expensive (around 60 GBP in polished aluminium).
 
ButterFingers said:
how would I determine which engine I had in the car, is it possible to count the bolts mentioned? 14 or other?
Peter
Click to expand...

If you look at this picture, you'll see a row of bolts just under the line of the spark plugs. There are 5 here, and 5 under the rocker covers. Now look carefully beside the dipstick, under the third plug, and you'll see that the head bolt is missing.



These are 14 bolt heads, but the block is designed for 10 bolt heads, so the outer 4 are left out. 10 bolt heads will not have the holes at all.

To clean the flame traps, use a small amount of petrol, outside and swish them about. Carb cleaner will do the job as well, just keep on squirting it in until the oil and muck has gone. Don't smoke with that stuff, it is highly flammable!

Richard
 
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mtb_tuli said:
With catch tank I mean the usual canisters used in "sports cars". The catch tank itself has an inlet from the crankcase (pure hoses, flame traps detached) and an outlet (i.e. with a filter) to avoid backpressure to the crankcase. I.e. in literature (Des Hammill) it´s recommended to take away the return hoses from the SU carbs and close these connections. I´ve thought about using a catch tank with twin inlets (the two rocker covers I would link together plus the one from behind the valley), they are not very expensive (around 60 GBP in polished aluminium).
Click to expand...

The hoses to the SUs create a small amount of vacuum to pull out the gases in the crankcase. If you close them off the air won't circulate in the engine so will get dirty a lot quicker.
 
Hmmh...
so, would use a venturi pipe at the exhaust downpipe and connnect to the outlet from the catch tank :D
 
mtb_tuli said:
I´ve thought about using a catch tank with twin inlets (the two rocker covers I would link together plus the one from behind the valley),
Click to expand...
The one from behind the valley is an air INLET and needs a small filter on it to allow clean air INTO the block so that it can circulate and come out the tappet covers.
 
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