In my experience even a worn shaft to the original design works better than the modified type.
Peter
Are the shafts hardened, not allowing redrilling?
Are your head and block sufficiently flat to seal well? No warps, no locally-pulled high points? How flat, quanitify? No bubbles in the radiator water when full to brim and warm? No cottage cheese in the oil or inside of rocker cover?
Plenty of oil flowing down the pushrods will not create smoke in the exhaust (assuming no head gasket issues). How much oil is pouring on the valve tip? That could matter if valves are loose fit, have you measured valve to valve-guide clearances? Too large a valve guide clearance can be a smoke source.
Still recommend a divide and conquer approach. Is the smoke water vapor, burning oil, too rich gas mixture, or combination? If oil, is it from above the head gasket or below? Good luck!
What colour is the smoke? Black is fuel, blue is oil, white normally water/coolant
Yes they were previously machined and had seals fitted directly onto the valve guide on all inlet and exhaust valves.
I removed these in favour of the o ring type under the collets but my next plan is to now refit these back on the inlet guides and see if this reduces the smoking.
Thanks for your interest.
Regards, Graham.
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Yes I’m sure they are hardened.
The one I replaced when I first purchased the car the previous owner had taken to the machined flats with a grinder making them bigger for reasons unknown. It allowed sooooo much oil in the rocker area the rocker, nearest the breather into the air cleaner, would throw oil out into the air cleaner filling it to a point where once the car was stopped the accumulated oil would run out of the air cleaner into the carb intake. When you attempted to restart the car it would immediately oil the plugs.
Hence my first job on this car was to change the rocker shaft. This was some 12 years ago.
Why a replacement rocker shaft would be re-manufactured but not like the original design is anyone’s guess.
It has created a problem instead of fixing it.
Regards, Graham.
Inlet valve stem clearance to guide is listed in Service Manual as 0.002" to 0.004", page B.46. Oil flow to valve stems can be stopped briefly as described above to check if oil down the inlet valve guides is contributing to smoke. My experiences with inlet valve clearance oversize smoke problems have been solved by putting guides in with clearances matching the Service Manual.
I’m curious about longevity of valve setup putting seals on factory design valves and guides. Are there any friction enhanced wearing issues, reduced lifetime? What mileage have people gotten with seals?
Hi Robin.
Smoke is blue.
Regards, Graham
Hi
Is this gasket for Jaguar MK5 ?
What oil is being used?
Is the motor completely run-in?
Since addressing the over-oiling of the rocker shaft due to the drillings being in the incorrect position and reinstalling valve stem seals on the inlets I have not had any further major degree of smoking. The engine also doesn’t get as hot as it did now that I also improved the cooling through the radiator by blocking off all gaps around it and wrapped the exhausts and manifolds.
The engine has now done 600-700 miles since being rebuilt and, touch wood, is performing ok.
Still. It was some terrible workmanship I received from the engine rebuilder.
Engine oil is Castrol 20-50W.
Regards, Graham.
Hi Graham,
Glad hear that you are getting the engine sorted. For best preservation give up using mineral oils and convert to fully synthetic.
Peter
Hi Peter.
Now that I have got past the head gasket issues and contaminating my oil with water perhaps I could.
I have just had a similar issue with my 2 1/2 SS engine rebuild.
Even after having the head fully reconditioned the rebuilders failed to notice a hole between the water jacket and inlet port resulting in when I filled the radiator with water it came out the carbs. Fortunately, this time, it did not enter the cylinders or
sump so didn’t have to dump 3 gallons of new oil.
Perhaps after running thee engines in and a bit of regular use the more expensive synthetic oil could be used.
What type do you use?
Regards, Graham.
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Hi Graham,
I have been running both engine and gearbox in the SS on fully synthetic for the last 10 years and just love its properties of not draining from parts when in storage and preserving its lubrication under extremes of temperature and pressure without degrading. In recent times I have been using Ford Formula F 5W-30. The same oil that I have used in my modern turbo diesel for the last 7 years.
Peter
Congratulations Graham. Please do give an update on how the inlet valves perform over time with the valve seals in place. I’ve yet to find reports of how guide wear is altered when seals are inserted into these engines.
Hi Peter.
Don’t you find a drop in oil pressure with that viscosity?
Graham.
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Hi Roger.
Other than having a catastrophic failure (like a dropped valve) due to the limited mileage this car is likely to do it may never be known. I add an upper cylinder lubricant mixed with the fuel that may help.
It was also the lack of workmanship by the engine rebuilder, by reinstalling worn valves, that added to the issue.
It seems to be operating well at this stage. I have just installed an auxiliary electric fan I can run on those very hot days when stuck in traffic. This was the times it would smoke the worst.
Regards, Graham.
Hi Everyone,
I was sorry to hear about Grahams misfortune and I hope he resolves his oil burning problem out without resulting in any major surgery.
The timing of Grahams post and some of the very interesting replies have however been a great help to me, particularly the one from Peter regarding the design differneces between the earlier and later rocker shafts.
On Saturday morning, after a total 6 month overhaul, I ran my 2.5 litre engine on a test bed for abouty 45 mins in total (the last time it ran was in 1975).
The only concern I had was there was a little too much blue (oil) smoke from the exhaust (after allowing for the assembly oil to disperse) so following the second run I decided to remove the rocker cover and see how much oil was being distributed but to my surprise, there was very little compared with what I was expecting.
My oil pressure was 60 psi and I confirmed the oil supply to the head and re-confirmed the correct alignment of the oil feed hole in the front pedistal aligned with the hole in the shaft.
I also ran it with the shaft locking screw removed and there appeared to be adequate oil flow within the shaft.
After readind Peters comments about the 0.003" flats on the shaft and the twin bushes in the rocker arm, the problem became apparent.
My shaft has small drill holes that align with the rocker bush centre lines but I have only single solid bushes with no central oil distribution channels.
When I rebuilt the rocker gear I confirmed the longitudal drill holes in the rockers were clear and they aligned with the drill holes in the rocker bushes but because there were no groves in the bushes, I now realise that the oil flow to the pushrod and valve pad drillings would be minimal.
The engine obviously ran in this configuration previously and there was surprisingly little evidence of and wear in the valve gear or indeed, the tappets,valves and guides, so there must have been sufficient oil supply when it was running around.45 years ago.
That said, I am not happy with the present arrangement so I am thinking of machining the 0.003" flats into the shaft and similar depth grooves in the bushes between the feed and drill holes but any other alternative suggestions would be much appreciated.
John. “Barn Find” 1948 2.5 Saloon in Birch Grey.
Hi Graham,
No, my hot oil pressure is between 40 and 50 psi whilst running and about 25 psi at idle. Fully synthetic oils retain their properties much better than mineral oils.
Peter
I would put the correct two bushes in each rocker arm, the oil that goes out through the arm to the pushrod should be in fairly generous amounts as it is that which runs down and lubricates the face of the cam followers ,and cam lobes.
And take the opportunity to replace the wicks in the rocker arms.
Twobushesed :> )