saving the cam shaft's

[johngosnell]

I don't know what the members think, but I am concerned about wear on the camshafts, because the car is not used very much I start the car up to run the engine but it is this initial start up every time that concerns me because of the dry upper end until oil gets to the top. I know the obvious answer is to use the car more often but as most of you know it is difficult for me.


Regards John


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[cass3958]

John there is an addictive I have used when assembling engines and also in my racing engines called Activ8 https://www.activ8lubricants.com/. I assume it is a bit like Molyslip which is used in gearboxes and back axles.
I have seen demonstrations of this stuff being used in friction situations where it out lasts oil, stays cooler and protects the bare metal. A small amount is added to the normal oil you use in your engine but it alleges that it coats the metal surfaces and protects them especially on start up.

I do not know what Glyn knows or thinks of this product and if the assertions are true?

Researching on the interweb I found this gem which is possibly what Glyn is going to say.

Activ8 is what is known as a "EP" additive, meaning Extreme Pressure. These are a class of compounds that do nothing to improve oils under normal hydrodynamic (ie oil film) lubrication conditions, but which form a chemical surface film on the rubbing surfaces under the effects of temperature and pressure when hydrodynamic lubrication breaks down. That surface film gives the rubbing areas extra protection for a short time in the absence of oil. This is known as boundary lubrication conditions and should rarely if ever happen in an engine. Typically EP additives used to be favoured in old gearbox oils, hence ratings such as EP90, because at low speeds and high loads you may not get sufficient oil film (think waterskier, at speed the water holds him up but at low speed the water moves aside and he sinks - it's the same with oil films in your engine, there should be no moving metal to metal contact and always an oil film in place). This is why the "bike show" demo works. They create a situation of slow movement and high point loading - exactly what doesn't happen in your engine, then show how a boundary lubricant will allow it to run for a while in the absence of an oil film. What is happening is that the EP additive is attacking the surface of the metals to form solid lubricant compounds..... and in the meantime the acidic nature of the additive is also attacking every other component wetted by the oil.The oil companies have known about EP additives for years and they don't use them, for 3 good reasons. First, they aren't needed. Modern oils protect very well and cling to surfaces for protection during cold startup. Second, they cost money and if they aren't needed why put up the cost of your product to no end? Leave it to the suckers who want to pay more for the additive than the oil. Third, as I said they are acidic and will attack other components in the engine.The late great JR of PB did a test some years ago of various additives on a sensitive dyno and found absolutely no change in power outputs.Of course, if you plan to run your engine out of oil something like this may help you run for a couple more minutes. But TBH about the only good thing I can say about it is that unlike Slick 50, a slurry of PTFE particles, it won't block filters and oilways.

[johngosnell]

That seems to be a good suggestion, I will wait until Glyn has commented and then try a bottle. Thanks for the suggestion


Regards John


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[Glyn Ruck]

Don't put Sulphur Phosphorous (EP) gear oil additives anywhere near engine oil. To start with they are completely incompatible & will react with the Calcium in EO's & foam clear out of the breathers. Causes severe air entrainment.

Run the car on a high grade synthetic engine oil approved against Mercedes Benz 229.5. It will give you all the cam protection you need even after standing & it's cold start viscometrics are such that it will get up to the cams very quickly on startup.

I suggest that you don't mess about with any aftermarket additives. All they do is mess up the carefully formulated oil & take it out of spec.

Small quantities of the correct friction modifier are present in many so called "fuel saving" engine oils. Let the oil company do that as friction modifiers can severely damage the shear stability of multigrade oils.

Your cams & tappet buckets are no doubt thoroughly run in/bedded in. The most dangerous time for the cam & tappet interface are initial start up of a new engine where machining asperities have not been "polished" off of the contact surfaces.

[johngosnell]

thanks Glyn for the info , on the next service I will move over from 20/50 to the oil recommended, I Know that it was discussed before but any recommendations of suppliers.'



regards john


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[Glyn Ruck]

Depends on availability in you area. Any product on the approved list here is fine.

http://www.jagstyperegister.com/forum_n ... 3650#p3650

[JCS]

John

I don’t know how much you are prepared to spend on your steed, but have you considered fitting a pre-oiler unit? These work on the system of flooding oil through the oil ways before engine start up, and can either be purchased as a kit or made up in the workshop.

All what we might term special engines, like large marine or industrial engines and large piston aero type engines usually encompass a pre-oiler system. If they deserve pre-oiling you might say your engine does. Ones that were not fitted originally have usually been retro fitted.

I have used both the kit type (Accusump) on my XK engine and the self-made workshop type on R-R 4.5 ltr, R-R military V12 petrol and Russian V2 diesel. I don’t care for the accusump, as it relies on a large O ring and piston to continually seal oil under pressure even when the engine is not running. Eventually my accusump will be removed and a workshop system refitted.

I prefer using a stainless tank that can be pressured with a 12 volt air compressor before start up. The tank capacity needs to be around 3 to 4 pint minimum and pipe work no less than ½ inch or so for an XK engine. Such a tank can be shaped to the users requirements, but you need access for oil drainage.

You may also find it worthwhile tapping oil off the main oil gallery, (there are about 4 plugs on the right side gallery) and running an extra oil feed to the rear of the inlet camshaft. This was done on later XK engines when the solitary oil feed came off the oil filter housing.

To fit an extra oil feed you will require a lengthened banjo bolt that will pass through both of the small banjo pipes at the rear of the inlet camshaft, a length of armoured oil pipe and an adaptor to fit the oil gallery. This modification provides a quicker pressure feed to the front of the camshafts. The banjo bolt is available from Ken Jenkins or Barratts, pipe and adapter at your local hydraulic pipe supplier.

Norman

[johngosnell]

WOW, the idea of a pre lube system seems a great idea, probably beyond me though, being paralyzed and wheelchair bound but I like the idea very much.




Glyn thank you for the extra info


Regards John


1B1257BW

[Glyn Ruck]

Pre & post oilers are fitted to quite a lot of turbo charged heavy earthmoving equipment etc. & especially where operators are likely to have little mechanical sympathy/understanding. e.g. revving & loading the hell out of cold engines or not allowing a period of idling & oil feed to turbos still spinning at 100,000 RPM etc with no oil pressure at shutdown.

They certainly have their place.

[cass3958]

Thanks Glyn I knew you would have an opinion on additives and it is good to be able to put these things past you. I have never had a problem with the Activ8 in my engines previously (that I know of) and that is the problem. We rely on advertising hyp for these products and are not really told the truth. I have not used an addictive in the S Type engine and I am glad now. I will just stick to the oil you recommended. Thank you again.