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Wet oily plugs is a condition that can be traced to a few things, over rich mixture and more than likely worn valve guides and deteriorated valve stem seals allowing oil to actually seep into the cylinder.
 

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Discussion Starter #3 (Edited)
Hello Wraithman

Thankyou for the reply

I'm able to check the mixture myself however checking for worn valve guides and deteriorated valve stem seals may will be beyond my capabilities

I will check to see what's involved

Would worn gaskets cause a similar problem?

If the valve stem seals have deteriorated would you get excessive white smoke from the exhaust?


Thanks Alec
 

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How much do you drive the car, and how long/far when you do?


In vehicles of this vintage, if all of the trips are short and the car never has a chance to really heat up (and I mean really reach peak operating temperature for extended periods of time - say at least an hour, preferably two or more) you can get quite a bit of carbon buildup and it doesn't take much oil (and unburnt fuel) to create a wet surface.


The old phrase regarding "burning off the carbon" has its basis in fact. Not that you couldn't have some underlying issue, but you may not if all you take is very short trips.
 

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Discussion Starter #5
Hello Brian

You are spot,You have discribed my driving habits of late

The car has only been out for short trips ,maybe 20 minutes

Also with the constant rain here in the UK .The car has spent more time parked up ,weeks at a time between taking her out for short trips

Hopefully the lack of use is the culprit as you suggest

Thankyou Alec
 

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Brian is on point. Driving habit has a lot to do with plug condition. Plugs can actually tell a lot about the motor condition. Oil that weeps down valve guides and past seals will burn off and appear blue out of the exhaust whereas coolant or transmission fluid sucked up past a bad modulator valve will be white....and the plugs will generally not be black and oily, but if you are driving for short periods there is a water component in the form of condensation that will build within the exhaust system and eventually burn off with a good run at operating temp. You will usually see drops of water dripping from the exhaust when first started.
 

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Alec,


Take her out for a 2 hour drive at highway speeds, then check them again after the car has cooled down. You'll still probably have "dark" as that never quite goes away entirely but I'll bet you have "and dry."


Also, as a side note, if you haven't checked and cleaned your flame trap in recent times take the time to do so.



Compared to modern cars (and the SS-II was not modern, when compared against the technology common on other marques for years - including fuel injection for one) even when they were new. RR was a very late adopter of "the new" on the whole. I never understood how the braking/hydraulic system got past "the old guard" when it did, but once it did it was kept for a very long time, well past the end of the SYs.
 

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Hi Alec do you have the correct plugs in? Carburetor cars have hotter plugs to burn off the soot that injection cars don't need.
The lower the number the hotter the plugs.
4 for carbs 5 for injection (NGK)
Mike
 

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Discussion Starter #9
Thank you Wraithman for the explanation I'm very grateful ,my engine oil levels and coolant level are normally very good

I do see water droplets at the end of the exhaust on start up and ,white smoke which I always assumed was condensation but wasn't totally sure so you have reassured me there thank you


Thanks Brian

I will take her out for a good run hopefully soon if the rain stops

I cleaned the flame trap only last month ,I have this down for periodical cleaning now based on your advice you gave me from another post I made some years back

Hello Mike

I have NGK BPR5E which after much research thought were the correct type for my car ,So you are suggesting I have the wrong type ?

Thanks Alec
 

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Discussion Starter #11
Hello Mike


I own a Silver shadow 2 1978 twin carb,
The NGK partsfinder site recommends BPR5E for silver shadow up to 1977

So maybe I don't have the correct type after all.

I Appreciate the help ,Alec
 

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Hi Alec, Have you checked the air filter lately? Clogged air filter can cause carbon build-up on plugs but as previously stated above a good long run might cure the problem, your plug in the photo doesn't look very oily but photos can be deceptive, Regards, Larry.
 

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The plug in the photo simply looks like an engine that's running around that hasn't fully warmed up yet because the choke is still on.
Take it out for a good run and check again.
 

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Another way of checking the valve stem seals is to get someone to follow your car and with a hot engine, coast down a decent hill, no accelerator at all, then at the bottom of the hill accelerate hard. Bluish smoke on acceleration is a fairly good sign of the valve stem seals getting tired.

I also do agree with other members, the plug looks more like the car needs a very good run then a quick check of a couple of plugs.

Jake.
 

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Discussion Starter #16
Hello Larry how are you ?

Air filter is fine I checked that when I cleaned out the flame trap

Maybe I have misdiagnosed the plug maybe it's just heavy carbon and wet fuel and not oil

Thanks Jeff

I have now replaced all the old plugs for new ones and she drives fine ,

I might try and test the old plugs for spark just of of curiosity

I agree with everyone that the cause may well simply be lack proper use

Thanks Jake

I appreciate the tip on detecting blue smoke from exhaust

I'm sure you are correct it just needs a good run

Thanks Mike

This may sound crazy ,

Can I replaced one of the new plugs with BRP4E a hotter plug so I could test the carbon build up against a new BRP5E in say 6 months time or would that cause a problem with the engine in anyway

Out of interest could any silver shadow 2 owners let me know what spark plugs you use so I can be sure I'm using the correct plugs

Christmas starts for me on the First of December that's when the brandy comes out so happy Christmas to all Alec
 

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Hi Alec, Currently I'm using NGK BP5RES and have encountered no issues, that said I've used various sets of different branded plugs over the years including Bosch and some supplied by Introcar Ltd but can't recall the brand names. Bottom line is that I haven't noticed any difference in performance between them. I don't think it would be a good idea to replace one of the plugs with a different brand as that might affect the timing, better to keep them all the same and with the same gap measurement in my opinion. On the question of spark plugs I suspect that there are many different and varying opinions out there and all have merit and that consideration of other high tension components e.g., rotor arm, distributor cap, HT leads, coil, electronic ignition components and ignition timing, fuel octane & quality, air supply etc all come into the equation. If your car is being driven only occasionally and hasn't had a fuel refill lately chances are that the fuel may be going stale which might compromise combustion. The ignition timing setting recommended for you car using 97RON petrol is 25 degrees before TDC @ 1300 RPM on a warmed up engine and then when you reduce the engine idle speed back to the recommended 650 RPM the timing should settle at approx. 11 degrees before TDC. If you're going to check the timing first establish the octane rating of the petrol you're using as the RPM settings vary depending on fuel. That's something you can play around with to keep you entertained on these cold winter evenings. Even though 650 RPM is the recommended idle speed on a warm engine per the manual I find that my engine happily ticks over at closer to 600 RPM when the timing is set, each car has it's own peculiarities I reckon. Good luck, Larry
 

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Discussion Starter #18
Hello Larry

Thanks for the advice,very informative and helpful as usual

You make a good point about fuel ,my tank hasn't had a refill for a while now

I do intend to check the timing next a good winter coat and large brandy will help those winter evenings seem more pleasant

Thanks Alec
 

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Hi Alec, If using a strobe light I usually place a spare car battery on the passenger side suspension turret for power to the strobe light as the battery in the boot is too far away, then one has to be careful with the H/T lead to the timing light from the No.1 spark plug as it crosses the engine near the pulley wheels. It's a bit of a PITA with the No.1 plug being on the opposite side of the engine from the timing marks. Easy on the brandy until the timing job is finished, Good Luck, Larry.
 

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Discussion Starter #20
Thanks Again Larry

Correct me if I'm wrong but I think you mentioned on another post using a multimeter to achieve the correct rpm

If so do you mind explaining how you achieve this

Carrying out the timing is a new project for me to learn

Thanks Alec
 
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