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Topic: Oil Bubbling around Plugs (Read 1633 times) |
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OldTuckUnder
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New Scorpio Owner
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Oil Bubbling around Plugs
« on: Sep 2nd, 2018, 1:44pm » |
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Cosworth BOB engine.
Newish to me Estate so not sure what is normal. Whilst cleaning in the engine bay yesterday I noticed that the top of the RH Bank Engine Cover (The one with the plug holes) had a reasonable covering of oil, and the pipe to the Power Steering Reservoir which is along side what also oily. I cleaned these up, and later whilst the engine was idling and got hot, I noticed a few spots of oil appearing back on the cover. Looking closely I could see that the oil was being ejected from around the rear two plug hole sealing rubbers. Almost like every two mins orso that there was a small pressure build up under the rubber plug and then a couple of tiny splashes of oil would be ejected on to the cover.
I haven't pulled a plug lead out yet as I suspect all I'm going to find is an oily chamber around the plug.
So how does that cover seal? Is there a gasket between the cover and the head that also seals around those plug cavities?
Can I just remove those covers and replace the gasket? or is this Inlet Manifolds off to do, in which case I think it will provoke some serious re-wiring (see other wiring problem thread).
Again sorry for newbie questions.
Alan
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Tompion
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1997 2.3 Ultima estate.
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Re: Oil Bubbling around Plugs
« Reply #1 on: Sep 2nd, 2018, 2:37pm » |
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Click on seals & gaskets here & click on the pictures to enlarge them, you'll see the gasket that fits around the plug holes & the cover gasket:
http://www.fordscorpio.co.uk/24vrebuild.htm
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OldTuckUnder
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Re: Oil Bubbling around Plugs
« Reply #2 on: Sep 2nd, 2018, 5:50pm » |
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many thanks for that! Think that shows me where the leak is.
Have soaked/mopped out the plug holes recon all three on the RH bank must have had about a desert spoonful of oily gunk in each hole certainly up to the ceramic of the plug and they were still running fine! (well as far as I can tell they were) at least it won't all drop down into cylinders when I take the plugs out! LH bank tiny trace of oil in bottom of hole but I'd say probably OK
Is the best thing for gaskets local(ish) Ford Main Dealer or anyone good to order from on-line given I don't know what part numbers to order?
Have had a good look and think if I disconnect the RH Inlet Manifold Octopus Branch leaving the main centre piece I can remove the cover without disturbing the 3 main wiring connectors! unless someone says otherwise? There is one further connector on RH manifold piping into some sensor about 1.5" long that looks as though it will have to come off, so hoping the wiring to that will survive or is easy to splice if it fails
Alan
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OldTuckUnder
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New Scorpio Owner
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Re: Oil Bubbling around Plugs
« Reply #3 on: Sep 2nd, 2018, 7:42pm » |
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Of course reading the manual (RTFM) for head removal does indicate that I should be able to remove the RH Inlet Manifold and get at the cover to replace gaskets and get away with only removing the plug from the Air Temp Sensor (my unidentified sensor) so hopefully only a couple of wires to repair if necessary 
So suggestions on best source for gaskets appreciated.
Alan
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Simmo
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Re: Oil Bubbling around Plugs
« Reply #4 on: Sep 2nd, 2018, 8:42pm » |
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Alan, Burton Power are often mentioned in connection with the Cosworth engines so they may be able to help.
Here
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a900one
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A scorpio is for life not just for christmas
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Re: Oil Bubbling around Plugs
« Reply #5 on: Sep 3rd, 2018, 4:28pm » |
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The plug holes will fill with a brown/black oil if the plugs are loose, its unburnt petrol.
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OldTuckUnder
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New Scorpio Owner
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Re: Oil Bubbling around Plugs
« Reply #6 on: Sep 3rd, 2018, 4:39pm » |
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Ah Duh! didn't think of that one! Slacked the rear right, took a bit of leverage to free it but it could be like that even if not seated fully due to carbon build up around the threads, but that one is back in tight now so can monitor it. In fact I think you have just tipped me into a new set of plugs and a change, then I can really monitor the condition and would be way simpler than a gasket change if it cured it. Its these stupid things on a new different car that would be first check on one of my others if I saw a weep around a plug.
I think I'm in its a Scorpio everything's going to be a major/expensive problem frame of mind at the moment!
Thanks
Alan
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OldTuckUnder
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Re: Oil Bubbling around Plugs
« Reply #7 on: Sep 6th, 2018, 8:07pm » |
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New Iridium plugs arrived yesterday, so in prep for a change I left old plugs in and squirted about 10ml of diesel down each hole to help dissolve any gloopy mess, and then put cotton cloth wicks down all 6 and left over night to soak it and hopefully any oil out, refreshed wicks this morning and after lunch they came out, and I cracked the plugs out, pain as I've never had anything with 16mm plugs down a deep recess, so whilst I had a 16mm plug socket I had to make up a rubber insert to grip the tip of the plug otherwise no way of getting them out of their pits.
I'd say all 6 had been sat in oil up past the body and about 1/4" up the ceramic, as the ceramic had burnt oily/rusty stain for about 1/4", but they had apparently been running OK.
Just possible there may have been a blow by a couple of them, but from the threads on the others which were clean I'd say not the cause of the problem. As when cleaning out the holes shreds of black silicon gasket seal came out of a couple I'd say its likely to be a gasket problem between the covers and the head. Not sure if those gaskets are supposed to be silicon'd in place or if someone tried instant gasket around them which is why there is/was a problem. Anyway clean as a whistle in all six with fresh plugs torqued up correctly (15ftlbs feels very tight when I'm just used to using a T bar on the plugs on the other classics and just nipping them up!) so will check in a few hundred miles and see if they are collecting oil, if they are I know it doesn't seem to cause an immediate problem, and will schedule cover removal and new gaskets for over the winter.
Looks like either Complete Engine or just Full Head gasket sets are available from several on-line suppliers for about what I'd expect to pay for any other car, so looks like getting them won't be a problem.
I'll try and remember to report back what I find in a few hundred miles.
Alan
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Simmo
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Re: Oil Bubbling around Plugs
« Reply #8 on: Sep 7th, 2018, 1:02pm » |
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Thank you for the update Alan and please do let us know how things go in the future. 
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OldTuckUnder
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Re: Oil Bubbling around Plugs
« Reply #9 on: Sep 7th, 2018, 8:05pm » |
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With a bit of time to think today, I realised on any of the other cars if I had a weep around a cover gasket I'd be also be suspecting increased Crank Case pressure. On the competition engine I have ended up with big 1" bore pipes to keep it down at high rpms.
So thought I do a bit of reading here to see if its a know problem. Found a few threads but nothing that helped. So thought I find out where the Pipes run from to, and where the PCV valve is.
Only real source I found was this
http://www.fordscorpio.co.uk/manual/engines/24v/24VDismantle.pdf
On page 00-01-3 at the top is says disconnect PCV hose, this is from the inlet manifold and I can find that.
Then on page 00-1-6 at the bottom it says remove PCV connector (LH side shown) but blowed if I can find it on the engine from the picture, Any Clues folks? also where is the PCV valve on the 24V engine I can find no picture of further mention, is it tucked up under the inlet manifold or something?
Probably a complete red herring re oil a round the plugs, but thought it at least worth a check that the pipes and the PCV were actually clear.
Alan
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Tompion
Administrator
1997 2.3 Ultima estate.
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Re: Oil Bubbling around Plugs
« Reply #10 on: Sep 7th, 2018, 9:18pm » |
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I did wonder about crankcase pressure as you said it was bubbling out.
The pdf may be wrong, not having a 24v I can't say for certain. However elsewhere where it mentions the thermostat housing it's not in the place where people with 24v's say it is - clamped into the lower hoses, not bolted to the engine.
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OldTuckUnder
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Re: Oil Bubbling around Plugs
« Reply #11 on: Sep 8th, 2018, 12:17pm » |
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Just realised I ought to investigate crank case pressure, as I posted a comment a couple of weeks back noting that I had a small film of oil on the Sump case, but that the bolts were only finger tight, and I had nipped them up. Will take a further look, as a leak there could also be symptomatic of high crank case pressure, I'm sure if I dig hard enough I'll find where the blasted pipes start on the block and where the PCV is on the 24V.
Alan
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Tompion
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Re: Oil Bubbling around Plugs
« Reply #12 on: Sep 8th, 2018, 5:37pm » |
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I assume the breather to the filter box is in place & clear.
Don't think this tells you what you want but some interesting details if you haven't seen it:
http://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl?board=admin;action=dis play;num=1268901956
In that post click on the link to the wiring diagrams
Open the folder "Scorpio Files"
Download "Scorpio Introduction.pdf"
The PDF pages are out of sequence, BOB engine details from p11 of the PDF - p9 of the manual.
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OldTuckUnder
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Posts: 85
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Re: Oil Bubbling around Plugs
« Reply #13 on: Sep 8th, 2018, 8:22pm » |
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Many thanks for link, Great Document! See it has the Thermostat in the correct place on the BOB engine.
Still silent on the PCV and piping, so assume its so obvious when I find it that nobody ever thought to document it!
Alan
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OldTuckUnder
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Re: Oil Bubbling around Plugs
« Reply #15 on: Sep 8th, 2018, 11:20pm » |
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Thanks for the link and picture, it can't be that hard to find something that big, can it?
Alan
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OldTuckUnder
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Re: Oil Bubbling around Plugs
« Reply #16 on: Sep 11th, 2018, 8:00pm » |
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Well it isn't easy, but have a few more clues, but still haven't seen it
Remembered an acquaintance who runs a rambling rural garage (mainly specialising in old Jags) had a BOB engine in the corner of his workshop, that he had planned to put in a Transit (I think its a project that has passed its time as I know the Transit has gone, but I won't ask him that as now realise where there is a spare engine if I ever need one!) .
But thought I'd take an amble over and see if I could find the elusive PCV on an out of body engine. Yes he still had the engine, but instead of being in a corner at some point in the last year they had had a tidy up and it was now slotted under a long work bench with a bunch of V12 jag engines. Fortunately is was ass end out complete with gearbox on, so I could get a good look from the back which I can't do in the car.
After 10 mins with a torch, found what might be two pipes coming up the sides of the block at the rear, which disappeared downwards towards the sump, unfortunately as I couldn't get to the sides to get a look due to it being wedged between two V12 lumps. And upwards they disappeared behind the exhaust and head heat shields. So not a lot of use, however has given me a good look at all the other EGR and water pipework round the back, and also highlighted that removing the inlet manifolds insitue apart from the RH one is going to be a bit fiddly as the EGR pipe will have to be unbolted from the bottom of it!
Well that was about it, but at least when I got back I could re-read some of the links above and try and make sense of the engine disassembly instructions where it is mentioned. Also found on the sump removal/fitting instructions a note and a pic to reconnect the PCV to the Sump (RH Shown) which I'm hoping means that there is another one on the LH side.
Also further reading on the engine disassembly page indicates that after removing the complete Intake assembly the PCV should be unplugged from the LH head cover, which I now think means that the valve itself is actually pushed into the head cover (which is why you can't see it anywhere) and then there are further references to disconnecting PCV pipes after removing the heat shields which is where from above I had a clue they disappeared.
So it looks like to physically check the PCV I've got to strip all the Inlet assembly off, which is what I'd have to do to remove the head covers and check the gaskets, so I thinks that's an all at once job this winter.
Which just leaves me pondering if there is any other way to check the crank case pressure? Might see if I can pick up a spare oil filler cap and tap it and run to a pressure gauge. On my competition engine I have breathers on block, head cover and timing cover, and am looking for as close to zero pressure in there as I can get, so I'd not expect much or very little pressure in the Cosworth block if the PCV is working properly.
Of course I'll find getting a spare oil filler cap is like hens teeth, and if I try tapping the original to put in a pipe fitting it will undoubtedly break! Lifes like that!
Alan
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OldTuckUnder
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Re: Oil Bubbling around Plugs
« Reply #18 on: Sep 11th, 2018, 11:20pm » |
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Thanks, very useful, starting to formulate a picture of how the PCV is plumbed!
More when I get there!
Alan
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