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Engine assembly paste - too much?


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This probably seems a strange topic...but more of an observation from both the Sprint engine I recently built and now my TR6 engine.

 

First, the sprint engine.

I knew it was a recent-ish rebuild but for peace of mind I stripped it for inspection and put a set of new rings in there as for me it was an unknown quantity.

With the sump off I found a thick silvery goop at the bottom of the sump that looked very much like congealed engine assembly paste.

Not talking inches, but enough to need a rag with some petrol on to shift.

 

Now this evening Ive had the joyous task of removing the oil gallery plugs on my TR6 engine so I can thoroughly clean the oilways before commencing the engine rebuild and I found the same sort of silvery gloop behind the oil gallery plugs.

No-where near as bad as the sprint but it got me wondering if too much of the paste could potentially be a bad thing?

 

I saw an engine the other day on a stand and it looked like it had been troweled on there like filler!

 

Perhaps on the engines Ive recently had apart the run-in oil change wasnt done on either engine at a reasonable interval and allowed the (im assuming) moly to fall out of suspension and settle at the bottom of the oil pan?

 

Thought and/or best practices with engine assembly lube?...lots or not lots?

 

Cheers

 

Andrew

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That's an easy one, you just use the correct amount :D

 

Mick Richards

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... or the correct product!

 

I take an assemby paste recommended if engine

will not be directly started. It avoids dripping down

from gravitation and can be bought from all the suspects.

Its like honey.

Good for mains, big ends and small ends.

 

For the cam lobes I have the Isky Moly paste I apply

like a massage on the dry lobes and lifter bottoms.

 

Piston rings and bores get motor oil.

 

I hope all products can be washed away from oil.

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The mineral molybdenum disulphide is silvery.

Too much moly may well be damaging - there is evidence it prevents ZDDP working.

But the more recent additive "MolyDTC" might be an improvement.

http://www.sciencedirect.com/science/article/pii/S0043164801008651

Ideally.. a paste with MoDTC not MoS2 ?

Peter

Edited by Peter Cobbold
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Last winter I fitted a new cam and followers to my TR6 and used assembly paste, I changed the oil after 1000 miles. This winter I had the sump off again (dont ask) and was amazed at the amount of slippery silver grey sludge that was in the sump, I was sure it was the assembly paste but the amount appears to be far more then I used. I suppose the good thing is its in the sump and hopefully nowhere else

 

George

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Its what they call in Star Wars "The Death Tar" :) Mix of different metal powders, carbon, heavy oil deposits falling out especially from mineral oils that don't get used enough and are left standing cold. The good news is that they seem to be good friends and want to clump together. Next time you have the sump off and clean it drop a large magnet in the sump, the next time you look most of it will have collected on the magnet.

 

The amount of metal wear even in a good engine is quite large, and even more in a rebuilt one, and if you have had the bores honed almost frightening! Fortunately most of it gets trapped in the oil filter, but some will make friends and settle out.

 

Alan

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I use Graphogen, and their website says, "Coat all components liberally with the compound."

But they would then, wouldn't they, like Mr.Colman making his fortune from what you leave on side of you plate.

 

Graphite would seem to be only good for this, and is claimed to dissolve in oil.

For the same reason, when assembling, say, needle bearing in a gearbox, I use vaseline, not grease, to stick the little ... things ... in place.

John

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Wonder if liberally can interpreted as a generous smear or 'empty the whole tube'

 

Just to address a few comments above..Definately moly/graphite substance on both engines. If the engine had shed that much metal the pistons would look like a thimble going up and down in the bore.

I asked the initial Q because the goop I saw in the oilways could potentially be enough to restrict the oil flow to the mains or in the case of the 6 engine, the cam in extreme circumstances. Given how sticky the goop was, particles could be sticking to the goop rather than being filtered out (and subsequently being thrown away when servicing).

 

Anyway..Liberal coating it is then.

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Hi Andrew,

don't panic about the amount of particles. The amount of wear on an engine giving the sludge a visually high metal content is very very small.

 

When the metal is shed its visual effect is magnified greatly. Its an illusion (but keep an eye on it).

 

compare to First Aid - a teaspoonful of blood when spread around makes a disasterous sight but has no effect (usually) on the body.

 

Roger

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We should not mix up two discussions.

Seems that the problem is not assembly paste related.

That may be put as a bigger piece somewhere and than

fly around in the engine and later diluted like butter.

 

That what looks like Moly is something that drops in the oil pan

from gravitation and finds a place where it is not affected and

mixed up from the oilstream.

It was at no time a bigger bunch of material but little particles

that preferred to sink down instead of being held back

from the oil filter next time they are pumped around.

 

So these particles come into that place part by part and drop and fix

at the bottom like glue. I think they will never get loose and

block something unless the oil quality is severly changed.

They have never been a bunch of material travelling through the engine.

 

I would look after that every 20 to 40.000 km, clean the pan and thats it.

I am used to lift away 2 to 4 tablespoons of that material whenever I open an engine.

The content is a lot of carbon deposite, not metal.

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Hi Stuart,

of course that looks bad and would not be wanted in your engine.

However what I was getting at is that it is not a great deal of metal.

 

If it all came from one bearing then it could be serious.

If shared between all the mains and big-end bearings and after a rebuild then it may not be serious.

 

Roger

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That what looks like Moly is something that drops in the oil pan

from gravitation and finds a place where it is not affected and

mixed up from the oilstream.

It was at no time a bigger bunch of material but little particles

that preferred to sink down instead of being held back

from the oil filter next time they are pumped around.

 

So these particles come into that place part by part and drop and fix

at the bottom like glue. I think they will never get loose and

block something unless the oil quality is severly changed.

They have never been a bunch of material travelling through the engine.

 

 

+1 NB I suspect that deciding to give your engine a treat and using flushing oil may also count as a severe challenge, IMHO leaving sleeping dogs alone may be the best option unless you are going in for the kill.

 

Alan

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The last time I rebuilt an engine, it had a bad case of the "Black Gunge" up top, that indicates long term abuse and no oil changes.

 

I cleaned out the sump, and found under the tar, a silvery grey deposit. It was ferric and could be picked up with a magnet, where upon it looked like , spiney spikes, needles of steel broken off, but in fact as Roger says was microscopic wear particles that felt like the smoothest skin cream between the fingers. It was remarkably difficult to remove, sticking like the proverbial to the sump bottom. Repeated rinses with engine cleaner and it was still there, and a wipe with a paper towel would coma up with more of it. I had a spare sump so the dirty one went in the skip.

 

Why so difficult to remove? Could the sump be slightly magnetised? Almost any lump of iron will be, I think and these wear particles are so small that a small magnetic field could grab them. The oil gallery plugs themselves might be slightly magnetised. Could that be what Andrew found?

 

John

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Hi guys,

 

Good discussion and some interesting science behind it..

 

To clarify however my fear was that when too much of this stuff (whatever it is made from) settles/congeals it would appear to be hard to shift when allowed to settle/packed down. Whether its the assembly lube or bits of bearing/engine particles. In my case it needed a plastic scraper to get it off the bottom of the pan.

 

Both the Sprint and the TR6 engine were when opened in fine fettle with the Sprint engine just requiring new rings (for peace of mind) and the TR6 a 20 thou overbore to take out the top of bore step so as not to break the new rings with new standard big ends and mains.

 

To add further, the gloop that came out of the oilway in the 6 was the silvery gloopy stuff, and hadnt dispersed after being flushed with degreaser neither. Im not saying that it would block the oilways, but any unwanted restriction is surely unwanted?

 

Wish Id taken a pic of it now!

 

Google throws up this:-

 

http://www.jalopyjournal.com/forum/threads/light-grey-sludge-found-in-bottom-of-oil-pan.155097/

 

Not sure about the lead theory?

Edited by AndrewP
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When I stripped my 112,000 mile GT6 engine, there was a layer of layer of greyish metallic-looking sludge in the bottom of the sump. I assumed it was bearing metal as most of the bearing shells were starting to show wear through to the copper backing.

 

I've recently needed to have the sump off the Ford Essex V6 in my Scimitar GTE, twice within the space of a few thousand miles. The first time there was a thin layer of greyish metallic-looking sludge in the bottom of the sump, which I cleaned out. The second time, it was completely clean. I beliive the first time I removed the sump on this engine was the first time it had ever been taken off.

 

The Ford engine has done 80,000 miles and the service history shows it's had oil and filter changes exactly according to the manufacturer's recommendation. Oil pressure and compression are good.

 

I suspect the sludge is bearing metal. The very fine particles may well pass through the filter. The fine, high density particles will then settle out in areas where the oil doesn't flow fast enough to keep it dispersed, as Andreas has said. If the sludge is bearing metal, I would expect most of it to be deposited early in the engine's life, as new bearing shells run in. Perhaps some of the sludge may also be from bedding in of piston rings and bores. I wish I'd checked the sludge with a magnet to find out but it's too late now.

 

 

Nigel

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Hi Folks,

back in the 80's I took the sump of my father-in-law's Vauxhall Viva HC as a big-end had gone.

With the sump off we soon found where it had gone.

All of the bearing material was in the sump - lumps of it

 

The numpties at Luton had fitted the wrong big-end half to the conrod (the rod had ie 'H' on it and the backing had 'F'

 

I only found this when I fitted new shells and the whole thing locked up.

 

The shells where completely stripped of white metal.

 

Roger

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