2-strokes have completely different bearings that can be adequately lubricated by a petroil mix. I don't think I'd ever be tempted to to put petrol in any separate oil system.
Why not just let the oil filter deal with it?
Re bearing type, yes that had occured to me and is a concern, but I thought 30% 2-stroke would be adequate for a short time in non-running engine.
Maybe it isn't worth the risk and I'll just do the short-interval changes with the 4-stroke oil.
Re letting the oil filter deal with it, I don't have much faith in standard full-flow filters. I understand they don't stop fine particles, and this one, though new, was an unknown Chinese brand (all I could find) and may well be worse than average.
After about 40 klicks on the freeway (when I realised what I'd done) the oil film was already greyish, suggesting rather rapid wear. After a couple of weeks standing a metallic slurry has settled out on the dipstick.
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I've seen it alleged, on the basis of Material Safety Data Sheets, that the add-in engine flushes (Wynn's style) are mostly white spirit (petroleum distillate)
I've also seen people advocate using, for example, kerosene, diesel oil and ATF as an engine flush, and allegedly getting away with it. Some of them even idle the engine with it in.
The first two seem likely to damage bearings. I'd have thought the ATF might be OK, since I believe from its usual application, that its a thin, high detergency gear lubricant and seal conditioner.
I've got a lot of hydraulic oil that I don't have any use for. Is that likely to be damaging used as a flush in a non-running engine?
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>>I've got a lot of hydraulic oil that I don't have any use for. Is that likely to be damaging used as a flush in a non-running engine?
What's the point of pouring oil into the top of an engine only to let it run out the bottom?
I thought the whole point of a flush was to wash it through the oilways, galleries and all the other parts engine oil is found, thus flushing them out.
I let the new engine oil flush mine and then leave it there for the next year.
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I think the idea of extended cranking of the engine is unwise. If you think about how the lubrication system works, it requires the engine to be turning over at a certain speed for the lubrication to be effective. At cranking speeds, lubrication is very poor because the crank isn't spinning quickly enough to throw sufficient oil onto the cylinder bores. At the top end of the engine, valve trains really suffer from inadequate lubrication at low speeds because of the high contact forces and low sliding velocity.
The use of a thin engine oil is a good idea. Thinning it further with ~5% petrol is a good idea. I would say that the kindest way to treat an engine with contaminated oil is to run thed engine at a slightly elevated idle ~1500 RPM or so. The cylinder pressures are low enough to help prevent debris being ground into bearing surfaces, but the sliding velocity is sufficient to ensure adequate lubrication to all parts of the engine. Run the engine for a few minutes varying the speed between 1000-2000RPM, then switch off. drain the oil and changer the filter. That's it.
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By non-running engine I meant turning over with the plugs out, the idea being that this wouldn't result in any cylinder pressure, and so should keep the pressure low on the big and small ends, and the crankshaft bearings.
If I get my gf to tow it in gear (should be a laugh), presumably in fourth, I might be able to achieve the same rpm as a fast idle, as is suggested below.
The suggestion seems to make sense, to me anyway. Thanks for the input, all.
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I'd simply replace the oil (use something correct but cheap for the short term) and filter now and then again after a few hundred miles.
Filter should have trapped any dirt anyway.
The only other thing i might be inclined to do is drop the sump if not too difficult and clean it out, giving you the chance to inspect the pick up strainer....you could even drop a main and big end cap to have a look see.
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Re: Engine flushing?
I bit the bullet and took the sump off.
Bit of a pain. Basically, the cross-member, front and back engine mounts, anti-rollbar, gear linkage, exhaust mount and pipe, and flywheel cover plate have to come off, and its a bit tricky getting it all lined up to go back on again.
Then again, I've only done a Marina (very easy) and a Lada (fairly easy) before, and new cars are probably even worse.
Probably worth doing though. Despite spraying the engine down with petrol/2-stroke from the top, there was still a lot of (probably metallic) silt that hadn't drained, and the captive nut thing for the sump plug was preventing varnish and gasket fragments from getting out.
<*** src="http://img833.imageshack.us/img833/9218/imgsumpchunks.th.jpg" alt="Image" />
The oil pickup strainer also had varnish and gasket fragments stuck to it. Close examination (though without a lens) showed a few of what looked like large grit/sand grains stuck in the mesh. Couldnt pull them out, so I pushed them through, then took the strainer off and squirted petrol through it. Hopefully this washed the particles out, otherwise I've just gone to a lot of trouble to make things a lot worse.
<*** src="http://img198.imageshack.us/img198/7345/imgoilpickup.th.jpg" alt="Image" />
In the process of doing all this, I discovered that:-
(a) My girlfriends mechanic-uncle hadn't fitted an exhaust flange gasket. No big surprise there, and it didn't seem to have caused a problem, but hot gases squirting around the engine compartment could be a bad thing.
I made one from folded aluminium foil/pertex sandwich, burnishing it down onto the flange, then cutting an X centred in the three holes. The folded-down excess in the pipe gets burned/melted off (probably bad for a catalyst, but good if you don't have one.) The excess in the bolt-holes perhaps helps the bolts not to seize. I've done this a few times before without problems, but that was with RTV silicone, so I'll keep an eye on this Pertex version.
(b) The flywheel-plate didn't have the specified silicone "instant" gasket along the sump join, giving another grit-path into the sump. Put some on, though this area is very difficult to see and I might not have put on enough.
<*** src="http://img404.imageshack.us/img404/5931/imgflyplate.th.jpg" alt="Image" />
(c) My front and rear rubber engine mountings are split, the front one quite badly.
<*** src="http://img339.imageshack.us/img339/9157/imgsplitmount.th.jpg" alt="Image" />
I tried supergluing, though not with much optimism.
"Do you expect me to torque?"
"No, Mr Bond, I expect you to die"
<*** src="http://img407.imageshack.us/img407/6181/imggluemount.th.jpg" alt="Image" />
I put some cable ties on to close the gap and give the glue a chance, but couldn't keep it aligned properly, so I put a lot more cable ties on to keep it under compression. Doubt they'll hold. I suppose I should have gone to the beach and foraged up some commercial monofilament fishing line for a lashing, but no transport.
<*** src="http://img52.imageshack.us/img52/5731/imglashmount.th.jpg" alt="Image" />
Dunno if these mountings are still available here, or at what cost.
There is quite a lot of web info on DIY engine mountings, made from eurethane casting , but they mostly seem to be replacing the existing bushing in a "caged" mounting. This mounting is trickier, since its open, and the rubber is loaded by engine torque (and is failing) in tension. Might still be possible to cast something if I can get the resin here in Taiwan.
I suppose that's a separate topic though.
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Havn't had the sump off yet but its about time. Looks to be only a mild hassle (remove cross-brace, and seal the rather convoluted sump flange with RTV).
Dunno about popping bearing caps though. If I saw something unambiguously nasty it'd probably be too late to do anything about it anyway.
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''If I saw something unambiguously nasty it'd probably be too late to do anything about it anyway''
Fair comment, though it would only take two minutes once the sump is off, if it looks worse for wear you probably have several months, at least, to search for another lump at your leisure, what price peace of mind?
I doubt i could resist nipping an end cap off if i had the sump in me sweaty mitt..:-)
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>>I doubt i could resist nipping an end cap off if i had the sump in me sweaty mitt..:-)
The problem with modern engines GB is they don't seem designed to be dismantled. Isn't there something about Fords bottom ends being stressed so they won't go back together the same? If so, are the parts available.
In the OP's case it's over twenty five years old. Are those parts available and if not is there anyone left who can re-do white metal bearings?
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BIG hassle swapping engines in Taiwan (assuming I could find one).
Used to be completely illegal. Now you have to re-register the car, lots of Mandarin forms to fill in. Engine has to be exactly the same model.
The admin fees/taxes alone would cost double what I paid for the car, without the sourcing and mechanical swapping costs.
As elsewhere, scrappies only keep cars for which there is parts demand. These are too rare. In general, (apart from a very few "cool" exceptions ("real" mini, VW Beetle, um...that's it) there is zero interest in old cars here. You couldn't sell anything else over 10 years to a Taiwanese.
Old car = poverty = major loss of face.
If it comes to it, It'd probably be a lot less hassle and cheaper sourcing another one of these (I quite like them, and, although they are rare, there are still a few around) and keeping the old one for spares.
I share the temptation to have a look at the bearings, but if there is a significant chance of me screwing up and (for example) the crankshaft/bearing going out of alignment, perhaps I'd better resist it.
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What a load of work for nothing !
An oil and filter change would have been fine.
The sump is exactly a sump,all the old rubbish,casting sand,swarf and bits of gasket sit there harmlessly for years,and dont get back into the engine.
If you knew how dirty engines were at point of manufacture you would be concerned.
Thats why they are filled with an oil that looks like water for the first 1000 miles. Its basicly a flush !
First service see's correct oil installed at the dealers.
If it aint broke - dont fix it !
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"What a load of work for nothing !"
Well, there's some truth in that. If I'd known how much hassle it was going to be, I might not have started, but I'm not sorry I did it, and I'll be a bit more efficient if I have to do it again
"The sump is exactly a sump,all the old rubbish,casting sand,swarf and bits of gasket sit there harmlessly for years,and dont get back into the engine."
Why don't they get back in to the engine? If you're assuming that the filter stops everything, then you've got a lot more faith in oil filters than I have.
Before I managed to contaminate my engine with grit, this car was putting a lot of ferrous metal into the oil, which wasn't being taken out by the filter. I initially noticed it when the car sat idle for about 6 weeks while I was back in the UK, and it settled out on the dipstick.
My best guess at this time is its valve gear wear due to the inadequate amount of zinc in current oil specs, but I don't know. A clean sump will give me a new starting point to monitor the effect of prevention efforts.
Even if the filter stopped the crap, it'd still get to the oil pump, and if your oil pump dies, so does your engine. With a lot of flakes of varnish (which I have) it would also be possible to fatally clog the oil pickup strainer.
"If you knew how dirty engines were at point of manufacture you would be concerned."
Don't think I would, since I have zero interest in new cars. I suppose its always good to have another reason to avoid them, though.
"Thats why they are filled with an oil that looks like water for the first 1000 miles. Its basicly a flush !
First service see's correct oil installed at the dealers."
Sounds like an argument for engine flushing, which I was proposing, and which you seem to object to?
"If it aint broke - dont fix it !"
Well, normally I'd agree, but occaisionally a bit of preventative medicine keeps the surgeon (or the undertaker) away.
For a while.
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With Respect.
If you know so much about everything mechanical,why have you bothered posting on here.
Reading through your (ample) posts,
any advice is obviously going to be ignored ?
!4 years as an inspector in engine maunufacture and testing in the best car plant in Europe seems to be wasted here !
Good Luck with your engine rebuild.
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With equal respect.
You may well be right that taking the sump off wasn't worth the trouble, but I've already done it, so its too late to take that advice.
Now I've done it, I may as well look on the positive side of the experience. I got a lot of muck out, and I found some other problems I wasn't aware of.
In this thread, as is usual, there's a range of opinion expressed. One has to pick and choose, and take the consequences. No disrespect is implied by those choices.
Its true, though, that as a general rule, the less I do, the less I screw-up. I seem to be screwing up more than I used to (an ageing brain, perhaps), so "If it ain't broke, don't fix it" is an increasingly appropriate guidline.
I'll try and bear it in mind.
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