Onan W3S-19 #4

As Martin P can testify, the latest Onan looks quite twee with its maroon paintwork and lining, too bad it was left outside with the plugs out!

It's an April 1944 model, same as our red one, and came at a fairly decent price.

One piston is severely stuck (rainwater in the bore) and the other is nearly free, both were within 1/4" of the top of the bore. It's been soaking in WD-40 for three days.

We blagged an offcut of 3" Nylon this afternoon, and turned it down to closely fit the bores. Application of a BIG nylon faced mallet brought some movement downwards, so we filled the bore up with WD-40 again and left it.

The pistons are aluminium so we don't want to crack them by applying too much force. Once we have the piston low enough, we can clean the bore above it and move it up to the top of the bore.

Magneto is missing, lots of bodgy bits here and there, but generally it is all nuts and bolts stuff: car wheelnuts used as spacers, that sort of thing!

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk

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Reply to
Peter A Forbes
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Having enjoyed a cup of tea with you this afternoon I can only heap praise :-)) Your business workshop is beginning to look like a Charity shop for old engines :-)) What ever keeps you happy.

Reply to
campingstoveman

Reply to
Charles Hamilton

To be honest, Charles, I haven't seen a can of Plus-Gas since the late 1960's, and we have bulk packs of WD-40 at the factory anyway.

I'd imagine that the Plus-gas formula would be better at getting down inside rusted parts as it has a lower surface tension, but I had another whacking session this afternoon and the piston has moved another 1/4" dopwn the bore. Time and patience will do the trick, I don't want to damage anything in the process.

I'd like to clean above the piston and then get it back up into the cleaned area so I can get at the lower end of the bore.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk

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Reply to
Peter A Forbes

A pal of mine has a workshop and use a mixture of old engine oil and thinners to make up his own 'wd40' He recons nothing will touch it ! his theory is the thinners carrys the oil down to the work and then evaporates leaving the oil to do its job . I must say - it has worked on most applications i have tried it on. One thing i did once wwas to use a gas axe to warm some pistons in a well seized mini - i had towed it around the block only to make the clutch slip! some gentley applied heat had enabled the piston to contract and i was able to turn the engine on the road wheel with it in gear ! julian

Reply to
jagojules

Plus Gas is a releasing agent which is still obtainable easily.Just re- stocked three weeks ago. WD-40 is a moisture disperser (duck oil) which is next to useless when it comes to freeing rusted corroded parts. Mark.

Reply to
mark

I guess the easily available WD40 has stopped you looking for Plus-Gas, I think Halfrauds stock it. B-) Damn good stuff best penetrating/release aganet I have ever used. I was also under the impression, probably gained from this group, that diesel was pretty good for releasing things as well.

Reply to
Dave Liquorice

Yes indeedy! I too am a Plus Gas fan & it helped me strip a Merlin that had been underground for 40 years!

I've tried all the things discussed here - paraffin (WD40 in a cheaper tin!), Duck Oil which is very good for protecting bare steel & oiling light use drive chains and of course Diesel. For big stuff, paraffin & sump oil

50/50 applied to hot metal is good and occasionally exciting, so best done out doors.

But it comes down to preference & what's at hand, does it not?

Regards,

Reply to
kimsiddorn

Well, we got the stuck piston out using patience, WD-40 and a bl**dy great BIG mallet!

It took an hour or so after we had it moving yesterday.

All but two of the rings in the pistons are freed off, the one with all the water and rust doesn't look too bad, the block and head cleaned up very nicely indeed, the only nagging problem is the front core plug seat which looks a little fragile.

Nothing was broken or damaged in the removal of the pistons.

Mr Hermetite did well on this engine, we must have taken a bucket load out!

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk

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Reply to
Peter A Forbes

I don't think WD40 is an especially good product, however you can buy the gallon containers (complete with ''free'' dispenser) for a very good price from Screwfix. I've taken to spraying the lathe beds etc, the cost is peanuts compared to aerosols.

Julian.

Reply to
Julian

It is if you look at wider uses and not just for engine work.

It is good for removing adhesives from painwork and powder coat for example, where more aggfressive solvents would be a problem, and it is also very good for lubricating electrical parts where you don't want a heavy oil or you can't get an oilcan in to the part.

We buy both the gallon and the 3-pack spray aerosols. They used to give the hand sprayers with the bulk packs, and that works out at about a 10th of the price of the aerosol cans.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk

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Reply to
Peter A Forbes

---------------------------------------------------------------------------------------- It was also used by RR as an anti corrosion measure on the Pegasus engine (Harrier) before it was fully marinised.Sprayed into the intake on shutdown. MH

Reply to
Mike.H.

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