Villiers MK25

Thanks to all who identified this as a MK25 supplied to the Air Ministry. If anyone has a manual,  scanned or photocopied or whatever,  we'd be most grateful.



It turns over freely but compression is lacking. Can't comment on spark as HT lead is perished.
Carb and inlet look in good shape.





Spark plug threads are gone so head will be paying a visit to Lockside Engineering for a helicoil.



Head off and lack of compression explained - exhaust valve stuck open. Looks like a job for De-coke boy.



Now to remove flywheel and check the ignition side of things.

Exhaust stub came off easier than we thought. A couple of notches in the nuts with a Junior hacksaw and a bit of work with a cold chisel and bingo. Not sure about the studs, they seem pretty tight. Ran a die nut down them and they cleaned up reasonably so we may just go with what we've got.
Note also the shiny new spark plug insert. While you wait service - brilliant!



Less success on the flywheel.
We managed to free off the nut but when we got to the stage where it starts pulling the flywheel off the shaft it was solid - even by hammer-tight standards. The lads in the RAF must use bigger hammers than I have.
So we flipped the engine on it's back and put loads of Plus Gas around the nut and retired for the evening.
This morning - DISASTER. The oil has drained from the crankcase breather all over the workbench. Fortunately my woodworking means I have plenty of sawdust and shavings.
Think we'll drain the oil today!

Been heating and applying Plus Gas all around the flywheel but it still won't budge
Patience required I suppose.  
Decided to try and remove the HT connection - top sheared straight off. What we can see of the threads are full of something red. Looks like some RAF fitter lost the felt washer and decided to seal it with Loctite. Hope he didn't do the same with the flywheel!

Finally got the flywheel off today - Plus Gas, patience and propane follow by a big hammer. Can confirm that HT connector was indeed sealed in with Loctite - dur.  Had to drill it out then spend a couple of hours with a scalpel picking bits of Bakerlite out of the threads. Good news is that, after a good clean, we seem to have a sound magneto coil, condenser and points.
Now shopping for a MK25 exhaust.

I know we're new to this game, but when you've got it nice and shiny it almost seems a shame to paint it.

i know what you mean mate
its always the weather that makes me paint them in this sunny land of england lol







and then i did another a fews years later
left the tank as it was as it was 99% original factory paint still left on it

kev

Nice work Kev. Very tidy.

Woodsman wrote:Nice work Kev. Very tidy.

thanks woodsman, think its why i do a good few a year for others too
have a pre 1916 amanco coming in over the next few weeks when the owner brings it over for the fun to commence
but historic or classic ,they all get the same tlc and finish from me
i was the first villiers aircooled to win the best display of section with my first mk25 at 8 rallys in one year
:
and my best is 3 engines in one S E mag, 2 for customers and one my own well good mnth that one
Just remember to high temp paint the cooling fins on cylinder from 3 fins up from bottom ,as this modern ht paint will discolour to crack with the heat from these engines
kev

Got a tank thanks to Blue Cat - now pickling in citric acid.
Engine Cowl has had first coat of primer so now we have to decide on colour. Original seems to have been a mix of blue on most of the engine and dark green on the cowl. Suppose we ought to go for RAF Azure blue but tempted to go 'off piste'. Any suggestions?

Turns out the valve seats and valves were beyond salvation so new valves to order and barrel off to workshop for re-seating. Anyone know where we could get valve seat cutter without having to part with an arm and a leg?



Good excuse to clean up the piston and rings


Tank is coming along nicely.

Great work!
What did you use to get that metal looking so good?

Presume you mean the tank ?
Wire brush to break up the paint then Home Strip paint stripper (got mine from Tool Station) overnight.  As for the rust  -see my post:

http://www.stationaryengineforum.net/t8394-rust-removal-using-citric-acid

Two overnight pickling sessions followed by wire brushing then finish off with wire wool or wet and dry.

Valve seats re-cut and new valves lapped in - loads of compression now
Got the piston back in without breaking any rings - phew. New exhaust and gaskets all round. Took a while to get the timing right on this one but got there in the end. Cowl and tank all primed up and ready to paint but it's -2 deg in the workshop so that's on hold.



Couldn't wait for a test drive though ...

https://vid1295.photobucket.com/albums/b639/y3531/Villiers%20MK25/MK25TestRun01_zpswkcwxtjj.mp4

Seems to bounce around a bit - see aerosol can on right. Flywheel is original and there are no vanes missing from fan - any ideas what might be causing the imbalance?

Almost there, just need a spade type spark plug connector and petcock and we're done.
Then I suppose it will have to be listed to fleabay to help finance another project.

Hi Woodsman,

Nice job on the engine

Best regards,

Steef

looking good there
kev

Thanks Steef & Kev. Seems a shame to sell it now but we need the funds and the enjoyment comes from the restoration rather than ownership.

Woodsman wrote:Thanks Steef & Kev. Seems a shame to sell it now but we need the funds and the enjoyment comes from the restoration rather than ownership.

true that one very true, always wanting a rarer toy to play with
kev