Author Topic: Flying flea engine  (Read 508 times)

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Offline TonyC

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Flying flea engine
« on: 29 Dec 2020 at 10:19 »
Hi all,
I have started stripping down the engine that I have for a flying flea. Engine number CE166. Can anyone advise on how to remove the through bolts that hold the rockers on? I don't want to damage them. Are they threaded into the top arms?
Cheers Tony

Offline cardan

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Re: Flying flea engine
« Reply #1 on: 29 Dec 2020 at 10:58 »
Hi Tony,

I think you'll find that the rocker spindles have a taper where they go into the head at the lower end - on the right in your photo - but they pass straight through the head at the top. Thus the 5/16" thread at the top, 1/4" at the bottom.

In principle a tap on the bottom (short) end and they will exit from the top. Usual cautions, particularly if there is rust.

Cheers

Leon

Offline eddie

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Re: Flying flea engine
« Reply #2 on: 29 Dec 2020 at 11:01 »
Tony,
          Although there are detail differences between your rocker gear and the DT type, I would think the general set up is similar. The through bolts have hardened steel sleeves that the rockers pivot on, so the bolts may be just stuck in the sleeves! I would suggest locking 2 nuts together on the top of the bolts to see if you can start the bolts turning. If they start turning reasonably freely, but won't come out - they are almost certainly in plain holes in the rocker pillars, but stuck in the steel sleeves. If the bolts only move less than a quarter of a turn before tightening up again, then they are probably threaded into the pillars (and again stuck in the sleeves). If they are threaded into the pillars, you will have to be careful until you establish whether it is the top or bottom pillar that is threaded. If it is the top pillar then unscrewing the bolt will just jack it out of the sleeve - if it is the bottom pillar, then you will have to be careful not to spread the pillars (a nut and spacer against the top pillar will counteract the drag in the sleeve). If you are lucky and the bolt turns fairly freely to start with, a longer spacer and nut on the top should draw the bolt out (the spacer and rocker sleeve will just have the top pillar sandwiched, and not putting any stress on the pillars).

   Hope some of this helps,
             Regards and best wishes for the coming year,
                                                                                      Eddie.

Offline cardan

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Re: Flying flea engine
« Reply #3 on: 29 Dec 2020 at 11:25 »
This is the early design, usually found with unsleeved rocker arms (and plenty of wear!).

Leon

Offline TonyC

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Re: Flying flea engine
« Reply #4 on: 29 Dec 2020 at 11:27 »
Hi Leon & Eddie,

Thanks for the advice
I have fitted a lock nut and tried to turn it and also fitted the 1/4 nut on the bottom and given a sharp tap. Nothing moves!
My worry is that because the top 5/16 thread has been drilled out it will shear off. I have had wd40 squirted on it over the last 6 months and although there is a lot of rust the nuts did release relatively easy. The rockers are free and move easily.
Would it be worth trying heat?
Cheers Tony


Offline cardan

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Re: Flying flea engine
« Reply #5 on: 29 Dec 2020 at 11:46 »
Yikes! I guess the most likely place for the spindle to be stuck is on the taper. (Given that you have the 1/4" thread at the bottom, I'm 99% sure the design is as per my photo. Others I've seen have 5/16 threads top and bottom.) I'm only a bumbling amateur, but if the rockers are free, and there is no corrosion around the top hole, I'd use a gas torch to put some heat into the area around the taper, and with the nut backed off a turn give it a tap with a copper hammer... but do go gently!

If the spindle won't free from the head with gentle persuasion, consider drilling it out rather than damaging the head. It will probably need replacing anyway.

Leon

Offline TonyC

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Re: Flying flea engine
« Reply #6 on: 29 Dec 2020 at 12:13 »
Thanks for the image of the shaft, it certainly helps!
So if it is the correct one then it must only be the taper that is holding it. There can't be a thread in the top casting as the shaft would not come out.
There is up and down movement in the rockers so will shim the gap before I try and give a harder wallop with a copper mallet!
Does anyone have knowledge of the 'Best' oil pump that is fitted to this engine? It has suffered from corrosion and a brass screw/ cover just won't budge!  The adjustment knob on the side comes out when the cover plate is removed but there is some sort of screw or pin holding it in place.

Cheers Tony

Offline TonyC

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Re: Flying flea engine
« Reply #7 on: 30 Dec 2020 at 17:48 »
Well the shafts came out easily with a sharp tap and look pretty good.
They are a different design to Leons and one pair still had the wick attached through the shaft. The other side had what looks like knitting wool inside the aluminium casing with non going the the shaft.
Would normal string be ok for the wick or is it special material?
Cheers Tony


[fix image aspect ratio.  -Doug, Site Moderator. 30Dec20]
« Last Edit: 30 Dec 2020 at 21:50 by Doug »

Offline Doug

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Re: Flying flea engine
« Reply #8 on: 30 Dec 2020 at 22:06 »
Tony,

Felt cord works best, but cotton string ought to work. Just avoid synthetic strings, they do not wick as well. On a similar function, was rebuilding a machine tool that used pipe cleaner to lift oil into the drill ways. Someone came up with several brands of pipe cleaners, some of which were part polyester or some other plastic and they did not work at all. Left them in a cup of light ATF oil for several days and some did not wick worth a damn.



Douglas seemed to be changing the rocker spindle design rapidly from the S1/S2 models to the OB. It must have been one of those things that was always giving trouble and they were looking for a better solution. The lube plays a big part with the wicking as well. Something that does not wick too well and continue to drain the oil reservoirs when standing, yet as soon as the engine warms up starts to wick and supply fresh lubrication. These days something the errs on the side of wicking too easily and leaving a stain on the floor is probably preferable to something that does not drip but runs dry.

-Doug

 

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