Author Topic: 1932 A32 350 oil pump failure  (Read 512 times)

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Offline woodsy

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1932 A32 350 oil pump failure
« on: 10 Jun 2021 at 10:02 »
Evening everyone that sees / reads this post .   I am new on this site ( first post ) and am asking for help as the oil pump on my bike suffered a seizure of the oil pump which luckily i spotted before any further damage could ensure , i have never heard of a oil pump seizing before but seeing is believing

It managed to shear of the drive teeth on the pump shaft and also crack the housing where the shaft enters the pump body .... some seizure !

If anyone out there in douglas land has a fix or knows of anyone who maybe is able to fix or even has a spare one they would be willing to sell me , i would be more than gratefull .... as what i am facing at the moment is a bit of a game changer

the last pic is my bike here in queensland , australia

thanks in advance ... ken

Offline Daren W Australia

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Re: 1932 A32 350 oil pump failure
« Reply #1 on: 10 Jun 2021 at 11:04 »
Hi $70 on ebay now ! www.ebay.com.au/itm/184561224686 Ta Daren
too many dougli not enough time!

Offline Doug

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Re: 1932 A32 350 oil pump failure
« Reply #2 on: 11 Jun 2021 at 04:34 »
ken,

Seized, or teeth on gear stripped? The later is not uncommon as the worm and gear mesh is not the best it could have been. Though earlier and a slightly different design, the EW plunger pump suffered the same fate of rapid wear on the worm gear teeth and they went to a coarser pitch worm & worm gear to try and alleviate the problem. If it jammed and jumped past the teeth that might have wedged and account for the cracked housing. Unless you see signs of scoring in the bore or metal pickup on the plunger, I would be dubious about seizure. Regardless if it seized or not, not really practical to fix the housing and you will need another worm gear/cam anyway. I am pretty sure that same pump was used on the lightweights to the final 250/350cc Aero of 1936. I'll compare a A31 to a 1935 250cc Aero over the weekend to verify. It also may well be the same as used for the 500/600cc Aeros to 1938, and I can check that as well. If so, the potential for suitable donors is a lot greater.

-Doug

Offline Doug

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Re: 1932 A32 350 oil pump failure
« Reply #3 on: 18 Jun 2021 at 18:34 »
I compared oil pumps between a 1936 Aero 600, a 1935 Cotswold (350cc) and my A31.



First thing I realized is that it seems my A31 had the oil pump replaced at some point with that from a big twin! However all is not lost as they are somewhat interchangeable. In the next image the arrow shows where a notch has been sawn out of the oil pump on the A31.



This is done so it fits within the smaller perimeter of the 250/350cc engine. The pump fitted to the 1935 Cotswold would appear to be what the A31 ought to have. The difference between the big twins and the lightweights is they used two pegs to locate the big twin oil pump, but did not bother for the lightweights. The location of these is shown in the next image:



The mounting bolt pattern, oil galleries cast into the pump face, and ports in the timing cover are identical between these three engines.



The gear and worm are also the same. One other difference, though not impacting you, is the oil spray pipe is longer and has a jog for the 500/600cc compared to the 250/350cc.



In conclusion I would say the oil pump from the A31/A32, 1934 Y/Y1/Y2, 1935 Comet/Cotswold, or 1926-37 Aero 250/350 would be the same. You could also use the oil pump form a 1936-38 Aero 500/600cc, but would have to eliminate the locating pegs and notch the base slightly to clear the timing chest joint face.

-Doug

Offline Keith

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Re: 1932 A32 350 oil pump failure
« Reply #4 on: 18 Jun 2021 at 23:13 »

An excellent resource Doug - thanks for taking the time to do this.
Filed with the many other info posts from this great site.  :D

Keith...

Offline woodsy

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Re: 1932 A32 350 oil pump failure
« Reply #5 on: 19 Jun 2021 at 00:13 »
My thanks too doug , all i need do now is find one of these ellusive little devils

cheers , ken

Offline Hamwic

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Re: 1932 A32 350 oil pump failure
« Reply #6 on: 19 Jun 2021 at 13:38 »
This is a cover from a K32, flea bay. St Helier, Isle of Jersey, UK, at the moment.
Oil pump appears to be all there, but the feed pipe has been broken off. They've had it a while, but might be of interest?
https://www.ebay.co.uk/itm/163919221903

Cheers for now
Doug