SDP restoration

[xtaffy2]

Here's one i did earlier.
Took about 2 mins to do, brushed on the cleaner left 1min with a bit of agitaion with a baint brush, then a few quick rubs with a green scouring pad and wash off.
Sorry for the shadows this was due to the SUN shine, i know you boys up north see so little of it you might have forgotten what it was.

[Oyster 49]

Impressive! That looks like a useful product

I'll try and get some...and then report back.

[woodbutchergraham]

Try MR Muscle oven cleaner, works for me. Spray on leave for ten mins use an old tooth brush to get in all the awkward places, cleans degreases it will work great on those crank case castings.
Oh and thanks for the sunshine i had forgotten what it looked like!

[Oyster 49]

I finally got a good result using alloy wheel cleaner which I noticed is phosphoric acid based. It needed a couple of minutes with a stiff brush the remove most of the corrosion, followed by a quick going over with a wire brush in the bench drill. Finally a run with wire wool dipped in metal polish, which tends to give a dull shine, which I prefer. Cylinder is now ready to go back on also

The alloy wheel cleaner leaves a slightly "etched" finish.

Upon putting the crankcase halves back together the crank is now slightly tight. Looks like I will have to strip it back down and fettle something. It was not like that prior to seperating the case halves! Baffling. All I have done is seperate the cases and clean them.

[Charles uk]

As SD's have no locating dowel tubes in the crankcase, I would recommend the following, before the piston it fitted to the rod, fasten the crankcase to the cylinder using no gasket & with all the crankcase bolts lose but almost tight, tighten the top 2 crankcase/ cylinder nuts tight, then the 5 crankcase bolts in sequence with the 2 lower crank/cylinder nuts, now check for tight spots.

If it's tight & you haven't swopped any of the crankcase halves clock the crank between centers, or insert the crank between the crankcase halves hold them firmly togther, then rotate the crank, if the 2 halves move against each other there is a strong possibility that you've bent the crank.

All of the Seagull production from 1931 to 1950 ish were not fitted with these dowel tubes, I use a ground flat steel plate with a hole for the rod for aligning the crankcase halves.

[Oyster 49]

Thanks for the guidance Charles, I stripped crankcases down and rechecked everything. Just the slightest of witness marks on one side of the crank. Out comes the wet & dry... Now better, but will take apart again and further check.

[Oyster 49]

I'm getting it all back together now After a final fettle the crank is spinning smothly and the cylinder is on.Both the crank, tiller stub and spark plug threads recut.

The flywheel has some quite deep corrosion pitting, possibly about 50% of the depth of the alluminium at one point. Shame as the rest of the flywheel is good, and there are not many of these early flat top flywheels about. I have a later (early AD) one with the radius on the corner, in good condition which I could use instead. Will think about it.

[Oyster 49]

While I leave the tank for a while to let the paint harden, I'm now perusing what decal this engine would have had on the tank. Given the fact that this engine is very late in the SD run, circa 1946, could this one have had the white seagull decal as fitted to post war 102s? I happen to have one of those from John.

Any thoughts as to when the decal changed from the all gold to the white flying seagull? Has anybody got any photographs of original decals?

[Charles uk]

I doubt that any of the wartime SD production carried a British Seagull logo, why would you make it look pretty & shiney?

They didn't even want to spend enough money to modify the rope sheave pattern to read British Seagull instead of Villiers so marketing didn't seem high on their list of priorities.

[Oyster 49]

This engine had the remains of a decal on a original SD steel tank, there are also pictures of other tanks with the original decal, so some engines must have had decals.

So what photographs have we got of an original SD tank with a decal? Has anybody got a late engine number SD (11000 or later) with what looks like a decal that could be original?

I'm wondering if later engines had the white bird decal fitted in the early post war period when the model D and C appeared. Did the SD and D and C engines overlap?

Lets see yer tanks!

Incidently this engine also has an early flat top magneto that says "british Seagull" instead of "Villiers Magneto" It's making me think that there could possibly have been a "transitional" SD? Charles S has an engine with a flat top magneto that came with some history that it had come straight from an army camp in Scotland and had not been touched?

[NeilF]

The flywheel has some quite deep corrosion pitting, possibly about 50% of the depth of the alluminium at one point. Shame as the rest of the flywheel is good, and there are not many of these early flat top flywheels about. I have a later (early AD) one with the radius on the corner, in good condition which I could use instead. Will think about it.

What would be the chances of filling the pits with HTS2000 aluminium - rather like lead-loading? Heat it up, tin it and build it up and then run a belt sander over it, or better still, put it on a lathe?

I used HT2000 to built up the crankcase such that the magneto plate was a tight fit. Your pits are another ballgame, but the principle is similar?

[charlesp]

It's Charles P (me) that has a late SD. It was fitted with a brass tank with a decal, sadly that was destroyed before I got it but it's the standard decal of the period, the one you refer to as a 'white bird' decal i suspect is the one we associate with FVs. It has the Jubilee clips, too.

I really don't know about what happened late in the run of SDs, I don't think anyone does for certain. I don't know if the last of the batch was flat topped, if originally fitted with a brass tank, or if they were produced in concurrently with D and C models. But I do know that the provenance of mine suggests it may have been original - no stronger than that. It has a chromed leg and silencer, too.

The Last SDs were made in 1946, that's when the C and D models appeared, more than that I don't know.

I'm a heretic in the matter of decals - I'm the one who isn't convinced that there ever was a post war all gold version, I think they all had the shaded white, but I'm happy to be proved wrong.

The small white bird I associate with the FVs is this one:

That appeared in the late forties. Remember the prototype FV with the earlier decal? - well that helps to pin down the appearance of this one to 1948/49. So no SDs with that one.

The problem with all this is that the production records - each motor itemised with serial, order details, despatch details - were all destroyed decades ago as part of a 'get rid of the old ways' project. Each entry bore details of modifications made later, repairs and refurbishments. It would be gold dust today but sadly it's long gone.

Of course it's quite possible that the production of SDs didn't finish with the end of the Ministry order, perhaps B.S. continued with a few for public sale, but with refinements, and maybe thy didn't see fit to give them a new model designation. There's precedent for the company making changes without changing the serial letters.

Regarding the filling of pits with HTS 2000 - I wouldn't want to try dismantling a flywheel in order to do the job, and I wouldn't want to be using all that heat so close to the magnets. Anyway I reckon the filled bits would be an obviously different colour...

[Oyster 49]

All interesting stuff Charles. Interestingly D510 (I think) was sold on ebay a few weeks back, not far from me. That would be circa 1946 and it was supposidly in original condition and had a brass tank with the white bird decal. Wish I had gone to view it now

As you say we will never know unless people share lots of information and photos of engines suspected of being original.

Personally I have a theory that in 1946 seagull were moving from ministry contract to civilian sales again, hence the later SD having some parts identical to the newly arriving D and C models, as stocks of the "SD" parts such as magnetos and steel tanks were used up.

[charlesp]

Which 'white bird' decal did it have? - is it the one I have shown above?

[Oyster 49]

Charles it had the larger white seagull decal, like the one John has. Not the smaller one applied to little forty models. I have one of the larger ones from John myself which I might use on this engine.

Perhaps somebody on the forum bought this engine? Model D number was D510 (I think) It was located at Belper, Derbyshire. Sold a few weeks ago.