Author Topic: Rocker cover defects - can these be fixed with welding?  (Read 2669 times)

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Offline graham-xrfx

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Hi Douglas folk
After I removed old paint from a Douglas rocker cover, I thought I could see light through one of the casting pits. I deliberatly stabbed it with a small screwdriver, and it went right through!

I buffed it up anyway, and the picture shows what we end up with.
I don't know anything about TIG / MIG welding, but my question is - is this the sort of thing that can be fixed with a couple of aluminium patches welded in?

Any advice appreciated. Many thanks..
Graham

Online Doug

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Re: Rocker cover defects - can these be fixed with welding?
« Reply #1 on: 06 Dec 2015 at 03:34 »
Graham,

Some of the Douglas aluminum can be quite miserable to weld, but by postwar the alloy was reasonably free from floor sweepings! I have seen rocker covers welded before, and I had to add a daub to mine around the retaining bolt to repair a crack. You make have to re-flatten the joint surface, as welding may introduce a little bit of distortion.

The main problem will be matching the 'hue' of the casting with the alloy of the patch and the filler material. Perhaps try a bead of weld on the proposed patch material, buff it flat, and compare to the polished rocker cover before committing. But I do not think you will have any problem with the welding itself. The more you weld on it the more it will distort, so perhaps just weld the outside surface. It is not all that critical; it just keeps most of the oil mist in, and the road crud out. It does not matter how ugly the inside is as only the rocker arms will know!

-Doug

Offline graham-xrfx

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Re: Rocker cover defects - can these be fixed with welding?
« Reply #2 on: 06 Dec 2015 at 08:59 »
Hi Doug
Thanks much for the reply.
A mis-matched colour showing a well made repair would maybe not be something to be ashamed of.
I had considered cutting out the two marked areas, and setting aluminium patches in place, held with a epoxy-glass cloth from the rear.
This method would show thin filler outlines on the outside, and might be taking the "show the scars proudly" philosopy a bit too far!

Of course, the fix of choice would be to weld it, so I had to ask.
Regards
Graham

Offline David Lawrence

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Re: Rocker cover defects - can these be fixed with welding?
« Reply #3 on: 06 Dec 2015 at 16:29 »
Hi Grahame,
Before you get too embroiled, I may have a new old stock pair of rocker covers, I would need to dig them out of the garage to be certain that they are a match for your engine, some early rocker covers were a different pattern even some with "DOUGLAS" set in a rectangle but proud of the casting. (I am sure you are aware that all motors after the generator and Mk 1 were a totally different pattern.)
If you are interested please email me via the email ikon below my avatar.
The price can be fairly reasonable!!
Dave

 

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