Topic: welded valve cover information request

[fang]

Hello all.  I am building another CB750/900cc engine (#3), (and soon will be building #4, which is mostly machined and ready for assembly...) and have been thinking about installing a welded valve cover.  I personally have never handled nor possessed one.  In spite of this it seems like a reasonably good idea, and am considering making one for this engine.  Plus they just look 'trick'!

Does anyone out there have a "pattern" for welding/drilling or any recommendations for this hopeful builder?

Cycle-X has a few on eBay right now, but I have so many spare valve covers just sitting around that there is no reason to spend money on one....

Here are the pics of the current Cycle-X ones:

This one appears to have aluminum nuts welded to the valve cover.  If this is the case, I would imagine it was made by first grinding four flat spots on the valve cover, then the holes were pre-drilled, and then the nuts were welded in place over the holes on the flat sections.....  At least, that's how I would do it.  The seller claims to have a black chrome finish (which maybe does not look so good in some areas -- maybe it was "black chrome" powder coated?).



This one appears to simply have had four big globules of weld built up in the approximately correct place for the four locations, then they were ground flat, drilled, and tapped.

I personally prefer the idea of welding in aluminum nuts, if I can pull it off.....

Any thoughts, ideas, suggestions, etc?


Peace and grease,
Steve

 

[Don R]

The welding is not as easy as you'd think, but there are people really good at it. Not me.

[Jim F]

Although the aluminum nuts would look nice, I don't think you would get the strength that your looking for
I am more practical than making something look good so the "Glob welding" and a little hand work would work for me
I have done a lot of welding on cast aluminum and its always a gamble on whats going to happen.
If I can help you can call me at 770-367-7320

good luck
Jim
www.jmfmicroweld.com

[markb]

I must be missing something.  Why is this a good idea?
Mark

[CPHjimm]

Mark @ M3Racing.com provides the service as well. from what I can see on the photos it looks like the studs was welded in and then the threads and surface was done afterwards.

this was the way I would do it as the heat from the welding can easialy f%¤# up the threads.

As Jim says, cast alu can be tricky!!!

If you find a patteren please share as I would like to do this mod myself.

/J

[754]

 The pattern is there on your valve towers, locate dril, instal cover ..drill.. move to the next one.

 I would make flanges bushings, easier to weld and more thread than a nut.
 If need be I could make some..

[MCRider]

I must be missing something.  Why is this a good idea?
Mark

A few schools of thought on this. RC Engineering pushed it back in the day. Action4s, and all the CA based speed shops were doing it. When one uses a big bump cam at high RPM, the towers will flex. Besides losing power, you can lose oil pressure under the towers at the small ORings, and increase wear on the valve train.

By using a reinforced rocker box, you thread those screws down to where they contact the spots on the towers that look like they were made for it. Essentially the four outer corners of each tower, this holds them in place, eliminating flex. Use a nominal amount of torque, like 5 ft/lbs, is all that's needed.

But the other school says they are not needed with modern cam profiles and springs that are less abusive. I am using a putz cam and am using the cover only because it takes me back and I love the way it looks. Mean.

Here's a picture of mine.



It is the welded in bushing variety. Made by Les barker, Vancouver WA, Little Engine Service; http://vintageadvantagemotorcycles.com/default_010.htm

While we're at it, Rob at Voxonda (forum member) told me he could make them.

[markb]

Interesting.  Makes sense to me now.  Thanks for the reply.
Mark

[nippon]

Here you can find some pics how we made them:
http://www.classiccyclecity.com/gallery/thumbnails.php?album=44

And here is a pic of the valve cover sitting on the cylinder head.
http://forums.sohc4.net/index.php?topic=93486.25


nippon

[MCRider]

Nippon: past tense "made them"? No more?

That is really nice work.

[nippon]

Not yet, too many other things to do.
Probably any time again.

nippon

[fang]

Thanks Guys for the feedback, Especially MCrider and Nippon for the links and pics.  Jim too for the offer of assistance.

I like the idea of welding in a larger, pre-drilled, but not yet threaded aluminum bushing.  Nippon's cover is a work of art; it is amazingly well done.

Nippon, Thank you for the links.  I ended up browsing through all the welded valve cover pics as well as most of your Seeley build pictures.  I appreciate your many wonderful pictures of a beautiful and meticulous build.  Truly fantastic!
(http://www.classiccyclecity.com/gallery/thumbnails.php?album=52)

I guess one of the unspoken questions was about the clearance from the inside of the valve cover to the cam towers.  I appreciated seeing that one picture of the inside of Nippons' welded cover. 

After your feedback I now have a little more to think about.

Thanks again for your input!
Steve

[754]

 A few more things, I have not done these, just saying..
 A fter drilling lightly spotface the outside part of the hole.. this orients the bushing perpendicular to the  surface the bolt contacts.. tack a few spots then weld around.
 Drill and tap first, its likely you will be using a hard grade like 6061. This will tap EASIER in hard than annealed condition, after welding it will be annealed. Welding around it will tend to Shrink the threads.. a light pass with the tap will clean up any shrinkage..
 Hope that helps..

[fang]

Good feedback 754.  I personally can't weld this old cast aluminum, so I will be prepping it all and bribing a skilled welding buddy with beers.  But I can drill, tap and machine up all the other stuff. 

If I fail so much that I loose two covers, then I will consider just buying one.  Maybe.

Peace and grease,
Steve