Here we go! Restoring 576/748

[Steve Swan]

Chris or Marty would have a better idea than me.  I'm sure the marks had something to do with the set up of the camshaft holder caps.  The caps are matched with stampings to their respective towers.

[kp]

Has anyone spotted something different here. Now fellas this is important and it relates to the underside of the cam cover. We saw the cam cover from Mark's engine and it's something I've never seen, now we have Wayne's cam cover which looks similar to most others. Well I have 2 covers (later) that are different again. I'll post photos of these on the weekend.
The point is that posting of these pictures by Wayne and Mark is revealing some significant finds for us and is giving us insights to changes that we may never have been aware of.
Fellow sandcast owners, If you can access your cam covers for diecast as well as sandcast PLEASE take a picture of the underside and either post them here or send to Steve or myself as this is of interest to us.
The second item of interest relates to the camshaft holders. Have a look at the holder Mark has pictured and then look at the holder Wayne has pictured. They are a different casting. Note the flat top section of Mark's and the rounded top section of Wayne's. Really interesting.
That makes 90 differences I believe.  KP

[Wayne]

Here's a closer shot of what I believe KP is talking about:

No I didn't put what looks like a felt marker strike on the holder )

[Wayne]

When I picked the bike up at noted that the head had been hit on the right rear corner cracking the cooling fin. I checked it and it seemed solid so I left it during transport with intentions of repairing it when I got the head off.



When I got my engine on the bench I noticed that the piece had now fallen out! I have no idea when or where. A good look around my garage revealed nothing.

If anyone has a salvage head laying around I could use a section to do a little grafting. Much appreciated. Here's the chipped fin.

[Steve Swan]

Let me jsut say I've had GREAT results straightenng really bent fins using MAP gas bottle on a propane torch head and a wide/square nosed set of pliers.  When the fin gets to working temp, can feel the metal move through the plier handles.  When moving the heated aluminum, feels like stiff butter.

As far as welding a later fin to an earlier fin, be sure you have a welder who has experience working with this older metal.  Even the metal in a later fin heats and reacts differently than a earlier head/fin.  Not particularly tricky as long as the welder knows the charactersitics of the metal he is working with.

[ashimotok0]

I can chop some pieces off some scrap F1 barrels if you like but obviously I am in the UK so postage may be a bit steep. I could send 50 gramme package for 1.98 GBP though, which is reasonable. Or perhaps a USA member may be able to chip in. I also have scrap K7 barrels. Which will fit? Any suggestions? ChrisR?

Best regards

Ashimoto

[Wayne]

Steve is it anything like welding old British cases/heads? The guy I use welded cases and a head on an old T120 Triumph for me. He actually took a piece of crankcase from another bike and welded it into my case. Also did some chips in the head cooling fins. All turned out well.

[Steve Swan]

Wayne, i'm sure it's the same issues, different content of elements making up the aluminum mixture as well as purity, although one would not think there would be that much difference in metallurgy between heads used on the same model/mfgr motorcycle in a short span of years.

i'd take Ash up on his offer !

[Wayne]

I can chop some pieces off some scrap F1 barrels if you like but obviously I am in the UK so postage may be a bit steep. I could send 50 gramme package for 1.98 GBP though, which is reasonable. Or perhaps a USA member may be able to chip in. I also have scrap K7 barrels. Which will fit? Any suggestions? ChrisR?

Best regards

Ashimoto

Ash, just let me know how much you want total and your preferred payment method. I'll message you my shipping information. Thanks!

[ashimotok0]

Just realized Wayne it's your head with the broken fin and I have barrels but I just chopped a piece off and compared with my 10/69 head fins and I reckon you could 'graft' a barrel piece on and reshape (see pic)

I packed the piece in the pic in a 'mail Lite' packet and it weighs 10g total so you could have a couple of bits for 1.82 GBP postage !! if it is too small let me know and I will see if I can get a bigger bit.

Let me know if you want it and i will post off tomorrow. You can refund the postage later by PayPal - no rush at all. obviously I need your address

Cheers

Ash

[Wayne]

Ash
Sent you a message. (look in the "MY MESSAGES" button in the top menu) I think the piece will work fine. Include your PayPal address in your response. Thanks!

[ashimotok0]

Got PayPal shipping payment Wayne for fins, so sending off today ( I chopped off a second and slightly larger piece too so you have two to 'play' with. Plus I have included 2 off 46 ID x 2mm section VITON 'O' rings for your oil pump which Honda do not list anymore as an obtainable part ( gave a few to ChrisR too). Same goes for you Mark if you need a couple. If you don't need 'em Wayne just pass them on to another member.

Cheers

Ash

[Wayne]

Thank you Ash. Your assistance is very much appreciated. 

[kp]

Wayne, At the risk of being howled down, I would like to add some input to your experience. Having had need to repair many many many many broken fins over the years, oils aint oils. The sandcast engines and this is all of them including heads and cylinders were cast using the sand-casting process (thats a revelation ) either permanent mold or green sand. It doesn't really matter as the issue is about the alloy used in the process. Some alloys whether sand or die cast show similar properties in their use and in some cases (not very common though) can be used in all molding techniques. In relation to heads, there are 2 very different casting methods and all later heads were die-cast. The alloy used was very different from that used in the sand-cast heads. Sandcast heads are made from nearly pure alloy and are a welders dream. Many diecast alloys are weldable but require specialised techniques and specific rods and equipment to weld. Welding a diecast fin with a specialised rod and tig welder is a piece of cake but only because of the equipment and rod used. The same rod used in welding a sandcast head won't have much success with a diecast job and vice versa. I'm neither a professional welder or a metallurgist but I've had advice from both over the years and had both welded. Some diecast pieces I'v had welded were total disasters not because of the welder or the equipment but because of the composition. Try welding a sprocket cover and you will experience for yourself.
I would suggest that welding a diecast fin to a sandcast head is not an ideal fix. The method I use is to have a good welding shop (a boat shop has a cue on good alloy welders) weld up the fin which is easily shaped back to original using a fine tooth file. You would be hard pressed to pick the fix at 12 inches let alone 3 feet. This head of mine pictured had the top fins repaired by the method just outlined and I doubt you could find the fin area repaired. With paint it will never be picked
Just my thoughts

[Wayne]

KP I respect your input totally. I would not even take this head to a welder until I have seen the input from others (the experienced) on this board. To be honest, it will probably drive me crazy knowing the fin is repaired. That's just the way I am. I would much rather drop a "perfect" casting on my project and sell mine.