Restoration of Sandcast #97

[markb]

I'm getting close to making a decision on my oil filter housing problem.  I started a separate thread to continue the discussion.
Thanks,
Mark
http://cb750sandcastonly.com/smf_forum/index.php?topic=480.0

[markb]

It’s been a busy week for me (too busy with everything but motorcycle stuff) so time for an update.  I’ve decided I’m going to have the oil filter housing surface machined off until it just cleans up.  One of the guys in the shop is going to help me tomorrow.  We had to wait until the mill opened up.  I’ll report back when it’s done.

In the meantime I’ve been spending a few minutes here and there on other stuff.  I’ve been trying to get the flat head screws out that hold on the exhaust flanges.  It’s taken many soak/heat cycles and an impact driver to get out seven of them.  The last one finally stripped out the cross.  So I drilled the head off and tried to work it out with a center punch on the outside edge of the screw.  It moved out about 1 thread and then didn’t want to go anymore.


So, I’ve heard of this trick but never tried it, I decided to weld a nut on the end of the screw.


I waited until cooled from red to grey, and while it was still hot, grabbed it with a pair of pliers and it turned out so easy.  Sweet!  Sometimes I wonder why I don’t just do the last thing first.

[markb]

I finally tackled the repair of the mating surface for the oil filter housing.  I enlisted the help of one of the machinists in our shop.  The best part about it is I know he’s good and I can “stay in control” rather than just sending it out somewhere.  After much debate (mostly in my own head) I decided to machine the surface to just cleanup the pitting.  That way I eliminate any concerns about what might happen with welding.  I also figured that if it was welded it would be best to machine the whole surface anyway to make sure it’s flat so might as well skip the welding.  I examined everything carefully first.  The only issue I saw with this solution was that the locating tab on a finned housing might get a little too close to the case.  Since this engine at worst will at least have a replica smooth housing it’s not a concern.  I mention this as a heads-up in case someone else wants to try this at home.  Here’s a shot of what I’m talking about.


Before starting I stuffed a chunk of a shop rag in the center hole and put a rubber stopper in the other hole to prevent metal shavings from getting into the oil holes.


Here’s a shot of it on the mill.  The case is bolted to a piece of ground aluminum tooling plate which is held in a vice which is mounted to a sine plate.


Here’s another view.  The mounting surface was indicated in to less than 0.001” (0.025mm).  We took off about .005” (.125mm) at a time to sneak up on it.  It took .030” (0.75mm) to get it although 0.025 might have been enough.  There’s a couple of small pits near the edge of the surface only.


We also machined the same amount of the center post just to make sure that all the internal relationships between the filter and spring and seals, etc., remained the same.  Start to finish was about 2 ½ hours.


Here’s the finished product.  I put a housing on and snugged it up and turned it to make a mark from the o-ring.  It’s hard to see but the o-ring contacts flat surface all around.  It will not leak.  Better yet, I scored on a smooth filter housing (99% sure it’s real, I’ll post some pics) and now I know I have a perfectly flat surface to mount it to.  It’s good to have this task done.

[markb]

Here are some pics of the oil filter housing.  I’ve never actually seen one in person but I’m pretty sure it’s the real deal.  There are no reinforcing ribs on the inside and the surface definitely appears to have a cast finish.


The outside has imperfections but I don’t think it’s road blast because it’s uniform all around the outside.


The front face definitely has road blast but I think it should clean up.


Is this the real deal?  If it is my list of needed correct parts is getting shorter.  Am I correct that the smooth housings were polished like the engine covers and not painted?  Any tips for restoring?
Thanks for any input.

[hondasan]

Nice find, and sure sounds like its an original. Pictures follow of the bowl from #302, prior to re-finishing.
It had remnants of clear coat, over a similar polished appearance to that of the other engine side covers.

Cheers - Chris R.

[markb]

I forgot to mention something I did this past week.  I was looking at my crankshaft main and rod bearings and decided they have to be replaced.  I don’t know why I was even considering reusing them.  I looked on the crank in the usual place for markings and everywhere else for that matter.  Nothing.  Maybe it’s because of the age?


Couldn’t find any markings on the rods either, except for a “2” scribed on one of them.  That, along with the journal on the rotor end of the crank (mentioned in earlier post) convinced me to send the crank out.  I need one more opinion on that.  I talked to APE and they’re going to check out the journal and repair if necessary.  While they have it they will measure everything for me and install the rods.  I mic’d the journals and my crank code should be JL-CBBBC PL-5555.  The case was stamped AABAA so selecting bearings for the crank shouldn’t be a problem.  I found it interesting that the main bearings should be green, yellow, yellow, yellow, green.  Yellows, being the thinnest bearing, would indicate to me that there wasn’t excess wear on the journals.  We’ll see how close I was when I get the crank back.

[kp]

That's an absolutely excellent outcome and I for one, am happy you went this way. That looks a great job Mark, well done.  KP

[markb]

Thanks, KP.  And thanks to you and everyone else for the excellent input.  I'm very pleased with the results.
Mark

[Riccardo]

Mark,
compliments.

Great work on the bottom case.

[cb7504]

Mark:
       Excellent results, nice head work on getting the case oil filter mating surface refinished, nice positive machine work. Marty K.

[markb]

So Wayne was asking me about the front oil gallery plug on the upper case.  I was thinking that the ultrasonic cleaning would make sure that it was clean behind there but…I kept thinking about it.  So I had to get it out to find out.  Saturday I squirted it a couple of times with Aero Kroil.  Sunday I got out the torch and heated all around the plug for a couple minutes, put a fairly heavy, slotted screwdriver on it and it came right out.  If that didn’t do it I was going try heating it again and go outside and grab an icicle to cool off the plug quick.  No damage to the plug either.  I tried to get a shot that would show the inside of the hole but no luck.  I almost expected a bunch of gunk on the end of the plug but was it was clean.  I doubt you’d find a case much dirtier than this one or one that should be stuck more than this one.  I had to know if the plug would come out and I had to know if the ultrasonic cleaning worked.   Now I know.  Thanks, Wayne.

[Wayne]

Great stuff Mark! I'll be pulling mine for inspection and final cleaning for sure. I ordered a new plug as I want a nice new one in there after I repaint the cases etc.

[markb]

I’d posted this in a separate thread but I’m still trying to figure out what the holes do in this picture of the clutch area of the lower case from E100.


Here’s a shot from the bottom.


But the bigger question is, why doesn’t the vertical hole go all the way through on my later sandcast engine E5491 shown here?

[Wayne]

Mark
Engine 748 has the same deal with the sealer shown in your 3rd pic.

[markb]

Mark
Engine 748 has the same deal with the sealer shown in your 3rd pic.

It's harder to see but it's on the center pic too.  But, is the hole drilled through or not on 748?