1933 Harley-Davidson VL Build: Preparing the Cases

[BoschZEV]

I wanted to ask if anyone has thoughts/experiences soaking cases in acetone (to remove any remaining oil residue)?

I'm in the middle of restoring an aluminum BSA head, which will require me to TIG weld some broken fins, and just this past week I started the cleaning process. Although oil passes through the valve areas of the head, it doesn't sit in a pool for years at a time as it might in a gearbox or set of engine cases. So, the amount of oil trapped in cracks and pores should be relatively little. Anyway, I wiped away all the obvious oil using rags, then let the head simmer on the barbeque for four hours at a gentle boil in a mixture of Dawn detergent and water, after which I left it to soak overnight before removing it. The water was pretty dirty, as would be expected, however the head looked quite clean.

Unfortunately, cleaning the head revealed that it had been painted black as some point in its life, with paint residue inaccessible between the fins. So, I then soaked it for an hour in a witches brew of MEK and trichloroethylene. There was still paint left in places after even that so I'm not done yet. But, after the solvents had evaporated from the pan the next day they had left behind a small puddle of oil (along with lots of paint residue) showing that cleaning all the oil out of even an item like this isn't easy.

The reason I used MEK and trich. instead of acetone is they are more effective degreasing solvents. However, they also are a lot more hazardous to your health. But, even with acetone, definitely do it outside and downwind from the house, not in the garage.

I could have set up a vapor degreasing operation for this. The advantage of vapor degreasing over immersing something in a pan of solvent as I did is the solvent is continuously distilled. Relatively pure solvent from a hot tank rises up, condenses on the colder part, dissolves some of the oil, and both drip back into the tank where the solvent is again distilled. This is essential for cleaning of semiconductor substrates, but is of relatively negligible advantage if the part you put in the solvent already is reasonably clean (say, after having been cleaned in detergent and rinsed).

As for baking, don't expect it to do much. The trapped oil will become less viscous at the elevated temperature and thus some of it will ooze out of pores by capillary action, but most of it will be left behind.

[wideglide38]

Sirhr,

Thank you for the info & feedback. I will definitely research IMPCO and back search the threads. I am familiar with Glyptal as my former employer used it in their electrical & electronics manufacturing processes. Though I've seen several painted cases I've had no further contact to see if there were service issues. However, I certainly do want gummed up works!

Ride safe,
William

[sirhrmechanic]

http://www.antiquemotorcycle.org/bbo...hlight=glyptal

William:

The above thread has a bunch of information on case cleaning and preparation. If you do a search on the word Glyptal, you actually get to a number of threads on aluminum case prep, cleaning and glyptal. Much more than I can re-type here easily.

The net is that Glyptal is good if you can get the cases perfectly clean and oil free. And you have to bake it (back to that indoor oven again.) Something to consider is vacuum impregnation. Not expensive for a pair of MC cases. Again, the process is described in at least one of the threads. The company Impco in Providence, RI does it and several folks here have used their services. The VI will completely seal the case without the risk of Glyptal peeling and gumming up the works, which can happen.

Mostly these days, I just use Glyptal for electrical work... covering coil windings, etc. I rarely use it in areas that will contact oil unless it is a new-production part. Even then, I prefer VI.

Cheers,

Sirhr

[wideglide38]

I read this thread with great interest. Since having just blasted my VL trans case. I've ordered some Glyptal to seal what I can't clean away. I wanted to ask if anyone has thoughts/experiences soaking cases in acetone (to remove any remaining oil residue)? I am having the case adjuster repaired (Tig welded) and wanted to remove as much oil residue before welding. Any negative side affects from the acetone? Pros or Cons? Thoughts? I can can bake the case; but, my only oven is inside the house and I'm sure the family wouldn't appreciate the smell. Though if baking, to what temp (assuming between 300-400 degs.) and how long? I lost my baking instructions! And don't forget the drip pan.

Thanks,
William

[billpedalino]

Amen to that brother.....

[BoschZEV]

This is going to be a very long thread if we comment this much on each of his installments!

Getting serious for a moment, one thing most of us probably would like to strive for is to improve restoration practices. We would like for the "quality" of restorations done today to be better than that of ones done 30 years ago. There is a tendency for people to say "that's how I was taught to do it," or "that's how I've always done it." Often they are right. How they were taught to do something 30 years ago is still the best way to do it, and so it is quite appropriate to pass that knowledge along to others. However, sometimes there is room for improvement.

Whether or not bead blasting cases is good or bad isn't the issue. We've already written enough on it here for people to decide one way or the other on that specific item. But, in a broader way, progress toward improving long standing rebuilding/restoration practices that might actually need improving comes from reasoned, respectful discussions like we've had here. Even if it does result in a very long thread...

[BigLakeBob]

Sirhr, Now THAT'S funny! Now I can't wait for the second installment from Jim! Dale

This is going to be a very long thread if we comment this much on each of his installments! Bob#6738

[painterdale]

Sirhr, Now THAT'S funny! Now I can't wait for the second installment from Jim! Dale

[sirhrmechanic]

Cheers,

Sirhr

[BoschZEV]

I guess this a point upon which reasonable men will respectfully disagree...

I agree. I mean, I disagree. No, what I mean is, I agree to disagree...

[billpedalino]

I will go with what I know works and what experience has taught me. I know how to properly clean cases when glass beading is indicated and I have not ever experienced the sort term (or long term) failure that Bosch suggests, although I've read some of his other posts and he's obviously very technically astute!. I guess this a point upon which reasonable men will respectfully disagree...

[BoschZEV]

How hard is the carbon formed on the piston on the Scale you mentioned?

Carbon black, the form that is probably closest to what's on a piston, is only ~2.5, i.e. it's softer than the bronze bushings.

I think we are getting too technical here.

Hey, all I can do is point out a problem, explain why it is a problem, and provide references to support what I've written. It's up to each person to decide whether or not to act on that information. It's certainly easier -- at least in the short run -- to ignore it.

[BigLakeBob]

Jim, thanks for the thread and I wish you the best with your journey.

With all the unfiltered air cleaners on the early bikes maybe the Cannonball should start further north, I mean a grain of sand may make it in the carb, past the valve through the rings and destroy the bearings before they make it out of the state. I appreciate what you are saying but maybe a little overboard. I think proper cleaning is the key. Ever put oil in a bike in Florida? Ever take off the oil fill on a tranny in Florida? It is very hard to get rid of all the sand/oil mix around the plug first, so sand is going to get in there, we live in a world of contaminants. How hard is the carbon formed on the piston on the Scale you mentioned? I'm not trying to be facetious but I think we are getting too technical here. Bob #6738

[sirhrmechanic]

And just to throw in my 2 cents of a dollar...

Bead blasting has its plusses and minuses. Plus is it's fast and scours well. Minuses are that it requires scrupulous clean-up. It's not that it should not be used... but it should be, as Toprock says, with caution and diligence. You can get a lot done in a hurry with it. You can also get yourself in trouble...

But the same is true with anything... Torches, hammers, vice-grips and adjustable wrenches are all miracle tools in the right hands and implements of destruction.

Make your choices but do it knowing that there are no shortcuts... fast bead blasting means slow, meticulous cleaning. Slow meticulous cleaning of castings with solvents and Scotchbrite negates some of the challenges of cleaning bead but is slow as hell and bad for my manicure. Glass half full... glass half empty... glass designed 50% too large. Take your pick.

The main thing we should get across is to use your available tools right... and like golf clubs there is one for every possible shot. You can try a 400 yard drive with a putter, but why would you use a putter if you have a 2 wood. (Man, you would think I played golf... I refuse to spend my time hitting a ball in a hole when there are bikes to play with... but it was a great analogy!)

Back to the OP... keep up the great posts on your VL! That's what I'm most interested in.

Cheers,

Sirhr

[harleytoprock]

Glass beading must be done with caution and precautions. First the case must be completly oil free. Threaded holes must be pluged and any oil passages also. Race surfaces must be masked. Then super cleaning must be done after. I bet anyone who has had problems with glass beading didn't start with oil free cases and then just blew some air after beading to remove the dust. A set of freshly glassbeaded panhead heads was brought me to have the seats cut and to assemble. Upon closer inspection I discovered that the oil passages were so packed with oily glass beads, I had to drill them out. After much super cleaning the heads were fine.
Aluminum oxide, course or fine, is really bad because it will imbed into the metal much worse than glass beads. Glass beads are round and should bounce off the surface.