Basic Metalurgy

[hanleyclifford]

Originally Posted by thatch

In order to keep this thread spinning out of control I'll throw another little thought into the mix. During my current A4 rebuild on my spare motor and on other engines where strength is not an issue I use brass. In the case of the A4, the brass will be studs locktighted (red) into the block and I will use brass washers and nuts to hold the parts in place. The 3 particular parts that will get this treatment are the transmission cover, the block side cover(water) and the 2 carburator mounting studs. Brass seems to about the least offensive of the non corrosive type of metals, and dosen't gall. The use of studs does a couple of things that I like, they save wear and tear on the threads in the block or manifold and and I find it easier to line up the parts for reassembly. Red locktite holds better in these cases like these and a little heat will loosten them up if you have to remove them. Any thoughts?
Tom

Tom, You did not specify which type of "brass" - various types are all over the galvanic series chart. Regards, Hanley

[thatch]

hanleyclifford,
In my copy of "Thomas J. Glover's Pocket Reference" book the brasses (Cu+Zn) fall in about the middle of the page, with Platinum being at the top and Magnesium and Magnesium alloys being at the bottom. If I were to ask the fellow at my local metal supply house what "kind of brass" all-thread he carried, I'm pretty sure he would just stare at me or use some foul words while telling me to leave. In short, I don't know, but since I have yet to see an "over the counter" brass nut or bolt that has caused a problem then I won't worry about it's content.
Tom
P.S. At about $11.00 I highly recommend "Glover's Pocket Ref." book; it is absolutely facinating!

[67c&ccorv]

Originally Posted by thatch

In order to keep this thread spinning out of control I'll throw another little thought into the mix. During my current A4 rebuild on my spare motor and on other engines where strength is not an issue I use brass. In the case of the A4, the brass will be studs locktighted (red) into the block and I will use brass washers and nuts to hold the parts in place. The 3 particular parts that will get this treatment are the transmission cover, the block side cover(water) and the 2 carburator mounting studs. Brass seems to about the least offensive of the non corrosive type of metals, and dosen't gall. The use of studs does a couple of things that I like, they save wear and tear on the threads in the block or manifold and and I find it easier to line up the parts for reassembly. Red locktite holds better in these cases like these and a little heat will loosten them up if you have to remove them. Any thoughts?
Tom

There is some pretty crumbly brass out there - why not bronze (which, to add to the confusion comes in a number of different compositions).

[hanleyclifford]

67c&ccorv - Good question. Bronze is much more durable than brass and generally stronger in tension. But before we forget, the issue of the galvanic cell does not arise unless an electrolyte is present. The use of brass on a transmission cover is no problem, nor bronze; on one of my engines I have bronze "wingbolts" for quick access (and a touch of vanity). Same with the carb studs; in fact I would prefer bronze over brass in this location. The mixing of dissimilar metals in the A4 is well established. Consider the oil pump - cast iron, pickup screen - some sort of bronze, the screen frame - aluminum or some sort of "white metal". Now Tom's plan to use brass in the water jacket is a little disturbing because the brass will steal electrons from the casting if an electrolyte is present, not at the ferocious rate of bronze or stainless, but enough to be noticeable to the threads. Why not go with the cadmium plated stuff here too? I'm sure our new colleague, Felicity rebuild must think we are totally wrapped around the axle on details. So be it: I like to think of it as collective advancement of the technology.

[FelicityRebuild]

While I do think we're overthinking the problem a bit, I'm loving the controversy I've sparked. I do appreciate all the opinions. I'll probably go with the cad 5 provided I can find it easily and with minimal expense. I need top keep reminding myself that this isn't the warp drive on a starship. I'm just trying to turn my propeller for another 10 years.

[67c&ccorv]

Originally Posted by FelicityRebuild

While I do think we're overthinking the problem a bit, I'm loving the controversy I've sparked. I do appreciate all the opinions. I'll probably go with the cad 5 provided I can find it easily and with minimal expense. I need top keep reminding myself that this isn't the warp drive on a starship. I'm just trying to turn my propeller for another 10 years.

No, it's not the Starship Enterprise but we are, Atomic 4 owners and enthusiasts...some of us sailing and motoring along in vessals built when our dad's were young.

"Second star to the right, then straight on 'till morning."

[thatch]

Felicity,
This may seem like a party that you wish you hadn't accepted the invitation to but, I believe we have all benefitted from it. To answer your question about grade 5 cad plated bolts, they are about the most readilly available of the hardened bolt types. Please keep us updated on your progress.
Tom

[FelicityRebuild]

On the contrary Tom, I'm very glad I joined this party. I also feel I've benefitted from the conversation. I like a good debate as something is always learned by everyone involved.

67, I am also an enthusiast. If I weren't I would jump on the Yanmar Diesel bandwagon. My father (who owned Felicity before I did) has been trying to convince me to replace. I was also talking to a friend of mine this morning who bought a boat last summer with one of them in it. When he told me, I had the sudden urge to snear and take a step back. I don't have the heart to replace it. Especially now that I've found a bunch of fellow A-4 nuts (pun intended) who feel that this engine is one of the best ever designed and built. Why replace when we can fix. And now that I'm neck deep in my project, with it currently in pieces in my shed, pistons and valves currently soaking in a bucket of MMO, I'm considering rebuilding these beautiful beasts as a hobby. There seem to be plenty of them around here on Long Island. Yes folks, I'm in love. I told my girlfriend the other day she now has competition.

In any event, I'm loving the debate. Both on this thread and the valve guide thread. I'm taking everyone's advice, throwing it in my blender, applying a bit of knowledge about my own personal situation, and spitting out a result that suits me. I'll certainly let everyone know of my progress and the decisions I make as I go in the hopes that some other newbie will be able to learn from it all.

[sastanley]

FR - I bought my boat from my Dad as well (for lunch!) - He bought the boat new in 1977, and is now retired and living in Florida. He is a minimalist when it comes to maintenance and the boat was in disrepair, but I took ownership anyway.

He told me when we went over the boat during the pass-down that he thought the 'engine was near the end of its life, but it will probably get you in and out of the creek if you baby it'. I had it running 9 hours straight on a no wind day @ 2,050 RPM last summer..that doesn't seem 'near the end of its life' to me...mine's just needed some TLC.

All the credit goes to Moyer, Inc. and this group..the best thing my Dad ever did was have a Moyer A-4 manual on board when he handed me the boat papers.