#1
IP: 73.238.247.118
|
|||
|
|||
Heat Exchanger Pencil Lead Fused!
The pencil lead in my MMI Exchanger would not come and broke off
leaving a wire core which broke off when trying to remove rest of zinc I removed rest of zinc using flat screwdrivers to punch thru zinc and ream it mostly free of zinc. then attempted to install new pencil lead, but the bronze threads of the cap peeled off. The paassage appears to have threads blocked with remains of old zinc and possibly flattened from reaming with screwdriver. I bought a 3/8 npt tap from Harbor Freight. I can't use torch due to proximity of Fuel separator. It was also suggested to not use tap as it could cut different threads I bought a steel or cast plumbing plug of proper size as well. Has anyone seen these weird Pencil Leads with a wire core? Suggestions on how to proceed appreciated Art |
#2
IP: 108.31.90.116
|
||||
|
||||
Art,
I had the exact same problem last spring. A zinc with a center wire that came apart. I cleared out the zinc remains, and had to re-tap the hole to get the new zinc in. But I started having overheating problems. Turns out that there was a lot more spent zinc crud still left inside. The only way to properly address it was to remove the end cap and clean out the HX. This is much easier if you can remove the HX from the boat. I pulled both end-caps, and flushed and rodded-out all the tubes. Really wasn't that hard. Replaced the rubber end-seals and rubber washers with new ones, and kept the old ones for emergency spares.
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#3
IP: 107.0.6.150
|
||||
|
||||
What is meant by the term "spent" zinc?
|
#4
IP: 73.238.247.118
|
|||
|
|||
Quote:
Thanks I believe that I may have used a cheaper zinc which had the wire in it the source may have come from a on line discussion . I will only buy zincs from trusted suppliers and test one by cutting it open to make sure no wire. The material the zinc was made of must be quite different than that normally used for Sacrifical Zincs and obviously not appropriate Last edited by ArtJ; 04-24-2016 at 12:16 PM. Reason: Add comment |
#5
IP: 108.31.90.116
|
||||
|
||||
The sacrificial zinc is more electrochemically active than bronze or stainless, so galvanic currents cause it to corrode, protecting the other metals.
The process of corrosion turns zinc into (primarily) zinc hydroxide [Zn(OH)2], which has a low solubility in water. This the grey-white "paste" you see collected at the bottom of the HX.
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 Last edited by edwardc; 04-24-2016 at 12:35 PM. |
#6
IP: 73.238.247.118
|
|||
|
|||
Ed
Zincs normally dissolve, this one didn,t . The material must be different such that Galvanic action deposited it, rather than disintegrated it. Maybe even could deposit itself in the SW pump ?? |
#7
IP: 73.238.247.118
|
|||
|
|||
This may be the source of these zincs
Home > Martyr Anodes 3/8 Dia Pencil Complete MTR-CME0
Martyr Anodes 3/8 Dia Pencil Complete MTR-CME0 Martyr Anodes MTR CME0 Review(s) | Add Your Review Availability: In stock Regular Price: $3.89 Special Price: $2.14 Qty: 0 Add to Cart -OR- Checkout with PayPal Add to WishlistAdd to Compare Quick Overview Martyr |
#8
IP: 73.238.247.118
|
|||
|
|||
Bottom line:
Bottom Line : How do we recognize which type of Zincs are appropriate and which will cause harm??
|
#9
IP: 108.31.90.116
|
||||
|
||||
Don't know. I guess the easy answer is to buy them here!
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#10
IP: 73.238.247.118
|
|||
|
|||
Since these pencil zincs look just like the good ones, they need to be
identified as to source of origin, material composition( why they coat surfaces )so that they can be purged from all A4 stock, otherwise heat exchangers, plumbing and possibly pumps are subject to damage. |
#11
IP: 108.31.90.116
|
||||
|
||||
This all starts to make some sense now.
I change my zinc every spring. Until about 3 years ago, I would go through about half of a (MMI) zinc in a season. The end would be cleanly gone, and there was no internal wire. About that time, I found some inexpensive pencil zincs at a local chandlery and bought a pair. Two years ago, when I removed the zinc, it was almost completely gone, leaving an internal wire exposed. I flushed things out as best as I could and installed a new zinc, but it went in with difficulty, and barely grabbed enough threads to seal. One year ago, when I tried to remove the zinc, the cap twisted off, leaving the wire behind. I managed to grab and extract the wire (does this sound familiar, Art?) but the opening remained completely clogged. I managed to dislodge the crud with a screwdriver, and had to clean out the threads with a tap, but the new (MMI) zinc went in all the way. That's when I started overheating, and had to pull and clean the HX that you saw earlier. By the way, that HX cleaned up perfectly, with no damage or corrosion to the HX. It was just clogged up with a mix of gritty paste. This spring, the zinc came out easily, with about half of the end cleanly gone and no internal wire in evidence! Clearly, these "internal wire" zincs are of some alloy that leaves a much more solid corrosion product behind. I found a little information on "wire" vs "non-wire" types here: http://www.rotometals.com/Pencil-Engine-Zincs-s/46.htm I also found some comparison of Zinc Anodes vs Aluminum anodes here: http://www.performancemetals.com/anodes/AnodeFAQs.shtml The description makes me suspect that the "good" zincs that we want are actually made of aluminum! As for determining if there's a wire inside, the only way I can think of that doesn't involve cutting one in half is to X-Ray it. (not practical unless you happen to be a dentist!) It should be possible to tell Aluminum anodes from Zinc anodes by the weight. The Aluminum ones (actually an Aluminum/Zinc/Indium alloy called Navalloy) should be much lighter: http://www.performancemetals.com/anodes/navalloy.shtml
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
The Following 5 Users Say Thank You to edwardc For This Useful Post: | ||
ArtJ (04-25-2016), Easy Rider (04-25-2016), ndutton (04-25-2016), sastanley (04-25-2016), tac (04-25-2016) |
#12
IP: 73.238.247.118
|
|||
|
|||
Cut 2 open
I just cut the last 3/4 inch off 2 zincs.
Weight was similar One I had and unsure if wire type , one new from WM. Neither had the wire and weighed similar and both stamped Martyr . In the past WM zincs had to be cut to length. Unsure if Martyr also makes wire style as well |
#13
IP: 24.152.132.65
|
||||
|
||||
Have you considered contacting Martyr? If you do, maybe ask them if there is a preferred alloy for boats kept in estuaries (brackish water) where water salinity can vary greatly. Boston Harbor and the Chessy are both estuaries and I would expect the deeper into the bay, the lower the salinity.
From Performance Metals Products: Quote:
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 04-25-2016 at 10:49 AM. |
#14
IP: 73.238.247.118
|
|||
|
|||
Zinc has been used forever in mass and Cape Cod Never had problems
till now. BTW the pencils were not necessarily provided by Marytr SP A good suggestion to call them Re: What's up with Pencils with WIRE core in them Last edited by ArtJ; 04-25-2016 at 02:17 PM. |
#15
IP: 24.152.132.65
|
||||
|
||||
I don't doubt zincs have been used forever but the question is whether an aluminum based anode would be better for your waters. Performance Metals Products suggests it would and who knows, maybe Martyr would agree. Won't know until the question is asked.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#16
IP: 70.192.40.205
|
|||
|
|||
I've been using Camp (a U.S. company) zincs for years, both for propeller shaft and heat exchanger (http://www.campcompany.com/home.php?cat=20). A couple years ago our local supplier stopped carrying Camp ("too expensive") and now carries Canada Metal "Martyr", made in China (http://www.martyranodes.com). They seem fine, so far. The heat exchanger pencil zinc appears to be solid metal, with no wire. The Canada Metal part numbers are the same as the Camp, except they start with CM. So the Camp pencil zinc E-1F (1/2" x 1-1/4") becomes the CME-1F. These dimensions are the O.D. and length of the anode only, not the pipe size of the brass plug.
Note that the pencil's thread and the plug's inside threads are a straight thread, not NPT. The plug's outside thread is NPT to screw into the heat exchanger. Some places sell pencil zincs as one piece (plug and anode pencil), and some sell the pieces separately. I once worked for a boat builder who insisted on buying replacement anode pencils only, because he could save a few dollars per engine. If you're laying up 50 engines every fall, you can save a bit. Here is an example of what's left of a one year old Martyr 1-1/4" x 1/2" heat exchanger pencil zinc (CME-1F). It is shown unscrewed from its brass plug. The whole assembly costs $4.95. The anode itself is $1.99. Last edited by tac; 04-26-2016 at 05:00 AM. |
#17
IP: 73.238.247.118
|
|||
|
|||
The Point
Quote:
material used in the pencils WITH A IDENTIFIED METAL WIRE CORE !! there has been no problem whatsoever with the Zinc based pencils. Nothing to do with brackish water. I have sent a email to Martyr |
#18
IP: 71.178.94.238
|
||||
|
||||
Replace every year? uh-oh!!!
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#19
IP: 24.152.132.65
|
||||
|
||||
Quote:
About brackish estuary water, my point was going forward after this incident wouldn't you want to use anodes that offer the very best protection for the type of water you're in? I know I would.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
The Following 2 Users Say Thank You to ndutton For This Useful Post: | ||
Administrator (04-25-2016), sastanley (04-25-2016) |
#20
IP: 107.0.6.242
|
||||
|
||||
Quote:
|
#21
IP: 108.31.90.116
|
||||
|
||||
I found this source for the Aluminum (Navalloy) pencil anodes:
http://www.go2marine.com/product/198...npt-plugs.html And, just to muddy the waters further, note that it too has the central wire, which they call "Secure Core"! I went to the boat today and pulled out my last spare zinc anode and examined it. It appears that the zinc rod is cut to length during manufacture, and at the right angle you can clearly see the end of the wire core in it! So at least it should be possible to non-destructively determine if a pencil zinc has a wire in it.
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#22
IP: 73.255.216.151
|
||||
|
||||
I had a diver tell me that my shaft zinc was fine and did not need replacement after 5 years in Florida salt water.
When I told him that it was 5 years he asked if I had a zinc in my heat exchanger. I told him yes, and he said that the exchanger zinc was probably eaten away. not sure what to think of that. Last time I had the exchanger out was 2009. The zinc was totally worn away. inside was a deposit on the end of the exchanger, right where the zinc was. It looked like the one pictured. I had used a zinc purchased from WM. |
#23
IP: 107.0.6.150
|
||||
|
||||
It would seem that the "zinc" is already a three way party before it even gets installed - brass, zinc, and whatever the wire is made of. It would also seem the whole group would get eaten by the (copper) exchanger.
|
#24
IP: 24.152.132.65
|
||||
|
||||
Maybe something to be learned here
Here are Defender's opening comments on anode selection:
and this from BOAT US (bold face added for emphasis): Quote:
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 04-25-2016 at 09:34 PM. |
#25
IP: 98.182.30.91
|
|||
|
|||
Quote:
Zinc is the sacrificial metal and copper has a lot more galvanic "pull" on zinc than almost anything. Copper dismantles zinc which then turns into zinc hydroxide and can plug up the HX. Sometimes it gets rinsed or pushed out before it plugs up the HX. Sometimes not. Try this sometime: Put a copper wire and a zinc galvanized nail with a wire on it into a lemon and touch both wires to the top of your tongue. Or if you don't want to go through the drill google "lemon battery". TRUE GRIT |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Heat exchanger clogged. | jstaff | Cooling System | 19 | 06-20-2016 10:26 AM |
Controlling and affecting proper operating temp | ILikeRust | Troubleshooting | 88 | 02-02-2016 01:36 PM |
Plate-type heat exchanger | Kelly | Cooling System | 22 | 02-23-2013 10:15 PM |
Moyer heat exchanger emptying | ArtJ | Cooling System | 47 | 01-31-2011 07:24 PM |
Heat exchanger zinc | jhwelch | Cooling System | 3 | 08-28-2008 05:04 AM |