Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-08-2018, 01:52 PM   #1
Veteran Member
 
City: Panama City Beach
Vessel Name: Journey
Vessel Model: Bristol 42
Join Date: Apr 2013
Posts: 34
Heat exchanger failure

We were taking our boat out to run the engines on Monday, I just throttled up once the engines were up to temperature when my bilge alarm sounded continuously. Turned out the end casting with seal and cover attached had blown off my Stbd Engine heat exchanger (Lehman 120) and we were pumping raw water into the engine room.
No real problem, just had to shut the engine down and get back in our slip on one engine.
It seems a strange failure mode to me, the pencil zinc was situated right next to this end and was fairly new, maybe the soldered joint has corroded away and failed, there is no obvious corrosion to the cast ring just some calcification.
Does anyone have any ideas?
Thanks, Steve
Attached Thumbnails
IMG_0029.jpg   IMG_0030.jpg  
Skeeter is offline   Reply With Quote
Old 03-08-2018, 03:34 PM   #2
Guru
 
City: Carefree, Arizona
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 9,262
When was the last time that heat exchanger was removed and cleaned out?
sunchaser is offline   Reply With Quote
Old 03-08-2018, 03:54 PM   #3
Veteran Member
 
City: Panama City Beach
Vessel Name: Journey
Vessel Model: Bristol 42
Join Date: Apr 2013
Posts: 34
Cleaned thoroughly about 2 years ago and checked regularly for build up since.
Skeeter is offline   Reply With Quote
Old 03-08-2018, 04:12 PM   #4
Enigma
 
RT Firefly's Avatar
 
City: Slicker?
Join Date: Oct 2007
Posts: 15,649
Greetings,
Mr. Sk. Looks to me that the soldered edge has given up the ghost. From picture #2, it looks like the end cap is still attached (bottom most piece against your thumb) then the rubber gasket, THEN the thicker piece that should have stayed on the HE. That thicker piece should be soldered to the HE and failure of that solder joint is the cause of the blow-out. Absolutely no evidence of solder so this is NOT new development. Best suggestion I can make is take off the HE and either do it yourself or have the cap soldered back on. Not sure if OEM was soft (lead) or hard (silver type) solder.
__________________
RTF
RT Firefly is online now   Reply With Quote
Old 03-08-2018, 04:44 PM   #5
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,797
Isn't there supposed to be a bolt in the middle of that cap to hold it on? They are supposed to be removable for cleaning...I thought...
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 03-08-2018, 04:51 PM   #6
Enigma
 
RT Firefly's Avatar
 
City: Slicker?
Join Date: Oct 2007
Posts: 15,649
Greetings,
Mr. X. I think the pictures are of the cap AND the fitting it bolts into (shown upside down) with the bolt on the bottom side. The whole smutz has let go.
__________________
RTF
RT Firefly is online now   Reply With Quote
Old 03-08-2018, 05:36 PM   #7
TF Site Team
 
Larry M's Avatar
 
City: Jacksonville
Join Date: Nov 2008
Posts: 9,872
My question is, “How old is the heat exchanger”? They have a finite life. We’ve been told to change them every 10 years, even if they pressure test ok.
Larry M is offline   Reply With Quote
Old 03-08-2018, 05:44 PM   #8
Technical Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,197
Solder failure. Did you get any freezing?
Ski in NC is offline   Reply With Quote
Old 03-09-2018, 08:59 AM   #9
Veteran Member
 
City: Panama City Beach
Vessel Name: Journey
Vessel Model: Bristol 42
Join Date: Apr 2013
Posts: 34
No no freezing, the casting you see goes into a recess in the end of the HX main tube, as RT says it looks like the solder has failed. I will pull it at the weekend. I plan to grit blast the mating faces to get a better look and maybe re-solder it for a spare. In looking further I have noticed that there is no ground bonding cable on that engine so maybe that has contributed. although I have regularly checked and changed out the HX pencil zinc.
I would have thought that the zinc still would have been sacrificed rather than the solder but maybe someone can advise me on that.
I will install a grounding cable to be certain.
I'm not sure how long the HX has been on there, I have had the boat nearly 5 years though, might see if I can contact the PO but should probably fit a new one to be safe.
Does anyone know the most economical place to order a new one, I'm in Panama City, Florida.
Thanks, Steve
Skeeter is offline   Reply With Quote
Old 03-09-2018, 09:11 AM   #10
Enigma
 
RT Firefly's Avatar
 
City: Slicker?
Join Date: Oct 2007
Posts: 15,649
Greetings,
Mr. Ske'. Is the HE in question mounted directly to the engine by means of a soldered on bracket or is it mounted by means of non-metallic stand-offs? If non metallic stand-offs, for sure you will need a grounding strap.

I have no idea what solder was used to affix the tubing bundle to the outside housing BUT if soft solder, you will have to heat-sink that bundle/housing joint when you reattach the end casting. I suggest submersing the HE in water up to that bundle/housing joint to protect it's integrity. You should then have about 1" to 1 1/2" of the HE sticking out of water to solder to.

American Diesel and Bomac are the only two sources of OEM coolers I know of BUT I have seen reference to generic suppliers suggested by other members. As per usual, I can't remember squat...
__________________
RTF
RT Firefly is online now   Reply With Quote
Old 03-09-2018, 09:30 AM   #11
Guru
 
diver dave's Avatar
 
City: Palm Coast, FL
Join Date: Jan 2017
Posts: 2,052
I had this happen, although only to a leak, and not a blowout.

Turns out lead/tin solder is attacked by chloride from seawater.

https://www.osti.gov/servlets/purl/14961

Sandia Labs figured this out a number of years ago.

This is not a cleaning issue, and maybe even not a lack of zinc issue.
diver dave is offline   Reply With Quote
Old 03-09-2018, 09:47 AM   #12
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 24,009
had the end cap of a oil cooler fall off one day...

never looked like any solder was even used, but was on there 5 years.

5 years was when we changed them out on the assistance tow boats.
psneeld is online now   Reply With Quote
Old 03-09-2018, 12:19 PM   #13
Veteran Member
 
City: Panama City Beach
Vessel Name: Journey
Vessel Model: Bristol 42
Join Date: Apr 2013
Posts: 34
Thanks to everyone for the posts, RT, I had thought about filling the HX with water to protect the inner tube joints during soldering but immersing it also should be even better, thanks. I will check the mounting and bonding

Diver Dave, I have always maintained a good pencil zinc in the HX, the article you posted is interesting if a little over my head, you would think this would be a more common problem if it were just a salt water corrosion problem

The faces on the casting that blew off look clean (once cleaned off with a wire brush) with no trace of solder, if they were tinned properly you would think that there would be some indication of the solder in the surface of the brass. I'm assuming that a lead/Tin solder is used rather than a Silver solder?

I've just sand blasted the casting and still no sign of solder, see pics.

I am a little concerned that the soldered joint on the smaller internal tubes are being affected by the same phenomenon so i think I will have to bite the bullet and buy a new one (as cheap as I am!). I'm just wondering about the other engine HX now!

Thanks again Steve
Attached Thumbnails
IMG_0035.jpg   IMG_0037.jpg  
Skeeter is offline   Reply With Quote
Old 03-09-2018, 02:41 PM   #14
Guru
 
diver dave's Avatar
 
City: Palm Coast, FL
Join Date: Jan 2017
Posts: 2,052
The Table 2 in that study points to the chart of active vs non-active alloys to use. We think of lead being fairly non-reactive, but with seawater and CO2 attack, the lead portion of the solder is simply slowing going away. It is combining with Chlorine and leaches away.

Think about brazing the caps back on. I've not done a ton of brazing, but did do some using a copper alloy rod on copper fittings.
In your case, you want to inspect carefully the tube joints to the separator plates. These SHOULD be done with a higher melting point solder (or brazed) than the case and end caps. Otherwise, the heat required to pull off the end caps would disassemble the entire heat exchanger, tubes and all!
If they look good, I would certainly explore brazing the end spiders on. It might not be repairable in the future, but you could squeeze out quite a few more years out of them.
diver dave is offline   Reply With Quote
Old 03-09-2018, 02:52 PM   #15
TF Site Team
 
Larry M's Avatar
 
City: Jacksonville
Join Date: Nov 2008
Posts: 9,872
Sea Kamp, cupronickel heat exchangers for the Ford Lehman's are readily available for less than $700. I'd buy new and not mess around. When we changed ours out, we also changed the transmission and oil coolers. Less than $250 for the pair.
Larry M is offline   Reply With Quote
Old 03-10-2018, 10:08 AM   #16
Guru
 
twistedtree's Avatar
 
City: Gloucester, MA
Join Date: Jan 2013
Posts: 6,671
Quote:
Originally Posted by Larry M View Post
Sea Kamp, cupronickel heat exchangers for the Ford Lehman's are readily available for less than $700. I'd buy new and not mess around. When we changed ours out, we also changed the transmission and oil coolers. Less than $250 for the pair.
I think this is really good advice. Any mess up or leaks could put salt water in places it really shouldn't be, and cause significant damage.
__________________
MVTanglewood.com
twistedtree is offline   Reply With Quote
Old 03-10-2018, 10:17 AM   #17
Senior Member
 
Join Date: Nov 2011
Posts: 273
Better to replace the whole unit. Have old one replaced and carry as a spare. They care expensive. Contact American Diesel if you have questions.
MVDarlin is offline   Reply With Quote
Old 03-10-2018, 03:56 PM   #18
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 10,122
Quote:
Originally Posted by RT Firefly View Post
As per usual, I can't remember squat...
Mr. RT, I hope this picture jogs your memory.

Click image for larger version

Name:	woman-squatting-cute-young-business-sitting-down-position-blonde-crouching-girl-white-background.jpg
Views:	64
Size:	78.1 KB
ID:	73909

Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is offline   Reply With Quote
Old 03-10-2018, 04:24 PM   #19
Senior Member
 
Join Date: Nov 2011
Posts: 273
Also, if you replace oil coolers get larger capacity after market coolers from American Diesel.
MVDarlin is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 08:41 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012