6BTA 330 aftercooler reassembly – 2 questions

[Emerson H Hiller]

1. When I removed the core from the aluminum case I found that it had been previously reassembled with the narrow dimension facing the air flow so that air could pass by the rounded milled sides between the core and the aluminum case. It seemed to be running fine this way even though not all the air was being forced through the cooler core. I am prepared to reassemble correctly but was wondering if anyone had experienced this before. Comments please.
2. The milled aluminum at the top and bottom where the core meets the aluminum case has a couple of significant corrosion spots. I have sanded to smooth it a bit but I was wondering if some epoxy could be used to fill the corrosion pits and then sanded smooth afterwards. Alternative ideas and thoughts welcomed but in any case I will use copious amounts grease for reassembly.
Thanks
Buzz in Mass.

Topic

[Emerson H Hiller]

Thanks Rob…very helpful

[Rob Schepis]

Buzz, we’ve covered core testing in a number of threads, here’s one with a simple DIY custom tester:

https://www.sbmar.com/community/topic/aftercooler-shot/

[Emerson H Hiller]

Ideas on how to pressure test the core of an aftercooler th

I have been planning to reassemble the aftercooler and pressure test with water once assembled. A suggestion was made to pressure test the core beforehand. I have some ideas for using rubber pads, clamps etc, but does anyone have specific ideas on a jig or method for the best/easiest way to test the water side of the core?
thanks
Buzz

[Emerson H Hiller]

Follow up to 2 questions and pictures

Thanks for the response. You’re right Gene, the improper alignment does present more thickness of the core cooling fins but also leaves a gap on the edges open so that air can bypass the core on either side. I plan to assemble it correctly but wanted opinions in case others have seen this. The engine seemed to run fine with the improper alignment. I’m not sure about the other engine’s aftercooler (plan on pulling that one later) but since I’ve owned the boat for only one season I’m still working thru unknowns.

[Gene Fuller]

firehoser75 wrote:

Buzz,

Again, I defer to the experts, but as I stated before, there is a reason that the core is supposed to be aligned in one direction – air flow. I think air flow would be restricted with the core installed in the orientation you show labelled “improper alignment”.

I think you may have it backward. The “improper” direction allows the air to bypass the cooling fins. Not a restriction but rather it may result in poor cooling.

[firehoser75]

Buzz,
Again, I defer to the experts, but as I stated before, there is a reason that the core is supposed to be aligned in one direction – air flow. I think air flow would be restricted with the core installed in the orientation you show labelled “improper alignment”. Too late to change the past, but install with the correct alignment this time.
I also agree with Dave, that it would be best to test that core separately from the full assembly. Then test the full assembly if the core passes, otherwise, a new core may be in your future.
The corrosion in the housing does not look that bad to me (mainly talking about the mating surfaces), and on the interior part, you could use epoxy (and grease) (as Rob said) or just a lot of grease to protect the exposed surfaces.
Let us know what you find.

[Dave Carlson]

I think you need to test that core before going much farther.

[Mark Gambini]

Aftercooler reassembly

I had same problem with qsc 500. I replaced with new cooler from sea board. I will be doing other side next week. I got a nice t shirt for about 4,000.00
Good luck.

[Emerson H Hiller]

Follow up to 2 questions and pictures

Thanks for the responses. In reply to picture requests, I have included pictures below .
I am interested in any thoughts or ideas concerning core alignment (question 1) and corrosion at the edges where the core meets the top and bottom of the aluminum case – should I try epoxy filler to smooth out corrosion pits (question 2). Finally I included a picture of some stubborn corrosion residue in the core…ideas on removal using a detergent or chemical solution??
thanks for any ideas.

[Rob Schepis]

As Tom states, pictures are most important. I see no issue with the proper prep & application of the right epoxy, gray marine-tex, etc but for sure pressure testing needs to be part of the process.

[firehoser75]

I will defer to the true experts here, such as Tony and crew, but I would think that you had a “restricted” air flow with the core installed incorrectly. Follow Tony’s directions (with photos) here.
As far as the dealing with the corrosion is concerned, I think a few good quality photos showing the areas of concern would help you obtain the best advice possible.
Good luck, and once you “get on top of this” it should be much easier in the future.
Tom

[Author]

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