Aftercooler protocol progress

[Robert Vetrano]

I’ve sent Tony Athens these same pictures for review, but wanted to get a thread going with my progress for all to see. Twin QSBs. ACs have been serviced 1x by a previous owner (there were 4). I don’t believe they removed the AC and bench serviced.

I’ve only done my stbd AC at the moment. Slight green corrosion on both caps. No performance issues pointing me to any problems. Caps came off easily as expected. Top zinc was mostly intact with what looked like a lot of buildup around it. Bottom zinc was a nub that had broken off, and looked ineffective. I wouldn’t say I was thrilled at what I initially saw condition-wise, but I’d seen worse on this forum and others. They cleaned up great after an hour soak in HCL to water 10:1.

Bundle came out rather easily, about 5 “taps” with a 2×4 and a small sledge hammer. There was no noticeable buildup in the tubes, but I rodded our each one w a 3/16 rod. Then filled the tubes w 10:1 HCL/water and let em boil. I thought the weight of the bundle would be enough to set it on top of a rubber gasket; and keep the mixture in the tubes…..it was not. Careful to keep the HCL mix away from the air side I just ran the mixture through the tubes till they were reasonably clean. They were then put in my homemade test rig, and held 25psi overnight. Note the “brass termites” on the ring of the bundle……Tony indicates this due to cheaper alloys being used the last 10years, is ok and liberally apply grease and reassemble.

Housings were in ok shape. The black coating on the interior was corroding, as I kind of expected. Sanded that and will grease. The top and bottom mating surfaces looked ok. I block sanded them clean. The top turned out great. But the bottom has some weird ring around the surface that was pitted, and had a slight depth to it. Tony has indicated this looks average and to continue w the protocol w liberal grease.

I’m out of town, but the next step is to reassemble and pressure test the entire assembly. I’ll update pics when I do that.

I also did my stbd fuel cooler and gear cooler……they turned out great after sitting for an hour with the tubes full of HCL.

Upon install I plan on a freshwater flush setup to prolong this job.

Thanks Tony!

Topic

[Rob Schepis]

Roky, you could always give distilled white vinegar a try too. My last aftercooler service interval was rather short so tubes weren’t bad and the vinegar cleaned them up nice.

[Roky]

In Europe we don’t have Leslies or any Home Depo shops, I can find both variants “off the shelf” although the stronger one is called “Technical HCL”.

I’ve done some maths and I don’t think it’s much difference between the 19% and 31% HCL solutions when diluted on a 10:1 water to HCL ratio – it’s either a 2,80% or 1,70% solution…

[Tony Athens]

Common “off the shelf” pool acid from “Leslies” or Home Depot, or ???

[Roky]

HCL purity

Thanks everyone for their replies, it’s amazing how much knowledge is shared here!

I just wanted to ask you what is the purity of the HCL which you are mixing in the 10:1 ratio? Commercial HCL is not 100% HCL so it’s an already diluted version, locally I can source either 19% or 31%…

[Justin Riege]

As far as this Ratio thing, Tony asked if there was a final answer.

Here is my argument.

A simple way to solve engineering problems is to take them to the Extreme. This may be easy to confuse at 10:1 but what about at 1:1, which should be 1 part water to 1 part solution, 50% mix. You can’t do 1:1 any other way unless you argue that 1:1 means no dilution. Then when you move to 2:1 which would be 2 parts water to 1 part solution for a total of 3 parts.

Continue on with that logic and you wind up at 10:1 being a total of 11 parts.

According to Robs chart which looks pretty legit…

To mix up 32 oz you use 29 oz of water and 2.9 oz of acid. In other words whoever made the chart divided that 32 oz into 11 parts. 32/11 = 2.9 oz A quick scan around that chart shows consistency with this approach.

10:1 means 10 parts water to 1 part acid for a total of 11 parts.

That’s my two cents and its worth a lot less than that.

[JJM]

Thanks for the input

I ended up taking some EPDM membrane and making a gasket at the bottom and put some weights on top of it. Sealed ok. Filled with HCL. As for the fins I just sprayed them down with 6-8 cans of brake cleaner and then soaked in simple green. Rinsed it all down and blew it out with compressed air. Happy with the results. Thanks

[Tony Athens]

Think about your own cores–Aluminum fins, copper fins, Cu-NI tubes and a some kind of “brass alloy” in an acidic solution…………………………………………………………. The most “perfect mixed metal storm”

[Rob Schepis]

There’s no benefit to subjecting the fins to the acid and it’s simply too easy to just stand up the core and fill the tubes

2 users thanked author for this post.

KevinS, JJM

[Tony Athens]

IMO, the fin side of the aftercooler SHOULD NOT be cleaned with any type of acid.. Plus, what gets the fins dirty , acid won’t clean anyway.

[JJM]

After cooler core

The after cooler copper core bundle

[Tony Athens]

Aftercooler core or heat-x? Major differences.

[JJM]

After cooler Maintanence Air Side

Any harm in soaking the whole cooper exchanger in HCL rather then just the tube side?

[FERNANDO DACOSTA]

Robert Vetrano wrote:

Here is my test rig. It’s 2 pieces of 1/2” aluminum i got from my local welder. The gaskets are toilet bowl rubber from Home Depot. The pressure gauge is from a pool store, and the fittings are all Home Depot stuff. Once you get everything right so there’s no leaks in the test rig fittings, it worked great!

NICE

1 user thanked author for this post.

Robert Vetrano

[Robert Vetrano]

By testing both the core and housing (after assembly) you’re able to narrow down what is leaking if there happens to be a leak. If the core tests good, and then the housing doesn’t……then you know you have an issue with the housing. If you just test the housing after assembly you can’t be sure what’s leaking.

[JJM]

Thanks for the info. Should the after cooler be tested when assembled though as a unit ?

[Robert Vetrano]

Here is my test rig. It’s 2 pieces of 1/2” aluminum i got from my local welder. The gaskets are toilet bowl rubber from Home Depot. The pressure gauge is from a pool store, and the fittings are all Home Depot stuff. Once you get everything right so there’s no leaks in the test rig fittings, it worked great!

1 user thanked author for this post.

JJM

[JJM]

Great Post

Great post. Thanks for all the info. I am getting ready to do this myself and this gets me in the right direction. I just ordered Ton’y kit for the maintanence. Can you elaborate more on your test setup and or anyone else on the test setup…..?

[matt.schaefer86]

Any advice on the steps to take?
I have done Rydlyme before and have done it like this. Can I follow the same flow with the pool acid mixture?

30 min circulation in forward(rydlyme flowing in the inlet and out the hose that would be hooked up to the exhaust)

Let sit 30 min

30 min circulation in reverse

Then button everything back up and start the motor and let it run for 15 min.

That sound right??

Thanks

[Rob Schepis]

Thanks for the pics. So were there any termite damages where the o-ring sits or was it all above/beyond ?

[Robert Vetrano]

Block sanded my bottom mating surface some more, reassembled, and pressure tested good. Thanks for all the help. Other engine…..and both HXs are next!

Here’s some pics including the brass termites in relation to the O-rings.

5 users thanked author for this post.

firehoser75, rehughes61, JJM, Frank, Tony

[Author]

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