Pressure Testing a Cummins 6BTA After Cooler

[BillD]

I finished servicing the after coolers on my Cummins 370s.

Decided I wanted to "pressure test" the units after I took them apart, cleaned the cores,caps and housings.

How to do?? How to do ????

I picked up a "used" inner tube at my local tire dealer and a couple of clamps.

Cut the valve and a piece of rubber out of the tube and clamp blocked the ends.

I plugged the zinc threads and "aired it up"

1st try....a couple of leaks around the rubber pieces.

2nd try....and this is funny.....a "blowout" ! LOL too much pressure. Scared the crap out of me....sounded like a gunshot in my garage !!!!

3rd try......an assembled after cooler that "holds air" and should NOT leak!

FWIW,

Bill D.

btw, cost for pressure testing parts..........under $5 bucks

 

[gregs]

If there is a next time fill mostly with water then the air - water doesn't compress, much smaller pop
greg

 

[BillD]

Your procedure has tested the raw water side. you need to verify that you are or will not have any leakage from the turbo by pressurizing and verifying no leak down on the boost or air side. Your half way done.. Recommend 5 PSI more than max boost, No more

Gurry,

I may have this wrong but by pressure testing the "water side" of the unit and the fact the unit is "holding pressure" means there is no leak from the water side into the "air side".

Likewise if I pressure tested the unit using the "air side" and the unit held pressure then it stands to reason there are no air leaks into the raw water side of the unit.

Seems to me testing the one side is sufficient.

If I'm missing something here I'll stand corrected.

 

[BillD]

Your 98% correct, I have seen on rare occasion Jacket water cooled intercoolers test fine on the water side and have small leaks on the air side. This has been mostly on trucks in the 70s and 80s before air to air became the norm. As long as your check pressure exceeded you max boost pressure you should be fine. There may be come coolers out there that might not handle max boost pressure on the water side. But that's a whole nother conversation
I also have way to much time on my hands, so I would probably check both sides just for the "feel good" confirmation.

Good point. I am most concerned with the "raw water" side leaking or "misting water" into the turbo charge.

I'll probably "field test" (boatdieselforum term) both coolers when I fire up the engines in the water in a few weeks.

Simple enough to do. Leave the "air horn" top of the after cooler off that attaches to the intake manifold. Turbo side is connected.
Run the engines in neutral @ the dock and spin them up to 2200-2400 and watch for any "misting" on the air side coming out of the after cooler. If none, hookup the hose, tughten down and off you go !

Last thing ANY owner wants to do is provide a nice salt water mist to the engine intake .

Regards, Bill D

 

[Pedlyr]

Hi Bill-

Whenever I test aftercoolers (or any coolers) I try to do it in a pan of hot water. I have seen coolers test fine "cold" but leak when warm. I use an old CAT block heater for this.

I usually just use adjustable rubber plugs from the hardware store and an air regulator is a must. External leaks will show up easy enough in the form of bubbles. I don't usually use too much pressure unless I have too. Most leaks will show up with 10 lbs or less. Enough pressure can send those plugs flying!

 

[BillD]

Hi Bill-

Whenever I test aftercoolers (or any coolers) I try to do it in a pan of hot water. I have seen coolers test fine "cold" but leak when warm. I use an old CAT block heater for this.

I usually just use adjustable rubber plugs from the hardware store and an air regulator is a must. External leaks will show up easy enough in the form of bubbles. I don't usually use too much pressure unless I have too. Most leaks will show up with 10 lbs or less. Enough pressure can send those plugs flying!

The Cummins after coolers are not prone to leaking after a "routine" cleaning and servicing "IF" the correct O rings are used. Cummins after coolers were produced with one of two different sized O rings.

Tony sells O ring "kits" for 6BTA/QSB after coolers. He includes two sets of rings. Match up the diameter with the old rings taken off the cooler and you are O ring good to go.

http://www.sbmar.com/docs/MaintnanceFlyer.pdf

FWIW,

Bill D

 

[Toolate]

I would think you would want to know what pressure you are putting in as well, no? On the air side anyway. Maybe test it to 10 psi.

Rubber fernco parts would have been a good way to go. Cap/expanding plug (pluming supply) one end and a coupling holding a bushing to air pressure guage/schrader valve for pumping up.

Plumbers put air tests on piping and then spray the joints with soap/water mix so the leaks show up as growing groups of bubbles even tiny leaks.

Doesnt seem like there would be much pressure in an aftercooler on either side thinking about it...

 

[BillD]

I would think you would want to know what pressure you are putting in as well, no? On the air side anyway. Maybe test it to 10 psi.

Rubber fernco parts would have been a good way to go. Cap/expanding plug (pluming supply) one end and a coupling holding a bushing to air pressure guage/schrader valve for pumping up.

Plumbers put air tests on piping and then spray the joints with soap/water mix so the leaks show up as growing groups of bubbles even tiny leaks.

Doesnt seem like there would be much pressure in an aftercooler on either side thinking about it...

25-30 psi on the air (turbo) side
25 psi +- on the water side.

best to "field test" these in the boat before buttoning them all up.

 

[[email protected]]

I check B/C series aftercoolers by using a short piece of 1 3/4" hose at each end. Heavy wall exhaust hose but with no wire in it. One has a valve and garden hose adapter on it the other is bushed down to a radiator petcock. Put these on each of the aftercooler endcap waternecks and attach a garden hose. Set the aftercooler on its side on blocks with the petcock pointing up so that when you let the water in through the valve you can purge the air. The air inlet or outlet side is pointing down and let it sit under pressure with the valve partially open for 20 minutes or so. I have gauged it, city water pressure averages around 80 psi. Cummins B/C seawater pressure allowable is 12 so you are exceeding that 5 times over. Normally you will see the zincs leak slightly but you should see no water under the air outlet, and since the Serck coolers are angled on the sides any water from a leak runs right to the air outlet. I use the Cummins O-rings only because the B series went through some part # changes ( black to orange and black again)so I go by ESN. I know many people (my business partner for one) that use Tony's seal kits with complete success. One thing I learned from his article is to use marine grease on the end of the housing where the core sits and endcap O-ring. This they didn't show us at Cummins and makes a big difference in taking it apart next time as well as protecting that thin black corrosion barrier. And use the good consta-torque clamps as standard ones will blow right off during the test.

 

[Toolate]

THey recommend testing at 12 and you put water in at 50?

Where we live the water pressure can be as low as 40 in the morning when the whole world is water lawns/showering and up to 130 at 3 pm. Could be way more depending on what time of day..

Not criticizing, just asking. I am certainly no diesel tech but I do know that water pressure can fluctuate.

 

[BillD]

I check B/C series aftercoolers by using a short piece of 1 3/4" hose at each end. Heavy wall exhaust hose but with no wire in it. One has a valve and garden hose adapter on it the other is bushed down to a radiator petcock. Put these on each of the aftercooler endcap waternecks and attach a garden hose. Set the aftercooler on its side on blocks with the petcock pointing up so that when you let the water in through the valve you can purge the air. The air inlet or outlet side is pointing down and let it sit under pressure with the valve partially open for 20 minutes or so. I have gauged it, city water pressure averages around 50 psi. Cummins B/C seawater pressure allowable is 12 so you are exceeding that 4 times over. Normally you will see the zincs leak slightly but you should see no water under the air outlet, and since the Serck coolers are angled on the sides any water from a leak runs right to the air outlet. I use the Cummins O-rings only because the B series went through some part # changes ( black to orange and black again)so I go by ESN. I know many people (my business partner for one) that use Tony's seal kits with complete success. One thing I learned from his article is to use marine grease on the end of the housing where the core sits and endcap O-ring. This they didn't show us at Cummins and makes a big difference in taking it apart next time as well as protecting that thin black corrosion barrier. And use the good consta-torque clamps as standard ones will blow right off during the test.

Mike,

I get a "little crazy" thinking about my 370s burning "salt mist" so I field test the units @ 2400 rpms before bolting on the airhorn and connecting to the intake manifold.

 

[[email protected]]

THey recommend testing at 12 and you put water in at 50?

Where we live the water pressure can be as low as 40 in the morning when the whole world is water lawns/showering and up to 130 at 3 pm. Could be way more depending on what time of day..

Not criticizing, just asking. I am certainly no diesel tech but I do know that water pressure can fluctuate.

It's OK that you asked. Cummins B/C installation parameters say you should not have a seawater pump outlet restriction over 12 psi measured at the back of the R/W pump. This is for the engine package as a whole system (hoses, clamps, heat exchanger end plates, etc.) There is a small amount of restriction designed in when the R/W pump is 2 inch but the coolers and heat exchanger are only 1 3/4 inch. The aftercooler off the engine and by itself is what we pressure test to around 50 psi or so. Remember that those seals are also up against 32 to 35 lbs of boost at wide open on their other side. I've gauged it and water pressure here has never gone above 100 while I was using i. It is good to gauge the pressure, but believe me aftercoolers (if they're any good) easily hold more than 80 psi. Friday I tested one for a C 420 that is from 1997 and I resealed it 7 years ago. It held fine. Sendure heat exchanger endcaps however, blow out at around 25 psi, make a huge puddle in the shop, and really aggravate co-workers.

 

[[email protected]]

Mike,

I get a "little crazy" thinking about my 370s burning "salt mist" so I field test the units @ 2400 rpms before bolting on the airhorn and connecting to the intake manifold.

Bill, it's not crazy to be concerned about seawater injection into a valuable engine. A quick check is when an engine has been in service awhile, and you have that air elbow off, just look at the condition of the grid heater coils. If they are rusty most likely that cooler is pushing water. Its easy to do and only costs 2 red gaskets. As for the damage possible, I was once sent to check out two new B370's in a gas to diesel repower that the yard said sounded terrible. Yeah they did sound bad at anything over 1400. You know the little 1/4" pipe plug under the bottom of the AIR side where Serck now puts a drain and I'm supposed to use to check boost? That's where the installer plumbed the "feeds" for his dripless shaft seals and at speed the venturi action was sucking up huge quantities of seawater. The problem was fixed but both engines were replaced after one suffered a catastrophic failure shortly after.

 

[[email protected]]

Here's one that will probably upset somebody but I mean no harm and its only my personal opinion. I don't like Airseps on any aftercooled engine. All that blow by oil mist that they are saving my bilge from is now being directly injected into a 300 plus degree aftercooler core and is cooked into sludge. I used to clean all cores myself but no amount of brake clean or solvent completely got that (expletive deleted) off. Now I send the cores to a shop that specializes in commercial cooling systems and its like getting your old prop back from the propeller shop and it looks so good you can't believe it's the same one. On non aftercooled product the engine can just eat it up, but with a delicate high performance cooler it just makes for problems. Soon as I got my B into the boat, I pulled the Airsep off and installed a fleetguard paper filter. It has to be a good one like Fleetguard AH19002 or Donaldson DC207XA because without the wire screen on the inside that engine can pull the paper media in.

 

[Toolate]

It's OK that you asked. Cummins B/C installation parameters say you should not have a seawater pump outlet restriction over 12 psi measured at the back of the R/W pump. This is for the engine package as a whole system (hoses, clamps, heat exchanger end plates, etc.) There is a small amount of restriction designed in when the R/W pump is 2 inch but the coolers and heat exchanger are only 1 3/4 inch. The aftercooler off the engine and by itself is what we pressure test to around 50 psi or so. Remember that those seals are also up against 32 to 35 lbs of boost at wide open on their other side. I've gauged it and water pressure here has never gone above 60 while I was using it, and if it went double that my hot water heater would flood the basement. It is good to gauge the pressure, but believe me aftercoolers (if they're any good) easily hold more than 50 psi. Friday I tested one for a C 420 that is from 1997 and I resealed it 7 years ago. It held fine. Sendure heat exchanger endcaps however, blow out at around 25 psi, make a huge puddle in the shop, and really aggravate co-workers.

Sounds legit- I have never seen water main fluctuations like we have where we live and for the record, I have never held an aftercooler in my hands so my opinion means squat.

 

[[email protected]]

Sounds legit- I have never seen water main fluctuations like we have where we live and for the record, I have never held an aftercooler in my hands so my opinion means squat.

And I was a little off, it probably is closer to 80 psi if I'm the only one using water at the time. I'm much more comfortable putting a component back on if it has bench tested successfully to several times it's working load than if tested to less than what it gets in actual use.