My version of the boost leak detector

[jocko]

As I set about looking to do some minor modifications to my 7.3, I stumbled upon the link that teaches the reader how to make his own regulated pressure tester to find boost leaks.

How to: make a slightly more baller boost leak detector - evolutionm.net

As I contemplated following that design, I decided that I could do it cheaper and less complicated while retaining the same essential functionality of Whoflungpoo's design. Plus, Who's design was rather unweildy and presents a significant threat of breaking or cracking due to the long lever arm created by the ball valve/pressure regulator assembly.

I decided that if I used a tire valve stem and some sort of stand alone air pressure gauge, I could achieve the same basic results for less money and an easier to build design. Since I keep a 12v compressor in my truck to deal with unexpected flats, it made perfect sense to work this into a simple design, so that was a large part of my process.

So, I set about collecting the parts, which only turned out to be 3.

1)a PVC end cap to fit the I.D. of my air intake tube (the PVC cap is about 3 1/2 " i.d. and its o.d. is perfect for my 4" intake tube)
2)tubeless tire valve stem
3)air pressure gauge
Attachment 6571
I found an air pressure gauge at Wal-mart for 94 cents. It is a Slime brand and the little chrome fitting that you press against the valve stem unscrews to reveal a 1/8 NPT fitting underneath that provided the perfect avenue to mount the gauge into the PVC cap. All I had to do was drill the hole and use the 1/8 NPT tap I bought to mount my thermocouple when I installed my pyrometer. Once drilled and tapped, a few wraps of pipe tape made for a very nice install. I chose to mount the gauge on the side so that when installed into the intake tube, I could orient the unit with the gauge facing me while standing in front of the truck and the dial would be upright making the numbers easy to read without having to stand on my ear;-). You can drill and mount the gauge wherever you prefer as long as you stay far enough away from the open end so that you don't interfere with clamping the unit into the intake tube.
Attachment 6572
Next, you have to drill the appropriate sized hole for the valve stem. I bought the rounded PVC cap that is 3/8-1/2" thick on the end. Due to this thickness, a regular rubber valve stem is prone to tearing or pulling out unless you countersink your mounting hole. I didn't want to do this, so I decided to go with a heavy duty stainless screw-in type valve stem (Napa part #90-432). I used the 5/8" grommet that comes with it (they come with a 1/2" and 5/8"). I recommed the 5/8" grommet because the length is exactly the same as the thickness of the PVC cap, so once I drilled my 5/8" hole and inserted the grommet, it looked like it was made for this application. Once I inserted the valve stem body and installed the beveled washer and nut on the outside of the PVC cap, it looked like a factory made part. SWEET!!!! The curvature of the PVC cap and the bevel of the stainless washer make for a very clean looking install and it turned out better than I had planned. Another benefit is that the valve stem I used was a short stem that does not provide much leverage to facilitate breaking or cracking the PVC cap if struck, dropped, etc.
Attachment 6573
Attachment 6574
Attachment 6575

Overall, it is a very clean looking build that looks very nice considering it only took a few minutes to build. It might have looked like a factory made item if I had taken the time to paint the PVC cap before mounting the other parts.

Cost after sales taxes:
PVC cap - approx $3.50
air pressure gauge - $1
valve stem - $2.50

Total cost including sales tax - $7

Dude, it doesn't get much better than that!!

Testing:

I took it out to the truck and had it hooked up in less than a minute thanks to my DIY Tymar style 6637 filter setup. I turned on my small 12v compressor and waited to see the pressure gauges start moving. It pumped and pumped and pumped. 5-6 minutes and no movement of the gauges (neither the one built into the project, nor the one built into the compressor.) Curses!! What did I do wrong? I disconnected the airhose and heard a little bit of air leaking from the connection, which told me that there was a little bit of pressure on the system. Well, that's a start. So I scare up a spray bottle with some soapy water and hook the airhose back up (no "psst" sound which tells me the pressure had leaked out) and I start the compressor again. I start spraying boots and clamps, etc. It's now getting dark and I am not seeing any signs of an air leak so my spirits are dropping when I notice, by flashlight, bubbles building on the AIH (the one that everyone removes to increase airflow). I get a wrench and make a couple of small partial turns and the leak seemed to either stop or significantly decrease.

To be honest, a high capacity air compressor will do the job better, but my concept proved to work. I have not been able to test it with my larger capacity compressor yet because my big compressor was liberated from my garage (thanks you jerk!) along with my airhose and locking tire chuck. I have a smaller 5 gallon hotdog type compressor that will deliver up to about 120 psi (I know you should not pressurize this system above 15 psi, so please don't flame me. My point is that a larger unit with a greater CFM and pressure capacity will pressurize the system faster to help find leaks more quickly), but I have not gotten around to putting the new locking chuck on a fitting to chuck up on the hose, so my small 12v compressor is all I have to test with.

After I tightened the leaking fitting, it held a slight amount of air pressure for a couple of minutes. It held it long enough that I had to bleed the pressure through the valve stem to break it down and when I loosened the hose clamp on the intake hose, there was still a slight "psst" of pressure when I broke the seal. All good signs. I hope to be able to use my larger compressor in the next few days to see if I can get any movement of the gauge or find other leaks. Worst case scenario, I might have to spring for a more expensive gauge, or maybe an ATV type gauge that is made for lower pressures. In fact, I think I will try my small stick type atv tire gauge one day to see if I can detect a few pounds of pressure with it. We will see.

I will update as I get more testing done.

I will also post an update after this initial message to include a pic of the unit hooked up to my intake hose and the aircompressor all ready to go.

Thanks for reading this and thanks to all the folks who have posted their ideas in the past that have helped me. You guys are the reason I decided to share my little idea.

Jocko

[jocko]

I guess the pics timed out while I was proofreading and editing, so here they are in the order that I tried to put them in the original post. Sorry for the trouble.

[jocko]

Here are the pics of my testing unit installed and a pic of the leak I found right away.

Note my 6637 filter and home made filter cover. The cover is made from an old baseball jersey my son outgrew. It is polyester knit and spandex. Works great!!

The 6637 install makes installing the testing unit a snap!





Yeah, I know my boots are filthy! I won't bother with cleaning them until I do the crankcase ventilation mod and get all that oil out of the system. Then, hopefully, everything will stay a little cleaner.

[abjacq]

nice.. looks like i haveto try it now

[Jimco]

These work great I made one of these a few years back for my old turbo 240. Much better than using soap and water :P

[abjacq]

how does this actually stay in place? is does it not move under low psi?

[jocko]

The hose clamp on the intake tube holds it in place. From what I have read from other posts, as long as one does not exceed about 15psi, it should be ok. Think about it... engines with an opened up intake and exhaust and a programmer or chip will produce in excess of 20 psi, to the point that the computer will defuel the engine above a certain set point (cant' remember but it seems like I have read that it is somewhere in the neighborhood of 23-25psi). At these pressures, all the boots should stay put and they are also held in place by nothing more than heavy duty hose clamps.

DOH!!!! After my intial posts the other day, I had one of those Homer Simpson moments. It occurred to me - hey stupid, you installed a boost gauge, so use it! When I do more testing, I will watch my boost gauge to see what it does as I pressurize the system and how that compares to the gauge I put on the testing unit. It is made for lower pressures and I trust it. We shall see.

[abjacq]

oh man. thats actually a good idea! ill haveto try this in the next few days. ill let ya know how it turns out. where all should i look with the soapy water? where at on the turbo? if anywhere? thanks

[DIESELSITE]

How are you not presure testing the whole engine? Unless you've plugged off the crankcase tube that is.

Bob

[jocko]

You are correct. Thanks for pointing out my omission. If you have not done the CCV mod, you'll need to plug the tube either internally or externally to isloate it from the crankcase.

Sorry for the confusion.

[jocko]

I promised I would update the thread as I had a chance to do more testing. Well, I hooked it up the other day and watched my boost gauge in my A-pillar pod as the compressor ran. It quickly began to climb and it climbed steadily until it reached about 6-7 psi and then it did not seem to want to climb any higher. At that point, my small aircompressor could not pump a sufficient volume of air to overcome the leaks in my system. I shut off the compressor and stuck my head under the hood and heard air leaking from the boot that exits the intercooler. It was all covered with oily grime, so I expected this. I plan to remove all my boots and throroughly clean them and reinstall them using hairspray as a form of glue (I have seen this recommended by a number of members) and see if that stops the leaks. I did not check with soapy water this time, I just listened for escaping air pressure, which was very easy to hear once I turned off the compressor. Since I could only build 6-7 psi, I will assume that more than one boot is leaking and I will clean all of them before I do any more testing.

The thing I most wanted to point out is that at 6-7 psi, my built-in Slime tire gauge was not giving a reading. The gauge built into the compressor was giving a reading but it was a pound or two lower than that on my boost gauge.

My recommendation is that if you decide to build a similar design, look for a dial type-gauge made for ATVs or some other form of low air pressure gauge. As long as it has the right type of threads to allow it to be mounted in the PVC cap, it should work. No matter what gauge you use, compare the readings to your boost gauge, just to be safe. I trust the boost gauge the most since it is designed to be a performance related, precision instrument (not that an air gauge should not be, but I'm just saying.....) You might be asking, "If you are going to look at the boost gauge, why bother with putting one on the unit at all?" Convenience. If you have a gauge that consistently gives readings within a certain range of your boost gauge (example: always 2 lbs under the boost gauge, etc), you can just do the conversion in your head without having to keep going back to the driver's seat to check your pressure. If you only plan to do this testing with a small 12v compressor with a built in gauge, you might be able to leave the gauge off the unit altogether as long as you are comfortable with the consistency of the compressor's gauge. Either way, this will allow you to watch the gauge while you look and/or listen for leaks under the hood.

In retrospect, I kinda like the fact that the small compressor would not overcome the leaks in the system and continue to build more pressure. It prevents me from over pressurizing and blowing a boot off and, as I make repairs, I should see the small compressor be able to build more pressure. It obviously does not take much pressure to find some leaks, so I am still making progress even though I can't get up to a higher pressure yet. I would expect that as I make repairs, other leaks might surface as I am able to build higher pressures. My goal is to be able to build up to about 15 psi on the system and have it hold there for a while. If I can do that, I will be pleased.

[jocko]

ABJACQ,

I forgot to answer your question about where to look for leaks. First, look and listen around all of your boots and the AIH. Boots seem to be the most likely area to find leaks. If you are lucky, it will build and hold pressure and you will be done. If not, check the boots and AIH first. The IC would be another possibility, but IIRC, it is sandwiched between 2 other heat exchangers, so I would expect that it is very rare for the IC to be leaking (not much opportunity for punctures in there and you would have other A/C and/or radiator failures if you had a puncture that got all the way to the IC. I don't recall seeing any posts where the IC itself was leaking. I am sure there might be common places to have air leaks in, on, or around the turbo, but I have not gotten to that point yet, so I have not researched that. I am working from the easiest to the hardest as I go. Hope that helps.

[abjacq]

oh yeah, definitely helps. thanks a lot. gonna get this done one of these days... just gotta find time hah but thanks

[jocko]

No problem. Glad to help. Hey, I noticed in your sig that you have a couple 99s with the Dp tuner chips. I am really close to ordering one and I am wondering how you like the 120 race? I read a post that said there isn't much difference between the 80 econo and 100 perf tune, so you should get the 120 race instead of the 100 perf if you also choose the 80 econo. How does the 140 aggresssive compare to the 120 race? I drive a 6 speed, so I don't know if that would make much difference in choosing between those 2.

Thanks

[abjacq]

Originally Posted by jocko

No problem. Glad to help. Hey, I noticed in your sig that you have a couple 99s with the Dp tuner chips. I am really close to ordering one and I am wondering how you like the 120 race? I read a post that said there isn't much difference between the 80 econo and 100 perf tune, so you should get the 120 race instead of the 100 perf if you also choose the 80 econo. How does the 140 aggresssive compare to the 120 race? I drive a 6 speed, so I don't know if that would make much difference in choosing between those 2.

Thanks

well, i decided to get the 120 race so i could beat my buddys with quarter mile time. jody told me that this was best for quarter mile so i took his word and went for it. honestly, i hardly ever use the 120. i almost always use 140 aggressive. is someone deserves to have smoke poored on them, then this is what i use it for. I also mess around on the highways quite a bit too, and im pretty much always using the 140, and honestly, did not need to spend the extra 50 bucks for the 120. 80 doesnt seem to do much for me. i try using that and getting the best mileage i can, but its just about all the same. definitely a big power difference between the 80 and 140, ill be sending the tuner back soon for a tow setting though.
oh and btw, with a 6speed, you will poor out so much smoke on the 140. youll love it hah