pantera38

Hi,
I'm looking at 2 used sets of CMI headers - I think they are considered the E-top (2 piece design).
How do you go about testing or checking for leaks?
Are there "do it yourself" kits or do you need to take them to an engine shop or CMI to find out if they are ok?
Do the welded SS headers (regardless of make) typically rot out at the collector flange or on the head side? What happens if a tube is dented and the inside wall contacts the outside - is this destined to be a failure point? Any first hand knowledge? I don't know if they have been used in salt, but would assume thay have been.
thanks for the help.

puder

they leak at the flanges where they bolt to the engine.

generlaly you get tiny pin holes. Go to home depot and buy some fittign adn you can make a testing rig. Can one end of teh water fitting and hokoup a leakdown guage on the othe rend. then presureize teh thign and see if it leaks out.

youcan also us teh same rig witout the leakdown and just presureize it up to like 50-75psi abnd submerge the header in a tank of water. then look for bubbles. if its on the flange it can prolly be fixxed. Just make sure that when youa re done baoting you A. flush teh header jackest with fresh water. B. drain them after flushing so h2o (fresh/brackish) isn't sitting in the jackets.

i'll post a pic of the tesing rig i made later on.

RLW

50-75 PSI is way to high and not necessary. You'll probably do more harm than good at that pressure. You could end up damaging the header. Your engine certainly doesn't run that kind of pressure.
I would plug off each individual header pipe at the Flange location, with pipe plugs (if of course there is a threaded fitting to put the plug in to). Then I would make up a fitting that connects at the water outlet connection at the top of the elbow of the header. I used an assortment of brass fittings, rubber hose, and hose clamps for my apparatus. This fitting would have a pressure gauge and small ball valve ( with the gauge on the downstream side of the ball valve) so you could meter in 20-25 psig of air pressure off your compressed air source. Soak the area at the Flange, as Puder recommended, with a leak detector solution such as Snoop. You could also use a soap and water solution. The tank of water method works also but it is easier to find an external leak with the leak detector solution. It will form bubbles, kind of like looking for a leak on a tire inner tube. If there is an internal leak, you have to have the ability to pressurize the water jacket and then turn off the air and see if it holds the pressure. If it leaks down (drops in pressure) you either have a leak at your plugs and fittings/testing apparatus or an internal leak that you can't visually see.
Good Luck!

martiniboat

Pantera, you're certainly asking all the right questions.

Speaking from experience, stainless steel headers have a finite life expectancy due to the heating and cooling cycles that they are subjected to over their lifespan. The more hours on the header the greater the probability of cracking. Use your own discretion.

Fifty PSI is fine for testing those headers

Sincerely,
Brian Kamrath

martiniboat

Almost forgot,

RLW, is that a Cig or a Magnum in your avatar? It's a small picture. I've always loved 27" Magnums, I need one to restore.

Brian

RLW

Brian,
That is a 1989 27' Activator and I'll stick to my pressure recommendations.
Regards, Russ Withiam

Johno

Pantera 38,
I bought a used set, they cracked after 20 hours inside the collector. CMI checks the header up to 60psi for leaks. I bought the new Uni-tops from Teague $1895 + shipping. If you have a std Bravo setup they are great. No leaks where tail pipes join up. Iam pleased with the new headers, always thought they would last forever. I should have bought new. Unless they are a give away, buy new & atleast you'll know where & how they have been treated.
John

bob_t

I have just gone thru leak testing my 500EFI Merc headers. Only have 100 hours on them and just over 2 years old. Pressure tested 1st time by filling with water at 60 psi (house pressure regulator) via garden hose/adapter to header and blockoff at jumper. We let all air bleed out of jumper before blocking it off. Found several of the weld start/stops leaking where the 4 pipes join the 4 hole plate. Also found a leak (crack)at the machined tailpipe flange face. Those welds were poor quality Looked inside each tube with light and mirror to check for internal leaks, none found, while pressurized with water. Had all leaking welds repaired, flange face/inner pipe weld repaired and remachined and retested using air at 75psi and submerging the header in water. No more leaks found - also did leakdown test with air and pressure gage - no leak down. The header/tailpipe flange on the tailpipe also looked really bad - much pitting/cracklike lines in metal surfaces. Had those repaired (weld and remachine) also. No really good way to pressure test the tailpipes with silent choice because of the shapes and locations of the water discharge ports. The reversion cones that were in the tailpipes were nearly gone, rotted right out of the tailpipes! I had new reversion cones fabricated, old ones cut out, and new ones welded in. Remember, these only had 100 hours and 2 years old. Boat was rarely in salt, but regularly in brackish water and flushed after every use, according to previous owner. This doesn't say much for the life of 316L/317L stainless steel headers!

jrz

Pressure tests at CMI are done at 60 psi,using air in the water jacket area. To Bob T give me the serial numbers off of the header flange and I will tell you the real age of your headers. As for weld Quality and materials I will put ours up against anybody in the bussiness.

bob_t

The boat and engine are 2000's and were not put into service until late 2000. Build date on the boat was late 1999. Engine hours were 125 hrs, per Merc's scan tool, when the leaks were evaluated - mid July of this year. I will get the serial numbers off of flanges the next time I go out to the boat, probably this weekend - it is not stored at my house. I would prefer to call you direct instead of dragging this thru this website/thread. There were water "trails" visible on the tubes below the collector. When we pressurized the header, there several places where the welds were weeping water - and those places were at the weld stops/starts (there were visible craters in the welds, where the welder stopped the weld). Regarding the weld quality comment, I corrected my post above to those welds where there were leaks. Many of the other welds looked beautiful - also, many looked like auto-tig, and that is nice to see! I have pictures of what was left of the reversion cone when I had what was left of the one cut out and replaced. I don't post pictures on this site, and would not anyways, because I am not trying to bash/trash any one company's product! I am not trying to condemn your specific material, either. I do know quite a lot about welds and metals ( that is a large part of my engineering specialty) and I know what the differences are in 316/316L, 317/317L - 317 being nearly the same as 316 but slightly higher in chromium, molybdenum, and nickel, which enhances the 316's corrosion resistance, and the L meaning Low carbon, which enhances weldability. Since these are austenitic stainless steel, they don't repsond to heat treatment, although after weld, an anneal heat treatment is recommended to tie up the carbides that may come out during weld, giving better corrosion resistance in the areas of the welds. Again, I am not bashing your material, just pointing out that even "good" stainless steel can and will corrode.