Compression Test

[jlwelding]

Anybody know how many hours are charged for compression test. I am thinking if it to high might buy my own gauge and do it my self, course I have no idea what one even looks like.

[smokeythedodge]

Anybody know how many hours are charged for compression test. I am thinking if it to high might buy my own gauge and do it my self, course I have no idea what one even looks like.

Glad you finally decided to check it. Here is what I use http://buy1.snapon.com/catalog/item.asp?item_ID=68606&group_ID=1430 Also a gauge that goes up to at least 600 pounds.

[Mopar1973Man]

According to my shop labor book its 2.3 hours for compression test for a 2001 Cummins diesel.

[JOHNFAK]

you doing this JL ?? OR shop ?? or not at all ??

Pics would be AWESOME!!!

I had heard that better than a compression test was measuring the blow by a "xxxxxxx" forget the name ...... basically a tube of water that you measure the displacement of water at various RPM (connectied to you puke overflow line).

ISX posted on one of my threads about it ....... but search funciton here seems broke lately - MI=ike >??

--- Update to the previous post...

This is it

http://forum.mopar1973man.com/showthread.php/2001-high-oil-pressure

at bottom

[ISX]

I actually did this but you MUST use the "T" on the blowby tube with a .221" outlet. If you don't it will push all the water out of the blow by tube. I didn't read the T part Oh and if you put your finger over the blow by tube to keep the water from coming out, it will just push the pressure out of the dipstick, and since the dipstick is in a tank of oil, the principles of hydraulics will push oil out of the dipstick. :banghead: So don't skip the T haha.

[Mopar1973Man]

(Temporary hijack) Actually the search function suppose to be repaired by Version 4.2.0 (Back to the normal thread) I think ISX has all the specs on how to build it now he was playing with it and could exactly get it to work after taking to a few people he got it worked out... There is a tee and offrice added to the setup to make it work. (Never mind... :banghead:)

[ISX]

Yeah you are basically only measuring part of the blow by since the .221 thing relieves part of it. If that outlet is not there, there is nothing stopping it from either blowing out the dipstick or blowing all your water out. What you are building is a crude manometer.

[Mopar1973Man]

Another way to look at blowby... If your blow is so extreme that you loosing large amounts of oil out the breather tube its excessive. If the dipstick is dripping oil its excessive. If the oil cap on the valve cover pop out of your hand while loosen it the blow excessive. I seen this on a 3rd gen... OMG!

[jlwelding]

Sorry guys I just got back in town. Let me see if I got this right, I just need a tee in the breather hose with a cap then drill hole in cap to .221 then fill hose and meassure from line marked with eng. off and just do the rpm examples you gave. Times that by two and that will tell me weather it is crap or not, right?

[ISX]

Sorry guys I just got back in town. Let me see if I got this right, I just need a tee in the breather hose with a cap then drill hole in cap to .221 then fill hose and meassure from line marked with eng. off and just do the rpm examples you gave. Times that by two and that will tell me weather it is crap or not, right?

Yep. You just get a long clear hose then make a "U" out of it, try and make it as straight as possible so it's not a big arced U. But the remaining blowby that is left (that wasn't able to go out the .221" hole) will push the water a certain distance up the tube. Measure how far it went and then do all the math stuff. I would post my video if it wasn't wrong lol. But the pics I made that John linked you to is how you do it.

[jlwelding]

Ok I will do this tomorrow, right off the front of the eng. seems the easiest, it should make the U shape. Thanks for the infoOne other thing, do I need to reduce the hose size to 3/8 or can I just use the same size hose as what comes off the breather?

[guesswho512]

the manometer only measures blowby (ie rings and ?vacuum pump?) compression test would test rings and valves(valve seats) you could also do a leak down test with the tool and compressed air. when i first tried to find the tool, i could only find ones in the ~$100 range. i did just find this one. the stock pic looks a little shorter than the ~$50 ones i found last week, but the description says it works on Cummins 5.9 and for $15 i am going to order one on my next payday http://www.amazon.com/Diesel-Engine-Compression-Test-Adapter/dp/B000HI5AC8 isx...i'm having trouble visualizing the "T" piece. can you snap a pic?

[ISX]

the manometer only measures blowby (ie rings and ?vacuum pump?) compression test would test rings and valves(valve seats) you could also do a leak down test with the tool and compressed air. when i first tried to find the tool, i could only find ones in the ~$100 range. i did just find this one. the stock pic looks a little shorter than the ~$50 ones i found last week, but the description says it works on Cummins 5.9 and for $15 i am going to order one on my next payday http://www.amazon.com/Diesel-Engine-Compression-Test-Adapter/dp/B000HI5AC8 isx...i'm having trouble visualizing the "T" piece. can you snap a pic?

It's just a T, a splitter.. So blowby tube goes in one port, and your manometer hose comes out another. That leaves the 3rd port which you just have a .221" hole in. So if you put a plug in that port and drilled a .221" hole in the plug, that is how it would be.

[thebullet83]

the manometer only measures blowby (ie rings and ?vacuum pump?) compression test would test rings and valves(valve seats) you could also do a leak down test with the tool and compressed air. when i first tried to find the tool, i could only find ones in the ~$100 range. i did just find this one. the stock pic looks a little shorter than the ~$50 ones i found last week, but the description says it works on Cummins 5.9 and for $15 i am going to order one on my next payday http://www.amazon.com/Diesel-Engine-Compression-Test-Adapter/dp/B000HI5AC8 isx...i'm having trouble visualizing the "T" piece. can you snap a pic?

i think that one you found on amazon is for a 12v. at least by the threads on the one end. i might be wrong though.

[ISX]

i think that one you found on amazon is for a 12v. at least by the threads on the one end. i might be wrong though.

I think your right. Those look the same as my injector hold down nut.

[jlwelding]

Ok here it is @ 2200 2 3/4 inch rise

2500 NO CHANGE I thought that was strange

2800 4 11/16

Originally Posted by JOHNFAK

Where do you hook up the mechnical gauge to measure oil pressure

Also ...... how much blowblack when the engine is hot ?

I have almost none when cold ........... but once warm ...... can definately see it from the 'crankcase modification' running to bottom via pvc pipe - but how much is normal ?On mine there is a 1/8" NPT plug on the top of the oil filter mount, probably be the easier place to do a test gauge.

As for how much blow-by, this was on a thread a while back:

You need a blowby tool.

The Cummins blowby orifice tool is simply a tee with one .221" (15/64-in) outlet. Connect one end of the tee to the end of the blowby tube. Put a manometer on last tee outlet. That is your blowby tool. They sell them at the Cummins, but I have made my own plenty of times, less than $10. A simple manometer can be made by looping into a 'U' 6 feet of clear tubing with water in it half way. Measure how high the water level rises with a tape measure, multiply it by 2, convert it to LPMs.

Rough conversion is 1"= 27 lpm, add 3 lpm for each one inch (1/2'' of rise in the tube) of water

The reason for multiplying by 2 is that inches of water equals the water rise in the open end of the tube plus the inches the water is pushed down on the engine side of the water tube. For simplicity my numbers below are the measurement of rise only.

Cummins new 5.9 engine numbers are:

63 liters per minute(2.5" water rise) @ 2200rpm,

76 L/Min (3.5" rise) @ 2500rpm

85 L/Min (4.5" rise) @ 2800rpm.

Worn engine that needs rebuilding are roughly double i.e.

126 L/Min(10.5"rise) @ 2200rpm

152 L/Min(14.5"rise) @ 2500rpm

170 L/Min(17"rise) @ 2800 rpm

Beside indicating a compression problem the valves could also be out of adjustment.

Another way (mine), same idea, is to block the blowby tube with a 1/2'' pipe nipple with a cap that has a 15/64 hole drilled in it. Use 3/8'' id looped clear tubing with water in it slipped over the oil dipstick tube. Other tubing end remains open. Use a sharp tipped felt marker to mark the water level with the engine off, have a helper start an already warmed up engine and run the rpms up to 2.2, 2.5 & 2.8k rpms. Mark each water level with the pen, measure the distance from engine off mark then multiply each by 2.

This is all very simple to do, just hard to explain with words.

--- Update to the previous post...

Ok here it is @ 2200 2 3/4 inch rise

2500 NO CHANGE I thought that was strange

2800 4 11/16

Ok this is what I came up with.

So blow by test just shows that the rings are good and what else? What about cam lobe going flat?

I have a oil test sample kit coming in soon this should tell me if the cam lobe is going flat if there is high metal content.

The reasone I am testing oil is there is a loud tick when eng. is cold, I looked for exhaust leaks and cant find anything. It got to be in the head. Valvues been adj. 5 times so you would think I would have got it right by then, 8 intake 18 exhaust. The thing I thought about the click is exhaust leak, cant find so replace all gaskets? You would think there would be black soot somewhere.

Putting on wire harness this morning, wish me luck.