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Slobbery Deere, blowby question
- Thread starter fast_st
- Start date
I have an OTC leakdown tester but have never used it is it suitable for Diesel engine use? Nobody at work has ever talked about doing a leak down or compression test. I don’t have a ton of engine work experience yet either (we have a specialized guy who does most of the work)
So, I gave the manamana test today! step 1, don't pull the dipstick at idle, you get a nice spray of oil vapor, mark tube install on dipstick filled with super orange washer fluid as all the water around is frozen.
At idle, 1.5 inches displacement, at full throttle someplace between 2.25 and 2.5, there was a lot of wind from the fan at full bore.
At idle, 1.5 inches displacement, at full throttle someplace between 2.25 and 2.5, there was a lot of wind from the fan at full bore.
Well, if you could find a 12/14mm adapter to your fuel injector. or get some dummy injectors.
mg2361
Senior Member
Yes. I made an adapter for my leak down tester that fits the compression testing adapter.
Too much.
RZucker
Senior Member
I've used an extended rubber tip blowgun for a "quick and dirty" test to see where the leak is. Just keep your fingers out of the belts.
mg2361
Senior Member
Usually a converter stall will be enough to load the engine to rated rpm (rated rpm could be anywhere from 1800 - 2200 rpm, each family of machines have a different spec). Sometimes a combined stall (converter and hydraulic) is needed to reach rated rpm. Sometimes the blowby test fails just at fast idle without a load. But for Deere it should not exceed 2 inches.
John C.
Senior Member
The spec on most Japanese engines is one inch of water at full load. I did some Cummins engines a few years back where they put a restrictor in the breather tube and then check pressure. If the engine was in a warranty period, Cummins would just keep giving you higher pressures for the spec. When they got to sixteen inches, I didn't care what the factory specs were. There was something wrong with the engine. Cat doesn't use the crankcase pressure test. Their breathers were so big you would never get a reading. They use a wind meter plumbed into the breather. So much air has to go through the meter to get a reading. I used to do the manometer reading anyway on the smaller engines. I found out that the smaller engines had more and more pressure as they got newer. I'm guessing they had to plug the breathers into the turbos to keep from blowing out all the gaskets and seals on the engine. On the politically correct engines now days, the manometer is of no use so it just stays home on the tool box.
GregsHD
Senior Member
In the CTM1 6466 service manual it specs maximum blowby out crankcase breather tube @ 494 cu ft/hr, wonder how one would test that? (Edit) I didn't see JohnCs post above...
I've got the manual in PDF if you need it.
I've got the manual in PDF if you need it.
Last edited:
partsandservice
Senior Member
Take the turbo drain loose and run into a jug and see if the blowby goes into the jug.
Truck Shop
Senior Member
Crankcase pressure or just breathing hard, I have seen some engines that put out very little crankcase vapor but plug the breather tube with your thumb and in a few seconds it's pushing
oil out the dipstick tube and that includes Cat, Cummins and Series 60. But hot even with high hours I expect to see a slight/steady vapor fog out the breather. It's when you see it huffing
a vapor out the breather or oil fill that is concerning. And with 29,000 hours I would expect it to breath hard. The 3406 Cat is one that on the fuel island it's pretty common to see vapor
floating out below engine after it just came off the highway. The 12.7 L Series 60 in the tow truck I drive breathes hard but runs fine and has a long way to go. Until I see it huffing
it will just run the way it is. In most cases a percentage blowby test doesn't really mean squat, like I said breathing hard doesn't mean it's dead-Huffing She's got a problem, and that ain't
spray paint in a sack either.
oil out the dipstick tube and that includes Cat, Cummins and Series 60. But hot even with high hours I expect to see a slight/steady vapor fog out the breather. It's when you see it huffing
a vapor out the breather or oil fill that is concerning. And with 29,000 hours I would expect it to breath hard. The 3406 Cat is one that on the fuel island it's pretty common to see vapor
floating out below engine after it just came off the highway. The 12.7 L Series 60 in the tow truck I drive breathes hard but runs fine and has a long way to go. Until I see it huffing
it will just run the way it is. In most cases a percentage blowby test doesn't really mean squat, like I said breathing hard doesn't mean it's dead-Huffing She's got a problem, and that ain't
spray paint in a sack either.
John C.
Senior Member
When I'm looking at older machines with a breather hose and see any vapor coming out, I have to measure the crankcase pressure, if for no other reason than to provide a fact that can be checked again in the future. The decision on whether or not to tear into the motor is dependent on a lot of factors that are the concern of the owners. In my mind if it starts and doesn't use so much oil that it shows a stream on the ground, its good enough, unless there is some outside authority to force me to shut it down.
Truck Shop
Senior Member
Agreed.
partsandservice
Senior Member
Boost like anything else will take the path of least resistance . When a turbo pumps boost into the crank case it looks like blow by. The turbo drain should only have oil draining out never under pressure. Hence the jug. But I concur with the posters before that with those kind of hours I would just go on and build it. Can it be in framed? Of course turbo and injectors would need to be addressed as well.
Well if the manometer reads pressure and you could guesstimate the cross section. Of the breather, assume low friction loss and put in the numbers.