Blowby

[mrmo]

Took my oil fill cap off while the little oil burner was runnin, and HOLY CRAP, ya awta see the blowby? Yall w the diesel check it out, i thought my Powerstrokes had alot, this thing smokin for sure

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[Rusty PW]

Next under the hood. I have to check it out.

 

[mrmo]

i was pretty surprised, figured it wouldnt be much...i was wrong...

 

[j.o.y.ride]

Here I thought "blowby" was going to be some new gadget to buy

 

[Keith Diesel]

These engines use "low-tension" piston rings, some engines seem to set the rings better than others. Is this a low mile engine? It is good to pull a mid-size trailer for a few hundreds miles with varying speeds. This will help set the rings and can reduce blow-by. I run the oil level closer to the min line as reduces oil foaming from rotating crank and less oil through CCV system.

 

[Jefe1018]

I’ll give it a shot tomorrow, I’m curious now.

 

[mrmo]

These engines use "low-tension" piston rings, some engines seem to set the rings better than others. Is this a low mile engine? It is good to pull a mid-size trailer for a few hundreds miles with varying speeds. This will help set the rings and can reduce blow-by. I run the oil level closer to the min line as reduces oil foaming from rotating crank and less oil through CCV system.

Just hit 8700 & change, i did a decent break in. Back roads thru the mtns for several 100 miles, then several trips of 700 miles on the interstate w varying speeds...oil consumption stopped around 2000 or so. Fairly sure the rings are sested. I keep oil at full on dipstick, doesnt smoke or anything. I was just surprised how much blowby was coming out. Not pressurized really, just vapor emmision

 

[Jefe1018]

I’m at 10,xxx miles and no visible blow by here. I drove about 5 miles to warm it up before I took this video. Every time I spot check my oil it looks to be in spec.

 

[1is2many]

There is a good video on why these engines benefit greatly from a catch can...

 

[mrmo]

There is a good video on why these engines benefit greatly from a catch can...

I looked around, who is makon a catch for the Gladiators? I have one on all my other vehicles. I want it to look like it was factory installed. Ive looked at where i could cut the molded line going to the intake, route to a can, then tie back in but make it a clean install Not all cobbled up

 

[Rusty PW]

I've seen that video before. Far as I know. No one makes a JTD oil catch can kit. You have to piece one together. Sounds like a project to do after the 4th of July.

 

[1is2many]

I looked around, who is makon a catch for the Gladiators? I have one on all my other vehicles. I want it to look like it was factory installed. Ive looked at where i could cut the molded line going to the intake, route to a can, then tie back in but make it a clean install Not all cobbled up

Yeah his is "rigged" up but it works and he has a ton of miles... I will look but haven't yet, I just got this thing.

 

[Maximus Gladius]

Blowby is something I’ve never put much thought into until a couple months ago. My neighbour bought some used Honda and asked me to look at it. (He should have had a mechanic look at it, piece of crap). With engine running he pulls off the cap and it blows out of his hand! He catches it and says “it’s good, right?!” WTH??!!

There’s similar air flow from my hair dryer on high! I was shocked and said that is so NOT RIGHT. I then looked it up on YouTube and in a nutshell, it’s air blowing by from the intake, passing through the rings and into the crankcase. If it isn’t blowing the seals, it’s coming out the PCV or you feel it when the oil cap is pulled off while engine running.

Told him his Honda is crap. So we turned out attention to his 2022 electric hybrid Jeep he got earlier this year. He had been out in it all day so the engine was nice and warm. Fired it up and pulled the cap. So much air was blowing out, I put my hand over it and it was blowing oil out as well, covered my hand and I slapped the cap back on. ?????!!! I asked him what the hell is wrong with those rings? Looks like weak compression. Should get that in I told him.

He then asked about my Gladiator. I’ve never checked the Blowby in it. I’d been out with it so the engine was hot. I fired it up and pulled the cap. NOTHING. It wouldn’t have blown a feather off my finger, absolutely no air flow. This engine is a good one!

 

[ATX_Jeeper]

I checked mine after everything was at operating temp and was surprised at how much vapor was coming out after the oil cap was removed. My video won't load by it was double to triple the amount compared to @jefe's video in post #8. I didn't check to see if there was enough pressure to wiggle the cap but it didn't appear to be enough. The truck is new to me and has 19k miles so I would be surprised if the rings were not seated by now.

 

[ShadowsPapa]

Blowby is something I’ve never put much thought into until a couple months ago. My neighbour bought some used Honda and asked me to look at it. (He should have had a mechanic look at it, piece of crap). With engine running he pulls off the cap and it blows out of his hand! He catches it and says “it’s good, right?!” WTH??!!

There’s similar air flow from my hair dryer on high! I was shocked and said that is so NOT RIGHT. I then looked it up on YouTube and in a nutshell, it’s air blowing by from the intake, passing through the rings and into the crankcase. If it isn’t blowing the seals, it’s coming out the PCV or you feel it when the oil cap is pulled off while engine running.

Told him his Honda is crap. So we turned out attention to his 2022 electric hybrid Jeep he got earlier this year. He had been out in it all day so the engine was nice and warm. Fired it up and pulled the cap. So much air was blowing out, I put my hand over it and it was blowing oil out as well, covered my hand and I slapped the cap back on. ?????!!! I asked him what the hell is wrong with those rings? Looks like weak compression. Should get that in I told him.

He then asked about my Gladiator. I’ve never checked the Blowby in it. I’d been out with it so the engine was hot. I fired it up and pulled the cap. NOTHING. It wouldn’t have blown a feather off my finger, absolutely no air flow. This engine is a good one!

I thought yours was gas?
Should be a slight vacuum.
Vacuum in the crankcase helps seal rings - pressure differential seals rings. Higher pressure on the top, lower pressure on the bottom, the shape of the rings causes them to push against the cylinder wall. Also pressure from above getting behind them a bit helps seal.
It's one reason some race cars are built with a vacuum pump to evacuate the crankcase and keep a bit of vacuum down there - helps seal rings.

I'm talking gas - since I thought yours was a gas engine.

These guys are talking diesel - still - never seen modern one with anything pushing out the top.

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