Excess Exhaust Issue

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Bart
Glow Plug
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Joined: Thu Jul 21, 2011 6:54 pm

Excess Exhaust Issue

Post by Bart »

The last time I had my engine worked on the mechanic installed a hose from the top of the engine down along the exhaust pipe out to the back of the van. I believe it was to relieve pressure inside the engine. Anyways it runs great however there is a lot of exhaust that exits that pipe, and it's really stinky outside and inside the van. A friend who isn't too familiar with diesels suggested a breather box. I looked into them and it sounds like they are used for air-cooled buses/vans, and mostly to control any loss of oil out of the top of the engine. Do you'all think installing one on my water cooled diesel vanagon would help? Any other suggestions to deal with the smoke/odor issue?
caveman
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Re: Excess Exhaust Issue

Post by caveman »

If you have so much smoke coming out of that "breather "pipe, your ,engine is finished. There should be a negligible amount of crankcase smoke . Your mechanic put a bandaid on a much bigger issue. If you believe the engine is still good, do a search for the original style breather system for a diesel. The best is the type that uses the black hockey puck on the valve cover
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Bart
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Re: Excess Exhaust Issue

Post by Bart »

The engine was just rebuilt a couple of years ago. It always was a little bit of a smoker/stinker. I'll take a look for those breather box you mentioned and see if it aids the problem. Thanks for the input and if anyone else has an idea, let me know...
Fatmobile
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Re: Excess Exhaust Issue

Post by Fatmobile »

I'm not sure why you have stinky oil fumes in your engine bay.
Sounds like the crankcase is vented to the air.
It should go to the intake.
Try an oil catch can if there si so much blowby that your mechanic is afraid of too much oil getting into the intake.
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Bart
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Re: Excess Exhaust Issue

Post by Bart »

Yes - the crankcase is vented into the air, a change that occurred last time they did some work. I will reroute it back to the intake, which is where it was before. I'll let you know how it goes...
Fatmobile
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Re: Excess Exhaust Issue

Post by Fatmobile »

A runaway is caused by oil in the blowby entering the intake and being burned.
Turning the key off won't stop it.
The faster it goes the more oil gets blown into the intake.

They might have unplugged it for fear of runaway,.. if there is alot of oil coming from it.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
Bart
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Joined: Thu Jul 21, 2011 6:54 pm

Re: Excess Exhaust Issue

Post by Bart »

Yeah, there's definitely some oil coming out of the hose from the crankcase. Looks like I'll have to install some sort of oil catch/breather box to prevent oil from entering into the intake. Looks like there's lots of different kinds around, from fancy to some dude who said that he made one out of a 2 liter coke bottle. Don't think I'll do the coke bottle (for obvious reasons) but something else that will allow easy access to the filter for cleaning/monitoring purposes. Any recommendations on one to purchase?
rsxsr

Re: Excess Exhaust Issue

Post by rsxsr »

This one is nice. http://www.airnowsupply.com/provent.htm You should consider solving the excessive blowby at some point.
Bart
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Re: Excess Exhaust Issue

Post by Bart »

Thanks for the tip I like the looks of that one. Do you think a breather box in series is excessive or a good idea to help with filtering of the oil/crankcase exhaust? I was thinking it wasn't a bad idea, and wouldn't hurt matters. And I agree, at some point I should look into the cause of the blowback, and find those valve grommets that are responsible for the leakage. For now though, besides the fumes, she's running like a champ. Just gonna get that exhaust thing in order so that I don't have to worry about my one year old sitting in the back while we're heading to the woods...
Bart
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Re: Excess Exhaust Issue

Post by Bart »

So I purchased the Mann ProVent CCV oil catch can (linked earlier). It's a little pricy @ $150, but it has many nice features and looked to me to be one of the best out there. Seems like there are a lot of others that are just not well thought out, tough to clean, and don't seem to do a good job of filtering the crankcase fumes. You get what you pay for. It has an easily removable filter, which only requires you to unscrew the top and not disassemble the device, and a hole at the bottom where you can add a catch to grab the extra oil that gathers. Installed it with the aid of a few hoses and clamps from the local hardware store. Of course, I had to make two trips because of two slight mismeasurements. But started her up, and the exhaust that I use to get from the freely vented crank case is now rerouted into the intake (as it originally was), without fear of oil getting in there now. It has taken care of my exhaust issue. Sure, it puffs out some smoke when she starts, but no more bad fumes in the van itself and I don't have to feel bad for those people behind me at the stop light. It sounds like it's even running a little tighter too, which a few people told me might happen as a result. Gonna take it to the woods this weekend, so we'll keep checking on it to make sure everything is running smoothly. Down the road I'm sure I'll need to address the larger issue of a poor gasket or two around the values. Thanks for the help you'all...
Kevin
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Re: Excess Exhaust Issue

Post by Kevin »

When I was installing my catback exhaust, one of the mechanics at the garage I was doing it at mentioned that after a while, I would start to hear a noise that would drive me crazy trying to figure out what it was. He said I would think it was a wheel or something. I kind of shrugged it off and never had any noises until about a year later. He said something about it being from all the excess space left from the big clunky stock exhaust... I don't think the noise I'm hearing is the exhaust "drone".. but it's more like how he said.. it makes me think it's a wheel because the noise is controlled by the speed of the rotating tire, and has a chopped rhythm.. like a washer machine on the spin dry phase. Is this actually just the exhaust noise bouncing around there and escaping and chopped up by the tires, is this exhaust "drone"? It is definitely getting progressively worse.
bscutt
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Re: Excess Exhaust Issue

Post by bscutt »

My son's Corrado does that - it's basically "beat" frequencies where there's a difference between the frequency of two or more things resonating at slightly different frequencies. Google that term and see if it makes any sense with regard to this problem
Bob

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300Dman
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Re: Excess Exhaust Issue

Post by 300Dman »

I am curious that no one has commented much on the Rebuilt Engine that has what must be more Blow-by then normal.

Either the Engine was not completely rebuilt or something was done improperly.

Unfortunately the common use of "Rebuilt" means different things to different People.

As an example a Person who replaces the Rings and Bearings on a used Engine and does nothing to the Bore in my mind as not Rebuilt the Engine Block.
Sometimes the above results in an improvement other time new Round Piston Rings in a in the used not round but oval Cylinder bores result in Blow-by and even Oil burning.

Worn Exhaust Valve Guides and or Exhaust Valve Stems can allow the Exhaust gasses inside of the of Engine and cause increased Blow-by.
If an Engine Block was rebuilt but the Cylinder Heads was not rebuilt the above can happen.
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