Oil fumes, blow by? Need new rings?

spence88mph · 11-24-2008, 01:50 PM

Hi Guys,

Ever since I turboed my car I've noticed oil fumes or vapor from the oil tank which is now vented to the atmosphere via a little k&n filter (so the boost wont pressurize it, it's usually feed back into the intake, it's a 3.2). When at operating temp with the oil cap off I get a fair amount of vapor coming out, it stinks and also comes out the small filter. The car doesn't blow smoke on throttle though and is still making lots of power, oil consumption is pretty normal though the car gets very little use.

Does this mean there's blow by? It did it as soon as I vented the oil tank, before I had even boosted the car so I'm thinking this was already there but just burnt through the engine previously. If it is normal I've been thinking about running it through a charcoal filter then venting it as the smell gets to me after a while of driving.

Thanking you in advance, Spence.

rsrmike · 11-24-2008, 03:41 PM

Normally, on the turbo cars, the tank is vented into the intake system, just before the turbo inlet, versus the close proximity to the throttle body as your car was in NA configuration. Depending on how your intake is plumbed, you may get good results fabricating a vent into the intake between the air filter and the compressor inlet.

Also, if you removed your catalyst in the process of converting to turbo, that will definately aggrevate the fumes. Just a rich running car w/ no cat can get to you after a while, I would imagine an oiltank venting to atmosphere would be just too much on a street car after a while

$.02 of course

F350Lawman · 11-24-2008, 05:09 PM

Mine did that when I removed the intake and went with a catch-can vent filter setup. It was no big deal when the engine was healthy. When the rings let go it worsened though, you will see the smoke come in puffs in time with the cylinder(s) with the bad ring. Take the cap off the tank and see if it is in time with the cylinders firing and compression blowing by.

spence88mph · 11-24-2008, 06:39 PM

thanks guys so a certain amount is normal?

I've been looking for an excuse to do a top end and go to 8:1 so not too worried if it does need new rings but I didn't want to do it for a good 6 months. I guess a leak down test will reveal all? I haven't ever done one on this engine.

I did want to reuse the cylinders, I'm hoping ring damage hasn't scored them...

Thanks for the replies.

DonE · 11-24-2008, 06:49 PM

Do a compression test and/or a leak down. During the leak down, listen for air escaping through the exhaust, intake and case. If you hear air through the case, it's rings.

Flieger · Flieger's Garage

DonE,

Where do you get your P-51 photos for your avatar?

spence88mph · 11-24-2008, 08:55 PM

Stop Bogarting my threads Flieger!

DonE · 11-25-2008, 05:04 PM

Quote:

Originally Posted by Flieger

DonE,

Where do you get your P-51 photos for your avatar?

It's in our hanger here in Peachtree City, so it's easy to get pics. Back on topic, when we do leakdowns on it, we position the motor to TDC using the prop. At 100 psi in a single cylinder, the prop will lift you off the ground if not perfectly set on TDC. 8% is acceptable on a cold motor. Also, plugs are $100 each. It needs 24.

A930Rocket · 05:32 PM

That makes our hobby look affordable!

Quote:

It's in our hanger here in Peachtree City, so it's easy to get pics. Back on topic, when we do leakdowns on it, we position the motor to TDC using the prop. At 100 psi in a single cylinder, the prop will lift you off the ground if not perfectly set on TDC. 8% is acceptable on a cold motor. Also, plugs are $100 each. It needs 24.

DonE · 11-25-2008, 06:01 PM

Prop - $60,000
Merlin fingers (cam rocker arms) - $15,000 (full set)
Radiator - $16,000
Engine rebuild (long block) - $145,000
taking the controls - priceless

psalt · 11-26-2008, 03:05 AM

Hello Spence,

Some by blow is normal and it does increase with age. Getting the hot vapor and oil out of the intake air is a good thing, they both have the effect of lowering the mixture octane and the knock limit. Take a lesson from the pre-60's road draft breather and use a couple of 90 degree bends in you breather tube before the filter. The idea is to have a large diameter tube to keep the velocity down and the suspended oil will crash into the 90's and drain back into the tank. On a 911 oil tank, I use two 90 degreee 3/4" copper fittings soldering into a "Z", then a small K& N filter. Adjust the fittings so that the breather is at the highest point, then solder them together. The filter will no longer drip oil if mounted correctly.

spence88mph · 11-27-2008, 01:20 PM

Thanks Paul,

My filter doesn't drip any oil, only vapor makes it's way out of there. The vapor smell is starting to make me feel ill. Stopping me from wanting to drive the thing, almost. Do you think if I ran the pipe out to the back of the car near the exhaust exit (mine exits on the passenger side in line with the oil tank) it may help or would oil possibly run out the line, maybe a syphon effect? I was also thinking if I could run it through a charcoal or carbon canister before the filter it may take away the smell.

A930Rocket · 11-27-2008, 05:03 PM

Sooner or later the fumes are going to saturate the filter and from there it drip. The idea is to condense or mechanically convert the oil fumes to a liquid and either drain it back to the tank or into a tank with a breather. I've got a moroso breather tank I got from summit racing. It has the breather on top and a valve on the bottom to drain the oil.

I need to plumb in a drain from the bottom back to the tank one day.

spence88mph · 11-27-2008, 07:43 PM

Thanks 930 rocket, I'll have a look for something like it, do you think it will also reduce the smell?

I found this article on a DIY separator: http://autospeed.com/cms/A_110826/article.html

Basically a container you run the fumes through filled with stainless scouring pads! wouldn't you just connect the pipe to the bottom of such a tank so the oil runs back down instead of having to empty it or a separate pipe going back?

A930Rocket · 11-28-2008, 05:00 PM

I think if you can mimimize the fumes, you will reduce the smell.

If you can get it to go in the bottom and the line is vertical, it would help, but the bottom fitting is usually small. My inlet fitting is a -16 and my vent hose fits right on it. A good idea is to stuff it with course stainless steel wool and drain it back to the oil tank from the bottom.

Quote:

Thanks 930 rocket, I'll have a look for something like it, do you think it will also reduce the smell?

....wouldn't you just connect the pipe to the bottom of such a tank so the oil runs back down instead of having to empty it or a separate pipe going back?