Smoking Oil Filler Breather

[jrcotner]

I removed the breather tube which connects the oil filler neck to the air intake, and noticed there was a lot of smoke coming out of the oil filler neck side. There is also a good smear of oil inside of the air intake. Is this normal? If not, what would be causing this?

[edzz]

Could be rings and or valve guides. A compression or better yet a leak down test would give you a good idea.

[westernair]

Could be rings and or valve guides. A compression or better yet a leak down test would give you a good idea.

Ed is correct Always start with both a leak down and complression check when it comes to internal motor issues.

Additionally have you looked at your oil? with the cooler weather upon us could it just be an oily steam comming out? if You see milky oil deposits just under the cap that is probably what it is.

[Twin Pinzies]

That's funny, I just experienced the same exact thing yesterday! I was kinda wondering myself too...

[jrcotner]

I get the milky goop in the breathers and clean them out every few months. The discharge from the breather smells like exhaust. I'll do a leak down and compression test this weekend.

[westernair]

number 3 cylinder is the one that typically goes first for some reason, may be time for a new set of rings. you will know once you do the compression and leak down tests.
Having just finishing the partial rebuid of my motor (pistons, rings and head rebuilds), I can say it is a fairly easy task. it does take time but no special tools or training is needed. Taking some of the cooling tin off and putting it back on was the hardest part for me. Took me a part of a weekend to disassemble and send the heads to a machine shop. next weekend I put it together and was driving it.
Rings cost 200 for a set, head rebuilding only cost me $220. then about $100 in misc supplies.
I am not saying this is what you will need, just pointing out that even in a worse case senerio it is not unsurmountable.
I figure if I would have taken it to a shop, it would have been $3500.

[jrcotner]

I've trolled for leak down procedures and found some conflicting info. Should it be done at TDC or BDC, and what is an acceptable amount of percentage?

[pinzinator]

TDC. Google "cylinder leak down test" and you will get all of the information you need.
I did the test on my 710 once and it was within normal parameters (TDC).
I have also been told to do the test at BDC because the engine can rotate, but everything I read says TDC.

[westernair]

I have always done it at TDC.
10% or less is great, or at least all 4 within 10% of each other. Report your findings both for the compression test and the leak down. Someone like Jim L will chime in and let you know his thoughts. Everytime I have called Jim about a problem, these are the very first questions he asks.
I am no expert on these motors like he is so I will let someone of his calaber respond.
Hope it is nothing major.
Good luck

[edzz]

Look here Jim makes some good recommendations. viewtopic.php?f=12&t=6604&hilit=leak+down+tdc&start=0

[jrcotner]

I'm still looking for a leak-down tester, but did a compression test this weekend and got 150 on cylinders one and two, and 130 on cylinders three and four. Any thoughts on these results?

[ExpeditionImports]

We prefer to see compression results within a 5% variance. However, doing a compression test without adjusting your valves quite often gives incorrect information. If we are outside of parameters, we will adjust the valves and then re-test.

Air Cooled motors are notorious for the water/sludge buildup in the filler neck. It is also very common to have crankcase pressure on these motors and is not a worry assuming your leakdown/compression are good. Hard to quantify on a BB what is acceptable and what is not when you pull the fill cap/intake tube, but I can tell you I have never seen a Pinz motor that did NOT have this.

If you run your truck for short bursts, around town type of trips, you will see more of the moisture buildup in the filler neck/cap versus if you give the engine oil time to evaporate the water out via longer engine runs.

Cheers,

Scott

[edzz]

Thinking out loud here, I wonder if adding a oil pan heating pad would help to reduce the condensation?

[krick3tt]

When in WA I noticed the white foam, very moist environ there. No so in CO as the humidity is very low.
Did not notice adverse effects though. Longer runs will help get the temps up and less buildup.

[jrcotner]

I got a leak down tester and went through the engine last night. I adjusted the valves first then did the test on a warm engine. Here's what I got:

Cylinder #1: 12%
Cylinder #2: 14%
Cylinder #3: 40%
Cylinder #4: 45%

I ran through test twice and got results +/- 5% for each cylinder between round one and two. All of the plugs look good (dry light tan). I couldn't locate specific locations of leaks during any of tests, though on cylinders #3 and #4 tests there was a change in tone when I put my finger over the dipstick hole. Also, I found gas had leaked from the carbs on the passenger side some time during the tests. The carbs were rebuilt less than a year ago.

Clearly there is something going on in cylinders #3 and #4. Any more thoughts on how to proceed from here? I'd like to exhaust all of my options before I pull the engine out.