Too much oil coming out from head breathers, on a 1973 914 2.0 FI Options

[velum]

Hi!

I have oil leaking from the air filter in my 1973 914 2.0 FI. So I did a test, and I unplugged the breather hoses, attached them to a canister and went for a ride. After driving about 50 km (30 miles or so), there was a lot of oil in the recipient and on the engine. I know oil vapors is supposed to come out from the head breathers, but my engine is spitting oil through the breathers. What could be the reason? I just got the cylinders overhauled, and I'm quite unhappy to see that.

Cheers!

JF

[jsayre914]

sorry to hear that, mine was doing that befor the overhaul...

http://www.914world.com/bbs2/index.php?sho...c=93263&hl=

i hope yours is not that bad.

do you see smoke on hard aceleration, deceleration, or both?

what type of oil is in there?

[type2man]

Fisrt make sure your oil level is correct. If the engine is new, the rings probaly did not seat or the piston rings might not have been staggered correctly. You could also be getting blowby from the valve stems on the heads.



Patrick

[velum]

Hi Joseph!

I haven't done any hard acceleration since the engine has just been rebuilt. If I use compression for deceleration, then I get smoke when I press on the gas pedal again. The mechanic who did the engine job on my 914 says this is normal with new rings during the first 500 miles or so because the rings have to adjust themselves.

I'm using only synthetic oil.

Cheers!

JF

sorry to hear that, mine was doing that befor the overhaul...

http://www.914world.com/bbs2/index.php?sho...c=93263&hl=

i hope yours is not that bad.

do you see smoke on hard aceleration, deceleration, or both?

what type of oil is in there?

[ChrisFoley]

Synthetic is a bad choice for break-in.

[velum]

Hi Patrick,

The oil level is ok. What does "seat" mean when you say "the rings probably did not seat"? Sorry, English in not my mother tong.

If piston rings hadn't been staggered correctly, we could expect oil to be coming from only one head, right? Unless they had all been staggered improperly, but this would surprise me, since the mechanic who did the engine job has a lot of experience with old VW busses or campers.

Also, in all the cases you mention, I would expect the sparkplugs to be full of oil, but they are dry. So there doesn't seem to be any oil leak in the combustion chambers.

It seems there is too much pressure in the engine causing oil leaking from the head breathers, but we haven't found why yet.

Any other ideas?

Cheers!

JF

Fisrt make sure your oil level is correct. If the engine is new, the rings probaly did not seat or the piston rings might not have been staggered correctly. You could also be getting blowby from the valve stems on the heads.



Patrick

[velum]

Thanks Chris for the advice!

My mechanic told me he would change the synthetic oil in my engine for 20-50 Castrol oil.

Cheers!

JF

Synthetic is a bad choice for break-in.

[ChrisFoley]

Most of the oils available at parts stores no longer contain enough anti-wear additives, particularly ZDDP, for our engines. Brad Penn is the brand most often cited as having proper levels of this additive, but there are others.
Also, straight 30 weight, non-detergent oil is best for break-in and ring seating.
LN Engineering has done extensive oil analysis and has a page with comparative data of popular brands as well as specialty oils with adequate ZDDP levels.

[74914LE]

I would check the valve guides. The same situation happened to me, and after
checking the rings twice, I found that the valve guide on # 3 Exhaust was so
bad that the valve seat started to wear, with metal showing up in the oil
strainer. The valve clearance will also change quickly, with a resulting change in
audible valve train noise. This started showing up after a ring job.

Good luck...it is no fun with that much oil.

[type2man]

By seating I meant the rings wear into the groove of the piston barrel and form a tight seal. Was your engine running properly before the the teardown? If so, I would think the pistons are causing blowby. I would at least drive it like this for a few hundred miles more and see if it gets better. Change the oil every hundred miles to keep it clean.

[velum]

Hi 74914LE!

When you had a similar problem, was your sparkplug #3 full of oil? Because mines are dry.

Cheers!

JF

I would check the valve guides. The same situation happened to me, and after
checking the rings twice, I found that the valve guide on # 3 Exhaust was so
bad that the valve seat started to wear, with metal showing up in the oil
strainer. The valve clearance will also change quickly, with a resulting change in
audible valve train noise. This started showing up after a ring job.

Good luck...it is no fun with that much oil.

[velum]

Hi Type2man!

Before the rebuild, except for burning oil and not being able to restart the engine when it was hot, I did not have other problems with the car. It was not leaking oil. However, my mechanic thinks that the problem might have appeared after the rebuild because there is now a higher pressure in the engine than when the rings were won out.

Since the rebuild, I have been driving the car for around 300 miles. Someone on another forum suggested I beat the engine with strong accelerations and decelerations to help the rings to seat in. When I replied that I did not think it would be a good idea during the first 600 miles or so, he answered that this is old school of thought. What do you think?

As it is, if I fill up the oil to the top mark on the dipstick, I can drive 100 miles before it gets to the bottom mark.

Cheers!

JF

By seating I meant the rings wear into the groove of the piston barrel and form a tight seal. Was your engine running properly before the the teardown? If so, I would think the pistons are causing blowby. I would at least drive it like this for a few hundred miles more and see if it gets better. Change the oil every hundred miles to keep it clean.

[type2man]

I would read the dipstick cold in the morning and take notice. I would ride it hard on the expressway and use the clutch to decelerate instead of the brakes. This helps to seat the rings. Put another 300 miles and see if it works out for you...

[74914LE]

With my situation, the plugs were in great shape. The case was being pressurized
because the valve guides were so worn out, that the valve was not correctly
seating, and gas pressure was leaking into the top of the cylinder head. It was
then getting back into the case from the push rod tubes. Oil was coming out
of the breathers just as you mention. At the time, I also thought it might be
a ring seating issue, and I went to the trouble of getting a whole new set
and following all the right procedures for break in. Both times, I had the same
result. I eventually pulled the motor and put in a spare I had sitting around.
When I finally got around to taking the motor apart and looking very closely,
I was at least very releaved to know what the issue turned out to be..

If the rings do not seat, you would get blow by, and lots of pressure as well, but
it is worth looking into the valve guides. I am not sure how you would check this
without pulling the head and taking out the retainers to check how much play you
have in the valves. If this were my motor and it did not clear up quickly, (200mls), I would pull it and check. Having a dropped valve, and the associated
problems are what could result, and that would be a really "bad day".

[type2man]

Another way of telling if its the heads or the pistons is to let the car idle for about 5 minutes. If when you take off you get a huge cloud of smoke, then more than likely its the heads. If you let the car sit and its smoking steady from the exhaust, then your rings are bad.

[velum]

Thanks for all your suggestions! I will try that during the next few days.

By the way, the heads have been redone and the valve guides are new.

I was going to order a new PCV valve to narrow down possible problems, but it seems to be no longer available. Do you know of any substitute for that part?

Cheers!

JF

Another way of telling if its the heads or the pistons is to let the car idle for about 5 minutes. If when you take off you get a huge cloud of smoke, then more than likely its the heads. If you let the car sit and its smoking steady from the exhaust, then your rings are bad.

[Bleyseng]

PVC valves were available from Porsche recently but I doubt this is your problem. As I said on the other Clubsite you have a ring seating issue from driving like a old lady and using synth oil for break in. GET the PROPER OIL for break in as you can also toast the lifters and cam using the wrong oil.

You might have already glazed the cylinders by using the wrong oll and by not following proper break in techniques for the rings....new rings and re honing might be the only cure.

[velum]

Yes, I understood. I'll drive my 914 like Ma Dalton would! ;-)

I was simply following the recommendations of my mechanic, a German fellow who worked all his life on German cars, mainly on VW buses I believe. He put the oil in my engine, and as far as I understood, it was synthetic oil... don't ask me why. He has now changed it for 30W oil without detergent.

As for the PCV valve, I simply thought it would be a good idea to change it since they recommend to do so every 20 000 km on http://members.rennlist.com/pbanders/PCV.htm

Cheers!

JF

[jmill]

In your mechanics defense, around 15 years ago 20/50 Castrol was the rage for VW's. I can't see him putting in a synthetic for break in, though. Unfortunately, oil formulas change faster than old German mechanics. The word "New and Improved" on the bottle are about the only indications that things aren't the same. I used Castrol 20/50 myself until I had some issues with it.