Blowing oil on rebuild.

74EMPI · Post by **74EMPI** » Tue Sep 03, 2002 6:34 am

Hi All,
I just finished rebuilding my 1600 DP and have been slowly breaking it in. When I drive it around town or quick shots on the interstate everything is fine. Today I drove it to work (40 mins at 60-65mph) and noticed that there was oil pooled up below the pulley in the tin. I never had this until the extended drive today. What would cause the oil to leak at higher speeds. The Engine felt fairly cool to the touch. I could hold the dipstick no problem. I did not see the source of the oil so I am assuming it is coming from the pulley. any ideas?

Mike

UncleBob · Post by **UncleBob** » Tue Sep 03, 2002 6:59 am

Excessive crankcase pressure can blow oil past the slinger on the pulley. Is your oil-filler vented properly? If so, a sand-seal pulley will keep the seepage to a minimum. But, before assuming oil is coming from the pulley, MAKE SURE, by cleaning thoroughly and trying to make it leak again.

Mitch · Post by **Mitch** » Tue Sep 03, 2002 7:00 am

What kind of pulley are you running?

74EMPI · Post by **74EMPI** » Tue Sep 03, 2002 7:18 am

Hi,
I am running a stock pulley. The Breather is vented down through the tin and the top vent(that ran to air cleaner) has been blocked off. I have another air cleaner that I will be using that will accept the breather tube. I have cleaned the pulley area and it appears to be coming from there or from the dipstick. I just checked my oil and noticed the dipstick was not all the way and I am sure it was when I checked the oil before leaving for work. Could the pressure be working the dipstick loose and allowing oil to spit out that way?

UncleBob · Post by **UncleBob** » Tue Sep 03, 2002 9:02 am

I would try putting the other air cleaner on, and venting the oil filler into the air cleaner. The intake helps alleviate some of the 'blowby', by pulling it through the carb. Do you feel this 'blowby' at the bottom of the vent tube that's exiting under the motor? Could it be stopped up?

74EMPI · Post by **74EMPI** » Tue Sep 03, 2002 9:18 am

UncleBob,
The vent tube on the bottom is not plugged up and I haven't checked to see if I could feel it. As I stated it only appears to be haappening at high rpms/extended period of running. I emailed tech support at aircooled.net to ask about venting the case and John suggested I remove the oil filler cap to see if there was excessive air being forced out. There was not. I am assuming that this pressure increases with RPMs so perhaps when the engine is running at 4000 rpm or more the problem is occurring.

UncleBob · Post by **UncleBob** » Tue Sep 03, 2002 9:52 am

That's an okay check, but I think you would only notice MASSIVE blowby at the oil-filler cap. I mean, the hole is like 3 inches, ya know? If running at 4000rpms, your case could be building up pressure like a pressure-cooker. It's gotta go somewhere, either past the pulley, valve covers, maybe even your dipstick. Replacing the air cleaner and venting correctly are just suggestions, and should be done anyway. Is your dipstick pretty tight? I had a close call last week with my billet dipstick (the one with the round handle), I was attempting to check my oil, and the handle pulled right off, leaving the 2 flat pieces stuck in the dipstick hole. The smaller of the 2 could have easily fell into the case. There was just enough coming our of the tube to get some needle-nose vise grips on. Back to the stock dipstick I go. I have heard of people losing oil out of their dipstick hole, and using twine wrapped around the dipstick (under the lip) to help seal it up. Anyway, I'm always one to try the no-cost fixes first, before I buy parts!

74EMPI · Post by **74EMPI** » Tue Sep 03, 2002 10:10 am

I will connect the other breather tube to the air filter. Yes the dipstick does seem a little loose. I will try one off another engine that I have.

74EMPI · Post by **74EMPI** » Tue Sep 03, 2002 12:01 pm

New Piston and cylinders. I will try the oil filler cap off.

vicsvw · Post by **vicsvw** » Tue Sep 03, 2002 11:44 pm

If you instaled a ring upside down it could be the problem. Try driving with the oil filler cap off. (High Speed)and see if it still leaks. Make sure the oil is not over-filled. Vic http://www.1800vw.bizhosting.com/OilLeaks.htm When you said rebuild, did that mean new P&C kit or rings.?

bugmeister · Post by **bugmeister** » Wed Sep 04, 2002 12:59 am

Has anyone heard that the excessive clearence between the pulley hub and case can also cause the problem. True or false?

Also would blowby be worse under load, I have a similar leak however it only seems to occur under load from what I can assume.

74EMPI · Post by **74EMPI** » Mon Oct 07, 2002 12:53 am

Hi Guys,
Still having the same problem. I am considering a sand seal. Has anyone installed one before and do you think this would help. Again the problem is only after driving 30-35 min at 65 mph. No leaking around town.

Mike

rich2481 · Post by **rich2481** » Mon Oct 07, 2002 7:16 am

maybe your oil pump cover is leaking and it isnt blow by. If you are sure the cover isnt leaking then check

Are you runnning stock air cleaner and is your vent tube going to it???

74EMPI · Post by **74EMPI** » Mon Oct 07, 2002 7:21 am

I am pretty sure it is not the cover. I tightened it when looking for the leak. The vent tube runs from the bottom of the filler neck through the breast plate tin and the other goes to the air cleaner. I am running kadrons.

I ordered a sand seal pulley kit this morning. I hope this solves the problem. Any experience with these?

Mike

Post by **Marc** » Mon Oct 07, 2002 7:21 am

I always advise avoiding ANY sustained steady-speed driving until the rings have had a few hundred miles to seal. If you have to drive a distance on the highway before then, vary your speed/throttle opening as much as practical (like, accelerate up to ~70 and coast back down to ~60 instead of droning along at 65). It'll cost you come gas mileage of course but the rings'll break in quicker.