Subject: Rings probably OK Author: cheung1 as Patrick C 88 750 160K : member since March, 2004 : 1168 posts Posted on: 2008-07-09 14:09:05

At 150K miles my engine was going through oil at a rate of as high as 400 miles per quart. You didn't mention oil consumption so probably your rings are fine.
Base on that assumption oil comes into the engine via PCV, or through the valve stem seals. Furthermore, your PO removed the whole fuel canister and breather system so no worry there. This is except we don't know what your fuel tank does to equalize the air pressure--may be the vent tube to the front was left open thus you'll constantly smell gasoline in the engine bay.
At this point to find out if the PCV is introducing oil to the intake, you can isolate the PCV by plugging them from the intake and plug off the non-return valve going into the rubber flex hose aft the MAF. The crankcase can be temporarily vented to air through a long hose to get rid of the blowby. Hypothetically if there is loads of oil already collected inside the intake runners you'll have to remove the runners and thoroughly clean the inside of oil. Now with a oil-free intake and no new oil from PCV you should see a big change if indeed the oil came from PCV.
While the runners are out, you can peek into the intake ports and check if there is any oil streak marks on the back of the intake valves. That is a clue of leak through valve stem seals. And of course, always pull out some spark plugs to examine the tips for clues of rich combustions.
Lastly, I suggest you buy two used unmolested MAFs and perhaps its time to change out the three coolant temperature sensors by the firewall and the two air temperature sensors on the rear end of each intake runner.

Patrick C 88 750 159K

• How to screw things up..... (pic) - eliasazem 2008-07-09 13:29:31 (426 views)
  • I have the same problem..... - mcf 2008-07-28 10:29:23 (69 views)
  • whoooo hell yeah whats your trick for making the engine look so good!!! (nt) - beach911 2008-07-10 00:21:08 (97 views)
    • I want to know that also (nt) - steinway 2008-07-10 11:16:52 (78 views)
      • I had chromed all bolts, clamps and whatever I got my hands on.. (url) - eliasazem 2008-07-10 17:01:41 (123 views)
        • www.flickr.com/photos/bimmer_750 (nt) - eliasazem 2008-07-10 17:32:32 (122 views)
          • that looks exquisite - steinway 2008-07-11 05:44:18 (68 views)
            • left the engine in it's place and removed some parts...look (pic) - eliasazem 2008-07-11 08:33:10 (174 views)
              • what's that in the trunk at the right? - steinway 2008-07-11 13:58:28 (68 views)
                • Looks like a storage compartment where the 2nd battery usually is at with a 750 (nt) - Johan750 2008-07-11 17:53:13 (73 views)
                  • Never heard of a second battery usually in a 750..... (nt) - eliasazem 2008-07-11 18:04:23 (69 views)
                    • so have you looked what's behind it? - steinway 2008-07-12 02:55:51 (60 views)
                    • It's not big enough....do you have a pic to show me...thankx (nt) - eliasazem 2008-07-11 18:05:29 (62 views)
                      • all Highline for example have a 2nd battery (url) - shogun 2008-07-11 23:14:41 (104 views)
  • Change the oil - erwin 2008-07-09 14:40:45 (101 views)
  • Rings probably OK - Patrick C 88 750 160K 2008-07-09 14:09:05 (102 views)
    • i was burning oil at same rate 400mi/qt - ridgelyrocket 2008-07-10 21:19:08 (79 views)
    • Patrick is right. - alv12 2008-07-10 11:36:44 (77 views)
      • Re: bring banks in sync - steve209 2008-07-10 14:03:42 (97 views)