8V71 natural fuel entering crankcase need help!

[Mike Bronzini]

   This bus is a 1976 MCI with an 8V71 that supposedly has 8V92 heads. The problem is the fuel is diluting the oil rapidly, does anyone have a place to start with this thing??


               Mike Bronzini
           Brazel's RV Performance
            www.brazelsrv.com

[Dreamscape]

Might take both valve covers off and see if you have any cracked fuel lines or bad o-rings.

I myself have not had that happen, just relaying what I've leaned on the board.

Welcome to our little corner of the world!

The DD experts will chime in and point you in the experienced direction.

Paul

[luvrbus]

Sure pull the valve covers and check for a broken fuel line tap each one with a wrench the one or more that doesn't ring will be broken or loose , this is what happens when people try and reuse the fuel line to save 160 bucks.The best price is www.dieselpro.com   $3.79 each  they are aftermarket jumper lines but they are a good quality line.They may have the Kent/Moore socket also if not Snap/On sells it for 25 bucks


good luck

[Mike Bronzini]

   Great, that gives us a direction to go in! Thank you very much!

              Mike

[TomC]

You can easily tell the difference between a 71 head and the 92 head.  The 71 head has the 4 exhaust valves positioned in a square.  On the 92 the exhaust valves have the lower ones mounted wider then the top ones.  I doubt you have 92 heads on a 71 since the exhaust valves would hit the cylinder liners on the 71.  Good Luck, TomC

[Ncbob]

I'd be careful about tapping the fuel jumper lines with a hammer. Da Book calls for a specified torque for each nut and it takes a special crowfoot type cutaway deep socket to torque them properly. A clean rag and a good light will usually lead you to the culprit(s). The flat deck of the head will show lube oil dilution (RE: a clean spot). The fuel will have gone down the cam follower holes via the push rods. When in doubt...
replace any questionable jumpers. It could save you the price of an engine.

NCbob

[5B Steve]

  I had the same problem a few years back on my 92N.  The dealer (DD) could not find the leak,

  long story short, after spending several thousands dollars on everything that could cause the

  problem I call back the next day and a tech told me to remove the fuel line that goes in the

  head, place a air barb and take a air compressor not to exceed 10 P.S.I and listen for a hiss

  and that is where the leak would be. Wish I had known this before because I could have saved

  alot of money!!!!!   My 2cents worth.


   Steve 5B.......

[BUR]

    I have had this problem twice. The first time after a rebuild, had a o-ring leaking at high rpm only. The second time I had two injectors leaking.    Good Busin' Wilbur

[TomNPat]

Remove the valve covers, put air pressure on the fuel line coming from the fuel pump, and watch for spraying fuel.  I had a couple of crossover pipes leaking on my 92 and gained a couple gallons of 'oil' in not too much time.  I'd start here.

TomNPat

[luvrbus]

If you suspect a fuel leak on your engine the easiest way to find the leak is pour fresh oil over the area if the oil puddles your leak is in that area, I use the ping method works for me every time on the standard jumper lines pinging won't with  o-ring type  jumper tubes but the oil will

good luck

[Dreamscape]

Mike,

Please post back what you find so all of us can learn from it.

Paul

[Ncbob]

Just a tip if you're going to pressurize the fuel gallery. The fitting in the cylinder head is not a pipe thread..it's and inverted flare female and is what's called a restricted fitting (special) so don't make the mistake of thinking it's NPT (National Pipe Tap) and screw a 1/8" or 1/4" NPT fitting in it or you'll be making a call on your local DD Dealer for a pair of new ones.

NCbob