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Author Topic: 8V71 leaking oil and goo  (Read 1761 times)
ChuckMC8
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1977 MC8 and 1993 102C3 Temple Ga #322 F&AM




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« on: June 16, 2006, 01:25:32 PM »

I posted this message on the Yahoo DD board, and I just pasted it here and edited some of the trivia that folks here already know- 
 8V71 DD. Long story on the engine, but here goes:
  Engine was outframed with new cyliner/piston assemblies in 1995. Less than 250 miles (but more than a year) the engine dropped a valve. It destroyed the piston & Liner and also the cylinder head.
  When I bought the bus (8/2002),it was as listed above with dead engine.
 In the previous owners yard I removed the cylinder head and found the damage. (Dont you just love naive people?)At this point, I contacted the shop that had built the engine and they ordered the replacement piston/cyl assy that was the same as they had installed. I bought a replacement cylinder head and had it rebuilt ($500). I installed the components, fired her up and cruised on home. I had never seen a DD before and did not have the manual.I hired a local mechanic to help me install the head and then he adjusted the valves and fuel system.
   It runs fine, and now has 2000 miles since I repaired the engine.So, total miles on the outframe is 2250 or so.
  It has practicaly no drips out the slobber tube on the engine side that wasn't damaged. (I didn't remove that head) However, the drips are bad and seem to be getting worse on the side where I replaced the head,cyl and piston. I made a catch jug to spare my parking area. I emptied it today and it had a quart of goo in it.(In probably 300 miles)
  Also, I have an oil leak that I thought was coming from the oil sender unit, but after pressure washing the engine and re-evaluating, I beleive that its dripping from the exhaust manifold at appx the same location as the replaced cylinder. In looking at my DD manual, I see that I should have calcualted the proper gasket with a dial indicator.
  Would the delimina I describe be related to something that I did (or did not) do during the repair? I have confidence in the shop that repaired the head.
   Is this symptoms of a leaking head gasket? No coolant in oil, hasn't ran hot. Thanks, Chuck
 
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Far better is it to dare mighty things,to win glorious triumphs,even though they may be checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much,because they live in the gray twilight that knows neither victory nor defeat.  Theodore Roosevelt (1858-1919)
NCbob
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« Reply #1 on: June 16, 2006, 04:22:15 PM »

Ouch!  You have my complete and udder  Roll Eyes  sympathy m'friend.  Bit it's been too long since I left DD school to be much help. Embarrassed

Would it be Politically Correct if I said, "I feel your Pain"?  Cry

I have no doubt that one of our Wizards will have a reasonable answer.  Wink

C'mon guys...let's help Chuck! He's one of the GOOD GUYS!     

C'mon guys...let's help Chuck!  He's one of the GOOD GUYS
Bob



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Don Fairchild
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« Reply #2 on: June 16, 2006, 04:43:15 PM »

Chuck;

Give us some more info. what color is the goo. is it gray or black. does it sound like the engine is missing on that hole, does it lose some water over time.

Here are some things you can check. First pull the injector on that cylinder see if it looks alright, if it does have it pop tested. Next pull the air box cover on that cylinder and pressure up the cooling system  10-12lbs should be enough. See if it leaks
water out from arount the top part of the linner and the block, hand crank the engine over to put the piston on the bottom of the stroke ane see if any water comes out off of that hole.

Tell me what you find and I'll tell you some other things you may be able to do.

And Bob I thought every body on this board was a good guy or girl ??

Don

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ChuckMC8
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1977 MC8 and 1993 102C3 Temple Ga #322 F&AM




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« Reply #3 on: June 16, 2006, 07:33:30 PM »

I replaced the injector with a new one at the time I did the repair. It doesn't lose any water. The goo is black. It appears that the stuff out the slobber tube is different from the oil leak........it appears that the oil leak is coming from the exhaust manifold..but that isnt possible....it could be leaking goo/unburned fuel from the manifold tho......the engine is clean and I have a friend coming over in the morning to put another pair of eyes on it. We'll take it around the block and see what happens, and I'll post the results. The engine isnt missing, it runs great. Thanks for the help-Chuck
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Far better is it to dare mighty things,to win glorious triumphs,even though they may be checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much,because they live in the gray twilight that knows neither victory nor defeat.  Theodore Roosevelt (1858-1919)
NCbob
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« Reply #4 on: June 17, 2006, 02:10:22 AM »

You're right Don,  Chuck just happens to be a personal friend and I'm unable to be of any assistance.  Cry

Bob
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RJ
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« Reply #5 on: June 17, 2006, 01:01:13 PM »


We'll take it around the block and see what happens, and I'll post the results. Thanks for the help - Chuck



Take it out for a longer drive than just around the block.  You need to run it longer under load to thoroughly warm everything up and blow out all the gunk that's accumulated from idling.  Somewhere around 50 - 75 miles or so, freeway preferred.

HTH. . .
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RJ Long
PD4106-2784 No More
S13406 Now
Fresno CA
ChuckMC8
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1977 MC8 and 1993 102C3 Temple Ga #322 F&AM




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« Reply #6 on: June 17, 2006, 01:35:41 PM »

Sorry, Around the block is from Atlanta to Mississippi tomorrow. (300+miles)
  I did find a fitting on the oil pressure block that has the oil pressure sending units that was loose. I removed and sealed it with teflon tape and that seems to have helped.
Since I have my tachometer installed, Its much easier to help the Allsion Auto with gear selection to keep the rpm's up. I'm trying to keep it between 1500 and 2000 RPM's, so that requires manual downshifting at times. As it is, when the trans shifts gears, the rpms fall back to 1200 or so. I was dissatisfied with the power that the 8V71 makes in around town driving, but now that I can monitor and choose gears, it has made a terrific difference in the drivability of the bus.
   After this trip, if the slobber tube problem doesnt get significantly better, I will pull that same head and cylinder out and see whats gone astray-Chuck
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Far better is it to dare mighty things,to win glorious triumphs,even though they may be checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much,because they live in the gray twilight that knows neither victory nor defeat.  Theodore Roosevelt (1858-1919)
ChuckMC8
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1977 MC8 and 1993 102C3 Temple Ga #322 F&AM




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« Reply #7 on: June 27, 2006, 10:41:22 AM »

Well, bus did not make the trip to Mississippi last week. Instead, we took the Honda van. Returning home, I'm back to trying to figure out whass-a-matter with the bus engine.
  I removed the airbox covers to check the rings and cylinder #7 (if it was a chevy) had pieces of the cylinder liner broken out and were lying in the airbox cover. The whole liner thats exposed with the cover has broken out.Piston rings were protuding into the airbox.
 That at least  explains the blow-by and slobbering.

 I am horrified that the cylinder head may be damaged......

 What could have happened? This engine has 2250 miles on an outframe.....(although its been 11 years)
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Far better is it to dare mighty things,to win glorious triumphs,even though they may be checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much,because they live in the gray twilight that knows neither victory nor defeat.  Theodore Roosevelt (1858-1919)
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