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Message |
john montgomery (Johnjem)
Registered Member
Username: Johnjem
Post Number: 1
Registered: 3-2007
Posted From: 24.34.214.231
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 15, 2007 - 2:04 pm: | |
GUYS/LADIES HELP ME OUT!JUST BOUGHT A 1970 GMC 4905 THAT WAS PROFESSIONAL CONVERTED BY CAYLOR SUPPLY COMP,IN 1993 I BOUGHT IT NOWING IT HAD BAD RINGS WHAT DO I DO NEXT<get>HIRE SOME ONE TO RERING IT IN CHASSIE OR OUT>NICE COUCH WORTH THE MONEY<BUT I NEED TO FIND OUT WHAT WAY IS THE BEST WAY NEXT FOR THE MOTOR ANY HELP WOULD BE NICE THANKS JOHN (8V71 WITH JAKE) |
Jim Wilke (Pd41044039)
Registered Member
Username: Pd41044039
Post Number: 132
Registered: 2-2001
Posted From: 69.77.151.82
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 15, 2007 - 4:15 pm: | |
Hi John,
Why do you believe it has bad rings?
Any hard info on how many miles since last overhaul?
Jim-Bob |
john montgomery (Johnjem)
Registered Member
Username: Johnjem
Post Number: 2
Registered: 3-2007
Posted From: 24.34.214.231
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 15, 2007 - 5:00 pm: | |
Hey jim, thanks for the reply i took off the oil pan and found rings in the pan.187,933 miles,when it was converted in 1993 it had 17,333 on it i know the old owner he never since 1993 had it overhauled so if it was overhauled befor conversion?? your guess is as good as mine I will have pics up soon. john |
Jim Wilke (Pd41044039)
Registered Member
Username: Pd41044039
Post Number: 133
Registered: 2-2001
Posted From: 69.77.151.82
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 15, 2007 - 6:24 pm: | |
John, it would be easy enough to do an in-frame. In my book the deciding factor is how badly the seals leak, etc. If you have leaking front & rear oil seals, it might be better to pull the engine which would give good access to replace the seals. It is also easier to overhaul the engine out of the vehicle. If you do a full overhaul out of frame, it will be clean & nicely painted & likely would add value to the bus. If your budget is tight & the crank seals aren't leaking, an in frame would be less $$.
If the engine runs well & doesn't smoke once warmed up, you might just pull the heads and clamp down the liners, you should be able to bar the engine over and you should be able to see the cylinder or cylinders that have broken rings. Those rings can't get into the pan without causing damage to the liner. If all else is good, you might just change 1 or 2 cylinder kits. 200,000 isn't that many miles if it's been maintained. |
Douglas Tappan (Dougthebonifiedbusnut)
Registered Member
Username: Dougthebonifiedbusnut
Post Number: 29
Registered: 10-2004
Posted From: 75.69.44.219
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 15, 2007 - 8:52 pm: | |
Wait a minute guys,If John found pieces of rings in his oil pan the engine would smoke to beat the band,start hrd and geneerally run like &*%#$
Are you sure of what you found John?I really mean no disrespect by asking the question John. |
guy bouchard (Guy_bouchard)
Registered Member
Username: Guy_bouchard
Post Number: 8
Registered: 11-2004
Posted From: 161.184.192.176
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 15, 2007 - 10:18 pm: | |
One of the nice things about Detroits is that checking the piston rings is a non-invasive operation. Remove the air box covers on the side of the block and 'voila', you can see the pistons and rings and see what the condition is. If they are Detroit rings there will be black lines visible in the center of the rings. You can check them with a small probe to see if there is still some spring to them. You won't be able to see the oil control rings because they don't come up past the ports.
Guy 4905 |
Douglas Tappan (Dougthebonifiedbusnut)
Registered Member
Username: Dougthebonifiedbusnut
Post Number: 31
Registered: 10-2004
Posted From: 75.69.44.219
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 15, 2007 - 11:05 pm: | |
Oops! sorry Jim, didn't read your whole post. |
larry currier (Larryc)
Registered Member
Username: Larryc
Post Number: 51
Registered: 2-2007
Posted From: 207.200.116.13
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 16, 2007 - 1:29 am: | |
Hows it run? They may have been broken for years. If it pulls and you can keep oil in it, drive it cause your gonna throw the piston away anyway if it broke a ring. It will probably run forever with a broken ring, take it out and beat it, its a 318. |
john montgomery (Johnjem)
Registered Member
Username: Johnjem
Post Number: 4
Registered: 3-2007
Posted From: 24.34.214.231
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 16, 2007 - 2:27 pm: | |
I HAVE NEVER STARTED IT?WAS TO WORRIED TO CAUSE ANYMORE DAMAGE<I THINK I WILL GO WITH A OUT OF CHASSIE BUILD<COMPLETLY NOT GOING TO TAKE ANY CHANCES,IT WILL HURT THE HOLE IN THE POCKET BUT MAY SAVE ME IN THE LONG RUN<THANKS FOR ALL THE HELP GUYS,PS HOW THE HECK DO U GET A PHOTO UNDER UR NAME I CANT GET MINE BELOW LIKE 850X850?? |
larry currier (Larryc)
Registered Member
Username: Larryc
Post Number: 52
Registered: 2-2007
Posted From: 207.200.116.13
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 16, 2007 - 8:30 pm: | |
John, I'm not a 318 mechanic, but I,ve been told that a broken ring is not uncommon. Chances are its the bottom oil control ring since its in the pan. I'm not aware of any further damage that could be caused by a broken ring. Chances are it was broken when it was rebuilt during reassembly. If you have a lot of money, you can fix a lot of things. Its my understanding that you can take the pan off a 318, turn the crank just right and remove a piston from the bottom. Guy Bouchard told us how to diagnose which piston has the broken rings. If this was my boat anchor, (I got one too), and I was in a hurry to fix it,(I'd just run it), I would only fix the piston with the problem. If it was broken during inital assembly inspection may show a useable piston leaving you to purchase a pan gasket set and 1 set of rings. If the rings were broken because the piston was seized or has a hole in it, the head has to come off and the liner changed out. You can tell that with the air box inspection. If your engine only has 18,000 miles on it I think a direct repair of the broken part is acceptable. If you spend the money for a rebuild you should find a 8V71T or 8V71TA to invest in so you have a unit with a better future. Much less smoke and much more power. |
Cameron Jones (Crazy71)
Registered Member
Username: Crazy71
Post Number: 45
Registered: 12-2006
Posted From: 75.179.153.89
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 16, 2007 - 9:26 pm: | |
I'd fire it up and check it out.
I think I would get a compression check and see what your dealing with....maybe find you a GOOD old-school diesel mechanic.
The engine might be in very good shape. If the rings you saw were oil rings as others have mentioned and it was during assembly...you could have a very good engine.
I would get it checked out...
Wouldn't be that much to re-ring it. Especially if all the liners are good condition.
Ring job is not that labor intensive either.
I'm not sure whether I would rebuild a 8v71 or switch to a 6v92T...I guess price would be a big factor. You can find low mile great running used engines ready to go...would be a lot cheaper than a out of chassis rebuild. |