CATEGORY LISTINGS > DETROIT > Another 6V92 leaker! [ REFRESH ]

Thread Title: Another 6V92 leaker! Created On Saturday October 31, 2009 21:43

DieselBusParts Posts: 16 Joined: Jun 2009

Saturday October 31, 2009 21:43 I bought the bus Feb '08 and have put maybe 6 miles on it since buying, when I picked it up it was dumping a quart of oil from the air box over flow canister every time I moved the vehicle, I'm talking about moving 20 feet and stop (dump) move again 20 feet (dump) drive down the street and leave a very clear trail 6 miles long. I thought it needed new rings so I read up on the engine posted a message on this forum and talked with a friend that is very knowledgeable and has a 6v92 in his Eagle, anyway I started to pull the L/H head on my 6v92TTA (RTS transit bus) and uncovered the data plate, the engine is a Relibilt MFG:04/07 S/N:6ff21872 with a ddecII about the same date as is everything else, well to say the least it changed my way of thinking about this old bus and it's slobbering ways, so now I pull both air box tubes loose, start it up, leaking out of both hoses, pulled the air box cover on the R/H again and now it's full of oil and some non metallic grit on the covers (very fine, like silica not sand, smaller than a grain of salt). So I'm thinking it can't be rings or pins on both sides due to the age? So blower, right? I pulled the turbo today what a pita that was, took it apart and it was very greasy and oily inside, the exhaust pipe that it connects to is oily and wet, the exhaust manifold pipes that connect to the turbo are wet all the way to the head, the blower is bone dry and clean, I even put an old white sock on my hand, reached inside ran my hand everywhere I could and it came out clean! Could the turbo cause all of the oil problem or am I still looking at new rings/pins/liners? Another odd thing that I found was the fire ring when I pulled the airbox covers it looks like two chrome compression rings instead of a singular solid ring. One other thing is the turbo is an A/R:0.75 the turbos I have on hand are A/R: 0.96 is there a setting issue by using a different A/R value? wet=oil I haven't found any water leaks at all, anywhere on the bus.(just clarifying myself) ------------------------- http://DieselBusParts.com Edited: Saturday October 31, 2009 at 22:19 by DieselBusParts

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GoneFishen Posts: 1325 Joined: Jan 2007

Saturday October 31, 2009 22:31 You have either a blown piston pin retainer or a bad [maybe more] cylinder. The 'grit' is basically carbon, ignore it. The top rin on the pistons is a 1 piece item. Same with the compression ring. Only the oil control rings maybe are a 2 piece item. Since you have the inspection covers off look inside the engine and look for 1: a severly scored lined on the sides. This is caused from a piston pin loose and maybe has slid down and damaged the liner/piston. 2- Look at all the fire rings and compression rings. You are looking for burn't rings, stuck rings or any discolored pistons. 3- look at all the liners for the crosshatch found on a normal liner. You are useing a flashlight and mirror to look. Bar the engine over while you are doing this. The oil is being pushed up the connecting rod and lubes the piston pin. The steel retainers are set on each end to keep the oil pressure from entering the airbox area. The oil is then sprayed at the top of the piston to cool the piston dome. Good luck. ------------------------- DDA tech for 30 years,all 2 cycle,series 60,50 mbe also. 1995 F250, 191k mi. Lost Wages, Nv

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DieselBusParts Posts: 16 Joined: Jun 2009	Saturday October 31, 2009 23:17 I appreciate your quick response to my problem GoneFishen, any idea about changing the turbo from an A/R:0.75 to an A/R:0.96 and if I open all of the air box covers and turn the engine over to find the problem cylinder would that be a dumb idea? (disconnect the fuel first) ------------------------- http://DieselBusParts.com
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GoneFishen Posts: 1325 Joined: Jan 2007

Sunday November 01, 2009 07:50 Remove the covers and use a ratchet and socket to bar the engine over. I never use the starter for looking because I go slow to look at things and want to get it all at once. I have 2 mirrors 1 about 2" and the other a real cheapy about 1 1/4 diam. for looking. Make sure that you have a clear lens and god batteries for observation. The turbo compressor fins should be sharp and new looking, the turbine side should have no visable damage either, If it leaks change it but you said the blower is clean. The oil is coming from the head/exhaust system and making the turbo look bad. Changing he AR ratio will affect performance. Either the turbo will spin to fast or the to slow. The bypass valve at the back of the blower will allow the excessive pressure to bypass the blower so excess is not needed. BTW, I usde the cheapy mirror to actually fit inside the liner ports and look at the cylinder walls and if you aer lucky you can see the valves on the head. ------------------------- DDA tech for 30 years,all 2 cycle,series 60,50 mbe also. 1995 F250, 191k mi. Lost Wages, Nv

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DieselBusParts Posts: 16 Joined: Jun 2009

Wednesday November 11, 2009 19:17 I finally pulled the heads this week, I couldn't see anything through the air boxes, none of the cylinders look that bad to me, but I don't know what I'm really looking for other than scratches, all of the piston domes look burnt and oily I'm hoping thats normal. I just pulled the drain plug on the oil pan, I'll let it drip overnight and remove the rod bearings and pistons tomorrow. The A/R .75 turbo was the wrong one for the bus, I called Stewart & Stevenson with the engine s/n, the A/R .96 is the right one, so ABQ RIDE recycled an old turbo, I can't complain though I really want to, knowing they had the right part on hand and bought just for that engine. I hope everyone has had a good Veterans/Armistice day! ------------------------- http://DieselBusParts.com

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JoeZ Posts: 938 Joined: Dec 2008

Thursday November 12, 2009 05:01 Oily and burned is not normal. Which side of the turbo was greasy/oily as you put it? See what you find when you remove the pistons. If the turbo wasn't dumping oil into the engine, meaning the compressor side being extremely wet with oil, more than likely your lower rings are bad/broken. That would explain the wet pistons. The other thing that you didn't mention if you checked for oil contamination with fuel and overfill. These engines don't do well if they are overfilled. They will slobber oil like you wouldn't believe with one gallon overfill. ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.

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DieselBusParts Posts: 16 Joined: Jun 2009

Thursday November 12, 2009 15:24 JoeZ, the oil is on the exhaust manifold side the manifold, Y and everything else is oily all the way through to the muffler! The turbo is separated right now and the black longer fin section is oily & greasy, the shorter fin side (compressor) is clean with no oil on it. I pulled the oil pan an hour ago, the liners look good, the bottom of the pistons all look good. How do you normally remove the pistons on the V92 from the point I'm at now, cause I can't get the shells to separate and I'm a bit nervous about pounding on the dome of the piston. details would be highly appreciated! I didn't check the oil for fuel, it is pretty black, viscosity seems good, it's contaminated with antifreeze now, I waited to drain the oil till after the heads were off and I still have antifreeze spots in every possible place! I've got an old vacuum pump that I'll use to chase all those drops unless anyone has a better way? ------------------------- http://DieselBusParts.com Edited: Friday November 13, 2009 at 02:03 by DieselBusParts

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westcoast Posts: 982 Joined: Dec 2008

Friday November 13, 2009 03:54 Cut yourself a piece of aluminium or brass rod stock 1/2" diameter - put any piston at bottom of stroke ( below liner ports ) cut your rod so that you can slide it down into the liner and fit it across the liner into the ports - making sure that the rod is inside the diameter of the liner , remove big end nuts on the cylinder that you are removing and turn the engine over until the piston touches the rod - then you can bump remove piston and liner assembly together and then disassemble it on the bench . I personally think your engine has been dusted and when you strip your piston/liner assemblies down you will find either broken or worn out oil rings - check the top of your liners and see how much of a ridge you have and if your liners look polished . Regards David ------------------------- detroit

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DieselBusParts Posts: 16 Joined: Jun 2009

Friday November 13, 2009 13:35 The liners look polished, no cross hatch on any of the cylinders, I will change the rings, can I hone the liners with a dingle berry safely or will I have to use a solid hone? What do you mean "dusted" the engine has less than 50,000 miles on it, the Reliabilt engine was mfg: april 2007 and city of Albuquerque put it up for auction nov of 2007. So 6 months of service at most, they replaced the engines while waiting for the new buses to arrive, as one would come in an old bus with a new engine would be retired. ------------------------- http://DieselBusParts.com

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westcoast Posts: 982 Joined: Dec 2008

Friday November 13, 2009 14:56 50,000 miles - polished liners means dust , you,ll be able to tell when you look at your rings and ring grooves - check your intake all the way from air cleaner to turbo and air compressor intake if it,s mounted to blower top check both ends or if it has independent filter check for security and leaks , also make sure your rocker breather tube is on and is lower than the sump rail. You,ll be taking your blower off and removing aftercooler to clean the inside of the engine properly . You can have an engine with 100 miles on it and still dust it if your sucking dirt through your intake system - Truck and coach have different oil ring expanders ie: more tension on coach oil rings for better idling capabilities which means they won,t slobber as much without being underload but the downside to that is if they get dusted because they have more tension they wear out quicker Regards David ------------------------- detroit

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DieselBusParts Posts: 16 Joined: Jun 2009

Saturday November 14, 2009 17:40 LOL, I thought you meant the engine was shot. Pulled all of the pistons and no broken rings a couple of them were stuck, the liners are not as polished as I first reported, the hone hatching is very clear with no scratches just very oily, the piston domes are crusty on top just on the right bank, the left is just oily on top of the dome. It looks to me like a combination of stuck rings and wrong size turbo has caused all of the trouble, it could also be from not giving it time to seat the rings properly, at this point I'm just glad that the connecting rods are in good condition I still need to check the pin seals. Thanks, GoneFishen, JoeZ and Westcoast, you have all offered me a great deal of help without asking anything in return, I appreciate that and all of you, for all of your help, thanks again! Ken ------------------------- http://DieselBusParts.com Edited: Saturday November 14, 2009 at 17:42 by DieselBusParts

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JoeZ Posts: 938 Joined: Dec 2008	Sunday November 15, 2009 07:06 The piston pin retainer/seals are checked with a suction cup. ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.
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westcoast Posts: 982 Joined: Dec 2008	Sunday November 15, 2009 13:29 There,s only a coupling of things to give you stuck rings - so have a real good look before reassembly ! Regards David ------------------------- detroit
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JoeZ Posts: 938 Joined: Dec 2008

Sunday November 15, 2009 14:12 If by chance you removed the pistons and left the liners in the block, you may want to re-think trying to put the pistons from the top down.....it can be done....but it is DEFINATELY not reccommended.....and certainly not for the inexperienced on two stroke engines.... ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.

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JoeZ Posts: 938 Joined: Dec 2008

Sunday November 15, 2009 14:16 And if you have already pulled the liners, I hope you clocked them and marked which hole they came out of. If you haven't removed them and paln on doing so......mark each one at the 12 o-clock position and don't mix up where they go. ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.

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DieselBusParts Posts: 16 Joined: Jun 2009

Sunday November 15, 2009 17:41 I didn't pull the liners, cause I don't the have new seals to re-install with. I'm assuming the pistons stick in the cylinder real bad when trying to put them back in? The 2nd fire ring is the stuck one on 4 of the pistons (so far) they are very gunked over, I'm guessing oil + high temp = baked on crusty oil? I've got them soaking in diesel right now. As far as experience, I was a mech. in the army and TAMMS/PLL then motor sgt for 3yrs. total 16yrs. around diesels, most of them in APC's and recovery vehicles (tracked) we never did OH, those were sent to civilian shops (we were just parts changers) that was 20+ years ago, so I'm just rusty, not inexperienced! ------------------------- http://DieselBusParts.com Edited: Sunday November 15, 2009 at 17:43 by DieselBusParts

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JoeZ Posts: 938 Joined: Dec 2008

Sunday November 15, 2009 21:30 As I said.....inexperienced in two stroke.....not inexperienced. Putting the pistons back in from the top is going against the grain....very tricky.....not recommended.....and the problem is that if you damage the bottom rings, you won't know it until the rings fail. Myself....I have done it only a few times in all the years of doing two stroke....only when I was patching up an engine to get the guy home because he was broke and I just needed to get him out of the shop as cheap as possible. The other thing is that you don't know the condition of the liner seals and they could have been overheated at the same time the rings got damaged.... It's not my call.....but I wouldn't attempt what you are doing. ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.

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westcoast Posts: 982 Joined: Dec 2008

Monday November 16, 2009 01:04 I agree with joe - it,s bad enough doing it in the field when you have too but with coach expanders even harder - what you need to look at is what caused your problem in the first place ie; over fuelling - dust - low coolant temp or as joe said crankcase over full for an extended period then go and buy a set of liner seals and oversize liner inserts and pull your liners . We call it Rememberence Day and don,t get a holiday just one minute at 11 o,clock to pay your respects Regards David ------------------------- detroit

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DieselBusParts Posts: 16 Joined: Jun 2009

Monday November 16, 2009 13:25 I guess I'm pulling liners today. We get an entire day off for Veterans/Armistice/Remembrance minute, we have added more to the holiday than just WW1 observance, we use the day to remember all of our veterans, living,serving and dead. Our military is a vital part of our country and those that have served, have sacrificed more than just time, a lot of us are still feeling the pain and loss of wars gone by, and watching our children and grandchildren preparing to join the ranks of veterans makes the day a bit more solemn. ------------------------- http://DieselBusParts.com

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westcoast Posts: 982 Joined: Dec 2008	Monday November 16, 2009 15:26 All my family are either military or ex so it goes without saying that we observe all the rituals - problem is too many people forget that they,ed be speaking another language if it was,nt for the good guys !!!!!! . Let us know how you get on with your repairs Regards David ------------------------- detroit
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DieselBusParts Posts: 16 Joined: Jun 2009	Monday November 16, 2009 15:56 I have the three right bank liners out, the seals look good, I was just checking my manual to see the alignment of the connecting rods before I drop the pistons in. Ken ------------------------- http://DieselBusParts.com
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JoeZ Posts: 938 Joined: Dec 2008	Monday November 16, 2009 18:00 You do know that the pistons get loaded from the bottom of the liner using the proper tool.....ok? ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.
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westcoast Posts: 982 Joined: Dec 2008	Monday November 16, 2009 19:26 And make sure you check your liner heights before your assemble piston / liner assemblies Regards David ------------------------- detroit
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DieselBusParts Posts: 16 Joined: Jun 2009

Monday November 16, 2009 19:45 << You do know that the pistons get loaded from the bottom of the liner using the proper tool.....ok? >> I used to say there is no such thing as a stupid question............ I was double checking to see if there was a specific direction the connecting rods go in, there are two ways, so better safe than sorry, you did say to clock the liners? If thats the case then if there were a direction for the connecting rods I had better have it right before it hits the block, but I can't find any reference for that so I guess it don't matter. Yes, I have a DD V92 manual all be it from 1988, but it shows the specs for liner height, my next question is how do you get the liners back in and seat to the proper height? I was thinking to use old head bolts and a bar with my hydraulic spreader plus a block of wood Ken ------------------------- http://DieselBusParts.com

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GoneFishen Posts: 1325 Joined: Jan 2007

Monday November 16, 2009 22:42 That book should tell all you need to know on the spec's. Check section 1.5 for the rod direction. I would tell you but you will learn nothing that way. Liner heights are changed by the thickness of the liner inserts below the liner. I always install the liners w/o the seals and check with a depth guage and the hold down tool. You can make a tool yourself if needed. You MUST hold the liner down to check heigth. If you reuse the liner inserts check very carefully on a near perfect sealing surface. NO dings or dents. The book makes reference to the color of the inserts needed. NOT shims like on the 71 series. Inserts and their size. Make sure that you have them very close to the same dimension as the sealing is done with a flat head. Yes reuse the head bolts. Screw the torque turn method. Use the torque method on the bolts. ------------------------- DDA tech for 30 years,all 2 cycle,series 60,50 mbe also. 1995 F250, 191k mi. Lost Wages, Nv

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JoeZ Posts: 938 Joined: Dec 2008

Tuesday November 17, 2009 02:00 The reason I "clock" the liner, and rematch it to the same hole it came out of is because I have seen liners crack at the very top when they have been mixed up. When you properly install the pistons in the liner, you can easily twist the rod to any position. If by chance you install the piston, and it doesn't twist freely, you have a problem......take it back out. The other thing you mentioned was the liner seals looked good.....however.....I hope you are installing new ones anyway. As far as the liner inserts go.....we have a small supply of different sizes, but we haven't been able to replace some sizes because DD doesn't have all sizes available. ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.

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JoeZ Posts: 938 Joined: Dec 2008

Tuesday November 17, 2009 02:10 Afterthought.......try your best to match your height tolerances as close as you can.....in other words.....don't have one at the lowest and the one next to it at the highest......it may work, but I always try to get the closest match possible. ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.

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DieselBusParts Posts: 16 Joined: Jun 2009	Tuesday November 17, 2009 11:46 GoneFishen, I think you meant 1.6, 1.5 is Fly wheel housing in my book. When I said use old head bolts; what I really meant is I need to buy some bolts that match the head bolts to install the liners, I can then cut the heads off and grind them round to use as a head alignment tool. ------------------------- http://DieselBusParts.com
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JoeZ Posts: 938 Joined: Dec 2008	Tuesday November 17, 2009 20:29 If you get bolts 2 or 3 inches longer than matching the head bolts....you will find it is easier to get them out after the head is on.... ------------------------- One of the last 2 Stroke mechanics left. 44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.
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GoneFishen Posts: 1325 Joined: Jan 2007	Tuesday November 17, 2009 22:05 The head bolt size is actually an 11/16 thread. I have used a 5/8 thread bolt from a 71 sereis for guide studs. Good call. Sorry about the page thing. Memory plays tricks sometimes. ------------------------- DDA tech for 30 years,all 2 cycle,series 60,50 mbe also. 1995 F250, 191k mi. Lost Wages, Nv
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