Got white smoke (unburnt fuel) and the sound of exhaust making it past an exhaust valve on the right bank. Thought I'd check valve lash first (probably the simplest) then go in through the air box into the liner ports with a probe camera. Removed the valve cover and valve train movement looks normal. When the white smoke first started to appear (return trip from Alaska) it cleared fast upon warming but has gotten progressively worse now with blow by sound and no clearing. Any thoughts?
Only a compression test will show the problem.>>>Dan
What block ?
DD IL 671 Na 4 valve head
I'm trying to figure out how it can be a "right bank" issue when you only have one "bank" with an inline engine.>>>Dan
Quote from: Utahclaimjumper on October 02, 2016, 05:07:43 PM
I'm trying to figure out how it can be a "right bank" issue when you only have one "bank" with an inline engine.>>>Dan
Dual exhaust on the 6L-71 I love the sound of those
Use a if heat gun on each manifold outlet to pin point cylinder. Temp will be degrees lower than others, which should be pretty close.
Blow by is going to probably be a head gasket,or valve,I seem to recall somebody called me looking for a head for your bus several months ago.Could be if you changed heads you missed the adjustment on the bridges and burnt a valve
Do you ever run it 1500 rpm or less with full load on grades? That will cause burned valves on them over time with n65's or larger.
Quote from: chessie4905 on October 02, 2016, 05:39:49 PM
Do you ever run it 1500 rpm or less with full load on grades? That will cause burned valves on them over time with n65's or larger.
I may be wrong but I think this is the guy that added propane injection and was doing the ETG tests a while back
Appreciate the responses.
Negative on the lugging, always keep it revved, has never been over 195 (only for short period) since head replacement, mostly runs 180 or cooler.
I like the infrared gun trick on the exhaust manifolds, I'll try that after checking valve clearance.
Yes we're the one with propane injection, dual pyrometers never read above 950 degrees since head replacement (almost 10,000 miles since head replacement).
Propane injection has been helpful on our Alaska road trip, never seen a difference on the pyrometers with or without propane...
We're also the one with blower failure since the head replacement but the smoke issue manifested prior to blower failure, and ran well after blower replacement.
The head is coming off anyway then you can tell what happen,I am not a huge fan of propane, for some reason it makes the valve seats pop out on 92 series engines.Bully Dog took a big hit with their system years ago and quit selling the propane injection kit
I've heard the propane pros & cons. We'll find out more and post. My system is "at will" & very little "intermittently". Don't know if it would show in 10,000 miles and other variables of possible causes like excessive downhill speed and blower failure (not all at once)
Just toss the friggn propane and turbo your engine and be done with it,Bully Dog and others spent a ton of money trying to build a propane injection system for the 2 stroke and it nearly broke all of them.
You guys come along with 5 gal propane tank and 50 dollar valve and believe you can improve on the system I don't think that is going to happen.
Sorry if it sounds harsh but I just sent out a 8v92 that propane did a real number on and I ask myself why do people buy into to some of this stuff and it ends up costing in the end like $19,000 on the 8v92 but if you are happy with propane it's your call not mine, a turbo is way to go for more power
We recall lots of uphill where we saved a gear or two &/or needed to downshift farther from the bottom so it really does improve the performance (& diesel mileage).
We're talking about a 53 bus here with 7 to 9 million miles on it running a 69 block that has never been majored.
By the way, we have two 5 gal propane tanks for propane injection besides the four 7 gal for camping and only paid $40 for the valve!
I'd like a turbo but it costs a lot more than $40. No harshness about it, everyone is entitled to their opinions. We look forward to the replies - that's why we're here.
We're the ones that didn't throw the towel in, fixed things as they wore out, and completed our bucket list of 37 years dreaming in an antique that was converted prior to the internet and runs without computer that can sometimes be repaired with tie wire & duct tape... We're probably in a different league but still all bus nuts...
Yep I would have never installed propane on a 37 year engine that has given you no problems over the years,so far you replaced the head, blower and now a possible major overhaul since the propane install but it is your call. Fwiw you can turbo that engine for under a 1000 bucks depends on the rods and have power 24/7
Its actually a 47 year engine (2016-1969=47) And it has had it's repairs over the years but none major. The head replacement was unrelated to propane and acting up for a long time before impeding the thought of an Alaska round trip. During the head replacement it was well evident and established that it was a tired engine even with the head replacement. Yes it was our call and we did propane. A few grades we encountered took goosing with the toad to the top, in first gear. An adventure in itself and extremely exciting. Weather it was propane, nitro, gasoline, or what ever it was our call. And in the end, success is all we felt with a renewed spirit, less money and happier than we've been in decades - and we still savor that renewed spirit and success of completing the bucket list item of a lifetime, at least for us, and will do it again. The engine was going to get attention one way or the other. So you see propane is irrelevant in our minds. We probably wouldn't have pulled the 7000# toad or even attempted the 12,000 mile journey with out our call. Sure hate to upset you with your fix on propane. It was our call and we did it and would do it all over again. Because the satisfaction of success and completion with the gain of spirit outweighs the tired old engine in the machine that brought us home. We're in different leagues - propane pleased us, it seems to not please you. I guess that's why they call us nuts, right? Bus nuts, you know!
LOL it doesn't upset me I get paid to fix one,I don't care what you do, but with your system you flying by the seat of your pants. With Scott's system there is no measurement just flip a switch not knowing how much just pressure regulation.
The way I see it you are filling a 2 gal bucket (the air box) no intake valves just ports.I have a friend with a 8v92 with propane a old green 8v92 engine when I did work on it 10 years ago I disabled his system and he still tells people how great propane is and the thing doesn't even work that all folks
As long as your friend feels good, that's what counts. If he is your friend and you honestly thought you were helping him that is good. I hope he never experiences humiliation...
Quote from: dtcerrato on October 04, 2016, 09:08:38 PM
As long as your friend feels good, that's what counts. If he is your friend and you honestly thought you were helping him that is good. I hope he never experiences humiliation...
That one didn't come out the way I intended he knew I disabled his system but he still praises propane,I threw away his K&N filter too and he still likes those also but he is happy now spending no money on his engine,it was part of the deal I wasn't going to warranty the engine with propane and the K&N filter
Dan I can say after spending time on the phone with Cliff and following his ever helpful posts for years on here and having he and many others on here help me through two coach builds, he means well. He's a nice guy just trying to share his wealth of knowledge. Forums don't always convey feelings very well lol.
Sent from my iPhone using Tapatalk
Hi Scott
Not really sure who you are referring to as Cliff but have an idea. It's all good! I look forward to the diverse opinions. When you say "wealth of Knowledge" that usually comes with age. I think some of us refer to it as wisdom. We've always respected our elders and have lost most of ours, but that's common for being a youngster @ 65. It's all good, no worry and look forward to future conversation. While we're on the subject of wisdom &/or wealth of knowledge - what's your excuse you young buck you! We know you're younger than most and even so we respect the likeness of you. As we mentioned on another forum, you are ahead of the game and we admire that - you already have a wealth of knowledge. Thanks for the kind words. Cool you, good stuff...
Following up on the right bank issue. Checked & recorded valve lash, no tight valves, they all had clearance but the clearances were all over the place from 18 thousandths to 32 thousandths. Also did an infrared video (couldn't attach - too large) of the dual exhaust manifolds. Only three cylinders fired upon cranking, then the other two fired when it caught after second cranking. The fourth cylinder from the left isn't firing at all. Keep in mind that this engine is a 1969 block rebuilt. That's 47 years of service without any major work. The new cylinder head went on in the 47th year. Since the cylinder head replacement the engine sucked hard on an exploded blower - so anything is possible. There is a distinct sound of valve blow-by from the right bank tail pipe.
2 or 4 valve head ? those adjustment are all over map you may have lost a cam roller ,or on the 4 valve head you missed the adjustment on the bridges it is head pulling time regardless
4 valve head
I would rule out the blower sucking parts in from the blown governor that won't happen
You mentioned blown governor. The blower lobes were seized and broke up enough for us to fish out a fair amount of shrapnel in the air boxes. I appreciate your comments & observation.
You will never know till you pull the head ,when a blower seizes you are dead instantly and you will always find shrapnel,you need to figure why you adjustments are all over the chart
10-4, understood... The blower failure was far from leaving us dead instantly, as we were in a down hill coast in gear intermittently braking to control speed. Unfortunately we didn't realize we were without power probably minutes after initial failure (heard an unusual noise minutes before smoke) when thick smoke filled the rear of the coach. It was the last really traumatic engine occurrence thus I dwell on it a bit but am the type that needs to digest these kinds of events. When we found that it was the blower it was sort of a relief because we'd figured a blown engine as we are in that circle somewhat now. The erroneous clearances do puzzle me. Will do a compression check for general info prior to pulling the head Thanks for your input.
I wouldn't waste time doing a compression check. Just pull the head and view damage. Any debris from a damaged blower is going to get into the cylinders, especially directly across from it.Just like a turbo coming apart....the engine eats it. I believe that I heard that blower clearances close up as they wear.
With all the time taken reading as well as typing all the posts in this thread I could of had the head and blower off and know the answer.
--Geoff
In that order, right? OK, I hear ya. We're pulling it tomorrow...
"blower clearance close up as they wear" - Makes sense. Our blower disintegration was caused by a failed bearing housing. That would be an instantaneous lack of clearance! Even prior to housing failure, a worn bearing would create inconsistent clearance between the lobe & case.
The ports are at the top of the block not on the same level as the blower that pressurizes the air box from the bottom.I have taken bits of rings and liners from a engine that have laid in the air box for 25 years.DD built the blower from aluminum for a reason.If the blower had damaged the engine it wouldn't have waited 7000 or 8000 miles to show signs and a blower has nothing to do with setting he has posted IMO,and I know if you don't have the bridges set right it is going to take a valve out so will a injector tip
Valve clearances were good all except 1. One valve is slightly bent from closing on a piece of debris. Two pistons have impact damage and they are not next to each other. The head has a few dings but surprisingly looks nothing like the pistons. The liners are worn out with a very noticeable wear can be felt at the top of the liners. The really bad liner is toast but all others were still firing but worn out.
Scott,the spacing and everything is so round an uniform it looks like a old trunk style piston that separated above the fire ring,they moved the fire ring down on the later trunk pistons you will know for sure when you remove it,probably bent the rod too and i don't believe the blower caused that damage
Quote from: luvrbus on October 18, 2016, 04:59:09 AM
Scott,the spacing and everything is so round an uniform it looks like a old trunk style piston that separated above the fire ring,they moved the fire ring down on the later trunk pistons you will know for sure when you remove it,probably bent the rod too and i don't believe the blower caused that damage
nope...looks like overspeed to me.
When the head was replaced we mentioned a liner kit but figured the ole' girl had one more good run in her, & it did. I think the blower shrapnel that went through the engine was the fuse to have more things happen. When we cleaned out the air box prior to blower replacement, we were pulling blower shrapnel off of the liner ports (literally) that were too big to go through. We know there was at least more than a minute of full speed run after blower failure so what went through had already happened... My 2 cent anyhoo...
My bad on posting inaccurate clearances - that kind of stuff happens when a carpenter gets a set of feeler gauges in his hands!
Overspeed is always on the table with our standard shift & no jakes. On downhill runs it stays in gear with intermittent braking to control speed.
Quote from: dtcerrato on October 18, 2016, 10:08:05 AM
Overspeed is always on the table with our standard shift & no jakes. On downhill runs it stays in gear with intermittent braking to control speed.
Shrapnel complicated overspeed... a new diagnostic code is born :)
Over speed should not be on the table, ever. Do not let the engine go over 2200, 2300 rpm.
JC
Head is in the machine shop & planning on an in-frame rebuild. Its been a tired engine for quite some time now - doesn't owe us a thing, we will continue to keep it alive.
Hey - that is great Dan. Glad to know you are keeping your bus going! I'm sure you'll be very pleased once it is all back together and running like a top again! Keep up the good work.
Have them check spring opening and closing pressures.I would replace all the valves but that's just me.
Would like some feedback/opinions on High Zink break in oil & assembly lube & Engine Run-In Schedule as stated in da book (In Line Diesel Engine Series 71 Maintenance Manual). Thanks
They did away with the hi zinc oil when the silver was removed from the bearings and in the later book you assemble with engine oil mixed with STP your manual will have those pages replaced (like 140) if the little cards were sent in to Detroit.
Assembly grease is still good sometimes I use the Lubricate 105 if I know the engine is going to set for a long period of time before the install
Got the cylinder head back from the machine shop, all the valves were replaced in the bad cylinder, the rest of the head checked out ok, the seats were checked out & reworked where needed. No surfacing needed - it is flat. The head cylinder that was banged up a bit from ring fragment was touched up. Left the rods with them for checking for straight and magnafluxing, will go from there. Ran the caliper on the block bores and rod journals, everything is checking out. All the crank & rod journals are .010" oversize and looking ok, the block bores are looking ok for #2 standard liners. Will probably stay with trunk pistons. Never did find anymore model/serial #s on the block. Got the entire oil bath air cleaner system restored, pushing on...
Brian, thanks for the words of encouragement...
Now is a good time to change the filtration system over to paper,oil bath systems are not that good on the old buses
I hear what your saying & there may be good reason for it, if there is I'd like to see it. My personal testimony to oil bath: when we purchased the coach in 1979, the oil baths looked ok - but a buried unseen gasket deeper into the cowling of the system was breeched in shambles allowing dirt to enter the system. That was one of the first items we restored. Since than (36 years ago) that restored system has been running really clean, we're talking downstream from the oil bath filters...the airways leading to the blower are as clean as the day we restored the system - so please elaborate on what it is about the oil bath cleaners that us users of should be concerned about. Thanks
Paper filters are 99.8 to 99.9% efficient at all speeds the chart shows a straight line at all speeds and only pass .2 of dirt, the oil baths are 96. to 98.7 efficient and are on a curve at different speeds passing 1.3 of dirt.
That info is not from me or a filter manufacture but from the DD engineering bulletin #39.
When DaveC shows up next week I will get him to post the bulletin so all can read it,I have no luck scanning and posting here, it is a interesting read for sure that people should know
Quote from: luvrbus on November 04, 2016, 07:28:41 AM
Paper filters are 99.8 to 99.9% efficient at all speeds the chart shows a straight line at all speeds and only pass .2 of dirt, the oil baths are 96. to 98.7 efficient and are on a curve at different speeds passing 1.3 of dirt.
That info is not from me or a filter manufacture but from the DD engineering bulletin #39.
When DaveC shows up next week I will get him to post the bulletin so all can read it,I have no luck scanning and posting here, it is a interesting read for sure that people should know
That is interesting, the oil bath type did better than I would have guessed, but paper is more effective. Oil baths are cheaper to run if you service them yourself, and stay off dirt roads.
we used to swab the intake piping with 90 weight. it would tattle any dusting sized particles that were induced via poor filtration or loose clamps...
I'm OK with 98.7%. That is a good number. Paper is a little better but not better enough to change over.
Don't need to oil swab anything into the air intake as much as it needs to be swabbed out!
Looking forward to see the bulletin, especially the date on it... Thanks
Forgot to mention, can't stay off the dirt roads cause they lead to the best places!
The 98.7 is at full throttle it is the dirt passed that is the killer 1.3 vs .2 ,you can probably down load the bulletin on the net the info is Table 4 page 9. Mine is revision No. In 2 only the exhaust restrictions charts changed LOL surely I am not the only one here with the bulletin
Quote from: dtcerrato on November 04, 2016, 06:11:03 PM
Don't need to oil swab anything into the air intake as much as it needs to be swabbed out!
your motor your money your way...makes sense to me :)
Quote from: luvrbus on November 04, 2016, 07:09:20 PMThe 98.7 is at full throttle it is the dirt passed that is the killer 1.3 vs .2 ,y...
The best air filter is only just good enough for me.
Dan , sounds like the oil bath did the job all these years so why mess with it. I have a 4104, sorry to hear yours needs some loving now but I like the way you are tackling the issues,following your posts and reading how long you have had your 4104, gives us 4104 owners a lot of faith in these old machines, glad your going to keep her a live. We give our 4104 a lot of love too and really enjoy it, it's a great machine, keep up the good work! Nelson
Thank-you Nelson. With the help of these bus forums it's hard not to keep the vintage buses alive. Ironically even having been married to our 4104 for almost 4 decades, we have just got on board with this & other bus forums less than a year ago, including the first rally we ever attended last year. Never really visioned getting DEEP into drive line components. With the backup of the cumulative experience of the people on these forums, and the commorodity & willingness to share what we all know gives us all the ability to upkeep & maintain our busses. Now that we're into the guts of such an awesome machine is really no different in all the admiration we've had on every component we've laid our hands on. My hat comes off to the manufacturing & engineering sector of our private enterprise to join in with the federal government in time of world war to put such stout manufacturing into motion for military success and eventually civilian public service proliferation. Don't mean to go off, just really appreciate your kind words & the machines we own...
The 4104 and the 2 cycle Detroit, and all the trucks and airplanes of that era, were created without the help of computers. It seems that the 4104 is one of the best surviving buses of all time.
I was only making a suggestion I don't really care which filter system you use.DD upgraded that engine for 40 years squeezing more life out of it and they were successful they made a 2500 hr engine last up to 5000 hrs
No more miles than people put on the old engines oil bath filters should be ok. Oil bath filters have always had a problem with oil misting all one needs to do is look at the intake piping it will be covered in oil.
Air filtration for engines has changed drastically in the past 40 years
We must not forget to mention Naval vessels. It was common to see eight 671 Gray Marine Detroit Diesels (two sets of quads) in naval vessels. My favorite (maybe because Dad and Uncle - his only brother, served in the South Pacific along side each other) was the PT Boat & (destroyer escort) Lightest & fastest on the water made of plywood and powered by 671s. One of the facts that send me about the early post war GMCs was the fact that they were recipient of the vast stockpiles of aluminum and 671s that went to public service sector along with commercial aircraft & trains.
GM had Stewart and Stevenson in Houston where I grew up developed the 6-71 for military use, the quads were developed for oil fields by Stewart and Stevenson they still have the 1st made.
The aluminum blocks were all made by P&H and Gray added their thing Gray never built a complete engine from scratch.GM did do a ton of 53 series aluminum engines later for the military.
Those aluminum blocks 6-71 are the pits to install liners in you don't slide those in and out by hand like the cast iron blocks ???