I just posted about our experiences digging into the air filter failure that accompanied our engine overheat this summer.
Link: http://www.technomadia.com/2013/10/failure-analysis-did-a-baldwin-pa2721-filter-kill-our-8v71-engine/ (http://www.technomadia.com/2013/10/failure-analysis-did-a-baldwin-pa2721-filter-kill-our-8v71-engine/)
We can't know for certain that the Baldwin filter was at fault, but overall we've lost all faith in Baldwin and will not be letting a Baldwin product near our bus ever again.
I know a lot of people here were waiting for an update on our final analysis on what killed our engine. This is it - sharing all the details that we have.
Cheers,
- Chris
Thanks for the follow up. When you guys went through your ordeal, I decided to change my air filter as a preventative measure. Our configuration is the same as yours with the air flowing from the inside to the outside of the filter, although judging from your Wix number, we have a different canister. In any case, both the NAPA filter that we removed and the Donaldson that we replaced it with have substantial support around the outside of the filter. The NAPA had a steel mesh and the Donaldson had a perforated metallic sheet. I would really question whether a filter that does not have such protection could really be honestly specified for two way flow.
As far as the filter failing due to moisture, it would seem to me that driving in a serious rain or snow storm would be likely to bring a lot of moisture into the filter.
So your filter got wet, failed and debris got sucked into the engine. Evidently water got sucked in from the air intake during a rain storm while driving. I can't imagine the Florida dampness would weaken a filter to the point of failure in such a short time. Does your bus have some sort of baffle upstream of the filter to separate the water out of the air? My 5C did, until I built a custom intake that draws from high up on the side of the bus to ingest less dust on gravel roads. But I drill two 1/8" holes, one on each end of the filter canister (a Fleetguard, Eco type that flows from outside to inside) for water to drain out. I kind of doubt that it actually drains until the engine is shut down. I replace the filter once a year. I have cut up an old one, and was impressed at how sturdy it is, with mesh and hot melt beads inside and out.
JC
Great idea on a baffling system, we'll have to see what is possible in our configuration.
However, in the 10 months that we drove on this filter - I can only recall it raining of any significance once. It lasted about 20 minutes, and wasn't that strong of a rain. Any other rain we might have drove in was light and quick passing. And certainly we encountered no snow in Florida :D
In general, if the forecast is for rain - we stay put until it clears up. There's rarely anyplace we need to be that badly that we don't have the flexibility to wait for clearer skies.
- Cherie
Most air intakes will have some sort of moisture evacuation system. Usually a flat rubber looking thing commonly referred to as a kazoo. This will eliminate any water that is sucked into the system before it even reaches the air cleaner. Highly recommend you go with Donaldson-they make the Detroit filters also. Good Luck, TomC
Dina puts a Donaldson air/water separator in the intake before the filter. This should keep most of the water out of the filter. I still get some moisture into my filter. I go out to the Blackrock playa every year with the bus. The filter minder never tripped, but after a few years I pulled the filter and it had a thin layer of mud inside it. The playa dust probably combined with high humidity during Minnesota summers turned into mud. I should probably plan on replacing the filter again next summer.
Dina has the air intake up at the roof line. One problem with the design is there is no mesh over the intake and birds tend to nest inside and block the intake. When I got my bus the intake was partially blocked by a nest. I was able to make a temporary fix to bypass the nest to get me home. Once home I got the nest out and covered the opening with mesh.
The ECO filter does not use a vaculator as Tom referred to as a "kazoo" never heard that before ::) the ECO system has small holes to drain that is why they need to be installed level in both directions
High humidity will kill a filter it doesn't have to be rain or snow,Baldwin couldn't be that bad that is only filter I ever saw at Swift Transportation or Arrow Stage Lines in Phoenix
I have never used the ECO style from Baldwin but have used plenty of their fuel,oil and air filters over the years in applications from heavy equipment to cars
Clifford, do you think those little holes at the bottom of the Eco filters actually drain water while running? I am thinking that air would be sucked in through them, and that water would not drain until after shut down. So it would not help for as long as you are driving in a downpour, which could be hours...
And even with a water separator, wouldn't a fine mist of moisture be continuously drawn into the filter? That would be worst than sitting in a wet climate like Florida.
99.9% of air filters don't seem to be adversely affected by that in a one year period or 4000 miles. I have taken wet air filters out, and didn't think they were at imminent risk of failure...
So maybe Chris and Cherrie you were unlucky and picked up a lemon filter? Or something else got into it, like starting fluid?
JC
About two years ago I noticed that my Racor Eco-BC filter had several small splits in the inside of the material, probably due to old age and possibly also from some rain damage. I not only replaced it (Racor made me a brand-new filter to order, so I know it hadn't sat on a shelf deteriorating before I got it), but I also reworked my intake. I extended the 7" inlet pipe higher to reduce the amount of rain that could get sucked in, and I made a water trap inside the intake housing to safely drain away any rain that did get inside. The new filter also has a rubber drain valve in its base, something the old filter didn't have. Most importantly, I made the intake cover removable in a few seconds without tools, so now I can easily see down inside the filter to check that everything's OK. My Farr Filter Minder is still connected, but I don't trust it to tell me if the filter needs to be changed - if the filter's split and letting air through the gaps it won't help you. A few months ago I also installed a turbo boost gauge - if it begins to read less than normal I'll know I have a problem somewhere in the intake system. After my scare with the old filter I now check the inside of the air filter every few months.
Chris, could you arrange it so the inside of your filter is easily visible for inspection?
John
Quote from: lostagain on October 10, 2013, 04:39:18 PM
Does your bus have some sort of baffle upstream of the filter to separate the water out of the air?
Our bus draws in air from the passenger side, midway up. There is an intake screen and a large multi-baffle chamber before the air filter, making the direct ingestion of water an essential impossibility.
I have checked inside the baffle chamber and it is clean and dry and not obstructed.
- Chris
Quote from: Iceni John on October 10, 2013, 10:28:45 PM
Chris, could you arrange it so the inside of your filter is easily visible for inspection?
Unfortunately - not easily. Not unless we cut a plexiglass window into the filter canister anyway. And since the canister is part of the filter, I am pretty sure that would be considered a warranty violation.... ;-)
Our filter is mounted up over the engine in a location that is actually really difficult to get at - making quick checks impractical.
We initially added the Filter Minder just to give us some extra piece of mind because the air filter is so hard to get at for a quick look.
- Chris
Water gets in the GM filters from somewhere every oil bath filters I ever serviced on a GM had water in them even here in the desert a air intake design for oil bath filters could be their problem who knows for sure
JC I have tried to get the ECO to suck water in the drain hole must be the design I had no luck
John, how did you make your water trap in your air intake?
JC
Quote from: lostagain on October 11, 2013, 07:23:44 AM
John, how did you make your water trap in your air intake?
JC
My engine air intake is about 7 feet above the ground, behind a louvered grill that is behind the last window on the right side. The 7" intake pipe for the air filter itself is vertical, set back a few inches from the louvers, and in the space between the pipe and the louver I put a small plastic tray with a length of tube attached that drains away any rain water that blows in through the louvers. Another reason I did this was because I moved my DDEC fuses to a location directly under the intake housing, and rain was getting in and dripping down on them - not good! Now, if any water gets in, either it will harmlessly drip out the drain tube, or if it gets sucked into the filter the rubber drain valve on the bottom should (I hope) let it escape before it gets drawn into the engine. Either way, the pleated filter element should never get significantly wet. I think this was why my old filter began to split internally, but fortunately the splits did not go all the way through the material - there seems to be more than one layer of material in the Racor filters, so the outer layer(s) still remained intact.
The fiberglass interior cover for the entire air intake was originally screwed, glued and caulked in place, obviously never meant by Crown to be ever removed; I reattached it with two stainless pins and some aluminum channel to make it easily detachable, and when it's removed I can easily peer down inside the air filter itself, sort of like a doctor telling you to say AAAAARR when he looks in your throat.
John
IMHO - From this armchair, it doesn't look like the engine "digested" enough filter element to cause an immediate catastrophic failure.
I'd guess too, despite the shredded element, that the air intake wasn't restricted when climbing blow-up hill. Mostly because symptoms of a "gagged" engine were not reported.
I'd guess that the element was "sucked out" before blow-up day, and so the engine had been breathing unfiltered air for some time; not good, but not cause for immediate catastrophic failure.
I didn't follow along every detail, but I don't recall reading about the "last chance" screen at the blower inlet being littered with filter element. Was it? If this was a recent and quick element failure, I would think that there would have been "confetti" galore present.
It's my personal opinion that the filter's sizing is pushing limits and that a step up in filter size would probably have prevented the blow-out. Although it's (barely) within CFM application spec, to me, it looks like things stacked up against the marginally sized filter. I wonder too if an over-speed -at some time- could have pushed flow up just enough to be able to suck out the border line element?
Ted
Thanks for the info.. will be going to Napa for a wix filter for my MCI 8v71 before my next trip. Did you post about your engine rebuild anywhere... Price? Who did it?
Quote from: jdpilot on October 15, 2013, 08:45:12 AM
Did you post about your engine rebuild anywhere... Price? Who did it?
We've posted thousands of words and hundreds of pictures:
http://www.technomadia.com/rebuild (http://www.technomadia.com/rebuild)
- Chris
Quote from: TedsBUSted on October 14, 2013, 08:44:57 PM
I'd guess too, despite the shredded element, that the air intake wasn't restricted when climbing blow-up hill. Mostly because symptoms of a "gagged" engine were not reported.
Indeed - the engine performed fabulously on the way up. It was not sluggish at all.
Quote from: TedsBUSted on October 14, 2013, 08:44:57 PM
I didn't follow along every detail, but I don't recall reading about the "last chance" screen at the blower inlet being littered with filter element. Was it? If this was a recent and quick element failure, I would think that there would have been "confetti" galore present.
The last chance screen had some paper in it - as did the blower. Not "galore", but I'm not sure how much at all would have stuck around if the filter had failed long previously.
Quote from: TedsBUSted on October 14, 2013, 08:44:57 PM
I wonder too if an over-speed -at some time- could have pushed flow up just enough to be able to suck out the border line element?
I've wondered the same thing - this is the top thought in my mind when I say that we are not sure whether the filter failure caused the engine failure, or was the result of it.
What might have caused an over-speed event? What would the symptoms be?
- Chris
The most likely over-speed to go unnoticed would be a downhill run that pushed the engine above governed speed.
Another over-speed scenario could be a "runaway" that's caused by either excess fuel, or lube-oil ingestion; had that happened it would have been obvious and not gone unnoticed.
My opinion is that from the beginning, for this application, the filter would have been marginal, at best.
Also, I believe that something was lost in the failed filter manufacturer's "translation" of a replacement for the original design and its intended applications.
It happens. Brings to mind a certain hydraulic filter application in heavy equipment. The OE manufacturer's filters work just fine. However, when "will-fit" substitutes are used, it's almost guaranteed that the element will be found to be blown-out at the next change, and sometimes with catastrophic side effects.
Ted
Ted, if they used the direct replacement like a Donaldson P537447 or any other ECO manufactures replacement for the Baldwin PA2721 it's still 1000 cfm and that is close on 8v71 for the 900 cfm for a standard 8v71
I use 1200 cfm on 8v71 engines with N65 or N70 injectors but we all do it different
Dang them old :onasty DD engine killing POS oil bath filters....oh wait, they didn't....
Quote from: TedsBUSted on October 15, 2013, 03:39:39 PM
The most likely over-speed to go unnoticed would be a downhill run that pushed the engine above governed speed.
Ted -Don't know if you're aware, but Allisons will automatically shift up to the next higher gear if the engine starts to overspeed. Even if you've locked it down manually into a lower gear, the transmission will still upshift if it senses overspeeding.
FWIW & HTH. . .
;)
How is a 730 in 3rd gear going to up shift if a engine over speeds it has no place to go, they over speed in 3rd being the 4106 has such such low rear gearing
To me it just got hot and pulled the liner it's the nature of a 8v71 I have 2 in my yard that did the same thing 1 a turbo 8v71 from a 4905 the other a 8v71 N/A from 4106 the filter had nothing to do with it
They can count their blessing for having the later 71 with water jackets it could have been a lot heavier on the old pocket book
A day of driving in the rain is going to get the air filter damp and wet. Maybe not that day, but some time earlier.Minimal excess filter capacity, a little dust and dirt in the pleats, filter distortion, then deterioration and collapse, not noticing exhaust getting darker and temp climbing for how many minutes???? It happens....these things make owners start to be more aware of their vehicle's operating conditions, almost to paranoia. I'll bet that you monitor conditions more closely now. Same when brakes get out of adjustment and barely slow down vehicle on grade, or tire blows due to low air or worn out, etc,etc. I.d at least make sure that the filters from now on have metal supporting mesh, and plenty of reserve capacity, and move on. Don't lug it, don't let it overheat, don't let the oil get get low to empty, don't let coolant get low, and don't over rev it, and it should run a long, long time.
We found a broken liner was due to being too snug in the block bore, and not dropping in and / or driving in with force / hammer. A proper fit have not seen one break.
Dave M
That causes it too Dave I saw that more than once where people did not know you can by liners in std or oversize size or the 1,2,3 in sizes they buy a std and drop in or force in it makes no difference as it takes to long for a person to hone a cylinder for a perfect fit loose can be as bad as tight, it doesn't me being retired all I have is time or what left of anyway lol
luvrbus,
Gee, that is a fact, along with the correct depth of liner so the compressin ring seals correctly, there are many areas where a guy can really screw up, but when they are right, they are RIGHT. All that is one reason I love the two strokers, once you get real comfy with them, evey thing else has no appeal. But being over the hill, I now have to pay for what ever is done, not able to crawl around and under like 25 yrs ago. Am lucky to have a good employee who is great at following directions and learning. Getting old is not so bad, you just have to laugh at lots of fools & foolishness.
Life is great as long as the ISM500 keeps puttin out. The ISM is no class like the 12V-71, that is class. ;D
Quote from: luvrbus on October 16, 2013, 08:02:32 PM
How is a 730 in 3rd gear going to up shift if a engine over speeds it has no place to go, they over speed in 3rd being the 4106 has such such low rear gearing.
Clifford -Sorry, I disagree.
A stock 4106 with a V-730 will have a overall final drive ratio of 3.588:1 in 3rd (high) gear.
That's "taller" than the stock 3.70:1 in an MCI, and lots of others.
With 500 rev/mile tires, that means they'd have to be doing well over 75 mph to overspeed the 8V. (75 mph is 2250 with this tire/rear axle ratio combo.)
FWIW & HTH. . .
;)
RJ what are we calling stock I am just trying to figure it out using the 3rd gear ratio of a 730 at 0.875 to 1 and a TC 470 torque converter
good luck
Quote from: luvrbus on October 17, 2013, 07:51:53 PM
RJ, what are we calling stock? I am just trying to figure it out using the 3rd gear ratio of a 730 at 0.875 to 1 and a TC 470 torque converter
Clifford -3rd gear in a V-730 has a ratio of 1:1. Not sure why you've included the torque converter, once it's locked up it's not part of the equation.
The bevel gear set is 0.875:1 in this transmission. It's 0.808:1 in the 4-spd manual.
The OEM stock rear axle ratio is 4.125:1.
The
overall rear axle ratio is the product of the following math: (High gear ratio) x (bevel gear ratio) x (rear axle ratio) = overall rear axle ratio.
Plugging in the numbers gives you:
(1:1) x (0.875:1) x (4.125:1) =
(1) x (0.875) x (4.125) = 3.609375, or simply 3.61:1
(In the post above yours, I rounded off the bevel gear ratio to 0.87:1, hence the slight difference of 3.588 vs 3.609.)
Either way, it's still a "taller" ratio than the others.
Running the numbers for the manual gearbox and you get an overall ratio of 3.333:1, which, with 500 rpm tires, sends the 4106 down the highway a little over 80 mph @ 2250 rpm. Since it's been said often here and on other Detroit-related websites that 8Vs have be set to 2400 rpm in certain applications, certainly 2250 is not "overspeeding" the engine. Not recommended, obviously. . .
If you really want to go slightly crazy, then we could include installing V-730s in 4905s! ;D
FWIW & HTH. . .
;)
You lost me with the 1:1 final on V730 and no thanks I did a 4905 2 years ago :-* that was
1st 1.71:1
2nd 1.21:I
3rd 0.85:1
reverse 1.46:1
The up shift can be anywhere you want or done away completely we have no way of knowing what theirs was at least I don't and I always include the torque multiplication we went to the TC 470 converter with 3.25:1 the transmission had a TC 490 2.51:1 and he thought it may be a little on the light side for a 40 ft bus living in the mountains
Quote from: luvrbus on October 18, 2013, 12:20:33 PM
You lost me with the 1:1 final on V730.
Yup, that's a common thing with the V-730. Lots of folk confuse the 3rd gear ratio with the (3rd x Bevel) ratio, but 3rd is actually 1:1. Same as an HT-740.
I'll try to find my V-730 sales brochure that has the specs and scan it for you.
I'm not well-versed on the various torque converter ratios, but I can quickly see were in "unlocked" mode the torque multiplication can be significant between the different models.
Speaking of unlocked, the shift sequence on a V-730 is 1C-2C-2L-3L. Which is another thing that confuses folk not familiar with them - they think it's a 4-spd because the 2C-2L feels like a shift.
FWIW & HTH. . .
;)
(Wow. . . Talk about thread drift!)
I have the V730 manual RJ no need to scan one,the V730 is just a 3 speed 740 a overhaul kit is the same for both only the bevel gear and shaft is the difference FWIW
I have often thought about trying to use the 0.875 gear from a V730 on a 740 I know the bevel gear changes the ratio I was always told 7% but Allison says 0.875:1 with the bevel gear so now I don't know
I do seem to remember there was about 4 different versions of the V730 when we were doing research
The one I installed was V730D from a 1982 bus he wanted a V731 with overdrive but the electronic would have been a major chore on the 4095
thanks I learn something everyday
The 740 doesn't use a bevel gear; only used because of the angle drive. The 4905 with 4.375 rear would have a high gear overall ratio of 3.83. Since the V730 doesn't have the low gear of the 740, it uses the torque converter to get it moving in 1st. (would be second in a 740, but somewhat higher gear or lower ratio because the bevel gear changes all the gear ratios in that trans).
I never said the 740 used a bevel gear I did say different but meant difference sorry and I corrected it
I am just going by what Allison says the final ratio is on a V730D and the starting is why I went to the TC470 torque converter
When he wakes up I going to check with the Allison guru Bob Ware and see what he says is the final ratio on a V730D is if anybody knows it will be Bob not that I don't believe you guys but I want his opinion I cannot under stand why Allison would say 0.875:1
Definitely check with him but all V730 models had the overdriven angle drive ratio of .875 to one. In another words, if the engine turns 1 rpm, the trans shaft turns 1.14 turn or 7% more. I imagine that GM did this due to constraints of making the angle differential gears of lower numerical ratio than 4:11. Although the vs2's had two angle drive ratios; 1 to1 and 8.75 to 1. They never made optional ratios for the V730, after studying the parts manual. Some have claimed that there was an optional bevel gear ratio when the V730 first came out, but what's the point. The coach would lose 7% top end. The 4104's did have 3.875 and 3.55 ratios in an angle drive, however at a different angle. Maybe the design of the 4106 and on didn't have enough meat or clearance to go any lower in ratio or startability would have been insufficient.
Ok I got him while he was drinking his morning coffee and in a good mood he says the V730 and the V731 have 3 different final ratios and 2 different bevel drive depending on what was spec and that transmission has other applications beside a bus that I did not know.
He says the two planetary gear sets produce the final ratio the bevel drive has nothing to do with the ratio and the 0.875:1 in lockup was the most common in the RTS they can have from 0.65 to 1.40:1 the 1.40:1 was used on a 6v71 engine in transit buses in some parts of CA he knew of
The 3rd digit in the model number will tell you the changes to the transmission that I knew, that is what he told me and now I am confused ::)
He did tell me I could use the V730 0.875:1 planetary gears on a 740 because he has done that for some Eagle owners that swapped to a 4 stroke Cummins he thought it was for B&B in Vegas he wasn't for sure on that, if nothing else I did get a answer on that part
good luck
I could see that different planetary ratios inside trans clutch units could effect the ratio spread of first and second, but it will effect the rpm drop of the engine upon gear change. Probably could be useful on a 4 stroke. My parts and service manuals are 1992's, so I'd like to get copies of the books on the new info, if they are still available. http://groups.yahoo.com/neo/groups/RTS-bus-nuts/conversations/topics/11247 (http://groups.yahoo.com/neo/groups/RTS-bus-nuts/conversations/topics/11247)
Here's some info from a few years ago:
Thanks I see where Geoff said the RTS had 2 different ratios for T series with a V730 I also read the Gurmman/Flx manual for the 870 transit it shows 3 different ratios for the V730 but I have no idea what GM used I used V730D from a RTS and shot the drive shaft with the wheel turning with my laser tach and could never make the math work to come up with 1:1 fwiw