couple newby questions

[thomasinnv]

i have done extensive research and lots and lots of reading on this board and the 'other' one, so i probably already know the answer but need to ask anyway.

1.  When i bought the bus and drove it 500+miles home it was still a fully seated coach.  The entire ride was not much over 500' above sea level, with a few mild grades up and down here and there.  The bus ran very well with plenty of power and temps never getting over 180-185 except for the few gradual grades where it approached 195 but never over.  mostly ran around 180.  Well, yesterday during the first day of our maiden voyage, we travelled from under 500' to just over 3200' where we stopped for the night.  in the first hour or so of the trip the bus ran as it did before.  Ambient temps were upper 90's to around 100.  A lot of gradual uphill grades that didn't seem like much, but they were there.  After the first hour the bus consistantly ran around 195 and approached 200 when the grade got slightly more.  None of the grades were a 6% or better, all under that.  as we drove into the evening with the ambient temps down to mid 80's it still ran consistently around 195 but not reaching the 200 mark as easily as earlier in the day.  Transmission is the alison 740.  I had to run in 3rd most of the way, if i tried to put it in 4th the temps would start rising.  I know i am much heavier than before the conversion, obviously.  I am also pulling a full size truck.  my estimated weight (haven't weighed yet, will probably do that at the next fuel stop) is i beleive to be somewhere in the neighborhood of 36-38k.  I also realize that being higher in elevation the engine will lose power because the air is thinner.  Am i experiencing normal behavior?  or should i be looking for a problem somewhere?  Are these temps to be expected?  I just want to make sure everything is a-ok.  Don't want to chance hurting the engine.

2.  Will those air scoops put on the outside of the radiators help much?

3.  what do people do to address the issue of oil splatter on the towed?

oh, and it is a non turbo'd 8v71.  just changed the oil and filter.  delo 100 40wt.  anti freeze is 50/50 mix.  blowers in good shape and new belt.  no otr a/c.

[Ed Hackenbruch]

Have you ever flushed your radiators? Adding a little Water Wetter may help some too.

[cody]

Too keep the oil splatter of our towd we try to not follow MCI's too closely lol.

[Ed Hackenbruch]

Our slobber tubes go into a small tank. We don't get splatter on the jeep unless i forget to drain the tank once in awhile......which reminds me, i should drain it.

[thomasinnv]

Have you ever flushed your radiators? Adding a little Water Wetter may help some too.

nope never have.  i suppose it might not be a bad idea.  they look good from the outside, lol.  obviously the outside is not a good indication of what goes on in the inside.  are the tank gaskets easy to come by?  a rodding might be in order.

Our slobber tubes go into a small tank. We don't get splatter on the jeep unless i forget to drain the tank once in awhile......which reminds me, i should drain it.

actually, there's really nothing coming out of the slobber tubes.  I did however find substantial pooling of oil under the front and rear of the blower.  put a gallon in after 500 miles.  I run it right at the bottom of the fill mark.(6 gallons)  is the blower job a big one?  can it be a diy for the seals/gaskets or does the rack need to be ran or anything technical like that?

[FloridaCliff]

Thomas,

After you have taken a little run (long enough to get up to temp) , take an infrared thermometer and go tube by tube across the radiator.

If you have some clogged tubes they will be noticeably cooler than the others.

if you don't have an IR thermometer, get one.  It is a great diagnosis tool.

Cliff

[steve wardwell]

Oil splatter on the car?  hoo ha ! give it a bath..... Early this morning 4 AM ish I was southbound I75 Georgia rolling at 60 in the Rh lane with a car to my left when I see a "hwy road gater" with nowhere to go but over the top   all over in 3-4 seconds...I'm glad I had my trailer and not my towed. Think I'm in the market for a diamond plate splash guard now to improve the looks of the  front of the trailer ...if our car was there $ ....sometimes you just have to  take your lumps ...........s.............

[DMoedave]

i would think with that load (towing) and especially those abient temps, you were running normal. With the auto trans (you do have a trans temp guage?) our engine temps rise as the trans temp rises. As you stated in 4th gear your temps rose as you started to lug (loss of revs on engine) Sounds like you were doing ok to me.

[thomasinnv]

Thomas,

After you have taken a little run (long enough to get up to temp) , take an infrared thermometer and go tube by tube across the radiator.

If you have some clogged tubes they will be noticeably cooler than the others.

if you don't have an IR thermometer, get one.  It is a great diagnosis tool.

Cliff

i do have one, and i did do that.  temps are very consistent across the entire rad from top to bottom and side to side.  the temp drops slightly as you move from the top to the bottom, as would be expected.  but there are no noticeable cool spots.  do those air scoops help at all?  think i'm a gonna go to lowes in the next day or two and get the supplies to put together a misting system.

[gumpy]

I would suggest you check your seals around your radiators and blower door, first. If your blowers are sucking air around the radiators, then that air is not doing much good to cool your bus.

You might also want to verify that the calibration on your gauge is correct. Put a manual gauge in and verify the two readings match.

You should also fill your engine oil properly. The low mark on the dipstick is there for a reason, and the extra oil will help some in cooling your engine.

I find it nearly impossible to use an IR gun to verify temps. The high temps occur when you are underway, and when you stop to check with the IR, the radiators cool down before
I can even walk to the back of the bus. The only way to get even a close reading is to shut the bus off immediately, and still just the act of slowing down will cause the radiators to cool
as air is being pulled through them.

[Tim Strommen]

With a non-turbo engine, you're not going to have sea-level power at altitude - but it sounds like you know this.

The non-turbo 8v71 from my DD books say you will get between 250-325 HP and between 780-1000 lb-ft of torque depending on your setup - your full sized pickup toad may have as much power (but moving easily 4x as much weight).

...actually, there's really nothing coming out of the slobber tubes.  I did however find substantial pooling of oil under the front and rear of the blower.  put a gallon in after 500 miles.  I run it right at the bottom of the fill mark.(6 gallons)  is the blower job a big one?  can it be a diy for the seals/gaskets or does the rack need to be ran or anything technical like that?

That's not somewhere where oil should be coming out of (and you're sure it's not fuel?).  Sounds like you might want to replace the blower seals - I think 500 miles is a little short of a run to burn off a full gallon of oil...  AFAIK, the blower job doesn't require removing the heads (maybe the valve covers), so you shouldn't have to mess with the rack - but if you've never had it done on your engine, you might want to anyway.

I saw mention of the intention of installing a diamond plate splash guard on "the trailer" - that's good, better than putting it right on the bumper of the bus (that would block air exiting the engine compartment out the back and force hot air out the sides where it can be re-injested by the radiator).  A wide mudflap right after your rear wheels would lower the air pressure at speed under the engine compartment and help the fan pull air into the engine comparment through the radiators.

Like Gumpy says right above, check the seal around the blowers - you want the air to have a "path of least resistance" being ONLY the radiator core, if there is even a small gap around the radiators to the fan, the air will take it.

I think, in the end - you will want to just sit back on your chair and take pleasure in going slowly up the grade - it's not a 600HP 2000lb-ft monster...

-T

[thomasinnv]

all the seals around the radiators are good.  there were some missing but i replaced those and installed new seals around the blower access door also.  did that before starting this trip. 

as for the oil level, that seems to be a debate on this and the 'other' board.  it seems from most of what i have read that filling right up to the full mark is a waste of oil as it will blow it out to a level where 'it' is comfortable.  on the 500 mile run home when i bought the bus it blew a gallon out in the first 200 miles, the po had filled it right to the full mark.  she settled down a bit after that.  I think the blower seals are getting worse though.

i have verified the temp guage against a mechanical guage and it is within about 5 deg.

i am checking into locating some air scoops for the radiator intakes, and will be putting together a mist system before leaving Albuquerque.  we are sitting in an rv park right now, gotta take it in and have the generator fixed in the morning.  just shut down yesterday while we were parked eating dinner.  Thank God for warranty.

A budy has an MCI7 and he told me "i have just accepted the fact that i can and WILL go 19 mph up any hill.  that's just the way it is."
i never expected to fly up any hills.  i just want to know that what is happening is to be expected and not indicative of a problem.  The stats shut me down twice yesterday.  when the temp really starts rising i slow down and grab another gear, and hold it against the governor.  just wasn't quick enough those times i guess.  The bus is completely original. no air scoops, no misters, no upgraded blower pully or anything else.  one thing i just went at looked at though, the dome shaped flaps or seals or whatever you call them that are inside the blower housing, there are a few small chunks missing out of them.  would that make that big of a difference?

please excuse my ignorance.  that is why i ask questions here, to learn.  please don't get on me for not knowing, we all have to start somewhere.

[Tim Strommen]

Don't worry about asking questions, it's what the board is about.

For the engine performance, if you have a driver’s side exhaust, the smoke color will tell you quite a bit about how the engine is running – thick black smoke means your engine is blowing incompletely/un-burnt fuel out the pipe so you are putting more fuel in with your right foot than the engine can burn…  If you are seeing black smoke and you are decelerating on an incline – downshift, this is one of the early signs you are lugging (and that will heat your block up really fast).  Keep in mind that if the fuel doesn't all burn in your cylinders, it can continue to burn after the exhaust valves open and keep burning as the exhaust gets blown out your un-cooled exhaust manifold.  Once the cast iron gets hot, it takes a long while to cool off (and with that pool of oil around your blower I'd be a bit more than somewhat concerned...), so even if you do downshift you may not have enough thermal headroom to avoid overheating while continuing your climb (which will put you on the side of the road while it cools off).  It also makes "scavenging" less efficient (the intake portion of the exhaust/intake stage), so the next combustion will be even less efficient (so the condition compounds).

One other thing that I didn't see mentioned as a "thing to check," is the condition of the blowers themselves (are they all intact? any fins in the squirrel-cage missing/damaged?).  It would also be really interesting to see what your actual combined vehicle weight is (bus+toad) just for the sake of discussion and reference (any public scale nearby?).

Remember, at 20MPH, you probably won't get much additional air ingestion on an incline with a scoop but on the freeway at speed it will probably help.  Two basic low-risk modifications will give you a little help in this area - a pulley size change for the blowers (spin the fans faster, move more air), and ventilation for the engine compartment (there was another recent post illustrating how cheap ingenuity can make a difference).

Misters are a topic that comes up here a lot - there are two general (contentious) camps from my observation (for full disclosure - I don't use misters, no reason, I just don't):

• "Misters work, and I like them"
• "Misters work, but they destroy your radiators"

You can get patio misters from just about any hardware store, but you need to come up with a way to provide water at pressure for a sustained period of time, and it will need to be controllable (you won't want it running all the time).  If you use domestic city water for the misters there is pretty good consensus from the experienced that you will get mineral deposits on the fins – you can use a separate tank for the misters and put in only distilled water, but this will probably end up being a constant issue for refilling.  One way or another, if you are misting in a high dust environment, you’ll probably get a dirt build-up in the fins that will need attention (cleaning, corrosion checks) frequently.

The reality of misters is they do work, but there can be a significant long-term risk to the radiator core down the line - this “negative” point may not be an issue for you, it’s a matter of personal taste.  As we say here on the board a lot – “Do it your way”.

Hope this helps, let us know how this all ends up – we like to hear how stories end here.  All-in-all, it sounds like you don’t have your head in the clouds, and have your feet firmly on the ground – the best thing you can do is ask more questions .

Best,

-Tim

[Tim Strommen]

You know, it just occurred to me you have the same transmission I have - a problem I've heard of with the Allison is the lock-up converter (torque converter).  The transmission probably has an oil-to-air heat exchanger, and it's probably in front of one of your radiators (the heat will leave the exchanger and make the ambient temperature the radiator gets to work with a lot hotter, making your engine temperature problem worse) - you might want to find a way to relocate that exchanger out of the radiator airstream.  It’s just one more thing to check…

About the lock-up thing, if the torque converter doesn't go to "lock-up" the input turbine (the part attached to the engine side) will squeeze transmission fluid against the output turbine (the part attached to the transmission) - and that generates a TON of heat (actually I don't know the specific BTU's generated it may actually be a TON or more of heat ton = 12,000 BTU).  There is a clutch in the torque converter that free-wheels until the two turbine speeds are close enough, and then it sets or “locks-up”.  There are articles out there on triggering lock-up (you can force it), but down-shifting into 3, 2, or 1 should also "encourage" the transmission to use lockup more.  If I recall correctly, the 740 doesn’t like to use lockup when running under 25MPH road-speed – so if you’re doing less than that – there is a really good chance that you are not locked up and you’re actually overheating your transmission (especially with all that weight).

I'm not intimately familiar with MCI, but I believe the flaps in the blower are like shutter stats - they open to allow the blowers to pull air through the radiators once the fluid temps come up to normal temp.  An aditional check would be to see if you get full air flow with the flaps open.

Best,

-Tim

[RJ]

Derrick -

A long time ago, I used to put 80,000 miles a year on MC-8s and MC-9s in revenue service, and never once had one shut down on me - even climbing the notorious Baker Grade between Barstow & Las Vegas in summer.

First, the company I worked for has an extremely thorough PM program for their entire fleet - it cost's more than money when you have a breakdown - ask BK!  NONE of the MCIs had scoops and/or misters on the radiators - it was OUR fault, as drivers, if we screwed one up and had it shut down on us for overheating.

Second - you drive the Allison automatic like a stick shift when pulling grades - i.e., you shift it manually. 

Third - you keep the engine as close to 1800 rpm on a partial throttle when pulling a grade - NOT sitting on the governor with your foot thru the front bumper.  You should be able to accelerate slightly in the lower gear in case you need to, but concentrate on that magic number 1800.  Detroit two-strokes pull best between 1700 - 1900 rpm on partial throttles, and will usually do so easily w/o overheating.  This often translates into toodling along at 30 mph in 2nd gear going up 6% grades - don't stress, sit back and enjoy.

This link might help, be sure to read it all the way thru :

http://www.busnut.com/bbs/messages/12262/16204.html?1167073154


Scoops are virtually useless when pulling grades - you're going too slow for them to work.  They're also tree branch magnets, which renders them even less effective.  What seems to work even better is a 1" piece of aluminum "angle iron" mounted vertically along the leading edge of the radiator.  This breaks up the laminar air flow along the side of the bus, and creates a slight negative pressure area at the radiator intake screen.

Tim's suggestion of a full-width mudflap behind the back AXLE, not bumper, creates a low-pressure area under the engine, which also helps pull air thru the radiators.  GMC did this will all their highway coach models, starting with the 4104.

Since you're the one footing the bill, another tip/trick is to cut louvers in the lower engine compartment barn doors to help vent the hot air out.  Poor man's version is to prop the doors open slightly when you know you're gonna be climbing Rocky Top in the summer heat.

Several MCI owners have installed an additional air-to-air oil cooler for the transmission in the curb-side engine access door.  Use a Hayden fan on it, but make sure it's blowing OUT - the electric fan in the appropriate size for the oil cooler, doesn't have enough "umph" to overcome the huge air volume produced by the OEM blowers.  It should be plumbed to pre-cool the transmission oil before going to the engine's transmission oil cooler.

Water cools better than anti-freeze, so if you're spending most of your time in temperate to hot climates, you might try a 60/40 or 70/30 water/coolant ratio.  Don't forget the Detroit test kit for the cooling system, too!

IMHO, misters are a band-aid, but do it your way.

Weigh your bus for two reasons - so you'll know how heavy you are, thus creating a need for a "bus diet" plan, because excessive weight also affects fuel mileage.  The second reason is so you'll know what air pressure to run in your tires, based on the load inflation tables published by the tire manufacturers.

Other than that, what you described in your initial post sounds perfectly normal to me.

FWIW & HTH. . .