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Old 05-28-2016, 01:57 PM   #11
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Join Date: Feb 2015
Location: North carolina
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Year: 1986
Coachwork: Thomas
Chassis: Ford
Engine: Detroit 8.2
Rated Cap: 60 bodies
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Originally Posted by rty12345rty View Post
I have a 1986 Boyertown (Body) Trolley on a GMC School Bus Chassis, 8.2L Detroit Diesel, Allison 545 RM with a Rockwell International Differential with a 586 gear ratio, 10R-22.5 Tires.
I Have never owned a 8.2L aspirated Detroit Diesel. The question I have about the 8.2 Detroit is, when you take off from a dead stop the bus shift very well but when you hit four gear you are going 40mph, from 40 mph to 55 mph the engine is so noise that you cannot hardly hear inside of the bus the rpm are so high that it sounds like the engine is going to blow up. You let off the accelerator at 55 mph the bus will pull down in speed right away, the buses I drove with AT 545 when hitting four gear you can take foot off accelerator and bus does not pull down right away until you start braking
What can I do to fix this. Please Help! Ron
I have almost the same set up but mine is on a ford chassis.
8.2,545 and an eaton rear with 6.50 gears.
I only get 49mph.
I put the pedal to the metal and am a little slow off the line and am in 3rd gear by 25 and hit 4th around 35-38 and my 8.2 is loud.
I insulated inside and am working on the firewall and the backside of the dog house and it has helped some but I don't think we will ever really silence it down anymore.
One other thing I have an idea about and others have done it is to build a removable console over the dog house and maybe insulate it on the backside also.
To me the only way to quiet things down is to create layers to break/muffle the sound
All of the old 8.2 mechanics I have talked to say not to adjust the governors on the 8.2 that they are set for what the motor is designed at RPM wise.
My cheapest options are to change rear ends/gearing down into the 4.? Range and my tires are 9r20 tubed Dayton rims so I have been told by a few tire shops the 10r22.5 tubeless will fit my rims but looking at my rims I think I have to stay with tubes because the valve stem opening is a 2-3" long slot. Or maybe new rims are needed to upgrade tire size and whatever that gives me is what I get unless I hit the lottery and then a new power package and a lot of other wet dream ideas? It breaks my heart to waste 2$ on a ticket so I guess that part is another dream
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Old 05-28-2016, 02:12 PM   #12
Mini-Skoolie
 
Join Date: May 2016
Location: Elgin MN
Posts: 15
Year: 1986
Coachwork: Boyerville
Chassis: GMC
Engine: 8.2 Detroit
Rated Cap: 24 Pass
Quote:
Originally Posted by Jolly Roger View Post
I have almost the same set up but mine is on a ford chassis.
8.2,545 and an eaton rear with 6.50 gears.
I only get 49mph.
I put the pedal to the metal and am a little slow off the line and am in 3rd gear by 25 and hit 4th around 35-38 and my 8.2 is loud.
I insulated inside and am working on the firewall and the backside of the dog house and it has helped some but I don't think we will ever really silence it down anymore.
One other thing I have an idea about and others have done it is to build a removable console over the dog house and maybe insulate it on the backside also.
To me the only way to quiet things down is to create layers to break/muffle the sound
All of the old 8.2 mechanics I have talked to say not to adjust the governors on the 8.2 that they are set for what the motor is designed at RPM wise.
My cheapest options are to change rear ends/gearing down into the 4.? Range and my tires are 9r20 tubed Dayton rims so I have been told by a few tire shops the 10r22.5 tubeless will fit my rims but looking at my rims I think I have to stay with tubes because the valve stem opening is a 2-3" long slot. Or maybe new rims are needed to upgrade tire size and whatever that gives me is what I get unless I hit the lottery and then a new power package and a lot of other wet dream ideas? It breaks my heart to waste 2$ on a ticket so I guess that part is another dream
Thanks For the information.
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Old 05-28-2016, 02:26 PM   #13
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Join Date: May 2016
Location: Elgin MN
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Year: 1986
Coachwork: Boyerville
Chassis: GMC
Engine: 8.2 Detroit
Rated Cap: 24 Pass
If I change the gearing on the rear end what ratio do you think I should have so the bus will go 65 mph so the engine is not screaming. Do I have to do anything with the transmission. When I bought this trolley the trolley had 8.2 turbo engine in it from the factory, which engine would you go with if the engine in it now blows up in trolley aspirated or turbo.
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Old 05-28-2016, 02:57 PM   #14
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Location: North carolina
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Do you have an RPM guage in your dashboard? If not the first thing I would do is install one and make sure your screaming motor has not already been adjusted outside of its factory settings?
Which for me is a data sticker located on the drivers side valve cover near the firewall.
If you are already screaming more than the factory design then you will be wasting your time changing gears because your motor is gonna give up before your tranny or gears and when you re-power you will be back at the gears again?
Figure out what your screaming meemi is doing match that to your 545 rpm's (mine is not an RE) but my data plate is on the passenger side of the tranny.
There are many rear gear/differential calculator's on the web but you need to have the data plate info in your head to use them.
I know my engine hasn't been adjusted from factory settings and was well maintained because I bought directly from the school district.
Many opinions there also but they all agreed on rear gears for more speed and don't change the motor governors or the tranny and motor are wasted.
We can still get parts but there are no true old school 8.2 mechanics still in the workforce unless you get lucky where you are .
Fluid changes are adamant and if you have been keeping up with the forum there has been a recent thread about the 545 fluid change to synthetic (transynde) and a transmission temp guage also (which I don't have yet) another member here has turned a lot of us on to Blackstone Laboratories for fluid samples when you do change fluids. The sample bottles are free and the analysis is 28$ per sample and you get a full report of what your fluid says about your engine/tranny condition.
Lot cheaper knowing before you blow it up than setting on the side of the road.
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Old 05-28-2016, 04:10 PM   #15
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Join Date: Jun 2013
Posts: 252
Quote:
Originally Posted by rty12345rty View Post
If I change the gearing on the rear end what ratio do you think I should have so the bus will go 65 mph so the engine is not screaming. Do I have to do anything with the transmission. When I bought this trolley the trolley had 8.2 turbo engine in it from the factory, which engine would you go with if the engine in it now blows up in trolley aspirated or turbo.
To answer your question there is one more Factor we need to know which is the tire size.
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Old 05-28-2016, 04:30 PM   #16
Mini-Skoolie
 
Join Date: May 2016
Location: Elgin MN
Posts: 15
Year: 1986
Coachwork: Boyerville
Chassis: GMC
Engine: 8.2 Detroit
Rated Cap: 24 Pass
Quote:
Originally Posted by Jolly Roger View Post
Do you have an RPM guage in your dashboard? If not the first thing I would do is install one and make sure your screaming motor has not already been adjusted outside of its factory settings?
Which for me is a data sticker located on the drivers side valve cover near the firewall.
If you are already screaming more than the factory design then you will be wasting your time changing gears because your motor is gonna give up before your tranny or gears and when you re-power you will be back at the gears again?
Figure out what your screaming meemi is doing match that to your 545 rpm's (mine is not an RE) but my data plate is on the passenger side of the tranny.
There are many rear gear/differential calculator's on the web but you need to have the data plate info in your head to use them.
I know my engine hasn't been adjusted from factory settings and was well maintained because I bought directly from the school district.
Many opinions there also but they all agreed on rear gears for more speed and don't change the motor governors or the tranny and motor are wasted.
We can still get parts but there are no true old school 8.2 mechanics still in the workforce unless you get lucky where you are .
Fluid changes are adamant and if you have been keeping up with the forum there has been a recent thread about the 545 fluid change to synthetic (transynde) and a transmission temp guage also (which I don't have yet) another member here has turned a lot of us on to Blackstone Laboratories for fluid samples when you do change fluids. The sample bottles are free and the analysis is 28$ per sample and you get a full report of what your fluid says about your engine/tranny condition.
Lot cheaper knowing before you blow it up than setting on the side of the road.
Jolly
what engine do they use to repower 8.2 in a GMC chassis like this one.
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Old 05-28-2016, 05:27 PM   #17
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Join Date: Feb 2015
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Year: 1986
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Chassis: Ford
Engine: Detroit 8.2
Rated Cap: 60 bodies
Many an option and opinion and the tranny and rear gears will need to be added to the change.
Your platform was powered for a specific purpose so either make it work for you or plan on changing the entire drive train.
I am going to make mine work so that every component is happy and be happy driving on the back roads because I have already built my house on my platform,in,under,and all around and I can only afford to make edducated decisions and make what I have work and not back up.
If and when I do all the rear gear and tire/rim changes I am looking at ?
I will still only hit 59 in a perfect world so back roads all the way for me and if all of my money and changes still leave me on the back roads? Why change at all? Just plan on more time between point A and B.
I grew up on oil top back roads in TX so I love back roads and when traveling you usually find the real gas stations and grocery stores that have been there forever and still going.
My first job as a 14 yr old in texas was a full service gas station and if I had the money I would bring them back especially during the beach's tourist season.
Daydreaming again?
Make what you bought work or plan on thousands to re power? This is just my opinion?
Good luck on your build/decisions.
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Old 05-29-2016, 04:43 PM   #18
Mini-Skoolie
 
Join Date: May 2016
Location: Elgin MN
Posts: 15
Year: 1986
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Chassis: GMC
Engine: 8.2 Detroit
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Quote:
Originally Posted by jake_blue View Post
to answer your question there is one more factor we need to know which is the tire size.
10r-22.5 front and rear
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Old 05-29-2016, 05:05 PM   #19
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Engine: 8.2 Detroit
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8.2 Detroit

Quote:
Originally Posted by jake_blue View Post
To answer your question there is one more Factor we need to know which is the tire size.
Jake Blue the tire size is 10R22.5 front and rear
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Old 05-29-2016, 09:28 PM   #20
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Sorry about that, I looked back at the original post and you did state the tire size. My apologies for making you repeat yourself.

Based on what I can glean from Google on that engine, transmission and axle, and considering the tire size, the adjustable variable being the differential gear ratio means that to achieve 65mph in 4th gear you'll be turning about 2,200 rpm with 4.10 gearing or about 2,000 rpm with 3.73 gearing. Compare that to current and you're probably turning 2,700 rpm just to achieve 55mph. As with all things there's a trade-off to regearing for highway speed which in this case will be it won't get up as fast from a dead stop like it does now. I also don't know about how the transmission is to cope with this kind of gearing but it's a common transmission in school buses that assumedly can get up to speed just fine so my instinct is to say it should get fine, just not as peppy. There are also other gear ratios available but not sure which ones will work in your differential.

I hope this helps.
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