short-bus advice on engine, tranny etc

Ray_WA · 01-23-2009, 12:13 PM

Quote:

Originally Posted by vanguy67

When you say "traditional" front end, short bus, do you mean like a van in the front end or like a "regular" school bus just shorter? There is a world of difference between them.

Yup, yup. Some folks actually consider those "van nose" things to be a bus!!! Every time we see one of them my girlfriend laughs and says "they think thats a bus!"

Seriously... all kidding aside... from a conversion standpoint one big difference is width. My bus is very short but I think it's as wide as a regular school bus. I like the maneuverability the shortness gives me but those extra inches of width let me pack the most into that short space. Others might want the narrower width of a van nose bus to give them even more maneuverability.

I think the van nosed buses also have a bit less heavy duty chassis. This means lighter weight and possibly better fuel mileage. But it will also carry and/or tow less weight.

-Ray

Jarlaxle · 01-23-2009, 08:58 PM

Quote:

Yup, yup. Some folks actually consider those "van nose" things to be a bus!!! Every time we see one of them my girlfriend laughs and says "they think thats a bus!"

This is coming from someone driving something built on the running gear of a BREAD TRUCK?!?!

*ducks and runs*

Ray_WA · 01-23-2009, 09:54 PM

Quote:

Originally Posted by Jarlaxle

This is coming from someone driving something built on the running gear of a BREAD TRUCK?!?!

hehe.. You can't have a short bus of any kind without taking this kind of ribbing now and then. I love it

-Ray

TKFT · 01-23-2009, 10:04 PM

Quote:

Originally Posted by Ray_WA

Quote:

Originally Posted by Jarlaxle

This is coming from someone driving something built on the running gear of a BREAD TRUCK?!?!

hehe.. You can't have a short bus of any kind without taking this kind of ribbing now and then. I love it

-Ray

This is true. Friends keep calling mine the short loaf. I mean its not even brown...

Ray_WA · 01-23-2009, 10:36 PM

Quote:

Originally Posted by TKFT

This is true. Friends keep calling mine the short loaf. I mean its not even brown...

Maybe I should name my bus the Bread Bus!

-Ray

Ray_WA · 01-24-2009, 11:21 AM

Bunny? I'm not a bunny kind of guy.

-Ray

Ray_WA · 01-24-2009, 02:32 PM

No bunny bread here. How about Wonder Bread? Everyone knows about Wonder Bread!!

I was seriously looking at painting my bus white anyway! Add a few colored "wonder" dots and I'd be set!

-Ray

Ray_WA · 01-24-2009, 08:01 PM

I'm no expert but I'd say that gear ratio is the bigger factor in top end speed. You can have as big a motor as you want but if the gearing is too low you aint going very fast. From the factory I'm sure they wouldn't put higher gearing than the motor could handle but if you change gears on your own you might end up with too little motor to do the job. So look for gear ratio!

I'm sure somewhere on the forum is a formula for figuring out speed based on gear ratio, tire size, etc... You might find more if you search the forums.

-Ray

Jarlaxle · 01-24-2009, 09:23 PM

Assumming 22.5" wheels and normal-sized tires (10R or 11R22.5), you want about a 4.10 ratio for a diesel, maybe 4.30 or even 4.88 for a gasser. Any deeper and you'll have a screaming engine on the highway. The truck I drive at work has 4.11 gears and 295/75R22.5 tires (same diameter +/- an inch as a 10R22.5)...60MPH is 2000RPM.

A shorty with lo-pro tires will need taller gears...example: 265/70R19.5's and 3.54 gears give ~2100RPM at 60.

Seriously, though...Ray's bus looks to be built on the Chevy P30 chassis, same as thousands of motorhomes & Stepvans.

Ray_WA · 01-24-2009, 11:40 PM

Quote:

Originally Posted by Jarlaxle

Seriously, though...Ray's bus looks to be built on the Chevy P30 chassis, same as thousands of motorhomes & Stepvans.

The data plate says GMC but doesn't give a model. GVW on the plate says 5000 front and 11000 rear. I'd be curious to know just what chassis it is if you know.

-Ray

Jarlaxle · 01-25-2009, 08:48 AM

Quote:

The data plate says GMC but doesn't give a model. GVW on the plate says 5000 front and 11000 rear. I'd be curious to know just what chassis it is if you know.

Ahem...

Quote:

Ray's bus looks to be built on the Chevy P30 chassis

*smack, smack, smack*

Ray_WA · 01-25-2009, 11:25 AM

Hey! No lip smacking or drooling over my bus!! And don't lick the windows!

Soo... Chevy P30... or is it a GMC P30? What do I tell them when I go asking for parts?

I found this Chevy P30 Bus surfing google images:

It is pretty much just like mine.

To offer a bit more relevancy to this thread, I don't know what the gear ratios are and I've only had it up to 50-52 so far, but it's got lots of pedal left at that speed. I expect it'll go faster than I care to go on flat ground. It was a bit sluggish going up the hill to my house but it's a rather steep hill in places.

-Ray

paul iossi · 01-25-2009, 11:56 AM

they all come down the same assembly line the only difference is the title and the emblem, just like a ford lTD and a mercury marquis, only difference is the paperwork.

timbuk · 01-25-2009, 12:31 PM

Ray i have never seen a bus like that here in BC sort of looks like a wonderbread wagon,i guess? How long is yer bus?(i know its the short bus)

... i like it,i am known for liking the odd ones!

Ray_WA · 01-25-2009, 03:30 PM

I think it's about 20 feet long though I've not measured the outside dimensions. Inside I have 13.5 feet behind the drivers seat to the back of the bus, 91" wide and 6'4" high.

-Ray

Ray_WA · 01-26-2009, 05:42 PM

Some would say that a short bus is more a state of mind than reference to physical dimensions.

-Ray

Ray_WA · 01-27-2009, 06:36 PM

Thank you! While it's not very helpful maybe it's closer to true... To someone who has a full length 40 foot bus anything less might be a "short bus". But someone with a 30 footer might not feel like he has a short bus! Mine is only 20 foot but it's the biggest thing I've ever driven. If there is a specific definition of "short bus" I don't know what it is. Anyone else?

-Ray

Hearse Driver · 02-25-2009, 10:24 PM

Quote:

Originally Posted by Ray_WA

Some would say that a short bus is more a state of mind than reference to physical dimensions.

Hmm... I'm not sure if that is a good thing or bad...

Ray, I just realized that your bus might be a bit shorter than mine. From the rear of the step to the back of the bus on mine is almost exactly 15 feet.

the_experience03 · 02-25-2009, 10:31 PM

P30's tend to have some cool stuff going on transmission-wise. The 4 speeds are typically SM465's, the same granny geared dumptruck transmission that GM used 40 years ago and are tough as nails. Anything newer than about 1986 should have a beef 32 spline output and a hydraulic clutch. 5 speeds tended to be either an NV4500 or a big Clark 5 speed. The Clarks are worth something because it is a heavy, medium duty transmission that comes with the appropriate adapters to go to a Chevy block making them popular with the offroading crowd. Automatic transmissions in the 3 speed variety will be either a Turbohydramic 400 or a TH475. The TH475 is another beef part because it uses straight cut gears on the planetaries making it stronger. It is usually identified by a large parking brake drum on the output though the TH400 could be found this way as well. As for 4 speeds...I've never seen a 700R4 in one, but that doesn't mean they didn't find their way into those trucks. I think you're probably more likely to find a 4L80E or an Allison.

Ray_WA · 02-25-2009, 11:05 PM

Quote:

Originally Posted by Hearse Driver

Ray, I just realized that your bus might be a bit shorter than mine. From the rear of the step to the back of the bus on mine is almost exactly 15 feet.

Yup. Yours is a bit longer than mine by about a foot and a half I'd say. I'm very jealous!!!

-Ray

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