Griff in Fairbanks
AK
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Joined: 04/21/2005
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@StingrayL82 - Checked out that site you linked to ... reasonably accurate, assuming you have right tire diameter. Also, site has a fairly good list of transmission ratios. Because I'm/we're interested in highway RPMs, final ration is really only significant for our purposes.
1970 Explorer Class A on a 1969 Dodge M300 chassis with 318 cu. in. (split year)
1972 Executive Class A on a Dodge M375 chassis with 413 cu. in.
1973 Explorer Class A on a Dodge RM350 (R4) chassis with 318 engine & tranny from 1970 Explorer Class A
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Griff in Fairbanks
AK
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For those who don't know how to read and work with tire sizes:
LT stands for Light Truck and P stands for Passenger. If a tire doesn't list LT or P, I assume it's a passenger vehicle tire.
I'll sometimes use 'P' tires (or tires without a 'use' designation) on 1/2-ton trucks, depending on how I plan to use it primarily. On 3/4-ton trucks I prefer 'LT' tires. On 1-ton and heavier, I only use 'LT' tires.
The first number is the tread width, in millimeters. I use my computer's calculator to convert millimeters into inches because it's proven to be accurate. (When I get a new computer or operating system software, checking the accuracy of the provided calculator is one of the first things I do ... using a variety of conversions and calculations.)
In the recent discussion, we've been using 235 millimeters for thread width ... this converts to 9.25 inches. (Actually, 9.251968503947 inches but we don't need that decree of accuracy ... as long as we're not using furloughs per fortnight.)
The second is the sidewall height, as a percentage of tread width. if the tire size is 235/75, the sidewall height is 6.9375 inches. (9.25 inches times 75 percent -- or 0.75) For 235/85, sidewall height is 7.8625 inches. (9.25 inches times 85 percent -- or 0.85)
(R stands for Radial ... bias ply tires are rare now so the R is kept mainly because that's the way it's been done since the switch to metric tire sizes.)
Third number is rim diameter, in inches.
Tire diameter is sidewall height time two (both sides of rim) plus rim diameter.
So, LT235/75R16 tires are 29.875 inches in diameter. (9.25 times 0.75 times two plus 16) LT235/85R16 tires are 31.725 inches in diameter. (9.25 times 0.85 times two plus 16)
Tire circumference is tire diameter time pi. (3.14159 if you like doing things the long, tedious -- but more reliable -- way I prefer.)
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StingrayL82
Nampa, Idaho
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Joined: 06/27/2017
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Griff in Fairbanks wrote:StingrayL82 wrote:I use this site and plug in the numbers
(1:1 on the transfer case, since it's a 4WD site): Final Drive RPM Calculator
2587 RPM @ 55MPH
2822 RPM @ 60MPH
Something's wrong 'cause I'm getting slightly different figures ... working them out myself.
Maybe you used LT235/75R16 instead of LT235/85R16. (Larger tire diameter and circumference means lower RPMs.)
Will post my figures in a few minutes ...
My tires are 225/75-16 (29.29" tire diameter), which is the closest thing I could get to the original 8.00-16.5 tires. Funny thing is that, per the service manual, my rig should have had a 39-tooth speedo gear, but when I had it rebuilt, we found a 38-tooth. Having done the math, the 38-tooth gear will work very well with the new tires, to within 1/2MPH.
Fred
Retired Army Guy
2005 Monaco LaPalma 37PST
Workhorse W24 chassis
8.1L Vortec
Allison 2100 MH
Onyx Color Scheme
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StingrayL82
Nampa, Idaho
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It was a 12-hour day today. My son and I went balls to the wall and got the engine in, mated to the transmission, and the accessories are mounted. I can't tell you all how at ease my mind is right now. Getting the engine in was pretty straightforward, but there were a few minor issues, which we worked out relatively quickly, mainly clearance issues.
Here are the pics.
Getting ready to take the engine off of the engine stand. Notice the original Monaco engine block being used as a counterweight. Worked like a charm.
![[image]](https://i.imgur.com/GwqsCVel.jpg)
Taking a break, while we look at the checklist.
![[image]](https://i.imgur.com/09Ysz1ql.jpg)
Ready to install.
![[image]](https://i.imgur.com/qYzzaB8l.jpg)
Everything is out of the way, or is it?
![[image]](https://i.imgur.com/ixIwQ9Ql.jpg)
The booster and master cylinder have to come out.
![[image]](https://i.imgur.com/cfA7YIBl.jpg)
Now the battery isolator solenoid has to go too, as does the last link from the hoist chain, the crankshaft pulleys, and the engine hoist plate has to rotate 90°, so I can clear the firewall.
![[image]](https://i.imgur.com/pZXq2Xml.jpg)
And we're clear!
![[image]](https://i.imgur.com/lU0hY6Yl.jpg)
After two years, the engine and transmission are mated again.
![[image]](https://i.imgur.com/z62Nw0pl.jpg)
Full frontal. You can see that behind where the solenoid and booster/master were is the dirt that was all in that engine compartment.
![[image]](https://i.imgur.com/L23Jcw8l.jpg)
Accessories installed.
![[image]](https://i.imgur.com/a0Uj13bl.jpg)
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j-d
Sunny Florida USA
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Joined: 09/04/2003
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Awesome! Memory lane, seeing how that goes together. Familiar parts like that water pump. One version looked like a pencil holder behind the pulley, another came to a narrow peak. I think narrow was the heavier duty one... Found the original alternators with pressed-in diodes more reliable than the newer "square backs" with diode bridge assemblies.
I like the Plate! I had a couple lifting tabs off of other engines then connected with a piece of chain.
So clean with that OEM compressor and mounting! Our aftermarket A/C put a big welded bracket over top of a lot of what you have in the open, then the bulky York compressor on top of that.
Good Job! Congratulations!
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB
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DRTDEVL
SPAM Town, USA
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Joined: 04/23/2014
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StingrayL82 wrote:My tires are 225/75-16 (29.29" tire diameter), which is the closest thing I could get to the original 8.00-16.5 tires. Funny thing is that, per the service manual, my rig should have had a 39-tooth speedo gear, but when I had it rebuilt, we found a 38-tooth. Having done the math, the 38-tooth gear will work very well with the new tires, to within 1/2MPH.
Interesting choice. I thought about going that route, but with a width of 8.9 inches, I thought that it could pose an issue in spacing between the duals. Of course, I was forgetting the fact that my replacement wheels would likely have more offset, coming from a vehicle that ran 235/85R16 from the factory (late 80s D350 pickup).
How is the spacing between the rear duals with the 225s? What wheels are you running?
Another thought I had was that we drive much faster these days than the 55 mph era. 55 is just plain dangerous here in the desert southwest, where the speed limits are 75 and 80. I looked for the tallest tire I could fit without rubbing, while still being narrow enough to ensure clearance between the duals. This gave me LT215/85R16E as my choice. 0.9 inches taller, and 0.5 inches wider. This reduces my final drive ratio by about 3%, and keeps me just under 3,000 rpm at 65... and in my first couple of trips, 60-65 has been my travel speed.
Resurrecting an inherited 1980 Minnie Winnie 20RG from the dead after sitting since 1998..
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StingrayL82
Nampa, Idaho
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j-d wrote:Awesome! Memory lane, seeing how that goes together. Familiar parts like that water pump. One version looked like a pencil holder behind the pulley, another came to a narrow peak. I think narrow was the heavier duty one... Found the original alternators with pressed-in diodes more reliable than the newer "square backs" with diode bridge assemblies.
I like the Plate! I had a couple lifting tabs off of other engines then connected with a piece of chain.
So clean with that OEM compressor and mounting! Our aftermarket A/C put a big welded bracket over top of a lot of what you have in the open, then the bulky York compressor on top of that.
Good Job! Congratulations!
Thank you! I AM SO SORE TODAY!!!! Most of the replacement parts came from two junkyard donors, an ‘83 & an ‘84 B150, the former being the main donor. I really like the simplicity and cleanliness of the factory compressor and, like you said, it unclutters the engine compartment.
I was missing the factory heat shield that goes between the exhaust manifold and the driver, and the ‘83 provided one, but the forward mounting tab is in the wrong place, so I’ll drill out the pinch welds and relocate it; my father-in-law will puddle weld it in place.
I also found a four-barrel air cleaner that’ll work, because the Mopar original seems to be a unicorn; a ‘79 Wagoneer will do the trick, and I’ll have warm air start-up, courtesy of the ‘84’s heat shield. I also bought new factory exhaust manifold bolts and made sure to coat the outer studs with sealant, to ensure no coolant leaks (dumbest design ever).
Did I mention I’m sore?
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StingrayL82
Nampa, Idaho
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DRTDEVL wrote:StingrayL82 wrote:My tires are 225/75-16 (29.29" tire diameter), which is the closest thing I could get to the original 8.00-16.5 tires. Funny thing is that, per the service manual, my rig should have had a 39-tooth speedo gear, but when I had it rebuilt, we found a 38-tooth. Having done the math, the 38-tooth gear will work very well with the new tires, to within 1/2MPH.
Interesting choice. I thought about going that route, but with a width of 8.9 inches, I thought that it could pose an issue in spacing between the duals. Of course, I was forgetting the fact that my replacement wheels would likely have more offset, coming from a vehicle that ran 235/85R16 from the factory (late 80s D350 pickup).
How is the spacing between the rear duals with the 225s? What wheels are you running?
Another thought I had was that we drive much faster these days than the 55 mph era. 55 is just plain dangerous here in the desert southwest, where the speed limits are 75 and 80. I looked for the tallest tire I could fit without rubbing, while still being narrow enough to ensure clearance between the duals. This gave me LT215/85R16E as my choice. 0.9 inches taller, and 0.5 inches wider. This reduces my final drive ratio by about 3%, and keeps me just under 3,000 rpm at 65... and in my first couple of trips, 60-65 has been my travel speed.
I have plenty of space all around, I’ll take some measurements and post later...I’m still in bed, and it’s 10AM....I’m sore as hell.
IIRC, the 8.00-16.5 was a 28.4” tire, so I’m about .8” taller, but I don’t remember how much wider I am. I went with factory Dodge and Ford dually steel wheels that I got from the tire shop down the road. Once I cut the locating pins off of the brake drums, the Ford duallys fit perfect.
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DRTDEVL
SPAM Town, USA
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StingrayL82 wrote:I have plenty of space all around, I’ll take some measurements and post later...I’m still in bed, and it’s 10AM....I’m sore as hell.
IIRC, the 8.00-16.5 was a 28.4” tire, so I’m about .8” taller, but I don’t remember how much wider I am. I went with factory Dodge and Ford dually steel wheels that I got from the tire shop down the road. Once I cut the locating pins off of the brake drums, the Ford duallys fit perfect.
How are you locating them on center? They are lug-centric coined wheels from the factory. That is why I went with a D350 donor, since it had 16 inch wheels, yet retained the coined pattern and locating pin setup.
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StingrayL82
Nampa, Idaho
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DRTDEVL wrote:StingrayL82 wrote:I have plenty of space all around, I’ll take some measurements and post later...I’m still in bed, and it’s 10AM....I’m sore as hell.
IIRC, the 8.00-16.5 was a 28.4” tire, so I’m about .8” taller, but I don’t remember how much wider I am. I went with factory Dodge and Ford dually steel wheels that I got from the tire shop down the road. Once I cut the locating pins off of the brake drums, the Ford duallys fit perfect.
How are you locating them on center? They are lug-centric coined wheels from the factory. That is why I went with a D350 donor, since it had 16 inch wheels, yet retained the coined pattern and locating pin setup.
The only thing those pins did was a line up both dual wheels, to ensure that the coins matched up. My new 16” wheels are still coined, so I just match the pinholes up. The only reason I cut the original pins, is because the Ford pinholes do not match up the way the Dodge pinholes do. Everything is still centered and works as it should
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