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'77 Gears/Carrier in '82 D44 and 9.25

chickendeluxe

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I put 33' Tires on my 1982 Ramcharger and its a pig. I think its 2.94 or 3.21.

I can get 3.90 gears from a 1977 W100 4x4.

The RC has Power Track Lockers I'd like to use.
I know Ill need the front carrier with the 3.90

Any Concerns? use new bearing/shim/seal kit?
 

AJ.

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Going from 2.94s to 3.91s will increase your rpm at any speed by 3.91/2.94= plus 33%
Going from 3.21s to 3.91s is; 3.91/3.21= plus 21.8%
But , 33s with 3.91s is still 65=2600 at zero-slip, maybe plus 3% in TC slippage. This is a reasonable cruising number but;
Off the line, at zero mph, with a stock stall, she will still be a pig, until the rpm gets up. So ......
3000 rpm with 3.91s, and 33s, in first gear, with a torqueflite auto; will be around 27 mph before she stops being a pig.
3.91s will certainly make her less of a pig, depending on the size of your engine.

If a 318, IDK man, that's a tough call.
The 77 318LA was a pig to start off with, never mind in a heavy 4x4 with 33s. IMO she needs more like 4.30s and a 3000 or higher stall. With 4.30s she would cruise 60=2900, and take-off with a ratio of 4.3 x 2.45=10.54 which corrected to 27 inch tires is the equivalent of 3.55s . A 3000 stall would about double the take off torque, and ease the piggyness somewhat.
A 360 would be better but only about 10 to 15%, it still needs the 4.30s and still needs a hi-stall depending what has been done to it.
All the best to you
 

chickendeluxe

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Thank you. Great response. I gained knowledge.

The motor is rebuilt with a mild cam, holley sniper, headers and duals .....nevertheless a dud , LOL.
I am adding parts as I get a good deal......

The 318 is a place-holder as a first cruiser for my son and while finishing the body, lift, and interior.
I just got the axles to convert to 3.90 when I do the suspension.
I do have a fresh racey 360, but not ready to that yet as well as a slew of former converters from my hot rodding days

I have collected most parts for a 440 swap as well. Just need to figure out if I like this truck enough to commit that inventory to a hardtop RC.
 

AJ.

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Well then what kind of cylinder pressure is the 318 pumping out?
If below 145psi, that is a big problem, and it will take quite a bit of convertor to get out of that hole.
The 3.91s will be a big improvement, and you always have Low-range.
Since you have several convertors to chose from, I would slam something in there that stalls close to or a lil under peak torque or no less than 3000. Now remember, if the 318 is low-pressure, it will likely stall at a lower rpm than you might expect.
 
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AJ.

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I wanna run something by you.
Lets say your current gears are 3.21s.
The ratios in the TorqueFlite are 2.45-1.45-1.00, and the transfer case is a 2:1.
In terms of road ratios (all gears times the rear ratio) this is;
7.86-4.65-3.21, and in low range this is doubled so 15.72-9.30-6.42
If you started in low range, and ran the auto thru all three gears, then out shifted the T-case into direct, and simultaneously backshifted the auto into Second you could get this; 15.72-9.30-6.42-4.65-3.21 and the splits are ; .59-.69-.72-.69
Take a look at that; firstly, you have 5 ratios, and secondly, the first three splits are pretty sweet, and the .69 last split is like an overdrive..
Lets convert those numbers to the equivalent of 27" tires.
I get 12.86-7.61-5.25-3.80-(2.62). Do you see how sweet that is? This is how those numbers would feel like with the 27s. That starter gear is bordering a race starter. Notice that the 4th ratio is 3.80 which is only a tic away from 3.91s, and the top gear of 2.62 will drop the rpm nearly 1/3!
Lets convert those numbers back to 33s and run the the 318 up to a 5000rpm shift, and lets assume a convertor slip of 10%. Your Road-speeds at the shifts would be 28-48-68-95-138... Now remember, at 68mph you are in Third in the Auto, but still in low range! So typically you would outshift the T-case into direct, and your rpm would fall to 68=2220@zero slip; perhaps 2300/2350 on the tach
With this combo;(the 3.21s) , you should not need any more stall than you already have. So you already have all the right components; All you gotta do to make this work, is make sure the transfer case can take this occasional abuse.
I would seriously like to drive that combo!
Ok wait, confession time; I already occasionally do that in the bosses 2002 Chevy lol, when getting up to speed dragging a 4000pound loaded trailer, but shifting at a much lower rpm..
Food for thought?
 
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chickendeluxe

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i found out quickly after putting on the 33"s i needed to shift manually.
I drive I barley saw 3G rpm.

When shifting manually, considering local traffic and road speed of new combo, I could wee mid to high 4G RPM.
This had reasonable pickup to not get run over by an 18 wheeler if merging on hiway.

So I got the 3.90's yesterday.
Time to gather an install and seal kit.
Recommendations?
 

AJ.

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i found out quickly after putting on the 33"s i needed to shift manually.
and that would be, because, the governor flyweights are all wrong.
The governor gets it's "signal" from the spinning driveshaft, which is now spinning way slower than before, because of the larger tires. The 3.91s will increase the driveshaft speed and so, the the auto upshifts will increase again.
If you had 235/75-15s before, which are about 30", and went to 33s, that is a change of 33/30= plus 10%
to get the speed-o and auto upshifts back would take a increase of the same 10%. So 3.21 x 1.1 = 3.55
But 3.91s is; 3.91/3.21= plus plus 21.8%, so then, your Speed-O will still be out and the auto upshifts should occur too early. This large a discrepancy cannot be compensated for by the Throttle-pressure/ KD mechanism. If or when you decide to go after this, you will need a lighter governor assembly. You can buy a kit from A&A transmissions, or you can chuck yours in a lathe and trim it down. Unfortunately, the governor is stuck in a bad place to work on.

Getting back to your combo.
you said you put a bit of a cam in the 318. And 'm sure you know that when you do that, you push the power-peak up higher and usually the peak ends up with a different, more spiky, shape. Also, moving the power higher WITHOUT a corresponding increase in cylinder pressure, usually makes the bottom-end softer.
The factory 318 cam peaked at about 4400 IIRC
Your new cam may not peak until close to 5000, depending on what "a bit of a cam" actually means.
When the power peak was pushed up, so was the torque peak.
The stock cam was on a 112LSA. Your new one is likely on a 110. This will increase overlap, making the torque below the peak, a lil softer again. But it gives it back in the midrange and beyond. All this adds up to having to hold it in gear long enough, so that, on the shift, the engine does not fall off the cam.
Btw, I'm pretty sure you know this, but just to mention; just because your cam peaks at 5000, does not mean that you should shift it there. The TorqueFlite 1-2 shift split is 59%. So whatever shift rpm you chose, the rpm will always fall to 59%. Therefore, shifting your 318 at 5000, will drop the rpm down to 5000 x .59 =2950 . If the power peak is at 5000 then the Torque-Peak will be at around 1500 less or 3500; so 2950 is well off the cam. Your only way around this is with a higher than 2950 stall, or to run the rpm up higher, before shifting.
To give you an idea; my 367 peaks at about ~5300, so the torque peak is ~3800.. But I have a Commando 4-speed, so my 1-2 split is 62%. I run my tach up to 6800 in first, and on the shift it drops to 6800 x .62 =4200; which is higher than the torque peak.. But the 2-3 split is 72%, so I run the tach up to 6800 again, to drop in at 6800 x .72 =4900, just short of the powerpeak, and the lil 367 keeps right on motoring.
Now, my engine was built, in 1999, to survive that, and it now has over 100,000 miles on it. SO;
I'm not suggesting that you try this, unless your engine was also built to take it.
But I think it's important for you to not blame the cam for the 318 being a pig........ if you are short-shifting it, or if the Convertor is strangling it with too low a stall.
Since you mentioned that you had " former HotRodding Days", I would guess that I'm not telling you anything that you don't already know. And I apologize if I'm re-hashing old news.
So to answer your question as to;
So I got the 3.90's yesterday.
Time to gather an install and seal kit.
Recommendations?
Altho I have rebuilt hundreds of those diffs, I have never run one; lol. The only advice I can give you, is if you intend to run thru deep water or sand; extend the vent up as high as you can and then turn it around and put an inverted U-bend in it, then fix it in that position. Do this at full shock extension/suspension droop. Make sure it cannot trap oil in the hose. And make damn sure it doesn't come off in the bottom of the creek.Your diffs breathe with every heat cycle, so you don't want it sucking in water or sand.
The reason that I have rebuilt so many of those is because the Company I worked for back in the 80s, got an Army-Contract and guess what; the majority of them came in, water-logged, lol. As did their transfer cases etc. I was a very busy boy for a few years. I had nightmares in the which the line-up of T-cases was endless, lol.

BTW; I'm glad you bought the 3.91s; it will make a big difference.
 
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7mopar

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With the combination he wants to run bottoms of creeks or anything off road would not be in my book of fun. 3g and 4 g starts bouncing off of rock and you had better have deep pockets. If you want a show truck and don't like the performance tow it or load it.
 

Cranky1

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With the combination he wants to run bottoms of creeks or anything off road would not be in my book of fun. 3g and 4 g starts bouncing off of rock and you had better have deep pockets. If you want a show truck and don't like the performance tow it or load it.
AJ has good info but didn't see anything about 'advancing' the cam upon installation. If he did, I missed it but when I was building engines for others, I'd advance the cam 4 degrees just to move the torque down in the rpm range a bit. That would make them 'peak' out earlier. It wasn't a drastic move but noticeable. No one ever complained and were happy with how their engine performed. With the teen having pistons down in the hole somewhat, valve to piston clearance wasn't an issue but did check that anyways just to be sure.
 

7mopar

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I don't think I would been shifting that chain drive transfer on the go. They definitely were not designed for it. That and the fact that 45 mph is max in four wheel unless the front is locked out. It's still running a lot of shock on the chain though and I have seen them explode the case when they went.
 

AJ.

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As for speaking about; " a bit of a cam";
Each "size" of cam, in the "bit of a cam" range, drives the power peak up about 200rpm. But in these small cam sizes, the peak is broad and flat so hard to pinpoint exactly where it is; And I've never been able to find A 200rpm change by seat of the pants, until Top gear, if at all. As the cams get bigger, and the LSAs get tighter, yes the peak is easier to notice. , but more because the cam falls over harder at the top.
Advancing the cam, one way or the other 4* will only move the power about 100rpm, and IMO, kindof defeats the purpose of the cam.
You'll get way better results with a increase in stall rpm. But
You'll get best results with increasing the Cranking Cylinder Pressure, to plump up the bottom end in the first place..

When you advance a cam, this is exactly what you are doing. You are stealing power duration to get compression duration, and IMO, this is surely not the best way to get pressure.
A typical "bit of a cam" might look like; 262/268/110
This cam would have (262+268)/2 less 2x110= 45* of overlap.... like a 340 cam,lol.
So then the total number of degrees for all events is 45 plus 2x360=765 degrees
Intake and exhaust are 262+268=530, so power plus compression are 765 less 530=235 degrees
If you install this cam on split overlap, the Ica will be 59* leaving 121 for compression.
therefore the power duration will be 235, less 121= 114 degrees, and The ICL for this is 108*.
Advancing this cam 4* from straight up will put the ICL at 110-4= 106*. This will steal 2* from Power extraction and give it to compression. This will pump up the CCP about 3 psi (whoopee)_So on a lo-compression 318, you are looking at from 135 to 138 psi at sealevel.
However the total of Power plus compression is still 235; so, 235 less 123=112 for extraction. IMO this is a bad idea because, almost without exception the burning gasses will still have plenty of useable energy in it, when the exhaust valves open. Energy that could have been used to propel the vehicle. At high rpm in a race car, this is not a big deal. But in a streeter, this is costing you money every time you pull up to the gas-bowser.

Ok lets do an exercise using the Wallace Calculator. Lets use a true Scr of 8.0:1, and 300ft elevation.
With an Ica of 59* I get 126.8psi and a P/V of 98
(Read about P/V here; Cam Timing vs. Compression Analysis )
Now lets advance the cam just 3* to an Ica of 56* and no other changes. At 56*, the pressure climbs to 130.2, and the P/V to 103, a solid increase of 5% P/V
Now lets put some new higher-compression pistons in that 318, put the Ica back at 59* where it belongs, and pump the pressure to the max for 91 gas, say around160psi . At 9.5 Scr, I get 158.5psi at a P/V of 122
Now, lets talk about P/V.
First the stock cam (240/248/112) . In at plus 4*=108, and at a true 8/1; I get an Ica of 50*, for 136.6psi At P/V of 113 So this is the baseline; and you know what that feels like. And so 113P/V is your target, or should be, so that the engine at least doesn't feel like a pig. And so, for me at least, 98 and 103 are NOT acceptable.
>Next, go back to the first example; Ica of 59*@Scr of 8.0, 127psi@98P/V
The P/V has fallen by 1 less 98/113= 13.3% as compared to the stocker . If you had 160 ftlbs at stall, this will now feel like 139 ftlbs, a loss of 11ftlbs. To get the torque back, you are gonna need more stall.
>Next, lets look at the hi-Compression 318, namely Ica of 59@9.5Scr= 159psi@122P/V
The P/V has actually climbed by 1 less 122/113=plus 8%, compared to the stocker. Again from 160 ftlbs, this is an increase of 13ftlbs, at the original stall. AND you still have the 114* of power extraction.
>This is also a one-two punch for fuel-economy, namely adequate power-extraction and additional cruise torque, so you can cruise at less throttle opening or use a smaller rear gear, to additionally, decrease cruise rpm. which would be a Triple-whammy.
>Now, I have been talking about low-rpm (below 3000) with all these numbers. If you go to a 3000stall, then the bottom-end is meaningless , under most conditions except cruising.
However, the boost in CCP will pump up the POWER everywhere. The absolute power increase expected is said to be only ~4% at peak, but the midrange from stall and on, is fatter than that, and the throttle-response gets to be snappier, and the engine becomes more eager to pull.
Just look at the differences;
from a stock of 113P/V@8.0 Scr, to 122P/V@9.5 Scr = Plus 8%, and
the pressure increase from 137 to 159 = Plus 16%
At low rpm; this will feel like your 318 grew by Plus 8% = 343 cubes, compared to the stock lo-compression slug. A 262* cam is 3 sizes bigger than the stock cam, so the rpm will move up about 600rpm from 4200 to 4800... about. That 600rpm is worth an easy 25 hp or more, never mind the pressure boost could be another 4%, all other things being equal. Plus 4bbl, plus headers, dual exhaust, etc;

Now, I know your engine is already assembled and looks to be installed. So changing pistons may not look appealing, especially in light of a higher stall TC being a cheaper solution (to power off the line); and especially with your future plans. But I thought it was worth going thru an exercise for the next engine.
In case I didn't mention it, the higher stall is only helpful in getting moving.
Once the TC is "stalled " it's all on gears and engine. And
once she's in top gear, it's all on engine and final-drive ratio.
But I'm sure you knew that.

Btw; I have been referencing HFT cams (Hydraulic Flat Tappet) in all exercises. It is possible to install a Flat tappet cam with similar .050 numbers, but having faster ramps and of less effective advertised duration. Such a cam might give you more cranking cylinder pressure for the same absolute power, because the actual point of intake closing angle could be a tad less.
 
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7mopar

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You think maybe you lost them there? Guess we will see.
At some point reality of a build must take prevalence.
Jacked up 4x4 with large tires may look impressive at a monster truck run or in some parking lot show. But the buck to say stops there. I see this a a frugal attempt to get so to say slapped in the face and a worthless truck. I can not put it any nicer way.
 
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