A833OD inspection results... thoughts?
comments inside the quote
I think i was gonna run a 255 60 15 on the back. Thats a 27" tall tire isnt it? The math says yes
BTW American Powertrain Warehouse has a kit for freshening up the NP A833 O/D. Comes w seals, gaskets. Bearings, snap rings, thrust washers, synchro rings for $126 i figure thats a pretty good deal. If theres other issues inside it, they have gears, input shafts, hubs etc. Sounds pretty good to me. I've had to pay that much just for the back bearing.
Do you have a pic or 2 of the cross shaft pin I'm not trying to be a dork, but the pin I am referring to is usually called the countershaft, or cluster-shaft/cluster-pin . A cross shaft pin is found in a differential.
and area that's a problem-child with these O/D boxes.I don't think it's a problem-child when used as intended. Mine might even have been OK with straight gear-oil. I just know that in my combo it couldn't take it.I use 50% ATF,and 50% 80/90 EP oil. This gives me the shift quality I want with some wear-protection for the countershaft. I would like to run 100% ATF, but in my experience the counter shaft doesn't like that.The ATF just shifts faster at 7000rpm.
Along with more details on how to fix.See earlier post. If mine is undamaged, is there and easier way than a machine shop. I don't think so,unless you gave a milling machine. I got too many places out by me that are a little "shenady on the ding dang" if you know what i mean. If i can do this at home i'd prefer it. I got one shop that i trust w engine machining thats it. If the 318s gonna love it, maybe i should give that a mild refresh and forget the 408.
If you're already thinking this way, then just do it! Altho I highly recommend a 360. You can run a cam at least two sizes smaller for the same power, and reap the benefits of massive off-the-line torque, that you just can't get with a teener. And the small-cam 360 will also love that wide-ratio box. If you engineer it right, the 360 is a very diverse platform.
Although the thought of having a 408 boiling the hides up to 65 mph sounds kinda fun lol. You don't need a 408 to do that; you just need your engine to pull like a 408 from zero to 65mph,and those 255s will melt like butter. With street suspension, the 360 and 262 with the right gears,will spin 255s all the way to 65 as well.
You probably want to sit down and list your must-haves from your combo, so you can begin to form a game plan.
A lazy engine runs about .8 hp per cubic inch. this will burn any old crap gas, and get you moving reasonably well. For a 318 this is about 255hp, and a 360 is about 288hp. That's a 33 hp difference. and that is already at least one cam size smaller.
By 1.0hp/cube things are heating up.This would be 318hp, and 360 hp. This is now a 42 hp difference and about 2 cam sizes.
By 1.2 hp per CID, things are getting complicated, and the 318@382hp,is probably past using pump-gas. Whereas the 360@430 hp is using aluminum heads and still burning pump gas. This level of output is more suited to occasional use, than to daily driving, altho the 360 will do it with a good tune.
But here's the thing; why build a 430 horse powerhouse to hit 65 and then shut her down? Whatever that 430 does in the zero to 60,on the street, can be very nearly duplicated with just about half as much power, by using TM,(Torque Multiplication). And the reason is those skinny 255s. Or any street-tire you can fit in the stock tubs. These are the performance choke.Spinning ain't winning.
http://www.hughesengines.com/Upload/TechArticles/land_dyno.jpg
So in order for the smaller less powerful engine, to do that you just start with more rear gear, and more transmission gears. You just need to get the little engine up on the pipe and keep it there.
If it were possible to get your teener up to 250 hp by ten MPH, and carry that all the way to 60mph, with no tirespin, then you would average 250hp from 10 to 60 mph right?
But if you had a 430hp 360 with a 2600TC say, and 3.23s and a 2.45 low gear, and blasted off the line in a blaze of glory, what would your average horsepower be from 10 to 60? Well if you revved it to peak power say 5800rpm and held it at that rpm all the way, you would average 430 hp from 10 to 60mph right?
But which combo is gonna ET the quickest on those 255s, and how much faster will it be? and how much money did you have to spend to get that little margin?
Ok but this is all theory. How can you make a 318 jump to peak power, not spin, and stay there from 10 to 60mph? Well you can't and so we start with a 360 @288hp, an instant 38 hp increase at .8 hp/cube. And we throw in suspension and tire technology. And then we have to get more than 1 gear from zero to 60mph. And that leads to the first big hurdle; if we gear the car to use two gears to hit 60, then there's nothing left to cruise with.
So immediately we consider an overdrive,and, the cost goes up.
To keep the costs down, (cuz 5speed standards are really really expensive,you pretty much have to go automatic and overdrive.Or do what I did which was a GVOD. The A833od does not have suitable ratios to achieve this 2-gears to 60; the 1-2 split is just too wide. I tried this. I geared it with 4.30s to hit 60mph@5400 at the top of second.Perfect! The trouble came on the starting line.The 4.3 x 3.09 gives a starter gear of 13.29, which blows the tires away even as a 2bbl. And then your stuffing it into second a couple of car lengths out, and then the engine rpm gets sucked into the basement and it's a looooong pull to 60 in one gear. That was a waste of time experiment to me. I knew going in it was gonna be bad, I just never thought it was gonna be as bad as it was. With 4.30s the cruise rpm was 65=2465,which the engine liked.
So, what about an automatic?
Say you install an A-500 with ratios of 2.74-1.54-1.00-.69od I think that's what they are. With the .69od the max rear you might consider is 4.56, which would get you a 3.15 final-drive and 2540@65mph. Ok so what's that 4.56 get you in the zero to 60? Surprise,surprise, 60=5300 with 28s and 5% slip. Well hey that will work with a hot 318, but that's alotta cam in a 318.
How about a 360?
With a 360,this means we candrop a cam size or two,and back up in the rear gear. Lets work it out with 4.10s. And I get 60 =4950 Badaboom. This is about a 218 degree cam , so she'll make monster torque off the line with a matching compression ratio. And because of the 4.10s and the torquey cam, she won't want or need a hi-stall TC. OK but a 2800 would be so much fun. She is gonna burn so much rubber,lol.
So now we have a recipe;
A 360 with a 218/220 cam and matching compression
An A-500
4.10s in the back
and a 2800TC just for fun.
Some kind of traction aider
at least 275/60-15s @28" tall
So plug that into your desk-top dyno, and see what falls out.
Ok now back to the teener.
As to zero to 60;
The teener can pretty much do what the 360 can do; it just needs a bit more cam to peak at the same and MAYBE a bit more TC. Badaboom. The difference in ET from zero to 60 would be very small.
Now as to building this 318.
There is a tiny bit of a problem marrying the next bigger cam to the compression ratio. The next bigger cam is the 268 degree advertised, and it wants a 9.8 static compression ratio with iron heads.That calls for a total chamber volume of 75.3cc with a 662 swept. And therein lies the problem, trying to make the number, will get expensive. And why is that? Well the good gasket is 8.9cc and the eyebrows usually come in at 5cc and J-heads are about 72cc and pistons usually come quite far down in the hole and run 2cc to 12cc! cc. When you add all that up,with no machining, your total chamber volume will come in between 87.9 and 97.9, and that maths out to an Scr between 8.5 and 7.7...and that will make a really soggy take-off from zero mph. Really, to make that number (75.3ish), you need closed chamber heads and tall pistons, or spend a lot of cash on machining, and a lotta time on fitment.
So how about the 360?
Well now we can use a 262advertised cam,and we'll need an Scr of just 9.6, which with a swept now of 748.3, requires a total chamber volume of 87cc and as we have seen, that is easy.This is a zero-deck piston-install, 5cc in the eyebrows the .039 gasket at 8.9, and uncut large port iron LA heads at around 72/73cc, about as cheap a build as you can imagine. The only expense will be the zero decks. BUT we can even get around that. By skimming the heads a little and let the pistons fall where they may.
So that puts me all in favor of the 360, once again.
Like I said the 360 is a very versatile platform.
Now the big question;
Are you willing to go automatic? This is a cheap buy-in. And offers the most bang for the buck.
Oh I just gotta mention something else.
Imagine you're just tooling around at 30 mph, enjoying the music your pipes are making in second gear at say 2300rpm with those big 28s. And out of the blue the little guy on your shoulder says hit-it!! And you do. The tranny kicks down into first and the TC spools up and suddenly the engine explodes at 4000rpm, maybe just a little past peak-torque with that little cam; Ima guessing 300hp. Shazzam!! ,you are cooking!
Well, I'm just throwing this out there for your consideration.
