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1988 EXP 2.0l H.O on bike carbs.
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Discussion Starter · #1 ·
I was hunting down some info on gear ratio's trying to find what gears are different if any one a GT vs CFI trans. When I was doing the digging I found that the Diesel trans is geared rather high, likely for the for the lower HP motor. Then I got to thinking, a GT diff is 3.72 and a CFI/Diesel is 3.53. the first gear in a early Diesel trans is 3.92 vs 3.6 in a GT trans. Wuld a GT diff/finale gear fit a Diesel trans? If i'm not gettign my gear ratio stuff mixed wouldn't that make the car start off the line a lot faster?


 

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Without having experience with the first gens, I will guess "yes", but those diesel transmissions are going to be pretty hard to find!

Also note that only the 1985 diesel transmission first gear ratio is listed as 3.93, the other years being 3.6, or unlisted.
 

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I would assume any MTX-III internals are swappable, but I don’t have a definitive yes or no. Like Joey said, good luck in finding a diesel trans!
The pinion gear looks like it’s part of the driven shaft which would require stripping down and restacking the whole shaft. It may end up being easier to swap the first gear set, if that’s even possible.
 

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I've heard of someone doing this to their diesel but it is a lot of work, like Shorty said you have to restack the output shaft for the new diff. Fair warning it's going to make your rpms higher in top gear resulting in worse fuel economy while cruising, you also need a speedo gear matching the new final drive for your speedometer.
 

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Discussion Starter · #5 · (Edited)
I've heard of someone doing this to their diesel but it is a lot of work, like Shorty said you have to restack the output shaft for the new diff. Fair warning it's going to make your rpms higher in top gear resulting in worse fuel economy while cruising, you also need a speedo gear matching the new final drive for your speedometer.
Well the car is far from a cruiser and the speedo is already way off from the different tire size being used. The car is more or less a weekend racer. No AC, power steering, radio, heater, windshield washers fluid system, evap, charcoal canister, sound denting. It has bike carbs, coil overs, front and rear anti roll bars and a cam with over .5 degrees of lift. Been thinking of putting a 4 point cage/roll bar in it too. Right now I'm swapping the motor and trans, it had a built up CFI motor in it now it will have a rather over built HO, hoping for a extra 20-30HP on top of the all ready crazy HP it was puling. Needless to say it put most STIs and civics to shame at the track. Its only weakness aside form the flimsy body is getting off the line. The GT trans will help that a lot but I was hoping for more. The open diff will likely become a problem soon if I keep pushing the power on the motor, that will be fun to address. Once I get the HO lower end and head put in I'll likely be pushing 175 at the crank and at the limit of the bike carbs so yeah I"m pushing it to the max.
 

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Well the car is far from a cruiser and the speedo is already way off from the different tire size being used. The car is more or less a weekend racer. No AC, power steering, radio, heater, windshield washers fluid system, evap, charcoal canister, sound denting. It has bike carbs, coil overs, front and rear anti roll bars and a cam with over .5 degrees of lift. Been thinking of putting a 4 point cage/roll bar in it too. Right now I'm swapping the motor and trans, it had a built up CFI motor in it now it will have a rather over built HO, hoping for a extra 20-30HP on top of the all ready crazy HP it was puling. Needless to say it put most STIs and civics to shame at the track. Its only weakness aside form the flimsy body is getting off the line. The GT trans will help that a lot but I was hoping for more. The open diff will likely become a problem soon if I keep pushing the power on the motor, that will be fun to address. Once I get the HO lower end and head put in I'll likely be pushing 175 at the wheels and at the limit of the bike carbs so yeah I"m pushing it to the max.
Oh, I had this post backwards, thought you wanted shorter gearing in a diesel Escort. Yeah this is way different lol
You'll be making your gas Escort slower with that taller final drive unless you find your gears too close together right now. I hop up motorcycles and often times once you start making more power than stock you go through the gears much faster, some times too fast where you actually spend more time between gears than accelerating in them. Unless you feel you have this problem right now I wouldn't make the change to a taller final drive.

For the open diff supposedly you can use the MTX SHO diff (aftermarket available as LSD) in our MTXs and one guy claimed to have done it but I have my doubts until I try it - I have every version of the 81-90 EXP/Escort CVH MTX and have 2 MTX SHOs now so as soon as I have them side by side I can do more confirmation videos haha
Not to stray from the post but curious how you built up your 1.9, the 150hp mark is hard to beat N/A
 

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Discussion Starter · #7 · (Edited)
Sho transmission would require custom axles. Not sure what else it would need.
But I thought higher gears ratio accelerated faster? Witch is why so many put 4+ rear ends in drag car? So I want the lower raito diff from the CFI trans?

the cfi I have is about 140-150is if I remember right. The car hasn’t been driven in a wile and it was last dynoed years ago.
But its had anything and everything done to it, tuned exhaust, roller head, milled head, high compression pistons, stroked, big cam, custom ECU mapping, board 2.3l TB with red injector, ported head, bigger valves, lighten drive train and much more. Had to run 95oct with octane booster just to get it to run right.
The HO will have a lot more done to it. HOs are what, 20ish more hp stock? It would probably be in the ball park of 175hp. But that’s just guesstimate.
 

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Not the whole SHO trans, that won't work at all, just the differential from it

I don't quite follow what you have for a transmission vs what you want out of it, yeah a 3.73 will generally accelerate faster than a 3.52 and a 4.05 will accelerate even better - again that's only on paper, like I mentioned in the last comment going to extremes may kill your lap time if you spend too much time between gears.

How'd you stroke it? Been wanting to make a personal experiment where I make the 1.9/2.0 CVH interference for more compression. Yeah stock trim for stock trim the EFI hemi gets you 20hp more than the CFI. Is it the CFI or bike carbs right now? If bike carbs then switching to the Hemi won't yeild much more power (maybe 10hp) and that's assuming you put in high compression pistons too and even bigger valves than your CFI head can tolerate.
What does the lighter drivetrain involve? Didn't think the stock components could get much lighter
 

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Discussion Starter · #9 · (Edited)
Sho diff would still require custom axles or outputs. The splines/tooth count on the outputs are different. It can be made to work, I know one other user here years ago put a sho lsd into a mtx3 trans. But he had to make custom parts to make it work if I recall right.

the cfi had a modded tempo injection setup and aluminum valve train parts. That head is long gone, needless to say it didn’t last long. I mean welding a aluminum shaft to a valve would never last lol.
 

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From the early days of FEOA there was a long post about roller rocker arms specially made for the CVH engine, I don't recall the maker. Someone on this site got a set, but IIRC there surprisingly wasn't a huge number of 'Scorters who lined up with cash to pre-order for a production run [sarcasm].
 

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Discussion Starter · #11 · (Edited)
From the early days of FEOA there was a long post about roller rocker arms specially made for the CVH engine, I don't recall the maker. Someone on this site got a set, but IIRC there surprisingly wasn't a huge number of 'Scorters who lined up with cash to pre-order for a production run [sarcasm].
Yep, I have a set of those in if I remember right 1.7x:1 ratio. I forget the extra ratio but I know its 1.7 something.
They are about 2oz lighter then the stock rocker setup. The retainer were custom made by me, so they definitely didn’t last long as I made them with some scrap aluminum and a drill press.

The setup was ,ore or less for one weekend of racing before I put in a the HO. then things got into the way and I'm just now getting to the swap
 

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Ha! Small world.
Do you remember the manufacturer of the rocker arms?
I'm not sure what you mean by "retainer". I thought the roller rockers were a direct swap for stock, with no extra or modified parts.
 

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Discussion Starter · #13 ·
Valve spring retainers.

Harlem sharp made the rockers, they only have 1.6:1 rockers for the CHV motors last I looked. I wanted another set but they said anything over 1.6:1 is prone to problems. I don’t know if that is true, I only have a 100 or so miles on mine.

Edit, these are the 1.6:1 ones they sell now. mine were like 200$ back in the day, how times have changed.
 

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Thanks for the link. I am surprised they can still be ordered, although they are not in stock.
At that price, $400+, I suppose Harland Sharp just makes them on demand from their drawings.
Do you know the stock ratio?
 

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Discussion Starter · #15 · (Edited)
Thanks for the link. I am surprised they can still be ordered, although they are not in stock.
At that price, $400+, I suppose Harland Sharp just makes them on demand from their drawings.
Do you know the stock ratio?
1.65:1. Anymore most stuff on summits website is drop shipped. I buy all my car parts for my daily driver from them as they are not all to far from me and cheaper then the corner parts store.
 

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I don't think I'll be buying a set and reduce valve lift.
I checked Burton Power in England which has a ton of CVH stuff, but they only list stock Ford rocker arms and pivots, surprisingly.
 

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Discussion Starter · #17 · (Edited)
I don't think I'll be buying a set and reduce valve lift.
I checked Burton Power in England which has a ton of CVH stuff, but they only list stock Ford rocker arms and pivots, surprisingly.
from harland sharp
"We have advertised the rocker as a 1.6:1 ratio, taking into consideration spring load and deflection, however dimensional it works out to a 1.68:1 ratio rocker. "
So its more or less stock.
 

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in order to run a different ratio diff you would need to make sure the main shaft that drives the diff ring gear has the same ammount of teeth, otherwise you would need to swap the diff and the main shaft. i dont recall how many teeth are on the main shaft, but say you had a 373 gear and wanted to swap it for a 307 you would need to replace both due to the ratio. like on a regular diff, the ratio is made up by difference in teeth.. say 10 on pinion and 41 on the ring gear, gets you 4.10....
43 / 10 4.30
43 / 8 5.38
41 / 11 3.73
41 / 12 3.41
41 / 13 3.15
and so on.
 

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wouldn't that make the car start off the line a lot faster?
not a whole lot, but yes. diesels use tighter gears and torque to put more energy into the final drive, that is why the ratio is much less... so in mid 90's dodge diesels for example most of them came with 3.07 gears. this is where the function of 'hp vs tq' comes in.. high rpm gassers use the deeper ratio on the diff and less on the gears because they spin much faster than the diesel. but there is a mid range between low end power, pulling and hauling, and top speed. you could loose 20mph of total speed by going from a 355 to a 373... a lot of older big block race cars didnt go much faster than say 80 to 120. but they got to top speed much quicker and maintained it. modern cars take much more time to 'wind up' to top speed, and speed increases the further down the track they go. they need the rpm range to make speed. where as a diesel, or a 2000hp 440 makes it instantly, but the top speed is limited due to gearing.
 
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