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Old 04-12-2007, 12:46 PM
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reversing engine rotation?

so the project im currently working on currently is a rear engine 4x4 buggy. since the engine is in the rear, how can i reverse its rotation so i can go foward? I know about reverse rotation boat motors, but i have the drive train from a z28 i was gonna use. so what i was gonna do was just replace the cam with a "reverse" cam, and just use timing gears. both can had a boat engine places, and they are for the 350 so they should be direct replacements. i would also need to turn the starter around and get a reverse rotation water pump. other than that i dont think any other acceserys are rotation specific. it actually seems pretty simple.....which is why im asking for yalls advice. am i missing something here? thanks in advance
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Old 04-12-2007, 01:01 PM
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Power steering pumps and most alternators are rotation-specific. Alternators can be made dual rotation, but just spinning it backwards will make it charge the wrong way. Positive will be negative.

You're on the right track with the marine parts. Its pretty simple. Mostly its the cam and starter. Make sure you get the right drive gear on the cam and distributor gear on the dizzy so that it turns the right way.

The only problem I see is finding a reverse rotation transmission. An automatic won't work, and a manual would give you 5 speeds in reverse and one forward You might be better off just getting a reverse-rotation axle and swapping your direction there. Tell us a little more about the project and why you need reverse rotation. Is the engine backwards? Like meaning the pulleys are to the rear? If so, you don't need reverse rotation engine, you just need to change the direction of some component down the line. Transfer case, reverse rotation axle, whatever, but not a reverse engine.
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Old 04-12-2007, 02:23 PM
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Quote:
Originally Posted by curtis73
The only problem I see is finding a reverse rotation transmission. An automatic won't work, and a manual would give you 5 speeds in reverse and one forward You might be better off just getting a reverse-rotation axle and swapping your direction there. Tell us a little more about the project and why you need reverse rotation. Is the engine backwards? Like meaning the pulleys are to the rear? If so, you don't need reverse rotation engine, you just need to change the direction of some component down the line. Transfer case, reverse rotation axle, whatever, but not a reverse engine.
Actually, the reverse rotation engine mounted backwards DOES give you five forward and one reverse with a manual trans. That's the whole point of the reverse rotation effort. The problem is that due to the helical gears in the trans, the thrust direction will be wrong, which will cause premature wear in the trans. You're correct in that an automatic won't work due to the design of the pump in addition to the thrust problem and the sprags.
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Old 04-12-2007, 03:05 PM
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thanks for your responses guys.

yeah, technically i would have 5 reverse gears, but that would move me in the foward direction. and i have considered thrust direction. i knew it wasnt good, but i just really didnt know how bad it was.

my project is basically a tube chassis, with a z28 drive train going through a divorced transfer case. basically front wheel drive in 2wd. just take a truck and reverse the body, and thats what you get. im just doing it rear engine because its different, and i cant do anything the easy way there are some buggys that are rear engine, but they just get a front wheel drive drive train, weld the spider gears in the transaxle, mount it sideways and run a shaft to a transfer case

and im not set on the reverse engine either. like you said, i just have to change the direction somewhere down the line. and each option has its issues. you know, the axles were my first choice. after searching for hours and hours, i couldnt really find any answers on how to make them reverse direction. there seems to be a lot of conflicting views on this. i thought you could flip the axle and switch ends, or just flip 3rd members, but evertime i read this, people came along and say it will never work, or you wont get any pinion oil. im probably gonna use F&R dana 44s from a old jeep wagoneer.
if yall can shed some light on reversing at the axles i would really appreciate it.
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Old 04-13-2007, 04:28 AM
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Some dana gearsets (I think Ford) were reverse rotation. I recall a dana 61 as being a reverse 60. Peugeot 504s had an 'overslung' pinion (above the axle centreline) and I'm sure they used a pump to feed oil to the pinion.

What about the 'waves' on 12 bolt and early 10 bolt Chev rears, they were to direct oil to the carrier bearings. Wouldn't simillar internal baffles be easy to fabricate?
BTW, if it's a rockcrawler the oil would feed fine when upside down.
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Old 04-13-2007, 07:59 AM
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Ayuh,.......... I'd suggest you keep looking into the Driveline,.....

Reversing the Motor is alittle more involved than Just changing the Cam,+ going to timing Gears,......

The Crankshaft is the Only Thing that turns Backwards in a SBC,.....
The Pistons will need to be Swapped side to side, because of the reversed Thrust,....
The Crankshaft Seals need to be Changed, or they'll just Dump the Oil......
And,.. Because the Cam will be turning the Same way it's turning Now,.. The Dist. is a Non-Issue......

Good Luck,.....
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Old 04-13-2007, 01:04 PM
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Curtis:

"Power steering pumps and most alternators are rotation-specific. Alternators can be made dual rotation, but just spinning it backwards will make it charge the wrong way. Positive will be negative."

Alternators can turn either direction with no changes, they generate alternating current wich is later rectified into direct current, the only thing they need is being turned, doesn't matter wich way, to make it more efficient you migth need a new cooling fan designed to turn the other way but most oem's work fine both ways.

Spitfire5454:


Why not think about a "V" drive like the ones boats use and forget about the complications of a reverse drivetrain? you'll have the rear mounted motor but turning the rigth way, you will need 2 transfer cases one for the v drive and the other would be your 4x4 setup's, wich will be perfect for rockcrawling, you can doulble your crawl ratio.

Augusto.

Augusto.
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Old 04-13-2007, 03:34 PM
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i have heard about v drives, but i honestly dont know much about them. i cant find much on the internet about where to even get them. it sounds like a great idea and the easiest to do. if you could share some more info that would be great, as i am very ignorant in them. is there any gear reduction i would have account for or is it 1:1? If you dont mind, why would i need 2 transfer cases? why couldnt it just go trans-vdrive-t-case? why does it need one? i know that some were divorced, so i would have plenty of freedom to put them where the fit best. thanks in advance

Brian
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Old 04-13-2007, 04:07 PM
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You could always find a BigBlock front wheel drive Cadillac engine and transmission. Everything you need to push your project around.
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Old 04-13-2007, 05:47 PM
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Spitfire:

let me explain, first of all I understood your buggy was 4 wheel drive, am I rigth? if so here is the deal:

your basic layout must be the same as a regular 4wd vehicle with the engine up front but since you want it in the back, you take the motor and the tranny from the stock location, but leave the transfer case in place, hooked up to both driveshafts, now take the motor and tranny to the rear, backwards of course, now your tailshaft points forward rigth? then you install another transfer case there at the tranny's tailshaft, THIS NEW T-CASE WIILL BE THE "V" DRIVE, and run one short driveshaft from the forward ( in the normal direction originally ) output of the t-case to the input shaft of the t-case that you left from the original setup, it must be modified with a flange to accept the driveshaft. The rear output of the second t-case ( that now points forward ) is not used, you don't connect anything there.

Now you have 2 t-cases, and if you shift both into low gear you'll have twice the gear reduction wich is awsome for rockcrawling.

In a boat you also use a t-case as a v drive, the driveshaft goes to the front of the boat to the t-case and a second driveshaft comes back to the propeller from the front output of the t-case, both driveshafs look like a V now, one goes to the front and the other comes back to the propeller.

Did I explained rigth?

Augusto.

Last edited by Augusto; 04-13-2007 at 05:56 PM.
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Old 04-13-2007, 07:20 PM
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thank you so much.

it makes sense now. i thought you wanted me to a get a marine v drive and run transfer cases with it, but you are saying use transfer cases to make the v drive itself. i got it now. it just took me a little while to get all the rotations right in my head.
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Old 04-13-2007, 09:19 PM
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Why Don't you Just use a stock Motor & a Hydraulic drive train Like on a sod fork lift {the ones you see on the back of delivery flat beds }& reverse the Fluid flow for the direction you desire?


I'm sure there is a specific name for the Hydraulics I'm trying to describe but...DAMIFINO


I've been told Diesels run back wards.


R
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Old 04-13-2007, 10:44 PM
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Quote:
Originally Posted by bondo
And,.. Because the Cam will be turning the Same way it's turning Now,.. The Dist. is a Non-Issue......

Good Luck,.....
I think this has been discussed before. There were a very rare few same-rotation cams, but all SBC reverse rotation engines use a chain, meaning the cam rotates in the same direction as the crank (which is this case would be reverse). The distributor still rotates in the proper direction because the driven and drive gears are different, but no commonly-available reverse rotation engine uses the forward-driven cam.

If you go to the websites for Volvo, Mercruiser, OMC, Indmar, or any other marine manufacturer, reverse rotation SBCs all share the same timing chain part number as the regular rotation, but the cams and dizzy gears are different.

Also, Don't assume anything if you're buying a marine engine. All I/Os are forward rotation since 1973. Many inboards are reverse rotation, but all I/Os are regular. If you have a twin engine I/O setup and one is reverse rotation at the prop, the reversing takes place in the outdrive, not the engine.
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Old 04-13-2007, 10:46 PM
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Quote:
Originally Posted by Augusto
Alternators can turn either direction with no changes, they generate alternating current wich is later rectified into direct current,.
You're right... my brain forgot that part.
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Old 04-14-2007, 03:03 AM
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Not hard at all. Flip the axles upside down. You will then run on the coast side of the gears in the rear and the drive side in the front (normally you run on the drive side in the back and the coast side in the front unless you have reverse cut gears aka high pinion). Make sure you put some thought on how the pinion bearings will get oiled.
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