• Jimmy
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  • From: Collegeville, Pa
  • Registered: 2019-06-19
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Topic: Lincoln Locker in a Doba ?

Hey Lemons People. I have read as much about this topic on past forum discussions that I can find . And I apologize if it been answered before.

But...

With New Hampshire coming up I am thinking of welding up the diff on one of the Dobas to go up the hill ( Turn 2?)  .   They are both open diffs now and just completely spin a tire all the way up. Its not just at New Hampshire but that is the worse track.

Anyhow.... I think I know the handling pros and cons from previous posts, but more opinions are welcome.  The big question is -  do welded diffs live ?  Its  a  8.25 mopar rear with a super tall 2.40 (?) ratio


I do have a spare rear ( I am now the proud owner of  4 Cordoba's )  that I can swap out after the race when we get home if we hate the handling,  but I don't want to weld it up for it just to break on lap 5. 


Thanks!

Cordoba

2 Reply by chaase (edited by chaase 2023-08-10 01:49 PM)

  • chaase
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  • From: East Meadow, NY
  • Registered: 2009-08-06
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Re: Lincoln Locker in a Doba ?

I would recommend against welding a differential. It's a Cordoba, accept the handling issues or make it an LSD. There are numerous companies sell an LSD kit for the Chrysler 8.25 rear

1992 Saturn SL2 (retired) - Elmo's Revenge -  Class B winner, Heroic Fix winner x2
1969 Rover P6B 3500S(sold) - Super G-Rover - I.O.E Winner, Class C Winner
1996 Saturn SW2 - Elmo's Revenge (reborn!), Saturn SL1  Dazzleshipm Class C x2 and IOE winner
1974 AMC Javelin - Oscar's Trash heap - IOE,”Organizer's Choice" and "I got Screwed" award winner
  • From: Queens, NY
  • Registered: 2014-05-17
  • Posts: 655

Re: Lincoln Locker in a Doba ?

I was thinking of welded diffs before for my Opel. But the stress is way to great on the axles and after a while the tire wear and axle stress. Now if can lift inner drive wheel all the time than it be ok.

A clutch type  diff would be best for racing. torsen style only works if there is sufficient torque on the inner wheel. so got to consider it in the decision making.

What I noticed between all my crap cars is that you can eliminate near all need for LSD with adjusted suspension. In short, making the roll rate on the drive axle lower than the other axle. In other words, in a RWD car, the front axles to have stiffer sway bar, springs, good power shocks also. In rear no sway bar, softer springs, good compliant shocks to keep it from humping and jumping. Got to make sure though that the tires are consistent grip. So that if you run shit tires now, and decide to use nice tires later, you would have to redo a bit of it to make it work. I run typical RS4 and tire size set, so my tire is set, and I adjust the car around them. Shoot me a email, I can probably help with some 2c.

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This car....Is said to have a will of it's Own. Twisting its own body in rage...It accelerates on.
1978 Opel/Buick Isuzu(C>B>C>B) , Sold 1996 Nissan Maxima OnlyFans (B) , Sold 1996 Ford Probe GT(B),
  • Jimmy
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  • From: Collegeville, Pa
  • Registered: 2019-06-19
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Re: Lincoln Locker in a Doba ?

Appreciate the feedback chaase and Karkarot. Might not be what I want to hear but that's OK...thanks..

Good stuff . I know they are big old boats but messing around with them is what I really enjoy. You learn so much...  every race is an experiment.

I have started to adjust rear vs front stiffness with some good results .  I put a big sway bar up front , then it then it started pushing real bad so I got some cheap helper spring gizmos off eBay.... and that was cool to see how the made the car more neutral.

I know welding the diff up is absolutely cave man stuff,  but its tempting because it seems so easy to do....... Plus these stupid rears are geared so fast (2:45 to one ratio)  that most of the LSD kits wont work because the darn Pinion is so big. I could probably sort that out with different ring and pinions but that sounds like a lot of mission creep.

What I need to do is get a junk yard posi ( sure-grip to Mopar Maniacs) and in a perfect world a 8.75" Mopar rear with a removable carrier. That's the ticket. Gotta find and old cop car......

Everybody have a great weekend! ( I'm spending mine trying to roll new bearing in the Blue Doba while its in the car. - I'll be lucky if I get the pan down...wish me luck)

Cordoba
  • Mr.Yuck
  • Mr.Yuck
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  • Registered: 2013-12-09
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Re: Lincoln Locker in a Doba ?

Can't you just buy an 8.75 mopar rear and be done with it? FWIW Dakotas came with LSD 8.25's.

"get up and get your grandma outta here"
  • From: Birdsboro, PA
  • Registered: 2009-10-26
  • Posts: 896

Re: Lincoln Locker in a Doba ?

For years we ran a mini spool to lock the diff in the boat and later the Hombre, still being run that way to this day through two more owners.  We tried two different limited slips and kept coming back to the locked diff.  Amazing traction and the only thing that bothered us about it is that you have to be careful in tight turns in the paddock.  It’s fun to just stand on the gas going up the hill in NH.

Chris from 3 Pedal Mafia
  • Jimmy
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Re: Lincoln Locker in a Doba ?

Sonic wrote:

  It’s fun to just stand on the gas going up the hill in NH.

I had seen an old post you made about that ...I wasn't sure you felt the same , so thanks!. ( as always)

and  ......That is my dream! Going up that darn hill sideways!




As Far as changing to a 8.75 - I am guessing that ill need to change the drive shaft, and the tube width might be different depending on what it comes out of , brakes and the spring perches would prob fit.  And unless  I get a rebuilt unit ( $$$ ) a 40 year  Mopar sure grip after 1000 neutral slams  is most likely shot so ill need to rebuild it any how.

The Dakota 8.25 would  need ( i think) diff spring perches welded in and probably has a different  tube width , wheel bolt patter prob ok(?)  and the posi on that might be shot as well and need a rebuild


The only solution that I come up with is learn the mysteries and black science of re gearing and installing a posi and setting up the unit in what I have now .


Most importantly - Got the pan down and took a look on Blue Doba yesterday and it wasn't pretty ( lots of copper) but I think I'm gonna get away with rolling some brgs in - better to be lucky than good.


Thanks!!!!

Cordoba

8 Reply by chaase (edited by chaase 2023-08-14 07:59 AM)

  • chaase
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  • From: East Meadow, NY
  • Registered: 2009-08-06
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Re: Lincoln Locker in a Doba ?

Jimmy wrote:
Sonic wrote:

  It’s fun to just stand on the gas going up the hill in NH.

I had seen an old post you made about that ...I wasn't sure you felt the same , so thanks!. ( as always)

and  ......That is my dream! Going up that darn hill sideways!




As Far as changing to a 8.75 - I am guessing that ill need to change the drive shaft, and the tube width might be different depending on what it comes out of , brakes and the spring perches would prob fit.  And unless  I get a rebuilt unit ( $$$ ) a 40 year  Mopar sure grip after 1000 neutral slams  is most likely shot so ill need to rebuild it any how.

The Dakota 8.25 would  need ( i think) diff spring perches welded in and probably has a different  tube width , wheel bolt patter prob ok(?)  and the posi on that might be shot as well and need a rebuild


The only solution that I come up with is learn the mysteries and black science of re gearing and installing a posi and setting up the unit in what I have now .


Most importantly - Got the pan down and took a look on Blue Doba yesterday and it wasn't pretty ( lots of copper) but I think I'm gonna get away with rolling some brgs in - better to be lucky than good.


Thanks!!!!

You can just buy an LSD for the existing rear end. You don't need to buy a whole new rear end.

You can get them for the 27 spline and 29 spline

1992 Saturn SL2 (retired) - Elmo's Revenge -  Class B winner, Heroic Fix winner x2
1969 Rover P6B 3500S(sold) - Super G-Rover - I.O.E Winner, Class C Winner
1996 Saturn SW2 - Elmo's Revenge (reborn!), Saturn SL1  Dazzleshipm Class C x2 and IOE winner
1974 AMC Javelin - Oscar's Trash heap - IOE,”Organizer's Choice" and "I got Screwed" award winner
  • Mr.Yuck
  • Mr.Yuck
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  • From: Brookeville, Md.
  • Registered: 2013-12-09
  • Posts: 1,050

Re: Lincoln Locker in a Doba ?

Jimmy wrote:
Sonic wrote:

  It’s fun to just stand on the gas going up the hill in NH.

I had seen an old post you made about that ...I wasn't sure you felt the same , so thanks!. ( as always)

and  ......That is my dream! Going up that darn hill sideways!




As Far as changing to a 8.75 - I am guessing that ill need to change the drive shaft, and the tube width might be different depending on what it comes out of , brakes and the spring perches would prob fit.  And unless  I get a rebuilt unit ( $$$ ) a 40 year  Mopar sure grip after 1000 neutral slams  is most likely shot so ill need to rebuild it any how.

The Dakota 8.25 would  need ( i think) diff spring perches welded in and probably has a different  tube width , wheel bolt patter prob ok(?)  and the posi on that might be shot as well and need a rebuild


The only solution that I come up with is learn the mysteries and black science of re gearing and installing a posi and setting up the unit in what I have now .


Most importantly - Got the pan down and took a look on Blue Doba yesterday and it wasn't pretty ( lots of copper) but I think I'm gonna get away with rolling some brgs in - better to be lucky than good.


Thanks!!!!

just replace  the rod bearings. You'll be ok. I had a junk yard 440 that was like that. I replaced the bearings, t-chain and beat on it for another 3 years.

"get up and get your grandma outta here"