19 replies to this topic

[Mini-Hazel-Nut]

Ello all, has anyone on here managed a diff swap with the engine in? I ask because I`m getting an ex hill climb Min this week which I am going to mildly convert  (doesn`t  take much) into a classic hot rod for that genre of of oval racing (if they`ll let me). The diff in the Min is a 4.2:1 ratio which according to something I read today means I`ll need to use 3rd instead of the usual 2nd for blasting round the 1/4 mile track. I don`t fancy having the engine out because although it`s totally get-at-able (whole front  comes off) it`s a plumber`s nightmare and scares the hell out of me. I`ve read 2 opinions to say it CAN be done and it CAN`T, anyone had the experience?

[nicklouse]

Not possible.

[Tamworthbay]

I have heard stories of subframe mods that allow it to be done but have never seen any pics or evidence of it. I can't remember seeing it done on here.

[Orange-Phantom]

I'm pulling the engine out of mine at the mo to change the crownwheel and pinon.  Not heard of any other way myself.

[Cooperman]

The amount of structural modification to the front bulkhead would make it not worthwhile. It would need a large hole where body strength is needed and a lot of reinforcing structure would be needed.
Easier to take the engine out.

[Mini-Hazel-Nut]

That`s fair enough all. From what I`ve learned on youtube and elsewhere this evening I agree. Whilst it might "just" be possible to access the crown-wheel I can`t see any way of getting at the pinion with the subframe and everything else in the way. Basically that`s a unanimous...........NO! lol 

[nicklouse]

Crown wheel nope.

You can't get the diff cover off the studs. Then I'd you get the diff studs out then you can't really get the cover off the diff and crown wheel.


Getting it up onto the front subframe cross member is another issue.


But to be honest I would leave it as is and just start in second and shift up to third for normal running.


But if the normal gear use is 1-2-1 then I would look at a reverse lock out for now.

This would let you get to check how things are for the track and do you really need to change anything.

[jsor26]

Just finished swapping to an ATB diff, had no problem doing it with the motor in. remove exhaust, intake,driveshafts,shift link, remove 2 top steadys and left side mount bolts and gentlyslide  forward, remove header and had plenty of room. 6 hours and no problems taking apart

[MRA]

Seen people do it, but never bothered always seemed quicker to just remove the lump and do it on a bench.

[Mini-Hazel-Nut]

Just finished swapping to an ATB diff, had no problem doing it with the motor in. remove exhaust, intake,driveshafts,shift link, remove 2 top steadys and left side mount bolts and gentlyslide  forward, remove header and had plenty of room. 6 hours and no problems taking apart

Well there ya go, it CAN be done! Mind you if I tried that out in the Hot rod, after undoing everything the engine would just fall out of the front of the car anway! lol 

As for Nicklouse`s comment:- what happens normally is you start in first, into second pretty quick then just leave it there till the end of the race. It`s a second gear "blind" all the way through, or in my case THIRD gear blind.

 

Thanks for all of your various inputs, I like to get a good discussion going.

[timmy850]

Yes, but did you re-use the old crownwheel when installing the ATB diff? 

 

Getting out the pinion would be an absolute pain. You'd have to remove the radiator, engine mount, speedo drive cover to then undo the lock washer and undo the pinion nut. To get the nut off you need to lock up the gearbox and the nut is on bloody tight too. 

[Spider]

Doing it on the bench, you'll be able to clean all the old gaskets off, shim the diff so much easier and it would be WAY quicker, especially since the Pinion also needs to be changed.

 

 

 

Just finished swapping to an ATB diff, had no problem doing it with the motor in. remove exhaust, intake,driveshafts,shift link, remove 2 top steadys and left side mount bolts and gentlyslide  forward, remove header and had plenty of room. 6 hours and no problems taking apart

Well there ya go, it CAN be done! Mind you if I tried that out in the Hot rod, after undoing everything the engine would just fall out of the front of the car anway! lol 

As for Nicklouse`s comment:- what happens normally is you start in first, into second pretty quick then just leave it there till the end of the race. It`s a second gear "blind" all the way through, or in my case THIRD gear blind.

 

Thanks for all of your various inputs, I like to get a good discussion going.

 

 

I'm pretty sure Nick was referring to the pre-84-ish cars that used studs instead of the bolts the later cars have. Yeah, possible, but bloody hell, even if you're in torture it would be a dam pain in the backside way to do what is normally a simple job. I think having my finger nails pulled out by the mother-in-law would be way more enjoyable.

[MRA]

It is a painful job, the reason I would contemplate doing it in car is if I haven't got the tools or cannot remove something, but in reality it is 99% of the way out all you need do is lift it and the job would be easy...

[Dusky]

Done it on our racer. It has a semi custom subframe and a removable front.
Had to do it within a tiem limit and seemed to be the quickest option. Was not easy, and I don't think it would be possible to change the pinion within an acceptable time limit

[hhhh]

I've done it on an America (the North American 2-door 1100 variant that probably goes by something else in GB.)