The old "volvo diff into celica conversion"

[SHEPPO3930]

what ratio's have people found in their volvo diffs from wreckers? i've not heard of anyone getting 4.1 gears - my first choice of ratios, followed by 3.9's.

what is the most common ratio found in a 240 auto volvo (the most common volvos in my wreckers).

i plan to fit a truetrac #912A558 as that's what seems to be recomended by the manufacturer for performance (racing) applications. my car is a circuit racer/hill climb car.

[Toy77]

mine has 3.9's

I used to have a list of what ratio came in which vehicle - but unfortunately it was lost in a computer crash a very long time ago.

[SHEPPO3930]

Was the diff u broke a 1030(7.2") or 1031(7.56")? Not too many people seem to break a 1031.

I picked up a couple 240 diffs from the wreckers, no 3.9's or 4.1's. I'll transfer the Celica mounts over and in the mean time search for some gears.

[Toy77]

mine is a 1030.

mind you how many people do you know with over 500 rwhp, launching at 7000rpm on drag tyres?

not saying the diff is weak - rather the opposite... when I called all the diff specialists for a replacement, no one recomended a hilux, or a borg warner... all said that I was into 9in territory.

cheers
Stew

[SHEPPO3930]

500whp and launching slicks at the drags = 9 inch territory! pretty awesome the "weaker" of the volvo diffs could handle that! impressive considering they are only a 7.2" crown wheel! 300whp is all i plan on making so a volvo diff will be more than enough.

looks like i need to find some 3.9 or 4.1 gears so i can finish my diff!

[Toy77]

hi all,

in my surfing found a couple of links to add here...

aftermarket gear sets for sale
http://www.justdifferentials.com/category-s/1896.htm

and a listing of ratios and cars... not sure how appropriate it is to us here, or even how to use it, BUT if i dont put it some for reference i may never find it again
http://www.nuceng.ca/bill/volvo/database/reardiff.htm

Cheers
Stew

[Toy77]

oh and another gear listing - with the teeth numbers for each ratio
http://www.precisiongear.com/dana30.htm

cheers
Stew

[SHEPPO3930]

From my last couple weeks playing with these diffs, there's a ton of mis-information on the net!

Firstly the only way to properly identify a 1030/1031 is by the size of the gears. The rule of 2 rib, one rib, hump in the casting, fins on the bottom, etc aren't 100%. I have 3 volvo diffs and each one contradicts these rules.

Secondly the carrier is what's known in the jeep circles as a "3.73 and up". Regardless of what volvo ratio u have, the carrier is a 3.73 and up design.

Lastly, you can put a high numerical ratio set of gears into a low housing... I have done it. I have put a set of 4.1's into a housing that had 3.31's in it. What you can't do is mix and match 1030 and 1031 gear sets and housings. 1030 diffs will take any aftermarket gear for a dana 30, standard rotation short pinion jeep diff. 1031's use volvo gears and you can only use volvo gears as nobody makes aftermarket gears.

Hope this helps.

[The Witzl]

Thanks for the additional info Sheppo.

I too have some annoying information to add to this..... and that is my experience in sourcing the CORRECT axle bearings - or more accurately the inner collar that is pressed onto the axle.
After talking to the guys at Bearing Industries, the listing they have for a volvo 240 and 740 is the same, despite in another book there being mention that there are two different sizes for the outer diameter of the inner collar.

It seems that my axles need the smaller OD version of this collar, which happens to be the one that they DONT stock.
I need to investigate if i have a 1030 or 1031 housing now and see if this has anything to do with it..... but the short story is that the inner seal and this inner collar dont mix.

I check at the wreckers on a volvo 240, and this had the same smaller OD version of the inner collar ring.


I'll come back to this one day in the future when i need to fix this up.

[stidnam]

I had the same problem Witzl except the diff place that replaced my bearings didn't check and it wasn't until I got the entire diff back in the car and went to slip an axle in to find out they didn't fit. Took the whole lot back and they machined down the bearing retainer.

[The Witzl]

yep we are probably going to just machine down that collar as well.... a fuckload easier than pressing the whole lot off again!!

[stidnam]

So I've been making some enquires about sourcing undrillled rear rotors for the volvo diffs due to the whole neeed to redrilling the rotors stud pattern problem that you encounter when converting the volvo diff to 5x114.3 or 4x114.3.

RDA are able to supply undrilled rear rotors but they have a minimum order quantity of 50 sets which is waaaay more than I could use in a lifetime. Is there any interest here in a set or two of undrilled rear rotors as a group buy would be the only way this would be feasbile. I have asked for the price and will update this once I know. A stock pair of rotors looks to be about $80 on egay so I'd say the price would be about this or a little bit more. This is basically an EOI to see if there is enough interest to organise a group buy. The group buy if it goes ahead will go through official Toymods channels.

Example of swiss cheese drilled rotors for 5x114.3 conversion to show the problem shamelessly stolen from Toy77 earlier in this thread. Engineering in NSW does not allow for redrilled rotors BTW.

[stidnam]

Update got the pricing back from RDA

"RDA381 x 100 ( 50sets ) produced with no stud holes $30.00+ Gst Each at NO extra charge the rotors will also be finished in a gun metal grey coating which helps prevent rust / corrosion. If you wish to have slotted & dimpled with NO stud pattern I can do them also for $120.00+ Gst Pair = ( 50 sets)

From order / pre payment to delivery it will take 4-5 months to receive pending any delays with manufacture / shipment times. There will also be a freight charge to delivery pallet to you"

So a set of stock rotors looks like it will work out to be $66 + freight to Sydney + freight to where ever you are located. For the slotted/dimples rotors it is $132 + freight to Sydney + freight to where ever you are located

[stidnam]

Got the pallet freight charge to Sydney. Freight is $90 + GST = $99. Split out over 50 sets thats $1.98 which rounds to $2 each.

So pair of stock rotors comes to $68 + what ever post to you works out to, or you can pickup.

At this price it would be worth buying a second set as spares for future when you need to replace the rotors. If everyone bought two sets then we'd only need 25 people in total. I can already put 4 sets down as definately in.

[Toy77]

thats pretty cheap...

I would get some, but i am haveing to change my diff anyways
poor old volvo served me well....