johnny.race

Diffs

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1 hour ago, johnny.race said:

My understanding is that the 8.8 is/was the factory's replacement option for applications they would have used a 9 inch if they were still making them. A 9 inch equipped to the same spec as the Explorer diff would be a pricey beast indeed. I'm a 9 inch owner but fuck ... one of those 8.8's in the flesh is a big arse beasty of a diff. 

Hey Clint ... you must be running some 'up there' pinion offset by running 2 axles the same length?

I'll measure it tomorrow,  but the tunnel is offset in a valiant and it looks like it all lines up ok 

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BW78 gizzards can be shoehorned into a 75 housing with giving everything a birthday for around $500. 
time will take to see how long it takes me to break it.

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I've been pleasantly surprised at how well the bw diff in my vg has survived

All I've ever had to do was replace an axle with a twisted spline and it's done a million burnouts and a lot of drag racing. I pulled it apart once to check it and it was fine 

25 spline axles, 2.92 ratio, 4 spider lsd with some extra preload  

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9 hours ago, RUNAMUCK said:

for around $500. 

Hi Bart, can you give us a break down of prices for this project?

$500 seems pretty low.

How much was the BW78?

What axles are you using?

Etc.

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14 hours ago, 00quattro00 said:

What difference does it make having equal length axles?

Any diff that has equal length axles will not have the pinion centered within said diffs width. Most jap utes (I have not seen all of them but am talking about Luxers and Couriers et.al) have equal length axles. For instance the pinion offset of a OEM Lux is over an inch. This surprises people at times when they have lined up the pinion with the gearbox and then proceeded to weld stuff in/on then find they can run stagger if they want to. Then on the other side of the tree you have diffs like the BW78 which has the pinion more or less centered within it width. This is achieved by having a longer drivers side axle than what is found on the passenger side. Factory 9 inchers are like this also. Funny old world. 

Carrying this on and adding to what @cletus was saying about his A body (a Valiant) having some offset. He is talking about engine offset. You need to be aware of and factor this into diff swaps to if you are aligning tailshafts with pinions. Especially on those MoPars. Ahh, thank god for string lines and plumb bobs.

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10 hours ago, Valiant said:

Hi Bart, can you give us a break down of prices for this project?

$500 seems pretty low.

How much was the BW78?

What axles are you using?

Etc.

We already have a hoard of bw75's. 

A 3.45:1  lsd 78 was I think 200-250. New bearings were around $150. 

The axles will be shortened in house. 

Bit of jiggery pokery and the bw78 crown and pinion fit inside the 75 housing.  The lsd was pretty coozed. So the tape cones where machined to stop them bottoming in the housing. And shimed up to resurrect the side gear mesh. 

Bit of fucking around, but not super spendy.  Time will tell how long it holds up. Pretty sure the crush tube has also been replaced with a solid spacer too. 

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@RUNAMUCK 

Hey man do you do diff shortening? Ive got an aussie cortina BW75 housing id like to chuck BW78 axles and lsd into. Know any places to get a hold of a BW78 pref with disks already and falcon pattern?

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Not me sorry. 

You can put the 28 spline internals into the 75 housing. But if you have set up a diff before your have to pay the diff $hop to do it for you. 

@Valiant has a jig to shorten housings I think. 

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20 hours ago, J-W-G said:

@RUNAMUCK 

Hey man do you do diff shortening? Ive got an aussie cortina BW75 housing id like to chuck BW78 axles and lsd into. Know any places to get a hold of a BW78 pref with disks already and falcon pattern?

I have one that I'll be looking to move on, will be replacing with the 8.8 that as of last weekend have finally pried out of the explorer. Has discs, is LSD and came out of an AU allegedly 

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You can tell if it came out of an AU or not. The bearing retainer plate changed on the AU when compared to the earlier models. The AU housing flange is wayyy thicker than the earlier models and its bolt pattern is more of a square' as opposed to the earlier models rectangular shape. Different brakes also.

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On 20/10/2019 at 20:12, RUNAMUCK said:

We already have a hoard of bw75's. 

A 3.45:1  lsd 78 was I think 200-250. New bearings were around $150. 

The axles will be shortened in house. 

Bit of jiggery pokery and the bw78 crown and pinion fit inside the 75 housing.  The lsd was pretty coozed. So the tape cones where machined to stop them bottoming in the housing. And shimed up to resurrect the side gear mesh. 

Bit of fucking around, but not super spendy.  Time will tell how long it holds up. Pretty sure the crush tube has also been replaced with a solid spacer too. 

So I take it that 28 spline axles were got (probably from the same diff the carrier came from) and then cut down and resplined in order to replace the 25 spline items? I'm trying to follow what has been done. Question ... did you end up using the brakes that came with the 28 spline axles?

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They haven't been shortened yet.

The cutter that turned up off aliexpress wasn't the one pictured. So.another one is en route. 

Nah still.just running the shitty VG rear drum brakes with redrilled hubs to late pattern and vj drums.

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On 19/10/2019 at 23:56, cletus said:

Before I bought the 8.8 I did price up a new 9" build, and it was cost reasons for going the way I did. I got a quote for a new housing and axles which was going to be about $2300, I cant remember how much a center was going to be exactly but I recall a new one with a good lsd was another 2-2.5k or thereabouts, and that was without a brake setup.  So around 5k?

The 8.8 wasn't as cheap as I thought it was going to be but it was less. These are approximate prices but pretty close to what I've spent

$500 for the whole diff including brakes from a wrecker

$900 for rebuild parts, ring and pinion etc

$900 for housing mods and rebuild 

$200 new discs and brake pads

$150 for another short axle and some better spider gears 

$150 Fancy diff cover

$100 spring pads, paint, brake pipes etc 

So around $3k ready to go

 This is the first time I've added it up so I guess time will tell if it is an economic win or not  

 

 

 

 

similar reason why I decided to be bloody minded and use a hilux. considered 8.8 but for a fox body with the factory triangulated 4 link the upper mounts need to be on the sides of the centre housing. only the factory mustang 8.8 has those cast in and welding some onto the explorer section didnt seem like taht greatest idea v.s. welding onto a hilux housing. getting a mustang housing in nz is costly.

/hindsight should have sacked up and bought a 9"

On 20/10/2019 at 00:38, cletus said:

I've been pleasantly surprised at how well the bw diff in my vg has survived

All I've ever had to do was replace an axle with a twisted spline and it's done a million burnouts and a lot of drag racing. I pulled it apart once to check it and it was fine 

25 spline axles, 2.92 ratio, 4 spider lsd with some extra preload  

auto and 2.92 ratio ftw - bigger stronger pinion, and less torque load on axles / torque sponge to absorb shock loadings

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Diff gurus. I need to change the pinon seal on my EH diff. Can I mark were the nut is currently, count how many turns to undo, replace seal, re-install nut etc to same place. Or is it send to shop and just a new crush tube made etc?

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I dunno, I have never seen/worked on an EH diff but will offer up this little observation. I pulled apart a BW from out of a XY Falcon a few months ago and discovered it had a solid spacer fitted. I'm pretty sure it was factory and that I was the first one to pull it apart. So yeah ... there was a fair bit of solid spacery' going on in them days. Pay to check before paying a pro to do what can be done at home with a rattle gun. Just saying.

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if you put it back together with the same crush spacer you have to do it up just a liiiittle bit more. basically still to the same torque value, which is usually hooven tight.

If you feel that you have gone much past the point it was previously done up to by much its just deforming the crush spacer more and more and thats not what you want. tight enough that its only just starting to deform it again.

its not the right way to do it,  but i've done it before in  a pinch and the axle shaft broke well before the ring and pinion had a problem. but grain of salt /yrmv etc.

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1 hour ago, Testament said:

if you put it back together with the same crush spacer you have to do it up just a liiiittle bit more. basically still to the same torque value, which is usually hooven tight.

If you feel that you have gone much past the point it was previously done up to by much its just deforming the crush spacer more and more and thats not what you want. tight enough that its only just starting to deform it again.

its not the right way to do it,  but i've done it before in  a pinch and the axle shaft broke well before the ring and pinion had a problem. but grain of salt /yrmv etc.

Cool thanks for the info. Were could I get the info for a crush space? I could make a new one if need be.

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Question regarding 9inch drum brakes, my impala has a 9inch in it and took a look at the drums on it in the weekend. One shoe on each side had delaminated and were floating in the drum and one side is missing the guide for the adjusting cable so cable is just floating around. Now i have no idea what car the diff was out of so when ordering new shoes does it matter as long as I get the right size or are there variences in the shoes for different models? 

Second question is the current shoes are 2" wide but drums measure 2.5" is this normal to create tollerance or the wrong shoes have been put in? Was thinking 2.5" shoes in the 2.5" drums might be to tight? 

3rd question is there is a bit of grease seeping out into one of the drums how hard are these seals to replace? 

Cheers Michael

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