Diff cover???

[ac427cobra]

i might have been wrong earlier when i said that the mm aluminum rear diff mount would not be compatible with the lpw cover.

i haven't bolted it back up yet (pumpkin still at drivetrain shop) but it looks like the flat part of the mm mount goes towards the front of the car. i thought that the stepped side went towards the front of the car, which would interfere with the lpw cover. i was under that impression because mm's directions show a pic with the stepped side towards the front, but i think those directions show a pic that is wrong.
here are those instructions: http://www.maximummotorsports.com/content/install/pdf/irs/MMIRSB-40_1.pdf

here are some pics...











diff off to shop...


when i get the diff back i will verify the compatibility... :beer:

You have that rear support on the subframe backwards. Once you try to put the diff in the subframe you'll discover that. :read:

The step on the bracket goes against the rear of the diff cover.:idea:

Yes i used the MM bushings, I was going to spring for the solid stuff but I have seen two different IRS housings crack the ears because of using them, so thats why I used the others.

I think you should reevaluate your decision. Far more diff housings have been broken (front and rear) by flopping around in rubber than anything else.

If a front mounting eye was broken I would say either the bolts came loose and the housing was shifting OR..... the car had RWHP in the 800 range or above.

FWIW

:thumbsup::coolman::beer:

 

[P49Y-CY]

You have that rear support on the subframe backwards. Once you try to put the diff in the subframe you'll discover that. :read:

The step on the bracket goes against the rear of the diff cover.:idea:

ok bruce i will check that out when i put it back together - like i say i havent gotten the diff back from the shop yet...

but if i were to turn the blue support upside down in relation to the stock support (side by side in the pic), then the bolt holes do not line up?

and i am almost 100% sure that the stock support sits in the subframe the way i have it in the pics (?)

either way i will post up when i put it back together

btw bruce i sliced the upper control arm a little bit when removing the bushing - i'll ask your advice in your main ftb irs thread

thx :beer:

 

[ac427cobra]

but if i were to turn the blue support upside down in relation to the stock support (side by side in the pic), then the bolt holes do not line up?

When you flip the MM bracket the other way, the reason it doesn't fit is because you are dealing with TWO different aftermarket manufacturers here. Typically aftermarket manufacturers make sure their parts work with OEM parts not ALL other aftermarket parts. :read:

No Doubt you have some clearance issues trying to mate the MM solid rear diff support with the LPW rear cover. You are going to have to most likely take BOTH of those parts to a machine shop and get one or both of them milled or clearanced to fit. The LPW cover will work with the Ford rear diff support, and also with our Full Tilt Boogie Racing rear Delrin setup, but not the MM support. Also the MM solid rear diff support will also work with the OEM Ford rear cover NOT the LPW or Fore covers. :idea:

I wonder if we should make a steel or stainless steel rear cover like the OEM part that fits everything!!?! :coolman:

 

[P49Y-CY]

more mm info

When you flip the MM bracket the other way, the reason it doesn't fit is because you are dealing with TWO different aftermarket manufacturers here. Typically aftermarket manufacturers make sure their parts work with OEM parts not ALL other aftermarket parts. :read:

No Doubt you have some clearance issues trying to mate the MM solid rear diff support with the LPW rear cover. You are going to have to most likely take BOTH of those parts to a machine shop and get one or both of them milled or clearanced to fit. The LPW cover will work with the Ford rear diff support, and also with our Full Tilt Boogie Racing rear Delrin setup, but not the MM support. Also the MM solid rear diff support will also work with the OEM Ford rear cover NOT the LPW or Fore covers. :idea:

I wonder if we should make a steel or stainless steel rear cover like the OEM part that fits everything!!?! :coolman:

very cool bruce and i bet if you did, and it fit anywhere near as good as the stuff in your bushing kit, that it would be a big hit! :thumbsup:

i just got off the phone with mm because i was scratching my head about this all weekend.

even if we leave the lpw cover completely out of the equation, the maximum motorsport aluminum rear bushing holes DO NOT correspond exactly with the stock bushing holes. you can see it in the side to side pics above. when you flip the blue bushing upside down, the differential mounting bolt holes are then about a half inch lower than stock, relative to the subframe mounting bolt. that is why i had it mounted upside down on the subframe. but bruce is right, the differential can't fit that way because that increases the distance between the front mounting ears and the rear mount.

so the stepped side does have to go toward the front of the car, and therefore is not compatible an the lpw cover (without machining).

but i called mm to ask if they were aware of this - that their bolt holes differ from stock. and yes, they acknowledge that their blue bushing lowers the rear of the differential about a half inch - in order to help get a more desireable (nose-up) pinion angle. that is something that is not written anywhere in their instructions.

well sorry so long and detailed, but this is new information that i have never read before regarding the aluminum maximum motorsports blue rear bushing. :beer:

 

[greengt88]

so is a brace better or the lpw cover better with bruce's bushing kit? Can u use main cap studs on the 4 differential cap bolts?like u can with an SRA 8.8?

 

[bubblehead93]

First off, yes you can stud the differential main caps like a SRA - you can use any of the kits you would use for a 8.8 SRA.

I'm convinced most cover failures, similar to half-shaft failures, are due to wheel hop. If you have ever had the cover off, it is thin cast aluminum - I was surprised how thin it is, I think anyone should at least install a brace to transmit much of the load from the rear housing bolts to the differential casing vice the cover.

Other than pictures, I have never had a LPW cover in my hands. Though cast, it appears to be thicker and have more substantial webbing on it than the stock cover as well as main cap load support bolts. For the average street cobra that sees only occasional strip time, the decision comes down to what suspension components you want to run with the primary goal to eliminate wheel hop to preclude driveline failures. For the average cobra given the fitment issues highlighted above, I think a brace is sufficient as long as you have done the suspension mods necessary to eliminate wheel hop. If you don't eliminate the hop, don't care what you do back there, you will eventually break something.

 

[greengt88]

ordered bruce's bushing kit tonite and also have billetflow irs brackets installed. also ordered bruce's adj. tie rod ends. So now i have to decide on the cover or a brace. i will definitely purchase the main cap stud kit now that i know it'll fit. i have them in my fox. Does the lpw add additional fluid capacity?? I'll probably go with the lpw.

 

[P49Y-CY]

ok i got some pics to go with some of my earlier posts.

although not 100% necessary in my case, i cut one of the ears of the stock rear differential mount to go along with my lpw cover. it does not touch bruces delrin bushing at all (didn't even need to sand the delrin), nor does it touch the lpw letters at all. but, one of the ears would be resting on the diff cap jack screw on the lpw cover, and i didn't want that. i'm sure every case is different and ymmv.

also, in the bottom two pics, i mocked up the stock cover with the delrin bushed stock mount and the mm aluminum mount. you can see how the mm mount does in fact drop the rear of the diff by about 3/4 inch.

 

[black 10th vert]

wow great comparison pics - thanks for taking the time to post them up!

 

[greengt88]

So u can install the factory mount with bruce,s kit and have no clearance issues with the lpw cover? Purchased the cover this morning. Just need the 4 main cap studs from frpp. I assume now is a good time to be istalling springs and caster camber plates. Now steeda or mm stuff?

 

[greengt88]

Also think I might paint the cover black. Any thoughts on type of paint?figure engine enamel would work good

 

[P49Y-CY]

So u can install the factory mount with bruce,s kit and have no clearance issues with the lpw cover?

i didn't... but i have read other situations where folks have had some issues...

and bruce's instructions do recommend chamfering the bushing because it might hit the stock cover.

but in my case the delrin bushed factory mount did not touch anywhere on the factory cover, and only slightly touched the lpw cover at the pre-load bolt only

best of luck!