Melted Losi 5ive-T center diff

Billp

Well-Known Member
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123
I read about this but never saw it until the other day. My centre diff melted around the metal insert, spraying silicone oil and melted plastic everywhere.

What's the deal with aluminium diff cases? The RCmax one is considerably more expensive than all the others but is it actually any better than all the others? I run a Scott Finlay Pro MX 34. Thoughts? I don't want to add weight either as I run this on a track.
 

cbaker65

Takes pipe? from stranger's ?
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2,671
I read about this but never saw it until the other day. My centre diff melted around the metal insert, spraying silicone oil and melted plastic everywhere.

What's the deal with aluminium diff cases? The RCmax one is considerably more expensive than all the others but is it actually any better than all the others? I run a Scott Finlay Pro MX 34. Thoughts? I don't want to add weight either as I run this on a track.

Did you find out why it melted?
 

Seandonato73

King 🤴 Womble
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12,072
Overheated would be my guess. We have the same issue on the dbxl platform when you run hard for log (race) or run heavy diff fluid for longer bashing sessions. This is most noted when they go through several heat cycles as it starts to degrade the plastic. I've replace my front and center already... it makes sense if your racing at one point or another to have one of them let loose. Just my 2 cents.
 

Billp

Well-Known Member
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123
irc... rcmax doa nice housing in 7075..?.most others r only 6061 which is softer alloy..?.and wont last aslong as a 7075 one ?
I can't see a 6061 ever breaking. It's still a hardened aluminium and will never get hot enough to warp. My primary concern is design and the gasket leaking really. The RCmax has a self lubricating bearing in it but is it actually worth the additional £40 over a cheaper one when most leaks come though the O ring and I will be running it on a track, so never have anything thicker than 20k in it.
 
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i had a pair of hot racing 6061 cases for my5ive and both had elongated holes on one end which ment way to much play on the drive cup ends so yes 6061's will go south ??
so i sold them and went bak to stock cases fr/rear?
 

Billp

Well-Known Member
Messages
123
i had a pair of hot racing 6061 cases for my5ive and both had elongated holes on one end which ment way to much play on the drive cup ends so yes 6061's will go south ??
so i sold them and went bak to stock cases fr/rear?

The stock losi insert is probably 6061 but it was the plastic that failed. Given the TLR one is 10 quid cheaper than the RCmax ones from Rcmodelz I'd have reservations about without first hand feedback, I think the Rcmax is possibly the one to go with.

I wouldn't put stock in anything Hot Racing. Anything HR that i've bought or seen in person has had a good finish but I would bet they wouldn't pass any kind of test to verify it's even 6061, more like 5083 or something that isn't heat hardened. I had some Yeti XL diff cases from them that were clearly cast and had to be ground down to fit. Not buying their stuff again.
 

Seandonato73

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The difference between 6061 and 7075 in this case isnt really applicable. Like so many other times both will work fine in this application. If you want to spend a few extra bucks get the 7075. It is stronger. 6061 shouldn't fail.
 

cbaker65

Takes pipe? from stranger's ?
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2,671
Yeah same thing. It's one of the most debated things on the web. 6061 vs 7075. I've seen both used in way more stressful applications and neither fail. Crap alloy is crap alloy.

If I remember right ,in the application ,it was about the cooling ,not the strength ,the debate was over which one cooled better!

However ,in my experience ,it doesn't matter ,the aluminum stays hot as long as the heat source is still active ,the aluminum heats
up faster an stays hot until the heat is turned off ,then when the heat is off ,the aluminum cools faster!

Here is a couple of old Nova racing heads that I have ,the only reason that I have them ,is they looked cool .an at that time
period ,everyone was wanting & getting them ,so I jumped on the wagon ,however ,the head did feel cooler than the original!



 

Billp

Well-Known Member
Messages
123
So it turned up and it's nice and shiney as you'd expect but I'm pretty sure it's cast then machine finished rather than cut out a single block. On the inside where the inserts go, there's a gradient effect getting darker as it goes up. The slider bearing does have a proper oil seal on it though and it is light. Time will tell if it's worth £65. At least it won't melt.
 

AnubisBC

The Professor ?‍?
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1,130
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That'd be interesting if it were cast. In order to cast 7075 and prevent it having significant microstructural issues. The metal needs to be "hot worked" in some manner to homogenize the metal structure. If it weren't, it would just crumble under strain. Could be RCMax is using an outfit with the equipment to do this to cast their "'blanks" then do the finish machining after normalization.

Anyone here know someone at RCMax?
 
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