Maniflow LCB manifold fixing to gearbox?

[minstix]

Hi,

I know this subject has been touched on in the past but I was just wondering what the general thoughts are these days. I'm fitting a new Maniflow LCB manifold and RC40 exhaust system to my Cooper S MK2. The manifold came with a clamp and short bracket to clamp it to one of the screws that hold the aluminium remote casting to the diff case.

The bracket and clamp is never going to be an ideal fit. Is it going to be more trouble than it's worth? I'm wondering if fitting it puts more rigidity and strain on the exhaust and the thread in the aluminium diff casting than is good for them? it would mean the system is held by the studs on the head and the two rear subframe hangers. It's a solid system throughout so I cant see anything coming off or going anywhere. But is it important to have that extra fixing?

Any thoughts on this?

Cheers,

Steve

[BAD942B]

the LCB on my car may have an ST one not a Maniflow one but I fitted an RC40 in the early 80s when they 1st came out, made by Competition Silencers who where part of Minispares, I never had that bracket (didn't know there was a bracket then) & the LCB never cracked.
Looking it now its cracked where the Y on the outer 2 pipes meet & on the centre pipe by the flange, both look like overheating cracks, probably from being driven virtually flat out everywhere it went.
I have a new C-AEG364 from Maniflow now, it has the bracket but its much better quality than the ST one, so again I wont use the bracket, might be different if the car was a later rod change car, my mate has just said his rod change car used to break the Y piece regularly in the the 80s, today funnily enough

[LarryLebel]

I had an LCB on a Cooper S for a good 30 years without a bracket and now on my Traveller also without a bracket since 2007 without anything breaking.

[Polarsilver]

The Maniflow LCB that i have has the support strip of steel about 2inch long with two holes ..that one end secures onto a single bolt that also secures the drive shaft output seal Cover on the diff case.

[minstix]

Thanks guys. It hadn't occured to me that the 2 inch flat bracket attached to the seal cover. Maybe it's a better fit there.

I'm still undecided whether to use it or not. I'll see how well the bracket and clamp line up with the seal cover rather than a gear extension bolt tomorrow.

Steve

[1071bob]

Should look like this....

[Mudhen]

Why hasn't maniflow or someone come up with a nice flanged header/exhaust??? That connection kills me...I can never get it to seal, and when I try to separate it, it's always a torch job.

I can separate an r53 header in 2 minutes, throw in a gasket and be on my way again in no time.

Guess that's outside the OPs question, but thanks for letting me vent.

Happy Easter?

Pat

[BAD942B]

Why hasn't maniflow or someone come up with a nice flanged header/exhaust??? That connection kills me...I can never get it to seal, and when I try to separate it, it's always a torch job.

I can separate an r53 header in 2 minutes, throw in a gasket and be on my way again in no time.

Guess that's outside the OPs question, but thanks for letting me vent.

Happy Easter?

Pat

Not really enough room for a flange joint & if there was there wouldn't be enough room for your hands, the exhaust & flange gasket. The 1st time I had a problem seperating the joints was the last time after 43 years of being asembled. the gas torch is a waste, weld a little ledge on the exhaust pipe, the Y piece & just use an air chisel & flat blade with very light taps, soon gets it to pieces

[Peter Laidler]

That's what I call a xxxxing good idea....... A good bit of forward thinking. You wonder why it didn't already come with a small flange as described above

[Spider]

I've always found that any bracket that bolts up to the gearbox, in time, only pulls the threads from the gearbox. I stopped bolting up any of these brackets here nearly 40 years ago and never looked back. I've repairs load and loads of gearcases that have had damaged threads here all from the exhaust being bolted up here.

[minstix]

That's an interesting looking bracket 1071bob. I guess it's using two of the avaiable casing screws so spreads the strain on the threads to quite an extent. Was that custom made by you or is it a part that's available?

I'm still wondering, does the exhaust system really need support there? Does it do anything to help in any way or does it actually introduce extra rigidity into the system and it would be better without?

On the seperating the exhaust system parts after years on the road, I agree, it indeed is a pain, especially where exhaust sealing paste has been used. I've been through it twice before over the years and on both occations I've resorted to using an angle grinder with cutting disk and replaced with new parts.

Steve

[Peter Laidler]

The engineer in me is minded to suggest that to prevent the alloy threads pulling out, that instead of bolts, the use of doiuble threaded UNC/UNF studs into the alloy housing. UNC in the alloy housing with UNF nuts at the other end to retain the plate. This 'static stud' idea works on other alloy housings.

I say that the manifold definitely does meed support at the curvature, as shown. That is because without support there, the exhaust pipe us totally unsupported from the manifold to head joint, right along to the first exhaust pipe support some way back. And to make things worse, the rear support is rubber munted to boot!. Nope, definitely needs the support as shown by Bob. It is called good, sound engineering practice.

[BAD942B]

The engineer in me is minded to suggest that to prevent the alloy threads pulling out, that instead of bolts, the use of doiuble threaded UNC/UNF studs into the alloy housing. UNC in the alloy housing with UNF nuts at the other end to retain the plate. This 'static stud' idea works on other alloy housings.

I say that the manifold definitely does meed support at the curvature, as shown. That is because without support there, the exhaust pipe us totally unsupported from the manifold to head joint, right along to the first exhaust pipe support some way back. And to make things worse, the rear support is rubber munted to boot!. Nope, definitely needs the support as shown by Bob. It is called good, sound engineering practice.

Whilst I agree with you Peter about the studs not sure I agree with you about the support bracket

[minibitz]

The bracket shown is GEX7526 and works a treat at spreading the load across more than one of the diff side cover bolts. They were fitted to all SPI and later cars of which I've never come across one with a stripped threads although I have seen a few snapped and re-welded brackets. I believe there was also an earlier version that used 3 of the cover bolts but don't think this type is readily available anymore.

The cause of any damage to threads or bracket or LCB will be down to poor maintenance of engine steady bushes allowing the motor to rock back and forth excessively. Keep on top of this and there will be no issue.

[Spider]

The engineer in me is minded to suggest that to prevent the alloy threads pulling out, that instead of bolts, the use of doiuble threaded UNC/UNF studs into the alloy housing. UNC in the alloy housing with UNF nuts at the other end to retain the plate. This 'static stud' idea works on other alloy housings.

Pete, I did make some studs similar to that, but with a hex in the transition between the two, a double ended bolt if you like. I found that better, but not the answer.

Even the '3 pointed bracket' that Bob put up a photo of, while they were sorta kinder on the threads - for a while - the bracket would crack in two, then depending on where that first crack occurred, they may crack in a second place the result being either on the first or second crack that the exhaust hold tug and push on one bolt in the gearbox with the same net result, only taking a bit longer to get there.

[richardACS]

Am about to install this exhaust system myself so my question is (without any understanding of the space issue in this area) but could it not be formed in flexible pipe?

[Allen Brzeczek]

All very interesting but as LarryLabel I have never had any problems in many a year without any support or bracket.

[whistler]

I've always found that any bracket that bolts up to the gearbox, in time, only pulls the threads from the gearbox. I stopped bolting up any of these brackets here nearly 40 years ago and never looked back. I've repairs load and loads of gearcases that have had damaged threads here all from the exhaust being bolted up here.

Whenever I fit a bracket to a gearbox casing I make sure I use a slightly longer than standard bolt to make sure it uses all the threads in the aluminium.
Same goes for steady bar plate bolts. Last bad one I had need drilling out/tapping for a 3/8" UNC instead of the usual 5/16" UNC.
Just spotted Peter's post. I also use studs sometimes, especially for the forward facing steady bar on later cars to front of subframe.

[Peter Laidler]

The only reason I suggest a support bracket at the bend in the downpipe is based on the original BMC/BL Cooper ex manifold design. As we're all aware, those manifolds cracked down along the top/car side of the bend. Unipart (?) engineers concluded that this splitting was caused by the manifold not being supported by the large diameter, thick steel clip that bolted the manifold tightly to the gear lever extension - also bolted tightly to the engine and gearbox. This allowed a fatigue crack to develop and as a result Unipart would refuse to accept a warranty claim. The fatigue crack was in turn exaggerated by the additional weight of he exhaust pipe rearwards.

Unipart rarely exchanged split exhaust manifolds under their 12 month warranty....... according to my neighbour Terry who was a top man at Unipart here

That's the only reason for suggesting the use of a secure fixing in this instance, between the downpipe connector and the actual exhaust

[GraemeC]

That's an interesting looking bracket 1071bob. I guess it's using two of the avaiable casing screws so spreads the strain on the threads to quite an extent. Was that custom made by you or is it a part that's available?

It’s a standard part:
http://www.minispares.com/product/Class ... 2520search

There was one that used three bolts into the gearbox, but that one’s NLA