5/16" UNC.
Use a NEW (they are sharp) spring washer...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I use a stud in hole, tightened snug to bottom of hole, a flat washer both sides and a crimplock nut. Never had one fall out yet.

Don't recall the Brownriggs having any bracket at all at the base, the collector just held them in place. They never hit the steel diff unis. Main problem was on a lowered car the collector would often scrape a man hole cover or road hump because the Brownriggs came down a bit lower than most other exhaust manifolds because, I was told, they were intended primarily for racing not road cars.

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Slide
1965 Mini Van (1360)
1970 Mk2 Cooper S (1310)
1978 Rover SD1 V8 (4.6)
1996 Land Rover Discovery V8 (4.0)

hopefully there is *some* thread in there still - do you have 2 top engine steadies?

850's move around a lot, so yours may have worn the tread away... move the exhaust clamp strap out of the way and see if you can tighten a bolt in there

I see you're using those 2 clamps for the collector - bastard things, I want to leave them off, but maybe I'll put one on... I've set it up with easily 1/2" of pipe going past the split

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did I tell you that I won a trophy?

If the hole is stripped to 5/16" diameter, tap it out to 3/8 UNC. No drilling required (except to the side cover, make that 3/8). Can do all this in situ.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

It's an 1100S on a 22G1128 gearbox and an 850 diff and it has two top engine steadies.
I'm not sure that I'll reattach the clamp to the diff (but will refit the bolt) as this provides flexibility in the exhaust system.
If the exhaust is clamped at the diff, as the engine moves or the exhaust heats/contracts there is nowhere for the movement to be accommodated as it is almost a straight run to the clamp at the front of the rear subframe, and then another at the rear.
I suspect that's why that bolt gets such a workout and falls out.

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Find a job you love and you will never have to go to work !

My large bore Brownriggs have a bracket on them. They originally hung really low (the original exhaust guy raised them a little but it was still only 80mm off the ground when the car was sitting quite high on the hilos). It's in with a different exhaust guys who *seems* to actually know what he is doing and he said he got them up 1.5" higher. Which we expected when we looked when it was on the hoist. By shortening the two downpipes and being able to slide the collector up further.

It's a 2.25" system and he says it's tucked up nicely out of the way.

I pick it up on Monday and if anyone wants info or pics just let me know (I'll post some pictures in my buuld thread anyway).

Sent from my Nexus 6P using Tapatalk

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Build thread for Supercharged 1275 1967 Deluxe Resto
Build thread for Mini ute conversion 998cc Turbo

Since posting this I have had it confirmed that the clamp around the neck of the tail-pipe where it joins the extractors actually bolts to a threaded hole on the side of the remote change extension. Something new learnt.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Does anyone have a photo of the Minispares bracket installed

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Find a job you love and you will never have to go to work !