Snapped Manifold!

[rsawatson]

The downpiece of the exhaust manifold snapped tonight when I started the car - meaning it now sounds and drives like a tractor!

I trust its replacement should be a fairly straightforward job ?

[bmcecosse]

The cast manifold snapped ??? Amazing...... Yes easily replaced if you have a spare - but never ever heard of such a thing!

[rsawatson]

I wondered why new ones don't seem to be manufactured.

Trust me to be one of a handful of people in the World who have had this happen. It has snapped just above the clamp - I think I might have overtightened the clamp the other day when the exhaust was rattling. Very annoying.

[d_harris]

Depending where in West Sussex you are, I may be able to drop a manifold to you on the way to/from work on Mon...

[aupickup]

i have several if you are stuck i am in hastings and eastbourne

[alex_holden]

It happened to me too.

[chrisryder]

It's happened to me, but that was on a marina manifold, we got a bit angry at the exhaust, and hitting it with a hammer repeatedly to get the silencer onto the downpipe proved too much for the casting!

i also know of someone who reversed into a grass bank, and the tailpipe dug in and snapped the manifold.

i dont think they're manufactured, as they're not exactly consumable items, obviously nobody knows that they can brake!

it's a fairly simple job to fit, a line of 6 brass nuts (1/2 inch) along the head. get yourself a new gasket too. and you'll have to take your carb off, but you can do that without disconnecting either cable. you'll want 3 or 4 new carb gaskets while you're at it too.

i'm sure if somebody brings you a manifold they can show you the ropes while they're there!

[rsawatson]

Depending where in West Sussex you are, I may be able to drop a manifold to you on the way to/from work on Mon...

Thank you very much for the offer but fortunately I was able to source one today.

I've reassembled the exhaust, but there's a bit of blow to the front side of the join between the pipe and the manifold. I suppose the seal between the two isn't tight enough?

[chrisryder]

it's possible, what type of clamp are you using? i find the cast ones work best, the pressed steel ones are a bit of a false economy in my experience.

did you put any sealant on the flange face? i normally put a bit of copper grease, or holts exhaust putty if i've got any to hand.

[bmcecosse]

You're all so rough with your Minors.........

The pipe bell mouth needs to be perfectly shaped, the ball end on the manifold needs to be clean and the neck clear to allow the clamp to fit round. A smear of paste - then jack the pipe up hard against the ball - clean the threads on the clamp bolts (and use brass nuts) - smear of copperslip on the threads - fit the clamp and make sure it's nice and square and run the nuts up and nip them up but not too hard. Make sure the rest of the exhaust system is firmly supported - but not so firm it can't move with the engine. Also check the engine mounts are not broken - and is the steady bar ok ?

[chrisryder]

ooh, and clamps seem to have a prefered orientation. if you have the exhaust clamped up but not tight, the clamp can rotate in place, it'll have a best place, which you can often feel by rotating and tightening the nuts slightly, and re-trying. i don't know if it's a feature, or if it's just a coincidence that every exhaust i've fitted has the same foible! but give it a go, 'being able to reach the nuts' is not always the best angle.

[rsawatson]

I sorted the continued exhaust leak today - I enlisted the help of a friend to tighten up the clamp whilst I made sure the downpipe was pressed snugly against the manifold. I also employed a little of the Holt's exhaust 'toothpaste' and it seems to have done the trick.

Regarding the engine mountings and the steady bar - I had thought of these as possible causes too. The rubbers do look a bit perished - perhaps a job for me to do in the summer!

[rayofleamington]

You're all so rough with your Minors.........

I broke a Marina manifold at the same place - on a 948 engine.

As for being rough - YES! although I've seen another one fail (my sisters) with just normal road use.
I had a "brief excursion" on a sandy track at about 40mph, and ended up at least 6 foot airborne, smashing the front right hand inner wing upper bump stop area on the first landing (we landed on that side heavily first time) and breaking the exhaust manifold on the second landing (Second landing was on the left side - also very heavily).
We did keep going though! With the extra noise we thought it wise to stop and investigate a few minutes later when we got to a level area.

[chrisryder]

6 foot airborne? that's nothing, you obviously haven't seen the potholes around my way...

[rayofleamington]

Some friends of mine drove through eastern Europe, Russia and the stans.
Near Moskow one of them drove into a pot hole that was so big the roof of the car was below the tarmac and they couldn't get out... They were a bit stressed about it and kept trying to gas their way out until their mates accidentally drove into it too - and hit them hard enough that it helped them get out Then they had to get the second car out of it.

The locals knew to avoid that side of the road!