Exhaust manifold studs

[P D: SC Chester]

Differing opinions about best way to fit exhaust.
1: brass washer, brass nut tip up' ?
2: brass washer, brass nut tip down?
3: brass washer, no washer, nut tip down?
4: 2 steel nuts, no brass?

All of the above with locktite?

Another way mentioned was re tap and helicoil with 13mm bolt?

Opinions of, and previous experience appreciated.

[Adam_Winstone]

Is this question being raised because of another element, i.e. how do I stop an exhaust shaking a solid mount exhaust off an alloy barrel, which is typical before stripping threads in the cylinder?

... or just a general question?

Adam

[P D: SC Chester]

Exhaust coming loose on iron barrel, using normal fixings - brass washer and nut on studs. Tried locktite and liquid gasket on top of paper gasket, but eventually it comes loose.

Cheers

[Adam_Winstone]

OK, not so common on an iron barrel but very common on alloy.

Is this an expansion or standard box type?

If expansion it is unusual unless non-stub mount (at manifold) and without an end can bracket, which allows the exhaust to follow 'the law of the lever' and pivot around the main casing bracket, meaning that end can and barrel fixing are the furthest ends and swing the most... shaking loose.

Personally, I use the brass nuts (brass so that they do not rust to become one with the stud), thin nib away from the barrel so that the wider bottom edge spreads the load better across a decent spring washer. This works for me but you need to ensure that the exhaust is not being stressed by being pulled into place. It should fit correctly 'at rest'.

Adam

[Warkton Tornado No.1]

An alternative that I use is to acquire long M6 steel nuts (only 10 mm AF, so easier to ‘wrench’) that I cross drill @ one end to allow lock wiring to each other, & run an M7 tap through. Used in conjunction with thick, plain washers, the method is bullet proof.

Recently, I’ve even resorted to this method on the inlet side as a manifold had come loose, despite nylocs & washers.

[P D: SC Chester]

Thanks for the replies lads.
It is an expansion with no end can support. Perhaps a mock up support might help?
Mr Tornado, you don't happen to have a pic of the said modified nuts do ya?

Cheers

[HxPaul]

To answer your fist question,if you use the brass exhaust nuts.They're made round at one end and hexagonal at the other.I always fit them with the round part up.I figure that if they were to be fit the other way around,why not make the whole nut hexagonal.I think the round part is supposed to crush on tightening gripping the shaft of the stud.

[Warkton Tornado No.1]

Mr Tornado, you don't happen to have a pic of the said modified nuts do ya?

Cheers

Sorry about thje quality of the image, but you'll get the idea, I hope.

Lockwired nuts.JPG

[jonw]

I don't know whether this helps but I've been using K-Nuts for 3 years now and never had any loosening issues.

Old topic herewith: viewtopic.php?f=10&t=1847

[P D: SC Chester]

Thanks Jon, will invest

[Warkton Tornado No.1]

I don't know whether this helps but I've been using K-Nuts for 3 years now and never had any loosening issues.

Old topic herewith: viewtopic.php?f=10&t=1847

K-nuts are bl**dy marvelous as previously stated by several of us that have been using them for over 20 years

However, they should be selected to be of the type for elevated temperature in the case of M7, if they truly exist in that size. They certainly are available for other sizes where used, for instance, on race braking disc hubs, but I could never find them @ a reasonable price in M7. Perhaps knowledge about them has increased their use since I last looked in earnest...

[Stockists may charge a massive premium on less common sizes because they may have to pay themselves for an EOQ (Economic Order Quantity) for a batch manufacture] That was the principle reason I adopted cross drilled long nuts [or even cap heads in cast iron/Rapido barrels that can stand it, unlike alloy (threaded) barrels]

Do report back if you find them, though, please

[P D: SC Chester]

I've not found K nuts but, seen some tall brass nuts with drilled our holes and wire. Bit pricey at £12 but, if it means not having to remove foot boards n drop the engine to get the f'in Cowell off, probably worth it!

[Warkton Tornado No.1]

I've not found K nuts but, seen some tall brass nuts with drilled our holes and wire. Bit pricey at £12 but, if it means not having to remove foot boards n drop the engine to get the f'in Cowell off, probably worth it!

These might be more in your (& mine!) price range @ 75 pence!

http://www.racing-planet.co.uk/cylinder ... RL7n9LysdU

M7 nut.JPG

[Warkton Tornado No.1]

I stand corrected! Things have indeed moved on regarding high temperature M7 K nuts @ £0.99 each:


https://www.autosport-bearings.co.uk/pr ... 7QodOFUF4A


However, my personal preference remains in using the longer nut options (with lock-wiring) as they give greater peace of mind & are re-usable.

[jonw]

I don't know whether this helps but I've been using K-Nuts for 3 years now and never had any loosening issues.

Old topic herewith: viewtopic.php?f=10&t=1847

K-nuts are bl**dy marvelous as previously stated by several of us that have been using them for over 20 years

However, they should be selected to be of the type for elevated temperature in the case of M7, if they truly exist in that size. They certainly are available for other sizes where used, for instance, on race braking disc hubs, but I could never find them @ a reasonable price in M7. Perhaps knowledge about them has increased their use since I last looked in earnest...

[Stockists may charge a massive premium on less common sizes because they may have to pay themselves for an EOQ (Economic Order Quantity) for a batch manufacture] That was the principle reason I adopted cross drilled long nuts [or even cap heads in cast iron/Rapido barrels that can stand it, unlike alloy (threaded) barrels]

Do report back if you find them, though, please

Not cheap but not a "massive premium"... Hi Temp M7 K-Nut
https://www.autosport-bearings.co.uk/pr ... oCgHHw_wcB

[jonw]

I stand corrected! Things have indeed moved on regarding high temperature M7 K nuts @ £0.99 each:


https://www.autosport-bearings.co.uk/pr ... 7QodOFUF4A


However, my personal preference remains in using the longer nut options (with lock-wiring) as they give greater peace of mind & are re-usable.

I run a PM Tuning manifold which has VERY poor access to the studs for tightening so the small K-Nuts give me a bit more room to access tightening them.
For me they have been a fit and forget solution and I wouldn't use anything else now.

[P D: SC Chester]

It's all just nuts!

[jonw]

It's all just nuts!

It drove me nuts!

Not any more though

[Marty ULC]

I use the chain adjuster tab washers cut in half with the hole opened out to fit the 7mm stud.
As per sticky's book.
This stops the stud and nut coming out as if it were a bolt too.
I've been told that locktite melts and effectively becomes a lubricant at those temperatures.

[missing lynx]

I use std brass nut round bit towards cylinder and a steel spring washer and not had one come loose yet if your problem is the stud coming out make sure the hole the studs going into is clean and oil free as if you wind the stud in and there's oil in the hole the oil can compress in the hole causing an hydraulic affect forcing the stud out I put some stud lock on the stud