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Home > Technical Chat > Sodium-filled exhaust valves - worth it?

NDT

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4th Sep, 2020 at 04:41:23pm

I have a Metro Turbo head and a couple of MG heads.
I'm led to believe that the MG heads with the bigger valves have better ports to start with, meaning less work required on porting them.
I will probably turbo the engine... Are the original sodium-filled valves worth keeping?
Because if so, I either need t use the turbo head (which will need more modding) or fit the bigger turbo valve guides to the MG head.

steve1275

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Bromsgrove

5th Sep, 2020 at 08:48:00am

For me, get rid of the sodium cooled valves: larger guides so more port interference, they're friction welded,always a concern. I have run stainless valves for over 10 years at around 200 bhp without problem.

'Where does the engine go?'

Mr Joshua

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Luton Bedfordshire

5th Sep, 2020 at 11:11:45am

The Valves in the MG head will have a part number etched into them Tam 1062 comes to mind can't recall the other number, you can check the size from that. Keep the inlets and fit stainless exhaust valves. You don't want to be fitting anything bigger as you run the risk of cracking the head between the valve seats.

Own the day


stevieturbo

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Northern Ireland

5th Sep, 2020 at 09:40:08pm

For turbo, I'd want either sodium filled or inconel.

I would not use regular stainless valves. Even more so when they're in cast iron heads.

I abused the shit out of mine way back 25 years ago, and never once did the sodium filled valves present a problem.
That said.....are new ones even available now to be an option, or would they all be old ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Turbo Phil

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Lake District

5th Sep, 2020 at 09:54:41pm

All aftermarket modified A-series turbo heads run the stainless one piece race valves, they do need to be run in bronze guides though.
The original sodium filled exhaust valves weren’t available for a long time, but recently Minispares have had stock.
For a standard or low boost engine the sodium valves will be fine. For high output I’d look at the stainless ones.

Phil.

WWW.TURBO-MINI.COM


stevieturbo

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Northern Ireland

6th Sep, 2020 at 09:15:49pm




On 5th Sep, 2020 Turbo Phil said:
All aftermarket modified A-series turbo heads run the stainless one piece race valves, they do need to be run in bronze guides though.
The original sodium filled exhaust valves weren’t available for a long time, but recently Minispares have had stock.
For a standard or low boost engine the sodium valves will be fine. For high output I’d look at the stainless ones.

Phil.


How many aftermarket heads are there ? Most modify OEM heads.

I retained standard exhaust valves, although for a short time did run the larger 32mm I think it was that one person offered at the time....however, that in itself turned into a nightmare story on the 2nd head I ran due to the need to offset the valve..

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will


Turbo Phil

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My sister is so fit I won't show anyone her picture

Lake District

6th Sep, 2020 at 09:29:35pm

When I said aftermarket I meant all modded 5 port heads, rather than alloy castings etc


Phil.

WWW.TURBO-MINI.COM


tadge44

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Buckinghamshire

7th Sep, 2020 at 08:09:01am

20000 miles on a Turbophil head and up to 17psi and never had a problem (and it was used on track, hillclimbs,drag strip etc.

stevieturbo

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8th Sep, 2020 at 05:49:14pm




On 7th Sep, 2020 tadge44 said:
20000 miles on a Turbophil head and up to 17psi and never had a problem (and it was used on track, hillclimbs,drag strip etc.


Back when I ran mine, I probably did around 60k on sodium filled, as much as 25psi at times with a terrible setup ( no widebands etc in those days, and a daily driver )

I broke lots of things....valves weren't one of them lol.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

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