Few words about OE TC sodium cooled exhaust valves.

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Piotrek125p
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Few words about OE TC sodium cooled exhaust valves.

Post by Piotrek125p » Tue Apr 12, 2016 6:08 pm

Hi.

Last week I stripped an 8v Integrale head. Fortunately, the OE exhaust sodium cooled valves were fitted in this head. I thought that it is good time to make a thread here to help members how to recognize Fiat TC sodium cooled valves.

First thing, solid exhaust valves has a waisted stem, sodium hasn't, I think that this photo is a good example, look at a marked place
P1060059.JPG
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Second thing, in my opinion sodium valves has more thick valve heads (margin in my dictionary), see attached photo.
P1060062.JPG
P1060062.JPG (70.61 KiB) Viewed 1415 times
Third thing, some of these valves has A362 mark on top with Fiat logo.
P1060057.JPG
P1060057.JPG (58.74 KiB) Viewed 1415 times
This is in my opinion main differences between solid and sodium Fiat TC exhaust valves. I know that attached by me photos isn't world class, I made it with my mobile phone, if someone need a better photos I will try to make it with a professional camera.

Fill free to discuss here about this type of valves, maybe you, members, spotted more differences or simple want to talk about.

Sincerely.
Piotrek.
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Guy Croft
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Re: Few words about OE TC sodium cooled exhaust valves.

Post by Guy Croft » Tue Apr 12, 2016 6:30 pm

Piotr

you are right, good thread, the non-waisted stem is the sign,

sodium-cooled exhaust valves are a 'must-have' for supercharged and turbocharged applications. They have no equal.

G
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FiatRally
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Re: Few words about OE TC sodium cooled exhaust valves.

Post by FiatRally » Thu Apr 21, 2016 5:40 pm

People always moan to me that I am to technical and mathematical. So here I would like to add a bit of what makes me a Fiat Twin Cam fan.

Years ago Toyota launched the first RSI cars in South Africa. My father being a Petrol / Diesel Mechanic, that was also working in the Engineering field had something to say to their ads! He was a Fiat TC fan his whole life.

The ads pushed: Twin Cam, 16 Valve, Sodium Cooled Exhaust Valves

So when a Toyota Salesman was chatting about this "new" development in automotive engineering, my father asked him: Please tell me what is new to these engines?

The Salesman looked at my father as if he was an idiot and said: Don't you understand the technology that has gone into these "new" designed engines?

My father asked him the same question probably 2 more times, then gave him a mouth full that I will not repeat here.

And calmly in front of all the people present told him that Fiat has done it in the 60s already!

I don't know if Fiat was the first to run Sodium filled exhaust valves but they did use that technology very successfully over the years.

When I think of Twin Cams I always think of that day!
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Piotrek125p
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Re: Few words about OE TC sodium cooled exhaust valves.

Post by Piotrek125p » Thu Apr 28, 2016 2:36 pm

Today I done some inspect op to my sodium cooled valves. A set from OE Delta Turbo (OE springs, OE cams) had a not good looking valve contact damage.
20160428_162318 (1024x576).jpg
20160428_162318 (1024x576).jpg (163.56 KiB) Viewed 1374 times
It is a typical issue with this type of valves according to very narrow sealing surface ? Valve stems and tips are in excellent condition, only valve head are heavy polluted with carbon deposits.
If I will reface it in a valve grinding machine (they had a really thick valve margin) can I use it or it is a scrap ?

Sincerely Piotrek.
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Piotrek125p
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Re: Few words about OE TC sodium cooled exhaust valves.

Post by Piotrek125p » Tue Jun 07, 2016 8:49 am

GC, could you write a few words about valve from photo that I attached, please ?
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Re: Few words about OE TC sodium cooled exhaust valves.

Post by Guy Croft » Tue Jun 07, 2016 12:09 pm

I would have a go at regrinding them, they will probably clean up. That op wil drop the valves deeper into the head, you should measure the tip setup height (VSH) which is 40.5 - 40.7mm from tip to spring platform in standard spec, you can grind the tips down but always leave at least 1mm of stem above the collet groove. If you are using comp cams that extra height can help with shimming. The other way to cope with a tall VSH is to use two cambox gaskets but you'll definitely need adjustable camwheels then..

The old ex valves were probably stellite coated and likely that will get ground off, but underneath is austenitic 21-4n stainless steel which is an excellent valve material in its own right - so don't worry about it.

G
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Piotrek125p
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Re: Few words about OE TC sodium cooled exhaust valves.

Post by Piotrek125p » Tue Jun 07, 2016 12:13 pm

They will go for head with IIB ex cam with a new seats, I will measure all and decide how much tall seat should be.

Thanks for your information, this is very helpful. I was going to do the same, it is really nice that you confirm my decision.
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Re: Few words about OE TC sodium cooled exhaust valves.

Post by Guy Croft » Tue Jun 07, 2016 6:38 pm

glad to help Piotr

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