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steve82T

1982 Turbo restoration

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After originally receiving final stock of 3 valves that I could get my hands on,

and waiting many months for replacement genuine matching sodium valves

to complete rebuild - new valves arrived..... weighing in at 71 grams,

old valves were 55 grams. It would appear new Lotus replacement stock

is nolonger sodium filled and is also differentiated by black heat

treated coating.

Does anyone know what happed here? What happened to all the virtues of

sodium, or could it be new stock is just less hollow, hence extra

weight? So now I need to swap original three to complete the set.....

Steve

82T

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Upgrade today to remove Google ads and support TLF.

seems a big weight difference, but assuming Lotus have not changed the rates/specification of the valve springs, I cannot see why mixing the new and old would cause any particular problems. However, this is an issue I would probably check with Lotus.

Are the new spec valves now at an affordable cost???

cheers Steve

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Same cost.

My Australian Lotus parts supplier is apparently checking with Lotus, because if they are simply heat treated stainless steel now - you would have expected them to be a about half the old price.

This move away from sodium also opens up the market to many aftermarket suppliers, as it is relatively easy to obtain solid valves if sodium is not required - and I could have bought a set many months ago!

My head rebuilding shop advises that there are very few sodium filled valves used these days with most new models and the more exotic cars now having moved away from them, however you would assume this would be only after modifying water passages to aid head cooling etc.

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This arguement has been posted a couple of times -- stainless vs sodium. At the moment... nobody is using sodium valves anymore in the industry. Sodium valves (from what I've been told) were used because the metalurgical technology just wasn't up to snuff in those days. The Porsche 911 used the sodium valves before too, but they don't anymore. The heat dissapation of the stainless valves that I had made by SI valves is supposed to be just as good. The set is currently sitting at www.atomicspeedware.com and available for a good price. I will be using these valves in my engine build, and have used SI valves before without trouble in other engines.

BTW... the price is $296 for all 8 valves.

Edited by Mark T-C

Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

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this is what David Vizard said about the function of sodium valves..

'Although intake valve acceleration is important to output, the same cannot be said for the exhaust. This means weight is not so important. But there is still one more issue here. A sodium cooled valve will have less tendancy to bounce than you might think. Because th sodium sloshes up and down it acts like a damper so even though the valve may be about 10 -15 grams heavier it does not act that way in practice. Couple this to a less aggressive valve action and you can see that the sodium valve will not be a limiting factor in terms of output but it will be more reliable.'


If you set no goals you shall surely reach them..

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Well.. I was about to say that sodium filled valves aren't available anymore.. when I discovered this: http://www.ferrea.com/productlines.php#sodium

So... I shall give them a call now and see what they can do for us.


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

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Basically all too late for me now, but will read with interest what Lotus and other have to say out this.

After some 6 mths after initial head gasket failure I want to get it back on the road and have decided to fit new heat treated replacements supplied (Sodium or not). I do not plan to hammer, or race the car, but just seeking reliable Sunday drive/tourer.

To date simple head gasket leak has revealed a long list of earlier sins, following evidence of previous head gasket failure with rebuild escalating to :-

*straightening slight warp out of head via heat treatment (previously repaired by PO with use of silicon seal on top of gasket -this survived for three years on the road!!!)

*new valves/seats

*new type of headgasket/stretch bolts

*HC pistons & new iron liners (significant internal corrosion in original liner bores found once rehoned - as a result from original head gasket failure)

*new crankshaft (crack found during crack testing) & all new bearings

*replacement set of con rods (found to have one mismatched (different casting lettering & machined to reduce weight, however was some 20gms lighter than other three).

*rebuilt waterpump / new oil pump internals

*straightened inlet manifold.

and more....

It is surprising how well this motor used to run, and I thought that this was one of the strengths of the car!

I have welcomed reports that Esprit values are rising.....

post-314-1205726496.jpg

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Hi Steve

Quick question where did you get your liners from? Do they look good? Have you fitted them yet?

Cheers

Buddsy


 

"Belief is the enemy of knowing" - Crrow777

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Liners supplied from SJ Sports. I have only done a dry fit - with block cleaned they slipped in without any dramas with a snug fit, and nip heights and variations have come in well within specs. Was impressed with the close match with very little variation between them.

Currently awaiting arrival of liner sealant from UK, as not available in Australia (several close matches available however after all this effort I don't want to do this again because sealant failed!)

Steve.

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Those liners look better than stock!... mine don't look nearly that nice.


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

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