what size shims??

You need to check your clearances first, from there you can calculate what shim you need. See the 'how to section', as Bobby put up a very helpful post about this...
 

chopper

New Member
Yeah i had read that before posting but didnt know if there was a stanard size when the car came out new.
i dont fancy the feeler gauge trick rather get the propper stuff.
So basicaly if i dont want to do it myself i have to got take it somewhere, let them take it apart and fit the new cams and then wait for them to get shms in. could be weeks off the road..... bugger
 
P

pulsarboby

Guest
il fit and shim them for you matt as ive a shim bank of stock shims which ive hoarded up over 6 years.
always best to use the correct size shims but the other way works perfectly fine if your stuck

as said you wont know what sizes youll need untill they have had cams fitted and clearances checked!
 

PobodY

Moderators
Staff member
Yes, that's right. Plus the genuine Nissan shims are not cheap.

When it comes down to it, all a shim is is a piece of material (usually metal) to adjust the clearance between parts; that means that even a folded beermat under a table leg is a shim. - There's nothing particularly technical or special about them, so the feeler gauges are as good as anything for the job.
 

Thor

Member
Why not swap against 200SX valves and shims? I had swap mine to the inconel valves that fit in the 200SX head. The shims from the 200SX are without a hole are very easy to make with CNC and cheaper than OEM RNN14 shims ;-)
 

PobodY

Moderators
Staff member
I thought the original RNN14 valves were better because they are sodium filled (on the exhaust side only?) thus improving the engine's ability to run at high temperatures.

Does the inconel give you better resistance to DET or something; what's the advantage other than being able to use different shims?
 

Fast Guy

Moderators
Staff member
I thought all turbo exhaust valves were sodium filled to help with cooling ? I know they were on my old montego from 1988 and even on the old Shackletons I used to work on from about 1948.
I think inconel has a very good resistance to heat (if that's the right phrase) it tends to be used in exhaust systems from what I remember.
 

mikeyp

New Member
the standard s14 valves are also sodium filled. inconel is just a lighter SS material that can take high heat, used to make exhaust manifolds and tubing on race cars that can't afford titanium.

just had a look at the s14 manual and the shim and rocker guide looks very similar to the gtir version. infact the only part that looks much different is the lash adjuster on the s14 is hydraulic and solid on the 54c with spings???
 

Thor

Member
The Inconel valve are lighter and much better for higher temps. I have fit they for inlet and exhaust. So the S14 valves are directly fit on the RNN14. The shims for the S14 you can order all size still from nissan and if not you can cheaper made them with CNC. I have made few heads with these setup and they works fantastic ;-) For the change you must have S14 inconel valves, and retainer for the S14. Springs you can use all for SR20DET. If i get time i will send a pic tonight from my head where you can see it....

I mean these are the same valves:

http://www.ipg-supertech.com/cart.php?target=product&product_id=555&category_id=280

http://www.ipg-supertech.com/cart.php?target=product&product_id=563&category_id=284

http://www.ipg-supertech.com/cart.php?target=product&product_id=1014&category_id=756
 
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PobodY

Moderators
Staff member
inconel is just a lighter SS material that can take high heat, used to make exhaust manifolds and tubing on race cars that can't afford titanium.
Sorry to be pedantic, but it's not a stainless steel; it's a Ni/Cr alloy specifically for high temperature applications. I'd argue it's better than titanium, but it's a nightmare to work (I think it has to be TIG or laser welded). - Aren't the F1 cars using inconel exhausts?

That doesn't take away from the use of inconel valves designed for a Silvia though. - Looks like a nifty swap, but only if you're rebuilding the head anyway. My only concern would be trading the heat-pump qualities of a sodium filled valve for the inconel one.
 

Thor

Member
Looks like a nifty swap, but only if you're rebuilding the head anyway.
I´ll give you right! But i am sure that these valve´s much better than the OEM sodium filld valves! Here in germany the best engine builder only fit these valves!
 
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