Are Either Turbo or RS Sodium Exhaust Valves OK for 993 C4S?
02-02-2011, 04:16 PM
#1
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Are Either Turbo or RS Sodium Exhaust Valves OK for 993 C4S?
I know the 993 turbo and RS exhaust valves were sodium-filled, but the non-turbo 3.6 valves were not. Being now amidst a top-end rebuild (and needing exhaust valve replacements), I'd prefer the sodium valves, but are the turbo or RS valves retrofittable on the 97 C4S?
I left the lower engine tray installed for all but one of the 14 years I've owned this car, so heat might've become even more of an issue (now leaving it off), and I'm assuming sodium-filled valves would offer significantly extended service in my car. It's been very frustrating trying to find the answers to these questions out among the supply houses. Any help or advice would be greatly appreciated.
I left the lower engine tray installed for all but one of the 14 years I've owned this car, so heat might've become even more of an issue (now leaving it off), and I'm assuming sodium-filled valves would offer significantly extended service in my car. It's been very frustrating trying to find the answers to these questions out among the supply houses. Any help or advice would be greatly appreciated.
Last edited by Waldteufel; 02-03-2011 at 08:37 PM. Reason: updated information
10-12-2011, 09:41 AM
#2
Rennlist Member
I threw my pole and fished this thread 
I have just purchased a set of original 993 turbo exhaust valves, cheap, and they are the same size of the NA 993 engine valves, measured with my chopshop measuring caliper. They say they are sodium filled, I did not fall on this info in the workshop manual or WKD documents, so I do not know
The 993 RS exhaust valves are bigger, not the same size.
the seller re-posted another set for those interested
I have just purchased a set of original 993 turbo exhaust valves, cheap, and they are the same size of the NA 993 engine valves, measured with my chopshop measuring caliper. They say they are sodium filled, I did not fall on this info in the workshop manual or WKD documents, so I do not know
The 993 RS exhaust valves are bigger, not the same size.
the seller re-posted another set for those interested
10-12-2011, 10:06 AM
#3
I threw my pole and fished this thread
I have just purchased a set of original 993 turbo exhaust valves, cheap, and they are the same size of the NA 993 engine valves, measured with my chopshop measuring caliper. They say they are sodium filled, I did not fall on this info in the workshop manual or WKD documents, so I do not know
The 993 RS exhaust valves are bigger, not the same size.
the seller re-posted another set for those interested
I have just purchased a set of original 993 turbo exhaust valves, cheap, and they are the same size of the NA 993 engine valves, measured with my chopshop measuring caliper. They say they are sodium filled, I did not fall on this info in the workshop manual or WKD documents, so I do not know
The 993 RS exhaust valves are bigger, not the same size.
the seller re-posted another set for those interested
non vram 993 intakes are 49mm Na filled, exhausts are 42.5mm hollow
vram intakes are 50mm Na filled, exhausts are 43.5mm hollow
I've never seen the specs on the turbos but it would make sense that they used the RS Na filled versions there too as the RS and n/a vram used the same size exhaust valves
10-12-2011, 10:32 AM
#4
Rennlist Member
hello Bill how are you ?
I think this post is going to be atomic style, because Porsche 993 engine builders at factory were smoking something, and figures are not matching anywhere.
In the Pet, the NA non VRAM engine has the same inlet valves pn as the turbo, so same.
My valves on build 06/97 VRAM are 42.5 exhaust, and the turbo valves are 42.5 exhaust.
did they mix what they had handy ?
I think this post is going to be atomic style, because Porsche 993 engine builders at factory were smoking something, and figures are not matching anywhere.
In the Pet, the NA non VRAM engine has the same inlet valves pn as the turbo, so same.
My valves on build 06/97 VRAM are 42.5 exhaust, and the turbo valves are 42.5 exhaust.
did they mix what they had handy ?
10-12-2011, 10:59 AM
#5
hello Bill how are you ?
I think this post is going to be atomic style, because Porsche 993 engine builders at factory were smoking something, and figures are not matching anywhere.
In the Pet, the NA non VRAM engine has the same inlet valves pn as the turbo, so same.
My valves on build 06/97 VRAM are 42.5 exhaust, and the turbo valves are 42.5 exhaust.
did they mix what they had handy ?
I think this post is going to be atomic style, because Porsche 993 engine builders at factory were smoking something, and figures are not matching anywhere.
In the Pet, the NA non VRAM engine has the same inlet valves pn as the turbo, so same.
My valves on build 06/97 VRAM are 42.5 exhaust, and the turbo valves are 42.5 exhaust.
did they mix what they had handy ?
In the Pet, the NA non VRAM engine has the same inlet valves pn as the turbo, so same.
my stock exhausts on a '97 RoW vram were 43.5mm in PEt there are 4 separate listings for the 993 exhausts
993.105.409.02 for M64/05,06,07,08(non vram n/a)
993.105.419.06 for M64/21,22,23,24(vram n/a)
993.105.419.43 for M64/20(RS)
993.105.419.52 for M64/60(turbo)
so obviously there is some difference between the vram, RS and turbo exhausts, generally Porsche has used smaller valves on the turbo engines so it may be that they used Na filled valves of the same size as used on the vrams. As I said I have very little info on the turbos
