Differences in 993 Valves

[ruddster84]

Rebuilding my engine and I would like to increase the size of the intake valves (and probably exhaust valves) to the 96-98 valve size. I know the heads are +1mm, are the rest of the valve measurements the same? Thinking about going with custom valves since Porsche valves are very expensive and would like to have this info before contacting companies.

Appreciate the help!

[dannobee]

993's have smaller valve stems. 8mm vs 9mm for the earlier cars.

[JoeMag]

Intervalves are readily available versus a custom valve. What size valves r u looking for? I have some Porsche 993 valves... need to check size

[ruddster84]

I've heard intervalves sometimes require some massaging and most notably tend to be not concentric. But I have certainly considered those.

Looking for 50mm intake and 43.5 exhaust

I was able to get ahold of Steve Weiner and he confirmed the valves are the same except for the head diameter

[dannobee]

Try Ferrea, too.

[ruddster84]

That's actually who I am looking for specs for haha...they're the only ones to get back to me. I'm guessing others are very busy with race season stuff. I've tried Victory1 and Xtreme as well.

All recommendations are welcome!

[JoeMag]

ok... porsche valves i have are not that size.

Would be curious what cost you're quoted.

I've used intervalves 51.5 and 43.5 without issue to replace the factory ones. though they are little heavier (about 5-10 grams if I recall correctly).

[r lane]

Building a 3.6 using Intervalves. No good info other than pictures and dimensions. 43.5 on the exhaust and both have 8mm stems. What is most notable to me is the intake head takes up the whole seat. I am not installing larger seats, but was a consideration. The additional size does allow you to introduce more bell to the inside of the seat and was informed that the larger head spreads out the charge mo bedda. Bob