Light Int/Ex valves
04-29-2017, 02:10 PM
#1
Race Car
Thread Starter
Light Int/Ex valves
Has anyone spec'ed light weight intake valves for the 37mm 16V S/S2 or 39mm 968..?
Looking for hollow stem valves that are already available without me having to spec a custom valve sheet.
Trying to stay away from titanium, rather not replace seats.
18-20% weight reduction - noticeable gain in acceleration, reduced stress on valve springs, more safety margin at high rpms with aggressive camshafts, 3-600 more top end rpms.
TIA,
T
Looking for hollow stem valves that are already available without me having to spec a custom valve sheet.
Trying to stay away from titanium, rather not replace seats.
18-20% weight reduction - noticeable gain in acceleration, reduced stress on valve springs, more safety margin at high rpms with aggressive camshafts, 3-600 more top end rpms.
TIA,
T
05-01-2017, 04:48 PM
#2
Rainman
Rennlist Member
Rennlist Member
terry some ideas...
first have you seen the VW-spec lightweight hydraulic lifters that are available? quality issues of the past have been resolved and they are very inexpensive for something like a 30% reduction in lifter mass IIRC. current PN# is 050109309H and like i said..they are CHEAP ($130/for 16)
http://www.ebay.com/itm/NEW-8Pcs-Gen...38.m2548.l4275
a few folks (928) have gone so far as to lathe-down the stem between where it meets the valve guide and the head, for that "little bit extra airflow" and that would lighten the valve a bit.
alternatively you might try finding another car's valve and machining grooves (also on lathe) in the right spot to match the below spec sheet...
Ford GT valves for example.
http://www.buyracingparts.com/valvet...t--f1450p.html
first have you seen the VW-spec lightweight hydraulic lifters that are available? quality issues of the past have been resolved and they are very inexpensive for something like a 30% reduction in lifter mass IIRC. current PN# is 050109309H and like i said..they are CHEAP ($130/for 16)
http://www.ebay.com/itm/NEW-8Pcs-Gen...38.m2548.l4275
a few folks (928) have gone so far as to lathe-down the stem between where it meets the valve guide and the head, for that "little bit extra airflow" and that would lighten the valve a bit.
alternatively you might try finding another car's valve and machining grooves (also on lathe) in the right spot to match the below spec sheet...
Ford GT valves for example.
http://www.buyracingparts.com/valvet...t--f1450p.html
05-03-2017, 10:01 AM
#3
Race Car
Thread Starter
terry some ideas...
first have you seen the VW-spec lightweight hydraulic lifters that are available? quality issues of the past have been resolved and they are very inexpensive for something like a 30% reduction in lifter mass IIRC. current PN# is 050109309H and like i said..they are CHEAP ($130/for 16)
first have you seen the VW-spec lightweight hydraulic lifters that are available? quality issues of the past have been resolved and they are very inexpensive for something like a 30% reduction in lifter mass IIRC. current PN# is 050109309H and like i said..they are CHEAP ($130/for 16)
I was waiting on a reply from 928MS because they have them in sets of 32 so I was just waiting on verification that they'd break sets in 1/2 for me, lifters, heavy duty chain, etc.
Ferrea hollow stem versions claim up to 20%, a 944S/S2 intake comes in at 65gr, so you are talking 13 grams each x 2 per cylinder, that's nearly an ounce right there.
My goal is to take at least 1 pound out of the valve train.
Don't want to go titanium because of the Beryllium/Copper valve seats, not to mention bang for the buck.
I can get another 10 grams per retainer with the Ti replacements.
Appreciate it....., thought somebody might have already went this route.
Would save me the time of spec'ing the valves myself where I could just call up a part number and order them. Early days though. Looking to turn this engine 7500 at peak hp with aggressive cam so I need to lighten valve train as much as possible.
T
