Del West titanium valves
The lighter Valves will allow for better engine acceleration, like a lighter flywheel.
The lighter Valve will require less spring pressure, good for HP increase.
Lance
You can run bare Ti valves, but you should use a "softer" seat material such as beryllium copper or another material.
Do some research on the factory LS7 valve and seat issues and corrections. Polished stems, bronze guides, etc.
From a performance perspective, it's all about valvetrain control. Does your intended RPM range dictate a lighter valve? If you have a 6800 RPM limiter, a solid, hollow or Ti valve should meet the goal.
I doubt you would see a significant performance increase just by changing the valves alone, unless something was REALLY out of whack.
Cole
MANY times I have used a 30* seat angle with a TI Valve (a BBC valve as common) in the Ford 351-C at a cost of $12.00 (NEW)
I have fit a 30* seat in the LS-7 head (Off Road) to allow for LONGER seat life.
YOUR valves will require a new "face" AND the 30* will ADD margin over a 45* face.
I OFTEN DCL a Ti Valve.
The COLE report as to performance increase IS LIMITED, as stated, he has not done an acceleration test !
The engine will accelerate fasted, good for lower gear acceleration increase.
I do agree that Lifter Bleed Down will be less, if any, with a light valve.
DO NOT Polish the Valve Stem, if done, the protective coating could be removed.
Lance
MANY times I have used a 30* seat angle with a TI Valve (a BBC valve as common) in the Ford 351-C at a cost of $12.00 (NEW)
I have fit a 30* seat in the LS-7 head (Off Road) to allow for LONGER seat life.
You can't "add" margin to a valve once it's machined. It can be added during the design phase, but not after it's been cut. If it started life as a 45° or higher seat, then changing to a 30° would merely maintain the SAME margin and cut the backside of the valve more.
Yes, DLC "Diamond Like Carbon" is a good choice for Ti valve coating, as long as it is mated to the proper seat material. One of the more common coatings these days is CrN "Chromium Nitride".
Bottom line, the OP needs to decide if he REALLY needs a Ti valve because a factory valve is insufficient for HIS application or he just wants to put them in there for who knows what reason.
I have LSX-LS7 heads with factory LS7 Ti intake valves that were used when I got them. They are not coated from the factory. They were sent to Del West for polishing after I phoned them to see what THEY recommend I do with them. Another comment was that you most likely won't find a company to coat a USED valve. Too high a risk of contaminating their PVD spray booth with "unknown" particles.
with his report that a 60* EXHAUST was best for flow with an Inconel Valve ONLY fitted for best valve life due to the fact that an increase in seat angle will cause major wear with lower grade valve material.
I have found a 30* intake seat angle can increase low lift flow as found on GM BBC Ti Valves 3/8" stem I have bought in the past. I have fitted this valve into other engines with the same findings. When employed by HMS (Ford Race Facility) we used a 30* seat angle in the Ford's race engines, the FE.
The "tulip" shape of an intake valve/valve seat is what can add to flow at low lifts.
TRUE, the Del West Valves are coated to protect stem/seat areas AND they are machined, as I stated, when manufactured.
My statement was to "machine" if necessary AND as you state the change to a 30* angle would allow for NO reduction in margin, as I stated. (YOU TWISTED what I stated)
AGAIN, a "twist" about my valve machining tech : NEVER use a stone (grind) to face a Ti Valve as the stone material is EMBEDDED into the Valve Face.
True, as I have coated NEW TI Valves ONLY with DLC.
My guess is to ask Jake about a method to "recon" a Ti Valve with best available coating ?
Lance





