NASSEX

I've heard bad stories of supertech stainless valves on the intake side.

I want to get Inconel exhaust valves, but I can't find standard size Inconels. That's my first problem.

And now my second one is finding a good stainless (or inconel even) to go with on the intake valves because of the bad stories I read from only last year.

NA 1.8 bp4w head.
Building a high compression (11:1) turbocharged 8000-8200RPM build {e80 & w/m injection}. I'm ganna start up a build thread on it soon enough. It's mostly a chassis restoration project right now while I gather the funds and parts for the engine.
Lightweight engine internals and good engine management.

All help is appreciated.

Anyone else have bad stories with supertech valves or valve springs (Without machine work related errors)??

matrussell122

iTrader: (1)

Manley valves.

The supertech valves have issues. Not machine work issues. Like the valves just arent good.

NASSEX

Thanks 😊 where can you find Manley valves for a 99 bp4w cylinderhead? I was looking for them last night but couldn't verify if the fitment was right
Preferably stainless intake and inconel exhaust, both back-cut.

If available and a decent enough price then also inconel for the intakes too. But according to Manley, their stainless valves are suited for 1000hp as it is lol so scratch that

NASSEX

Will these fit? It says they're on sale lol
although correct me if I'm wrong, they don't appear to be back cut for better flow.
https://thmotorsports.com/67823-manl...1-8-valvetrain

Details: if you can't open the link
Manley 11101-8 Valvetrain
Products specifications Head Diameter 28mm
Margin .065"
O/A Length 101.52mm
Overall Valve Length (in) 3.996 in.
Overall Valve Length (mm) 101.5mm
Quantity Sold as a set of 8.
Seat Width .080"
Stem Diameter 6mm/.2362”
Swirl Polished YesSwirl-Polished Yes
Tip Length 3.5mm
Top of Head 20°
Dish Undercut Stem No
Underhead Angle/Radius 25° x 11/32"
Valve Head Diameter (in) 1.102 in.
Valve Head Diameter (mm) 28.0mm
Valve Head Style 20 degree dish Valve Material XH-426 stainless steel Valve Seat Width (in) 0.080 in.
Valve Stem Diameter (in) 0.236 in.
Valve Stem Diameter (mm) 6.0mm
Valve Tip Length (in) 0.138 in.
Valve Tip Length (mm) 3.50mm

NASSEX

Is manley the only one?
ive also seen good things said about SI valves. But how expensive are they I don't see prices online and they don't look to have inconel

NASSEX

Is manley the only one?
ive also seen good things said about SI valves. But how expensive are they I don't see prices online and they don't look to have inconel

matrussell122

iTrader: (1)

When I was still doing BP things my #ALLOFIT motor with fully built head had Manley valves ready to go in.

NASSEX

I just don't even understand how supertech can make a product that (according to vast reports) handles things not even as well as OEM valves can.

It makes me much more worried about even going with their valve springs+titanium retainers combo kit.

Anyone know of a good valve spring kit that should be good to handle ~340-400whp at 8200+RPM? Or is it just ST duel heavy.

The Australian

My research into this issue lead me to the conclusion that the SS ST valves require adequate seat pressure, and the failures on the intake side were due to insufficient seat pressure for the given usage (not an inherent problem with the ST valves.

I have just had a head built with +1 SS intake and +1 iconel exhaust valves. The installed seat pressures measured at 90lb.