News back from ST

Valves were in fact the newer stellite faced valves.

They are going to make a new run with a different alloy that is hardened by heat. Supposedly wont these valves wont withstand the temperatures of a stainless valve and aren't recommended to be used as an exhaust valve but should hold up fine as an intake valve.

 

Had a brief conversation with ST - they'll sell inconel exhaust valves in stock size for $38 ea. They do this by machining down the OS valve, which are more popular.

 

That's nice to know, thanks

 

Teetered back and forth for a while and settled on running Ferrea competition plus Honda valves, Custom guides, modified spring seats, and beehive springs with much more spring rate. More updates soon!

 

Twibs you’re all over this problem. Kudos!

 

I pulled 8 trashed ST intake valves out of a customer head a few weeks ago. 7500rpm max, shim-under-bucket solid lifters, Supertech heavy doubles, stock cams. I'm done with their valves for good.

 

I’m pretty sure the pot metal they use is to soft no matter what surface treatment they put on the valves. This is why the inconel valves worked because the entire structure was of better material.

The easy option for most people might be ferrea nissan valves or oem nissan and then sort out a keeper for miata retainers.

 

In post#38, is the difference between the good and trashed valve have to do with how "beat up" the intake valve looks or how flat the valve is? The intake looks relatively flat from the edge of the valve to the center compared to the normal exhaust valve?

I am going to be pulling my head soon (vvt head) to adjust the lashing back to spec, upgrade to supertech springs, and oem valve seals. I'd like to also replace any valves that are no longer usable but I don't have a basis on how a good one should look.

Also, are they seriously $27-$38 per oem valve, depending on if it's an exhaust or intake valve? That's a bit steep but hopefully if I do need to replace any, it's only 1 or 2.

 

We recently bought an intake valve for a bp6d from Mazda of Wooster for $21.54

 

8 years on ST valves, std size stainless intake and exhaust. Am I that lucky?

 

Do you have another source you're looking at?

Honestly all these crazy parts failures/QC issues showing up in BPs the last couple years has me wary of moving forward with doing anything with my motor. I've had 80% of the parts to build a motor for a long time, but i just don't want to deal with the bullshit.

 

I haven't had any issues with inconel. Yet.

 

me neither

 

Like many others, we have experienced no premature valve or valve seat wear with Supertech valves. After talking with Martin at ST, he indicates they did have some isolated valve wear issues with the BP and one other platform. But they were just that, isolated and not across all platforms.
They reviewed the manufacturing process and made a change about two years ago. We will continue to offer Supertech valves on the Supermiata.com website unless we directly experience or have physical examples dropped in our laps that indicate we shouldn't.
My only guess is that ST had some fluctuations in process that produced a bad batch that some racers then used with poor results. We apparently didn't order or install any valves from that batch.

We have probably built and raced more engines for more hours with ST valves that any other shop on the planet. Thousands of hours on track. ¯\_O_/¯

 

For what it's worth, I was told to steer clear of ST valves/springs for my K series for exact same consistency issues.

 

They are generally not well-regarded in Toyota land either, but they're lucky and even relatively obscure motors like a 3sgte have Ferrea valves available.

 

Yes, I'm trying a valve from someone else. Not Ferrea. Reasonably priced.

 

Please don't let me asphyxiate. <3

 

This is the most maddening part of it all. Guys like B Buddy and you have great runs and then other like myself > 10 hrs on a fresh head loose lash only to find the valve has tuliped. I think there’s more to the story. Last time around we made a slight different to the cut of the valves. I can’t recall the specs but we discusssed a slight performance degradation for hopefully better life. It’s worth comparing detailed notes on # of angles and width of seat cuts to see of we can find another common denominator.