Valves won’t close
 

Hey guys, looking for a bit of help

My 1990 1.6 head was built Supertec valve, double hive springs and titantim retainers from 949, OEM Mazda valve guides, and Felpro valve seals, and assembled using an OEM Mazda head gasket and ARP head studs, and new lifters.

After assembly, the engine ran great on the dyno while being tuned.

At the track the car started to show signs of issues during my second session. I pulled off and ran a compression test (120, 120, 90, 60).

Put the car on the dyno at the track to check AFRs and power. First two runs were perfect, on the third run I fully dropped #4.

Ran another compression test and #4 was at 0.

Took the head off, head gasket was perfect and cylinders/pistons looked great with no sign of blown head gasket.

had the machine shop check the head and everything looked perfect.

Re-assembled everything, same issue, #4 at 0 compression.

With the intake and exhaust manifolds NOT installed, I ensured the valves were opening and closing.

Performed a leak-down and air was pouring out of the intake manifold side of the head. (Intake and exhaust manifolds still removed)

Performed another leak down test with the cams removed, and head held air.

Performed another leak down test with the cams from a spare head, and air was pouring out of the intake manifold side of the head.

i also tried the original lifters with the same result

Needless to say I’m petty frustrated and any help would be appreciated

Sorry to say this but you are another victim of shitty Supertech Valves.

Your intake valves now look like this
https://cimg4.ibsrv.net/gimg/www.mia...4ab1ac1cf0.jpg

Inconel for the win.

And find a new shop. No excuse for rebuilding and not leak testing.

Yes, like the cats above said, the ST intake valves can be junk. They’re known to stretch/elongate and either drop seat pressure or in your case, reach negative lash and stick open.

+1 for dropping that shop over not checking for leaks

I just had 4 Supertech valves go bad on my motor. Built 20,000 miles, ago, wouldn't seal anymore.

If u ever had to do it again I'd tell my shop to use custom ferrea valves, - _-

Plus 1 for Ferrea valves!

Does anyone have the spec sheet to order custom valves? Could probably order a new ST valve and just send it to them I would assume.

https://www.ferrea.com/custom_valves.php

Unsure if there are quantity breaks, but you could investigate a group order for disgruntled ST users.

I found that but dont know the numbers to put into the blanks.

Headgames Motorworks deals with getting Ferrea custom valves all the time. They quoted me at about $40 each which is more than the ST. But they aren't having problems and have used them for years. They are being run on 20 heads that are competing in the TX2K this year.

It seems pretty flexible, but maybe going through a shop with established relationship with Ferrea wouldn't hurt for group buys.


They already had two sets of my valves in hand.

Yeah, I'm similarly lost aside from stem diameter, head diameter and overall length. TNTTUBA may be able to help

Wow, I’m fucking furious. Has anyone had any luck getting them warrantied/refund/etc?

I don't believe so. I think TNTUBA was able to get further with ST than most and I believe he received a replacement set that supposedly had some fancy stellite treatment on the stems, but they did the same thing. Its documented well enough that you could approach them about it, but you'll likely get told to go pound sand.

I no longer use Supertech Products nor will I ever again nor will I ever recommend them.

I was able to get a set of Supertech Valves to last buy running over 100psi of seat pressure (I run crazy cams....but I still think it takes more than their heavy doubles make out of the box to get them to last.) but was frustrated by the QC issues, the lack of transparency from the leadership and even when confronted face to face at PRI being told the issue was related to ANYTHING but Supertech only to find out later they actually HAD changed their manufacturing process.

If you want something off the self that will alst and not break the bank. I have had good luck with the Manley SS Intake valves. I am running a set of one off exhaust valves.

Recently Emilio edited his Engine Building Ideas thread so it no longer has the huge amount of information on it but up until then ST was recommended on that thread with lots of appreciation from people.
In that original writing it stated that depending on combustion temperature you should plump for a material not a manufacturer. (<1650 OEM, >1650 but <1750 Stainless, >1750 but <1900 Inconel).
It also stated about valve springs needed being from ST which through inference would point to ST valves too.

So if ST valve have such QC issues already known, so many people here run them, is there another brand used by others for off the shelf?
Custom is great and all but surely someone cares about our little cars?

It seems as though TNTUBA has had good luck with Manley.

Yes I did see that but TNTUBA is running a NASCAR boxed supercharged 2G pulling mental exhaustion car so I figured there might be another alternative too :giggle:
I've also had a look through the master catalogue and not found the BP engine mentioned although once again custom measurements can be taken.

I just typed in "Manley valves miata" in Google and this came up

http://www.manleyperformance.com/sc/...p_valves.shtml


https://5xracing.com/i-23993341-manl...-8l-miata.html

:confused:

Forum formatting quirk. I added some info about billet cranks and the site clipped the post in half. New character limit. Had to contact moderator to manually embed the edited text.
Took a while to fix. Correct now.

If it ever kills the OP again, the info is on our site: https://supermiata.com/tech-info-links.aspx

We pulled Supertech's valves off our site a few months ago. Twibs just had the same thing happen with their new stelllite valves. I have a set of Manley SS intake valves in a customer's head as well, I'll know more in a year or so when it has enough hours to know whether or not they are better.

Having said that, I doubt strongly that their valves are your only issue. It is possible to do this to any valve (even OEM) if your incompetent machine shop tried to get cutesy with the seat widths (see below re: your machine shop...), or if you are running too much RPM and not enough spring pressure for your specific setup. I trashed a set of OEM intake valves last fall in Rover running 7300rpm with HLA lifters and Supertech single springs. With everything else factored in, it always took several events and at least 10+hrs of runtime for this valve problem to show itself when I've seen it in the past. If you had it crop up after dyno time and 2 sessions on track, there was more going on than just bad valves.

Fire your machine shop, BTW. You sent them a head with tuliped valves and they didn't catch it. That is CC chargeback levels of incompetence IMO.

+1. The couple of times this happened to me, it was the machining.

My local shop has been doing a lot of K20-24 stuff lately. he said they are up to 200-250lb valve springs to keep those things together. food for thought cause in a miata, 90 lbs sounds big. not so much.

I don’t think spring pressure is the issue (running the Supertech double hive springs from 949) and my RPM is set to 7k.

Taking my head to a different shop tomorrow, will keep you posted

Your confused i went to their site and literally scrolled through their catalogue and it has no mention. Its all about the Chevy basically.

Thank you though.

I think you are confused, or just missed it. It's in the sport compact catalog on the main page. His link takes you right to it.

I couldn't find Chevy; maybe I'm missing something:

http://manleyperformance.com/sc/Manley_SportCompact.pdf

:confused::confused::confused::confused::confused: :confused::confused::confused::confused::confused: :confused::confused::confused::confused::confused: :confused::confused::confused::confused::confused: :confused::confused:




Just kidding around. The main page isn't really that intuitive because the links up top look the same, but point differently depending on whether you're using the sport compact part of the site.

Lots of talk about intake valves. Are there recommendations for exhaust as well?

inconel you cheap turds. Or have those failed?

I got a full set of Manley SS +1 intake and exhaust. Good price at Sport Compact Warehouse. Haven't really run it yet though I'll get back to you in a year!

I have never had an issue with any exhaust valves.

interesting.

Likely a combination of a few factors there. Exhaust seat widths are cut wider, the cam profile is not nearly as aggressive in the Miata, and (in turbo applications) you don't have the net-negative force of the air actively pushing the valve/lifter away from the camshaft. Thus, even with the same valve, they fail on the intake side and not the exhaust side.

ill be interested to monitor my engines health. OEM intake valves, OE seat width, double heavies, boost.

so to update anyone who's following this. I sent my valves, springs, retainers, keepers etc off to Supertech. Below are their findings.

https://cimg5.ibsrv.net/gimg/www.mia...ebefbe5fd6.png
https://cimg6.ibsrv.net/gimg/www.mia...dbcfd99990.png

If they wouldn't make the fucking things too long in the first place, there would be no need to cut them down, which would negate any potential interference issues.

So basically the keeper groove is too far up the stem of the valve?

--Ian

Standard Supertech answer. "The issue is clearly the fault of everyone but us even though all our parts break all the time."

I wouldn't put their parts on my lawnmower.

FYI I just did a comp. test and all were 200 across the board. The leak down was 1 1/2 to 2% . This is the 3rd season on this engine with the supertech inconel intake +1mm valves from Flyin Miata. I am now a believer as I used to cup the seat faces and loose lash in less then a season with the SS intakes no matter what brand. They ain't cheap, but neither is rebuilding a head a couple time a year, not to mention the time and machining.