I have disassembled a B18C6 engine with only 2.000Km to raise the compression ratio. It has supertech black nitride intake valves and supertech inconel exhaust valves. It also has TODA spec A2 cams and TODA valve springs.
The exhaust valves are pretty good, but the intake valves not.
They came out with difficulty from the guides, so I have measured with a micrometer the tip of the valves : there is a kind of mushrooming and they are from 0.02mm to 0.05mm (one direction and perpendicular) deformed!!!
A friend of mine has the same issue on an F20C S2000 head with supertech valves, TODA spec B and TODA springs.
Supertech says that this happens when there is valve floating, but I can exclude it because TODA valve springs are VERY hard.
Anyone noticed the same problem on supertech intake valves?

 

Metric, millimeters

 

when u did the exhaughst valve what did it measure at ? how did the keepers and retainers look when you looked at em ?

 

The exhaust valves are in very good condition, they measure about 5,45mm everywere.
Keepers and retainers are in good condition also.

This engine runs the same cams and valve springs on the OEM valves for 10.000Km, and there isn't any problem at all.

 

Did you lash the valves after you changed everything? if so, to what spec? most valve tip damage is caused by improper lash, valve float, or excessive valve guide clearance...

 

Valve lash was at 0.15mm IN and 0.20mm EXH.
Valve float is very hard to reach with TODA A2 and TODA spring. The TODA spring can handle the C2 camshaft profile!!!!
Valve guide clearance is a bit on the loose side on this head, but nothing excessive.

 

Those valve lash specs seem tight to me. Stock lash for the S2000 is .21-.25mm IN and .25-.29mm Exh I checked TODA's website for lash specs but couldnt find any... i dont know what they recommend, but usually aftermarket cams dont lash tighter than the factory...

 

I've had this same issue on a set of supertech valves as well. It was hard to pull the valve out of the head because the tip was snaggling inside the guide.

I went down to supertech and they told me the same thing, that the mushrooming happened because the valve was probably floating. The valve springs in my head were really old so the issue could have just been valve float but I wont know until I fire up my next motor...

 

ive just experienced this over the weekend. one exhaust valve was hard to pull out and u could see the mushrooming around the keeper so i replaced 4 valves that were no good and used supertech keepers to go with the spring retainer combo. if it happens again im using a different company

 

This lash was on the B18.
Anyway, I don't think that this kind of damage can really be lash related, not a tight lash at least.

I see that other similar experiences are coming out, I'm not so happy of it...

 

try these next time www.ferrea.com

 

You would have done that with any valve. I don't use Supertech valves in my heads unless they are supplied by the customer, but I can tell you that they are not weak in that area.

That mushrooming is from out of control valvetrain. What are the specs on that TODA spring? Seat pressure, open pressure, and were they installed at the correct height.

 

I'll measure them and come back

 

See if Toda provides a spec sheet. That will help right now to see if the spring is even in the right ballpark.