Well lads,
My engine decided to drop a valve the other day and ruin my built b18 again

Its the second time its happened now and its killing me and my wallet.

I am a mechanic and do all my own work but one thing i dont understand is why this is happening!

Story is this, 12.8:1 82mm b18c, wiseco pistons
The valves and valve springs are KMS items yet the valve stems clearly have the supertech logo etched into them??
Skunk pro1 cams etc etc
Im sure most other parts i have bear no relevance to the valve dropping.

Anyway, its my daily driver/drag car and the rev limit is set to 9300 ignition cut (ectune)

I was doing a hard pull, just pulled 4th gear and heard a noise so shut off straight away.

Towed it home and number 3 plug was very hard to come out so i knew i had done damage.

Pulled the head and found the expected, piston and head in sh*t.
3 of the valve heads had left their stems behind.
Now, of the 3, only 2 of them had stress cracks it the nitrate coating so i believe the 3rd one (exhaust) dropped and broke the other 2 off with some help from the piston!

I want to know why the head of this valve left the stem behind?
Is it RPM?
Heat?
The quality of valves?
The springs?
All the valve springs were still intact and were still holding the stems tight with the keepers!

This is the second time its happened using these valves and im not sure if i should use them again or is the problem elsewhere?

If you need anymore info on the engine etc just ask.

Any help appreciated!

 

KMS = repackaged supertech stuff.. supertech as of late has had a few problems with their valves.. there's a few post about it in the drag racing forum.

 

I've been leery of the supertech valves from the get go because they under cut them. Your situation among others unfortunately brings that fear to fruition. As far as I’ve read under cutting the valves shows no real gains in flow (coming from one side of the argument anyway); which makes me wonder why a company would do it to begin with? Can anyone help me out on that one?

 

Post up some pic's or if you dont want to post them up pm me for my email address,I have never seen or had a Supertech valve fail as far as KMS no idea after reading where there made by Supertech.I have had some issues with the stem on some of the Supertech valves but the was FIXED asap by them.I have 8 bent intake valves here after a cam gear failure but the did not break just the head is bent almost 45 degree's to the stem.

 

cams degreed in? how many miles on the motor?

 

How much valve to valve clearance where you running?

 

So you say stay away from the supertech ones then?

Are the valve springs also supertech coming from KMS then??

 

I have no problem posting pics, i will stick them up here later.

I doubt supertech will do much for me in this situation though, do u?

 

Yes, degreed to correct specs, gears have not shifted either.

No marks on any other pistons to suggest the timing slipped.

Approx 20,000 kilometers on the engine since last build, valves might have a bit more on them!

 

retainers and keepers was in good condition ?

 

stock keepers? Most of the time I see a dropped valve and there was no v2v or p2v contact, I ask about the keepers. So many people are quick to blame the valve, but I highly dought it was the actual valve that caused the problem.

 

I'd email supertech a link to this thread asap. See what they have to say.

 

For everyone that seems to have missed this part.

 

Super tech had previous problems with their springs/retainers but so far, i haven't heard anything as of late with any problems. I like their VT, its very strong.. but their valves seem to still be a work in progress. Normally with a Valvetrain - the company will supply new keepers, at least skunk2 did for me.

 

Something thats just crossed my mind. How were the guides ? Is there any play ? Also if a valve does not seat correctly for what ever reason it puts a load of stress on the lower valve stem (by the head) which eventually causes it to fatigue then fail. So were all guides, spring squareness, valve seats good ? And if guides have been changed then were valves re cut into seats ? Just some ideas....

 

I would suspect this too, did you check your v2v clearance? What were your cam gears set to?

 

This is a good post. You may not have enough spring for what you are trying to do, and that isn't ST's fault. If the valvetrain is out of control then its only a matter of time before you have a failure. Check closely on the good cylinders for contact with the piston. When you take the other cylinders apart, feel to see if the keepers "stick" when you compress the spring. That can be an indication that things weren't happy...they should come right apart with little effort. Inspect the valves that are good and see if the keeper was digging in. Test the springs to see if they lost pressure.

I think you just need to step up to a spring that can maintain control at high rpm, and you will be in good shape. Its not gonna be some $6 spring, but you won't be dropping valves anymore.

 

i will check all this when stripping the other cylinders.
uploading pics in a few mins.

4piston, you think the springs are not able for the rpm?
what would you recommend??

 

I have never heard of them. Send me the specs to my email and I can do my best to help you out.

 

another classic case of supertech valve failure, not the first and wont be the last...

 

same thing happened to me in november with ST. valve broke at the keepers and broke the other valves and busted open the water jacket. I wasn't even going to chance it and i went ahead and got Ferrea. Valves to me are the SKETCHIEST designed item in an engine as far as its installation design is concerned but oh well lol.

 

It doesn't matter if the valve is still in the retainer/keeper it may have been digging into the valve

 

Updates and pictures please ? I have sent Supertech a link to this thread as i'd like to hear there view. Something like this need to be addressed ASAP so other people don't end up in the same boat. Either it be Supertech's fault or be down to something else, we need to get to the bottom of it to help save others.

 

This is why I stick to OE or Skunk2/Ferrea. I too have had a couple friends lose their builds due to ST valve failure. I personally have never run them due to the bad reviews I have seen over and over again. They offer a pretty sweet deal as a package when you buy all the valve train components together...just too bad running all the same brand in this case means a ticking bomb.

 

I personally run ST valves on my engine, they were bought in like 2005 and did 2 engines before mine.
No problem at all and everything was inspected before my last engine by portflow.
Keepers are ST too.

9300rpm, 12.4CR and big cams.