Now that many people have been running cams in their cars for a year or more, I was wondering if any damage or failures has occured to the stock valvetrain by using upgraded cams. Specifically HKS cams. I have seen reported that using any cam with more lift than stock will damage valve seals. Has anyone had or seen this problem with HKS cams? Has anyone actually torn down a head and looked for this type of damage?

 

Actually this is a very good question...I hope people chime in if they have had problems.

 

My understanding is that this happens due to retainer contact (due to the increased lift) when using OE, or OE designed aftermarket retainers. The only company that I have seen specifically state that their retainers compensate for this is Revolver. I don't know if anyone else has researched the issue. I wonder if other companies have addressed it without advertising that fact. I do know that many of the aftermarket retainers out there are Ti reproductions of the OE retainers... which are the one that are supposed to be causing the problems along with stock ones. Someone could easily be having an issue with this, and it go un-noticed, or mis-diagnosed. I personally will be watching my own, as I will be running OE retainers (at least until a problem is noticed, which might be as soon as I hand crank the engine over).

 

Yes, we did notice that when flowing the head....and that is exactly why we only sell our cams as a kit, our low profile steel retainer offers plenty of clearance (retainer to seal), the stock retainer has a lot of material that captures the spring internally, and decreases the ammount of lift without contact. I will post some pics of the seals from a car running HKS 264/264. Any increased valve lift over OE, the retainer will make contact with the seal. We also offer our spring and retainer kits separately. I'll get those pics up later this afternoon. Take care.

 

Thanks for the feedback. Can you change the springs and retainers with the head on the car? Do the upgraded springs and retainers work with the stock valves?

 

Also, has anyone put Revolver cams in an otherwise stock engine car. Meaning, do these cams idle close to stock on a car with only bolt ons, or are these cams built for more race motors.

 

I'd like pricing on your kits individually please...

92Tsi,

I believe you can do the springs and retainers without pulling the head... there is a spark plug fitting for using compressed air to keep the valve from "dropping", and there is the old fashion "rope method". However, the latter can be a pain in the *** on these "deep head" DOHC engines.

 

If you do the 'compressed air' method, be sure to remove the oil cap. There is a small amount of leakage passed the rings and it can pressurize the crankcase and blow seals.
I've used the 'rope method' more, it is a pita, but I think it's much safer.

 

Yes, absolutely you must give the air that bleeds a place to vent.

These days I'm to old and impatient for the rope method... either way, a good magnet works wonders.

 

i have been runnin the hks 272's for more than a year now with tons of street drag and prolonged road racing use with teh teach near 7800... and so far the motor sounds perfect other than for the lumpy idle.

 

If this interference is real, I can't believe that this hasn't come up in a big way before on this board. If this is really a problem, then a lot of vendors selling cams have been incredibly negligent in advising their customers!!!

I've dealt with retainer clearance issues before on another car and they can be very subtle, but cause problems nonetheless over time. I haven't done cams on my car yet, but when I do I want to do it right the first time.

 

I heard of this after my first Evo Cam install... I didn't notice it then, but will look much closer next week... The theory makes sense though... and your Evo could be "using" a little more oil than it has to.

 

bump for an excellent question.

 

What is the lift on the stock cams? I didn't think the HKS cams had that much more lift than stock, just more duration.

If the retainers don't hit the valve seals I don't think it would "damage" the seals per se. They will wear very slightly more due to the fact the valves range of motion is more.

 

I think the stock cams are considered 250-something...dont know what the lift specs are though.