ACE VenTRa

As I've been putting together the parts for my heads I decided to weigh everything before and after. It's well known that a lighter valve train will allow for better valve control, faster revving, and according to some, more power. Without any porting at all or any cam changes, just by swapping the valve springs to KW and using Ferrea stainless valves with RC51 buckets, there is a savings of over 200 grams on the valve train to be had. Most of the weight is in the springs and buckets and substantially so at that. Even better, the buckets and springs are the cheapest, springs are about 70$ and the buckets I got for free with a set of RC heads for about 100$. FYI, the RC buckets are about 1mm shorter but weigh a lot less and have a coating on the inside. Same OD/ID and shim position and is a drop in swap that could be done with no effort at the next valve adjustment for what I suspect would be a cool cheap mod for top end performance and a little more pep in your step.

AV

E.Marquez

Interesting Did you measure the thickness of the top? or with a common valve and shim, measure installed height between the two buckets?
Which KW spring set are you using?
I use R/D springs and Ti tops in some builds and would be interested to see if there is a weight difference between their offering and the KW parts

ACE VenTRa

I don't recall the part number off hand but as far as I know KW only offers one spring set. I did not measure the thickness at the top but it is patently obvious that the weight is mostly taken from that area. That being said, it seems as though they are of a different alloy altogether from the SH. Overall installed height I have not yet measured but that is next on my to do list.

E.Marquez

Once both buckets are measured for thickness of the top it’s an easy adjustment uninstalled valve height so it’ll be interesting to see if the installer needs to make an adjustment from the standard valve tip installed height

ACE VenTRa

Anecdotally..the rc intake valve is the same overall length as the sh intake. The sh intake is the same height as the sh exhaust with interchangeable locks, springs, and retainers...extrapolate at will. *The rc exhaust valve is much shorter then the sh exhaust valve. It seems as though HRC achieved most of their gains in this manner: the exhaust valve is much shorter and lighter, the exhaust runner is a very straight with much of the backside of the valve visible, and the buckets are much lighter. Aside from that and a larger bore/shorter stroke with higher CR there aren't too many characteristic differences and oddly enough the power is not much better either. The RC and SH have the same torque but the rc beats out the sh in top end power by about 30hp. This makes sense given the choice in mods e.g. lighter valve train better flow/velocity #'s. What I found most interesting was that not only does the sh have the same size exhaust valve diameter which puts it out of ratio by a wide margin, but the sh exhaust has more lift and duration than the intake. I've been considering that perhaps swapping the intake and exhaust is a better option than running 2 exhaust cams, though I suspect it would only become obvious if accompanied by porting and CR increase. *The Ferrea valve faces are dished far less than oem, they alone will increase CR a little.

ACE VenTRa

Just to follow up with you on that, the RC51 Buckets are 7grams lighter each. The installed height of the RC51 Bucket is .00180" less than the SH bucket on the same valve with the same shim. So just shy of 2 grand increase on a valve adjustment would be needed.

AV

E.Marquez

So not enough to need the valve tip changed....002" is easily handled in shims.

Hmmm, interesting, guess 8 each LIFTER, VALVE 14731-MCF-003 need to get put on the list.

Thanks

ACE VenTRa

Indeed,

Though rather than buy new...a pair of used RC heads is, in my experience, cheaper and will come with (8) 40mm intake valves for when you want to do that part of the operation. I'm certain that you want 40mm intake valves. And you'll get locks, retainers and springs that you can have DLC and Cryo and or WPC treated. And you have two heads that can be cleaned up and resold as bare castings that someone out there is looking for.

AV

E.Marquez

That's not a bad idea for the buckest and locks, though personally Id not reuse the valves.
Too many bad experiences with used valves.
I'll look for some used heads and see if it makes sense based on my cost for the 8 buckets and new locks which is all I'll reuse

Thanks

Erik