MTIRC6Z

Or better yet get a less expensive version of the ti exhaust valve (one without the molybdenum coating) so you can use it with the stock valve guides.

Assuming everything is properly installed and all geometry is good there's no reason not to use the stock guide. Of course IF everyhting ain't properly installed with good geometry the bronze guide ain't gunna fix anything anyway...IMHO the ONLY reason to down-grade to a bronze guide is IF you can't get a stock guide.

Cheers, Paul.

Jawnathin

Why is bronze considered a downgrade? I think its an alternative material that can be used which requires an extra coating on a valve, but I haven't seen anything that suggests the bronze guide itself is inferior to the OE guides.

Random84

Simply put, the OEM sintered guides are superior (all other things being equal) due to their hardness, wear characteristics, alloy and heat dissipation. There IS a reason OEM uses them - and its not because of bronze's availability or cost.

The issues are when other things interact negatively (geometry, tolerance, the valve design or coating, etc). Most of the big name builders here will say as much - the common denominator is sourcing (or working through those other variables).

Katech_Zach

Bronze guides have superior wear characteristics. This is why we use them in 24 hour race engines. If iron guides were superior we would use them in the C5-R and C6.R.

RFE-57

Hey Jason,
What would be the best guides if you are targeting to use the Katech Titanium/Moly intake and exhaust valves?
THX
B

Katech_Zach

Bronze. It's your only choice with the moly stems. We (Katech/WCCH) use CHE.

MTIRC6Z

Okay then, I'm gunna have a hard time reconciling your experience with what Brian Tooley had to say on the subject...all be it his opinion seemed most directed towards street so maybe we can't assume what works for a race car will automatically work for a street car???

Powdered metal versus bronze guides
As many of you know I owned Total Engine Airflow from 1993 until 2004 when I sold it to Summit Racing and then worked with the guys at Trick Flow Specialties until 2010 where I developed every CNC program they have, as well as worked on new cylinder head designs. Of the dozens and dozens of used aftermarket heads with bronze guides that came into my shop using stock rockers, the number of heads that had what I would consider excessive guide wear (over .004”) was 100%.

There is no comparison in hardness between powdered metal guides and bronze guides. Powdered metal guides are far harder, and since they’re engineered with silicon they have good lubricity properties. I’ve checked OEM LS guides from a truck with 150,000 miles that only had .0001” of wear. Bronze guides when using stock rockers is a poor choice in my opinion, simply based on the guide wear that I’ve seen in my years of experience. I’ve seen bronze guides with 10,000 miles have .010” wear. Most shops never have the opportunity to check this. I’ve seen heads with no oil consumption or any other obvious issues have .010” of guide wear, this is a testament to how good modern valve seals are.

Katech_Zach

What he says is fine, we just have different experiences.

'06 Quicksilver Z06

Jawnathin

Perhaps this excessive wear related to bronze guides was due to the lack of molybdenum coating on the Ti valves or how SS reacts to bronze guides. And for Ti valves that don't have coating or OEM valves, or SS valves, maybe the stock guides are indeed better.

And perhaps bronze guides with the molybdenum coated Ti valves is the best combination related to wear characteristics.

Very insightful to know that bronze guides with the molybdenum coated Ti valves were used in the C5-R and C6.R. If its good enough for those cars in that environment they're certainly good enough for my car.

cyber gray

Yes very interested, thanks.

MTIRC6Z

Yeah you might have a good point there...the take away from all of this for me is WHEN I find it necessary to do my heads I sure as h*ll ain't gunna do the SS/bronze combination

I like the ti exhaust valve idea and will certainly be staying with the ti intake valve, it's just a matter of what guides to go with. Using the stock guides sure results in spending a lot less on valves but unfortunately isn't what's used in the C5-R/C6.R

Cheers, Paul.

Katech_Zach

The response to these valves has been excellent so we have gone ahead and ordered some for inventory. You can pre-order these now on our website. Delivery of the first set will be sometime in January. Depending on how the pre-orders go, we will place orders for more as necessary for round two and so on.

http://store.katechengines.com/titan...alve-p351.aspx

FNBADAZ06

Jason,

Will this only be available with the molybdenum coated Ti valves, or will there be an option for this valve so that it could be used with OEM powder metal guides ?

Katech_Zach

It's looking like molybdenum only. For us to be comfortable running a CrN coated valve without Mo stem coating we would need to perform durability testing. We don't like to make changes without proofing it out first. Also the hardness of the CrN would have to be >= the OEM intake valve.

FNBADAZ06

Gotcha....thanks for the update.

AzDave47

You could run stock Ti intake valves w/PM guides and these Ti exhaust valves with bronze guides

FNBADAZ06

Yep......I was just checking to see if this other option was going to be made available as well.

ramairws6

I take it these valves would be an issue on a nitrous motor?? Way to step up to the plate for the guys looking for another option on the exhaust valve. Just slightly skeptical since your so adamant the sodium filled valve is not the issue

SSMOKE

I have been wondering if this is an option for two reasons. One my car has low miles with likely good intake valves/guides and two, cost savings. Can someone buy only eight bronze guides for the new Ti exhaust valves?

Jason, your thoughts?