Re: Ti valve modifications...
Posted: Tue Oct 10, 2017 1:53 pm
They don't have to be coated.I have run them for several seasons uncoated.
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Ti valve modifications...
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Re: Ti valve modifications...
Posted: Tue Oct 10, 2017 2:27 pm
The stem have to be coated several processes, used so as to not wear out the guide
Re: Ti valve modifications...
Posted: Tue Oct 10, 2017 2:33 pm
Negative.The stems do not have to be coated.Out of several hundred sets of cup valves I have used none had the stems coated and only one set had the heads coated.The stems ride on a film of oil just like bearings do.Only stems I have seen coated were Manley.Never Del West or Exeldyne.
Re: Ti valve modifications...
Posted: Tue Oct 10, 2017 6:11 pm
I think the stems are always coated, ti is too sticky not to be. I can't remember the last time I saw a head that wasn't coated that came out of a cup engine. That said, I have cut down a lot of ti valves and never had one recoated. I have also put keeper grooves in the moly with no ill effects, though I suspect it is a no no.
Paul
Paul
Re: Ti valve modifications...
Posted: Tue Oct 10, 2017 6:36 pm
As far as I know all have some form of coating on the stems ,I have been using Ti valve for at least the last 40 some years and the stems have had some form of coating -moly -ti nitride- dlc-etc.MIKE
Re: Ti valve modifications...
Posted: Tue Oct 10, 2017 8:19 pm
If the guides were steel or aluminium, it would be a problem. But being brass AND lubricated, i don't think coating is really necessitated
Re: Ti valve modifications...
Posted: Tue Oct 10, 2017 9:57 pm
I've never seen a steel or aluminum valve guide. What engines come with those?If the guides were steel or aluminium,
Re: Ti valve modifications...
Posted: Tue Oct 10, 2017 10:54 pm
Re: Ti valve modifications...
Posted: Wed Oct 11, 2017 12:04 am
Re: Ti valve modifications...
Posted: Wed Oct 11, 2017 12:25 am
Lots of folks speak of 'cement' floors, even though concrete is only ~ 1/6th to 1/7th cement solids.
FWIW, steel contains more iron than cast iron does.
FWIW, steel contains more iron than cast iron does.
Re: Ti valve modifications...
Posted: Wed Oct 11, 2017 12:32 am
Every Del West or Exeldyne is coated with Chromium nitrite, on the stem and head, or chromium nitrite on the stem and titanium aluminum nitride on the head.perfconn wrote: ↑Tue Oct 10, 2017 2:33 pm Negative.The stems do not have to be coated.Out of several hundred sets of cup valves I have used none had the stems coated and only one set had the heads coated.The stems ride on a film of oil just like bearings do.Only stems I have seen coated were Manley.Never Del West or Exeldyne.
The Chromium nitrite looks just like shiny silver.
Molly coated stems and raw valve heads is old school.
Re: Ti valve modifications...
Posted: Wed Oct 11, 2017 5:37 am
All titanium valves have coated stems. As was mentioned, they are typically either molly, crn or dlc ect.
Without this stem coating, excessive guide wear and failure are eminent.
Without this stem coating, excessive guide wear and failure are eminent.
Re: Ti valve modifications...
Posted: Sat Oct 14, 2017 9:59 pm
Steel is iron with certain amounts of carbon added. Steel alloys have several other elements added for specific needs. For instance if the steel alloy contains at least 10 percent chromium, then it is described as stainless steel. Most stainless steel alloys however have somewhat more chromium, like 16 to 18 percent . . . . . Then there are are at least three major categories of stainless steel.
OP, remember - the Ti valves will need to have some sort of stem cap installed on the stem in order to insure their longivity.
Re: Ti valve modifications...
Posted: Sat Oct 14, 2017 10:06 pm
What Bill said! Both of them!engineguyBill wrote: ↑Sat Oct 14, 2017 9:59 pmSteel is iron with certain amounts of carbon added. Steel alloys have several other elements added for specific needs. For instance if the steel alloy contains at least 10 percent chromium, then it is described as stainless steel. Most stainless steel alloys however have somewhat more chromium, like 16 to 18 percent . . . . . Then there are are at least three major categories of stainless steel.
OP, remember - the Ti valves will need to have some sort of stem cap installed on the stem in order to insure their longivity.
Re: Ti valve modifications...
Posted: Sun Oct 15, 2017 1:23 am
For the OP, I've have dozens shortened by Jarvis Performance, wound up being about $10/valve. Mostly for BBM, so were 4.950, plus a lash cap. Seem to work OK so far.
https://www.facebook.com/jarvisperformance/
With the 7mm and larger stems, you may find hollow stem valves, which obviously can't be shortened. Kinda the risk of the game. I now have a 7 valve set of too long valves due to this discovery, lol. I think the exhausts are going to be solid, but I suppose they might be sodium filled or some awfulness. S/F....Ken M
https://www.facebook.com/jarvisperformance/
With the 7mm and larger stems, you may find hollow stem valves, which obviously can't be shortened. Kinda the risk of the game. I now have a 7 valve set of too long valves due to this discovery, lol. I think the exhausts are going to be solid, but I suppose they might be sodium filled or some awfulness. S/F....Ken M