|
Matronics Email Lists Web Forum Interface to the Matronics Email Lists
|
View previous topic :: View next topic |
Author |
Message |
mark.bitterlich(at)navy.m Guest
|
Posted: Wed Nov 07, 2018 11:33 am Post subject: Sticking Valves |
|
|
Dennis Savarese recently sent me a message correcting what I said regarding "sticking valves" and pointed out that varnish being deposited on the valve stem can (and will) cause valves to stick, and that adding MMO to the oil can and will cure this. He also mentioned that sticking valves are usually not caused by carbon buildup. What he really did was point out that the Devil is in the Details per se. So here is the longer more detailed reply.
So, ..... I misspoke. I talked about sticking valves being caused by carbon buildup. Well...,. yes, but I should have said "lead" instead of "carbon" and I should have talked to Dennis first. The real question is, just what does a "sticky valve" actually refer to?
Two things actually..... in my mind anyway. First is what Dennis referred to where varnish builds up on the valve stem, the valve then no longer slides through the valve guide easily and thus can "stick" without fully closing. MMO in the *OIL* (as he said) will reduce/cure or eliminate this to a large degree.
The second situation is where the valve does not fully close for another reason, and this is what I was addressing in what I wrote earlier. Typically this happens to an exhaust valve, and the reason it does not fully close is due to a buildup on the exhaust seat which sort of "wedges" the valve open a little bit. This can be a really bad thing, because hot exhaust gases formed during combustion tend to squirt out of this slightly open valve and can erode the valve seat. Depending on the severity of this erosion it can either be fixed by removing the cylinder and lapping the valve, or in the worst case, replacing the whole cylinder. This kind of thing is commonly found during a compression check where air is heard leaking out of the cylinder into the exhaust and sometimes can be cured by "staking" the valve in the hopes of being able to break loose the offending particle and allowing the valve to close and seal again. What do you call a valve that does this? I have always referred to it as a "sticking valve". Well in truth, it is not "sticking" it is a valve that is not seating properly, so my bad. In most cases, what causes this is lead/carbon being deposited on the valve seat and even the valve itself. This happened to me on three cylinders because I was running the engine cylinder head temperatures too cool, and I was not adding MMO to the fuel. Running the engine harder and adding MMO solved this issue for me. Of course this brings up the old MMO postings from over a decade or so, which got somewhat out of hand.
Mark
--
| - The Matronics Yak-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
Back to top |
|
|
Viperdoc
Joined: 19 Apr 2014 Posts: 484 Location: 08A
|
|
Back to top |
|
|
Ttail
Joined: 24 Jun 2013 Posts: 120
|
Posted: Fri Nov 09, 2018 3:32 pm Post subject: Re: Sticking Valves |
|
|
How much MMO in the oil is recommended ?
| - The Matronics Yak-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
Back to top |
|
|
dsavarese0812(at)bellsout Guest
|
|
Back to top |
|
|
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|