Broken valve

[NAM VET]

was a few miles from home this am, and a miss, then hardly run, and rattle, seemed to be from rear of engine, flatbed via Hagery insurance the few miles, hime, autopsy shows normal oil pressure and no compression on cylinder five, so pulled off rear valve cover, and it seems my third valve from the rear of the engine, I think intake, has broken off at the keeper. At last not at the valve top, so I doubt any cylinder damage. I will pull of cy head and manifolds, and replace valve and keeper. I don't see any metal parts in the valve area. Had new valves about a thousand + miles ago. A pic in a minute. hc

[NAM VET]

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[NAM VET]

hmmmm ..... Since the valve in question is right under the spark plug hole, I lightly tapped on the valve top, and it popped back down into position, and cranking the motor it moves up and down just fine. So for some reason it just stuck full open, perhaps some crud or oil crusting on the stem. I have asked Charles T since he has seen anything, what he suggests for me. Spring and valve are new. At least now it seems like something hopefully nothing requiring more than what I have already done to inspect it. HC

[RCrombie]

It’s odd that this happened while you were driving. It’s my understanding that sticky valves usually occurs from sitting, and the valve hangs open on startup which isn’t the case here. The other culprit that is often blamed is the use of ethanol gas.
If this was an overhead cam engine I would wonder if that valve was bent. That’s probably not the case here.
Just my 2cents, for what it is worth.

Rob

[Cal_Gary]

Glad it wasn't something more serious aka damaging, Hal! Thanks for the photo!
Gary

[NAM VET]

Charles T wrote me a long reply, said he has seen precisely this and it is not uncommon. It is his opinion that today's gas especially with ethanol is the culprit, and that a fuel additive called Essential Lube from Hydrotex works to prevent the buildup on valve stems. I am going to get this product, and per his suggestions head out on some longer hot drives. In the meantime, with the rear valve cover off, I am going to spray some Techron directly on the valves/springs before I button it up. My truck does not sit for long, I drive it at least weekly if not more often, and if not driving it, I will start it up and get the engine good and warm to operating temp. I have a nearby gas station with non-ethanol regular gas, which I use in all my power products too. I am well aware that premium gas has more additives and detergents and such, but I have no "hi-test" non-ethanol near me. It is possible that some of my original carb's oil bath air filter has contributed some to oil on the valve stem, as there is always some oil under the filer in the carb's elbow. I am going to find a oil more suitable for this, some sort of low ash oil, perhaps a two cycle oil. Or switch to a different filter system, like a clamp-on filter. The original oil bath filter would be great for dusty conditions, but I don't drive in that sort of desert dust, and a modern paper filter might be helpful. And my truck was at stop light and idling when the valve stuck. I will add some Seafoam to my gas in the meantime.

My valves and valve guides are new in the rebuild, so tolerances might be on the snug side, making this problem more likely. I can tell you how relieved I was to find I did not have to partially disassembly my engine for this. Charles did tell me that sometimes that is the only way to clean the valve stems, take the valves out.

If we did not have this forum, lacking information like this would make it much more difficult to keep our trucks on the road. If the moderators can PM me how to contribute $ I will do so.

All the best, and stay safe, hal, aka NV

[milstencil]

Hal,
Hard to believe there are no non ethanol stations near you.
Any place that has a marina usually has non ethanol.
Check here: https://www.pure-gas.org/index.jsp?stateprov=KY
The communist state of MA would never let us use it! Used to bring some
home when I visited my friend in OBX or on a visit to VT.
Regards,
Rick

[NAM VET]

there is a big gas station nearby, who has non-ethanol regular (not hi-test) gas, and in the summer lots of guys buying it for use in their lawn mower business. But in the winter (or what passes for winter in UpState SC) much less, so maybe the non-ethanol is older in the station's tanks. I have some can's of Mopar combustion chamber cleaner from years ago, this after noon will spray some onto the valve stems, and then after buttoning up the rear valve cover, will get the engine warm, and at high idle spray more into the carb intake. Then begin the additive suggested by Charles Talbert. His shop is about a hundred miles north of me, been there a number of times, he did a lot of work on my truck. Much easier to see into the valve area after removing the inner fender liner. Just bolts.

All the best, and stay safe, NV

[Murf]

Just remember 93oct isn't "better" gas. You want the lower octane so the cylinder temps stay where they need to be....higher. High octane = lower temp, lower temp=unburned fuel, unburned fuel = carbon buildup.

New powerboat owners with engines that require 87 oct gas always think it's better to run premium...why?? because it says "premium" and that means it's got to good, especially for a shiny new motor. Then they wonder after a while why they get a miss.

My suggestion, FWIW, Sure, use the additive and even non-ethanol if you can find it, BUT use the 87 octane so it keeps the temp up and that additive can more efficiently do its job.

[ashyers]

Hal,
Sorry to hear about the mechanical. I noticed that you said you commonly had a puddle of oil in the intake elbow below the air filter. This is not normal. I run the stock filter and see just enough of a film to wet the surface, and that's with thousands of miles on the engine. Is it possible the filter is overfilled or possibly the media is clogged to the point oil is being entrained into the airstream?

I have a suggestion for cleaning up the valve stem. Last week I was working on an injected Jeep and tried out some Seafoam Throttle Body Cleaner & Lube. I usually stay away from such things, but someone gave me a can and the throttle body in the Jeep was nasty. I followed the instructions and the stuff worked pretty darn well. I was thinking a dose of this down the spark plug hole while the valve is open would allow it to work its way between the stem and guide to clean out any carbon or sticky oil deposits. Might be worth a try.

Good luck with your fix!

Andy

[just me]

The intake tract should be clean and dry. Something is wrong with your filter. Check the oil level and clean or replace the element. I've been running oil baths for 50 years and that is an indication of a problem.

[NAM VET]

probably too much oil in the filter. I have about a half teaspoon of oil down in the crook. No change in the past year. And I just came in from spraying Mopar combustion chamber cleaner into the spark plug holes, and drizzled some Seafoam there too. Will be careful to not hydrolock anything. Kept turning the engine over via the fan. Will let it all sit for a few days, then put it back together, start, get warm, and spray some more Seafoam into the intake. But some oil vapor in the intake via the oil bath air cleaner may nicely lubricate the valves, and upper chamber, but then too it may "carbonize" on the valve stems with resultant problems. I don't know. I still think I will go to a paper or foam or oiled gauze filter. I think I just over filled my oil filter a year or so ago.

I may have enough to actually cover the filter wire, and my induction may be puling air thru the oil then into the filter. Will go back and read the operator's manual.

I was thinking earlier today, that in the '30's thru the 60's there were millions of simple 6 and 8 cy engines in cars and trucks, and wondered if they had problems with "sticky valves", but then of course no ethanol, but also less oil detergents and such. But when I pick up any "top cylinder Oil" or other product for engines, on the label will be claims that the product "cleans valves, removes varnish, gum, deposits" and so forth. Maybe there was a big need and use of additives in years past.

I wonder also how the military felt with the problem. Maybe it really is ethanol, which I don't use in my truck or power products. But I will do it differently henceforth.

Always good to hear from friends on this forum . NV

[NAM VET]

was just looking over clamp on air filters, and realized that the Dodge one is pretty good for keeping splash water out of the intake, whereas an open gauze type would let splash water in much easier. Checked the oil bath filter to see what the mark level is, but I had already dumped the old oil out. I think I will indeed keep the Military filter, and just put in a little less oil. Will look into 2 cy oils which lube well but burn with less ash.

Overthinking this. NV

[ashyers]

Hal,
Inspect your PCV system.

Andy

[NAM VET]

Will do. Also, just reading some authoritative articles specifically about ethanol causing varnish/deposits on intake valve stems. A few weeks ago, with my tank down to perhaps 4 or 5 gallons, went to my local station which has non-ethanol regular. Pulled up, and inadvertently put in about 5 gallons of ethanol, then stopped that, the first time my truck has had an ethanol fuel. Filled it with about 10 or or so gallons of my usual fill. I wonder how at most less than 5% ethanol mix for less than 50 miles of driving could have caused this. Must be coincidental. Now spraying my Mopar Combustion cleaner on the rear valve springs, and into the spark plug holes, with some Seafoam too. Soaking my spark plugs in the same. Will reinstall them, fire it up, and when warm spray more into the valve area, only the rear cover off. The articles I read stated that the usual gas aftermarket additives do a good job of limiting intake valve stem deposits. Will replace my PCV too.

I am going to burn up this tank of fuel as soon as possible, with plenty of the additive Charles T suggested.

I am just glad that I did not assume I had a bent valve and start a tear down. I was already looking at valve spring compressors. If my engine was an OHV engine, it would have bent the valve and wrecked the piston.

Will keep the forum informed, and perhaps my adventure will serve to caution others.

All the best, and stay safe. NV, UpState SC