Stuck valve

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trident sam said:
Really interesting Jim, thanks for posting.

What do you use as an assembly lube ?
sam
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Redline do good assembly paste Sam, I think you get it in UK from Deamon Tweeks.
 
Thanks for the video Jim. Didn't know STP was still around. I used it thirty years ago in an old Humber engine. It helped to reduce oil consumption a little.
The assembly lube Nick Guzzi is thinking about is more than likely to be Graphogen. Never tried this myself. For shell bearings & camshaft /followers I use Lubriplate or Torco assy. lube, both American made products.
I only ever use engine oil on valve guides for the fear of sticking. Seems like my fears could be justified!
Martyn.
 
When I was a kid I watched a neighbor assemble a rebuilt engine in his garage using grease from a greasegun they used on the farm as an assembly lube. The result was several stuck valves shortly after he started the engine. Jim
 
Nortons Model 16H WW2 sidevalve military slogger had grease nipples to lube the valves.
(sidevalve remember, out in the open air - with a cover over them).

The military required engines to be able to 10,000 miles at least before overhaul (no air filter or oil filter either remember),
and the grease lube was required to meet this spec. (otherwise they ran dry).

Maybe it depends on the type of grease ?
And the clearance supplied...
 
Rohan said:
Nortons Model 16H WW2 sidevalve military slogger had grease nipples to lube the valves.
(sidevalve remember, out in the open air - with a cover over them).

The military required engines to be able to 10,000 miles at least before overhaul (no air filter or oil filter either remember),
and the grease lube was required to meet this spec. (otherwise they ran dry).

Maybe it depends on the type of grease ?
And the clearance supplied...
Click to expand...

I'm sure that is right. The neighbors head had been rebuilt by a local machine shop and who knows what kind of grease was in the grease gun.

I know airiplanes with exposed valve gear use a special grease for lube. It is more of an oil than a grease. I keep some of that around for swingarms. Jim
 
watched the vidieo, All i can say is its not a true to life test...firsly the temp on the inlet valve was far in excess of real engine temp, and warms up more slowly!, the inlet valve as a cool constant air/fuel cooling it...and secondly STP is not added at a 25% mix!
Before you all chime in saying the exhaust valve gets that hot...the exhaust valve run's with more clearance and the valve is lower expansion ..Sorry Jim your test proves nothing!
 
john robert bould said:
secondly STP is not added at a 25% mix!
Click to expand...

But what Jim was attempting to demonstrate, is what can happen when STP is used as an assembly lubricant when the percentage of STP is likely to be much higher than normal.
 
Interesting test.
But - in use, anything used as a valve guide lubricant is likely to be blown out of the exhaust guide,
and sucked out of the inlet guide. (valve guide seals notwithstanding).
Leaving only a VERY thin smear of anything.

Noting that prior to the mid 1930s, valves generally ran out in the open, without any lube whatsoever.
You soon see what happens if you try and throw any lube at it.

??
 
john robert bould said:
watched the vidieo, All i can say is its not a true to life test...firsly the temp on the inlet valve was far in excess of real engine temp, and warms up more slowly!, the inlet valve as a cool constant air/fuel cooling it...and secondly STP is not added at a 25% mix!
Before you all chime in saying the exhaust valve gets that hot...the exhaust valve run's with more clearance and the valve is lower expansion ..Sorry Jim your test proves nothing!
Click to expand...

The ratio of 25% was what was used as the prelube on the valve that stuck.

The Kibblewhite intake valve and exhaust valve are both made of the same the same material.

The intake valve is does run as hot as I got it in the video. The temp of the valve head didn't exceed 500 F. The head itself was cool so the temp in the guide was not that hot.

This test was not to condemn the use of STP in a motor at the correct ratio. [not that I would use it] It was simply to find out why the valve seized in the guide on the job in question. It was an intake valve that had stuck so that is what I checked. And yes the intake guide clearance is tighter which I am sure is why it stuck first. Jim
 
john robert bould said:
Jim, Only one out of four valves? surly all 4 would have stuck?
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One of them had to stick first. That stopped the engine.

That's kind of like asking "why do you always find something in the last place you look." Jim
 
Jim Firstly i hold you in high regard, some work you do is behond me and proberly 99% on this forum, But after watching the video it left a lot of questions .
You did not show the valve stem "Gum" that you where stateing was causing the stem to stick...was there "gum" which was caused by the STP to tar up?






comnoz said:
john robert bould said:
watched the vidieo, All i can say is its not a true to life test...firsly the temp on the inlet valve was far in excess of real engine temp, and warms up more slowly!, the inlet valve as a cool constant air/fuel cooling it...and secondly STP is not added at a 25% mix!
Before you all chime in saying the exhaust valve gets that hot...the exhaust valve run's with more clearance and the valve is lower expansion ..Sorry Jim your test proves nothing!
Click to expand...

The ratio of 25% was what was used as the prelube on the valve that stuck.

The Kibblewhite intake valve and exhaust valve are both made of the same the same material.

The intake valve is does run as hot as I got it in the video. The temp of the valve head didn't exceed 500 F. The head itself was cool so the temp in the guide was not that hot.

This test was not to condemn the use of STP in a motor at the correct ratio. [not that I would use it] It was simply to find out why the valve seized in the guide on the job in question. It was an intake valve that had stuck so that is what I checked. And yes the intake guide clearance is tighter which I am sure is why it stuck first. Jim
Click to expand...
 
john robert bould said:
Jim Firstly i hold you in high regard, some work you do is behond me and proberly 99% on this forum, But after watching the video it left a lot of questions .
You did not show the valve stem "Gum" that you where stateing was causing the stem to stick...was there "gum" which was caused by the STP to tar up?
Click to expand...



There was a slight amount of some kind of buildup on the stem. It was very thin and not something I could photograph.

When I took the valve to the solvent tank after it had stuck you could feel whatever was on the stem when cleaning it with fine steel wool. The DLC coating did not feel slick and the steel wool would drag on the stem until I had scrubbed it long enough to get through whatever was there. Jim
 
Jim .
The valve appeared very hot..that gas flame looked very intence... enough to carbonize most oil. What temp would a inlet valve operate at? considering all the cold wet air passing over it.
comnoz said:
john robert bould said:
Jim Firstly i hold you in high regard, some work you do is behond me and proberly 99% on this forum, But after watching the video it left a lot of questions .
You did not show the valve stem "Gum" that you where stateing was causing the stem to stick...was there "gum" which was caused by the STP to tar up?



There was a slight amount of some kind of buildup on the stem. It was very thin and not something I could photograph.

When I took the valve to the solvent tank after it had stuck you could feel whatever was on the stem when cleaning it with fine steel wool. The DLC coating did not feel slick and the steel wool would drag on the stem until I had scrubbed it long enough to get through whatever was there. Jim
Click to expand...
Click to expand...
 
john robert bould said:
Jim .
The valve appeared very hot..that gas flame looked very intence... enough to carbonize most oil. What temp would a inlet valve operate at? considering all the cold wet air passing over it.
Click to expand...

I have no way of knowing the temp in a Norton, but for air cooled racing engines the intake valve head temp is commonly figured to be somewhere between 500F. and 800F. I would figure 400 to 500 for a normal Norton motor since the cylinder head itself commonly sees 400F.

When I tried the test the first time -before I got the camera out -I used an infrared temp gun and measured the intake valve head temp at about 500F. I don't know that this was real accurate. I measured it at the end of the first try with straight oil. I really didn't trust the temp gun for this so I didn't try to measure it any more. Jim
 
auldblue said:
Jim

May I ask was the build up like melted nylon or plastic?

J
Click to expand...

That is hard to say. When I first looked at the stem after it stuck there was really nothing obvious. It just didn't want to slide through the guide even after it cooled.
It was only when I tried to clean it with fine steel wool I could tell it felt rough or sticky. Right below where the valve entered the guide was the only place there was anything that could be seen and it was pretty minute. It looked like a tiny ring of brown oil that wouldn't wash off with solvent and a paper towel. Jim
 
jim,with all due respect,ive watched your vid numerous times and you appear to be heating the valve only,with a stone cold head and valve guide the only thing that is going to happen is a seized valve, no matter what magic oil concoction you put on it,convince me otherwise, chris
 
That is potentially a very good point.
Valves transfer their heat to a) the valve guides and b) the valve seat and c) to the oil on the valve stems.
The hotter the valves get, the more heat is transferred to guides and seats and oil.

Some aircraft engines are recorded as breaking (exhaust) valves if the oil flow to the rockers falls below a specified flow (per minute).
You would think a trickle of oil around the valve springs etc wouldn't make much difference, but apparently it does.
Pilots tend to notice these things, not being able to get out and walk home....
 
chris plant said:
jim,with all due respect,ive watched your vid numerous times and you appear to be heating the valve only,with a stone cold head and valve guide the only thing that is going to happen is a seized valve, no matter what magic oil concoction you put on it,convince me otherwise, chris
Click to expand...

1. It did not seize when I tried it first with just oil ,
and in the first try the valve was heated longer and the head was cold.

2. In the second try with STP the head was likely warmed a bit by the first attempt and the valve was not heated nearly as long before it stuck.

3. If it was caused by expansion of the valve [which would have required much more heat] Then why would the valve still be tight after it cooled?
Jim
 
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