Replacing Valve Stem Seals (in situ) Pitfalls?

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worntorn said:
Steve Maney is at the top of the Norton tree as a machinist and mechanic. There's only one other fellow I would put at that level and we all know him.
This Maney race engine regularly goes back to Steve for rebuild after a few hours of use, I can't remember how many but it wasn't very long.
Note the head joint leakage.
Steve noted that this wasn't bad.
Its strange that many forum users here can pop a Norton head off an on like nothing and have it turn out perfect while Steve Maney can't figure it out!
He has a fantastic shop, tremendous experience and skill, has manufactured scads of complete engines that are far superior to original Norton engines, but the head joint still leaks when used.

If you have a working Commando with a perfectly sealed head joint, you have a rare model.
Click to expand...

You're comparing a tuned race engine to a comparatively docile street motor. That's a disingenuous comparison and, frankly, pretty derisive. I'm not sure how many members have leak free cylinder heads on their road bikes, I know a number of them personally, but that's anecdotal evidence and certainly not grounds to compare one persons skills to another. So I'm not seeing how any of this relates to Steve's skills. But please, explain the correlation. My inserts were installed by "the other known guy" btw... and they've held up pretty well over the years
 
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worntorn said:
Steve Maney is at the top of the Norton tree as a machinist and mechanic. There's only one other fellow I would put at that level and we all know him.
This Maney race engine regularly goes back to Steve for rebuild after a few hours of use, I can't remember how many but it wasn't very long.
Note the head joint leakage.
Steve noted that this wasn't bad.
Its strange that many forum users here can pop a Norton head off an on like nothing and have it turn out perfect while Steve Maney can't figure it out!
He has a fantastic shop, tremendous experience and skill, has manufactured scads of complete engines that are far superior to original Norton engines, but the head joint still leaks when used.

If you have a working Commando with a perfectly sealed head joint, you have a rare model.
Click to expand...

I suspect that engine gets used a little harder than most of our road bikes
My commando head gasket dosent leak ,I must be lucky
It's just horses for courses
We are now into 3 pages I would have done the job several times by now ! But then I keep all the gaskets/seals on the shelf
 
The Maney engine also gets a professional shop rebuild every few hours.
The road bike is expected to run for many thousands of miles often in tough conditions and still stay leak free.
From what I've seen, those that get used a lot tend to develop some leakage over time.

Re the time zerts, 390/400 inch pounds holding power doesn't leave much margin of strength, virtually nothing.

Glen
 
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worntorn said:
I wouldn't count on the Time Sert for much, they pull like they are in soft cheese.

Steve Maney is at the top of the Norton tree as a machinist and mechanic. There's only one other fellow I would put at that level and we all know him.
This Maney race engine regularly goes back to Steve for rebuild after a few hours of use, I can't remember how many but it wasn't very long.
Note the head joint leakage.
Steve noted that this wasn't bad.
Its strange that many forum users here can pop a Norton head off an on like nothing and have it turn out perfect while Steve Maney can't figure it out!
He has a fantastic shop, tremendous experience and skill, has manufactured scads of complete engines that are far superior to original Norton engines, but the head joint still leaks when used.

If you have a working Commando with a perfectly sealed head joint, you have a rare model.
Click to expand...

That's exactly why I want to avoid pulling the head.
 
worntorn said:
The Maney engine also gets a professional shop rebuild every few hours.
The road bike is expected to run for many thousands of miles often in tough conditions and still stay leak free.
From what I've seen, those that get used a lot tend to develop some leakage over time.

Re the time zerts, 390/400 inch pounds holding power doesn't leave much margin of strength, virtually nothing.

Glen
Click to expand...
I agree it's not unusual to see a commando with a small weep at the head ,more so on the 850s
But it's not the rule
I have owned three 750s and one 850
I've had a share of oil leaks but I have always sorted them out
I can't stand oil leaks
My A10 leaks a little it drives me mad
 
My 850 head joint was dry for years, but it took 3 tries to get it there.
It gets used pretty hard sometimes.
For example WOT for 30 miles racing a Vincent up the Salmo Creston in summer heat. Not a lot different than what a race bike has to do, just without all the tender loving care and frequent new parts.

It held just under 100 mph on that grade, I was very proud of it. It actually left the Vincent about one half mile behind. The Vincent owner did not expect that! The Vincent people convinced him that Commandos are easily beaten by mighty Vincents.


After 20,000 miles of this sort of thing the head joint has started to weep so it'll need to come off. Not looking forward to it.

Glen
 
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worntorn said:
Re the time zerts, 390/400 inch pounds holding power doesn't leave much margin of strength, virtually nothing.

Glen
Click to expand...
I just re-watched the video carefully. I'm a little confused. The 5/16" studs get 20ft-lb and the 3/8" get 30ft-lb (35ft-lbis using the cNw ARP set). 400in-lb is 33.3ft-lb. However he lubed the studs before his test and he was using 16tpi studs. I have no idea what lub he used and what difference 16tpi makes but he was clearly putting quite a bit more torque on the inserts than he states due to the lub. Clearly if you need to fix pulled fine threads that can stand up to 30ft-lb, inserts with their larger OD and course threads will handle significantly more than 33.3ft-lb!

The test is still interesting because it shows that the inserts are not the issue - they all performed basically the same and without testing each at least three times and averaging, I would say they all are equivalent.
 
marshg246 said:
Yes, on the exhaust side - until the intake side is well flooded it's not a drain at all for the intake side.
Click to expand...
That would be true on an Atlas where the head gasket is parallel to the ground. With the Commando's tilted motor, all the oil other than what's in each valve area should drain down the pushrod tubes. I am getting ready to replace the SS's head gasket and I will test the theory when I get the head off.
 
worntorn said:
I wouldn't count on the Time Sert for much, they pull like they are in soft cheese.

Steve Maney is at the top of the Norton tree as a machinist and mechanic. There's only one other fellow I would put at that level and we all know him.
This Maney race engine regularly goes back to Steve for rebuild after a few hours of use, I can't remember how many but it wasn't very long.
Note the head joint leakage.
Steve noted that this wasn't bad.
Its strange that many forum users here can pop a Norton head off an on like nothing and have it turn out perfect while Steve Maney can't figure it out!
He has a fantastic shop, tremendous experience and skill, has manufactured scads of complete engines that are far superior to original Norton engines, but the head joint still leaks when used.

If you have a working Commando with a perfectly sealed head joint, you have a rare model.
Click to expand...

Steve is also now retired! ;)
 
marshg246 said:
I just re-watched the video carefully. I'm a little confused. The 5/16" studs get 20ft-lb and the 3/8" get 30ft-lb (35ft-lbis using the cNw ARP set). 400in-lb is 33.3ft-lb. However he lubed the studs before his test and he was using 16tpi studs. I have no idea what lub he used and what difference 16tpi makes but he was clearly putting quite a bit more torque on the inserts than he states due to the lub. Clearly if you need to fix pulled fine threads that can stand up to 30ft-lb, inserts with their larger OD and course threads will handle significantly more than 33.3ft-lb!

The test is still interesting because it shows that the inserts are not the issue - they all performed basically the same and without testing each at least three times and averaging, I would say they all are equivalent.
Click to expand...
Here's an article that explains the need for lube when tightening to a specification.


"It’s not possible to determine an accurate Nut Factor for dry threads. Unfortunately, when you don’t have lubricant, there are many other substances that may act as lubes on your fastener that you might not be able to see.

One of them is the oil used on them during manufacturing. For example, we have seen a stud where the oil has been “baked off” using an oven have a Nut Factor of about .26, while a stud that still has oil residue is about a .20. (It’s worth noting that particles of solids still on the stud that will also affect your Nut Factor).

That is a big discrepancy.

Hex Technology recommends that you do not try to solve this problem unless you have the proper equipment and understand the “Turn of the Nut Method.”

Partially Lubricated Bolt Nut Factor:​

Let’s say you’ve done your homework and understand the nut factor for your lube. If that lubricant isn’t applied generously/properly, the dry parts of the fastener will increase your Nut Factor and result in different bolt loads on each of your fasteners.

So you might be using a calibrated torque wrench, and have a known Nut Factor, but if your lube isn’t applied properly, your torque value (bolt tension) will have changed.

(Learn more about how to properly use clicker wrenches.)

Properly Lubricated Bolt Nut Factor:​

When testing your Nut Factor, you put it in the best and most repeatable condition, then you replicate those conditions in the field. By properly lubricating fasteners, you achieve the correct ft-lbs, clamping force/preload, and gasket stress.

How Much Lubricant Should You Use?​

Proper lubrication means that you’ve put lubricant on every thread so that the valley of the stud is full.
 
Danno said:
That would be true on an Atlas where the head gasket is parallel to the ground. With the Commando's tilted motor, all the oil other than what's in each valve area should drain down the pushrod tubes. I am getting ready to replace the SS's head gasket and I will test the theory when I get the head off.
Click to expand...
Simple test. Pour a bunch of oil in the intake side and see how long it takes to drain. Or, run the bike with the intake cover nut removed, shut it off, pull the cover and have a look. Especially with cold oil you'll be shocked at how much is in there! Valve seals are most definitely not required when the tops of the guides are not drowning in oil!
worntorn said:
Here's an article that explains the need for lube when tightening to a specification.


"It’s not possible to determine an accurate Nut Factor for dry threads. Unfortunately, when you don’t have lubricant, there are many other substances that may act as lubes on your fastener that you might not be able to see.

One of them is the oil used on them during manufacturing. For example, we have seen a stud where the oil has been “baked off” using an oven have a Nut Factor of about .26, while a stud that still has oil residue is about a .20. (It’s worth noting that particles of solids still on the stud that will also affect your Nut Factor).

That is a big discrepancy.

Hex Technology recommends that you do not try to solve this problem unless you have the proper equipment and understand the “Turn of the Nut Method.”

Partially Lubricated Bolt Nut Factor:​

Let’s say you’ve done your homework and understand the nut factor for your lube. If that lubricant isn’t applied generously/properly, the dry parts of the fastener will increase your Nut Factor and result in different bolt loads on each of your fasteners.

So you might be using a calibrated torque wrench, and have a known Nut Factor, but if your lube isn’t applied properly, your torque value (bolt tension) will have changed.

(Learn more about how to properly use clicker wrenches.)

Properly Lubricated Bolt Nut Factor:​

When testing your Nut Factor, you put it in the best and most repeatable condition, then you replicate those conditions in the field. By properly lubricating fasteners, you achieve the correct ft-lbs, clamping force/preload, and gasket stress.

How Much Lubricant Should You Use?​

Proper lubrication means that you’ve put lubricant on every thread so that the valley of the stud is full.
Click to expand...
But, all published torque values for Norton are dry. This is really clear if you look at the MKIII Workshop manual.
 
I just read through the sequence on refitting the head (MK3 Workshop Manual)
I didn't find any mention of dry or wet regarding the bolt torq. Perhaps I'm not looking in the right place.

In any case, on re-torque, count on oiled threads, there will be at least some that are.

Glen
 
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worntorn said:
I just read through the sequence on refitting the head (MK3 Workshop Manual)
I didn't find any mention of dry or wet regarding the bolt torq. Perhaps I'm not looking in the right place.

In any case, on re-torque, count on oiled threads, there will be at least some that are.

Glen
Click to expand...
See "General Guidance - Torque Recommendations" in Section A on .pdf page 17 of the MKIII Workshop Manual. Also, the entire current thread "Lubricate bolt threads - graphite?" Not sure how we got this thread off on this tangent when there's another current thread on this subject.
 
We got off when you questioned the use of oil in the video, have a look back!!!
:)

My manual does not have page numbers. It has alphabetical sections, then numbered topics within.
No mention of General Guidance.

Glen
 
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The video (post 61) is what did it (or maybe your mention of timesert in post 60), followed by several posts and then mine. I was trying to be nice by saying I didn't know how it happened - at this point I wish I had kept my fingers off the keyboard - I knew this was a tangent and that there was another where this was being thoroughly discussed!
 
worntorn said:
We got off when you questioned the use of oil in the video, have a look back!!!
:)

My manual does not have page numbers. It has alphabetical sections, then numbered topics within.
No mention of General Guidance.

Glen
Click to expand...
No, it doesn't have page number, but it does have sections - I stated section A. I also said .pdf page 17. If you have a printed manual rather than a .pdf file count to page 17.
 
No worries, it's all relevant info anyway.
The known problem of Commando head studs letting go ( video) is most definitely related to the question of pulling the head/ not pulling the head.
Glen
 
I haven't been able to get someone to follow me and observe my exhaust but a have had people observe as I accelerated away. It seems that there is no smoke until I shift 2nd to 3rd gear and then there is a pretty good puff of smoke.
 
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