Wildguzzi.com
General Category => General Discussion => Topic started by: oldbike54 on January 08, 2016, 01:37:50 PM
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OK , let's try this one more time . The question is how cool enough to adjust valves . The general consensus seems to be room temp , or about 70 degrees , although on a 90 degree day that might be tough :laugh:
Dusty
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OK , let's try this one more time . The question is how cool enough to adjust valves . The general consensus seems to be room temp , or about 70 degrees , although on a 90 degree day that might be tough :laugh:
Dusty
I say 70F is the goal, but that there's probably at least a 20F swing in both directions that would be fine.
I also say that my garage is attached to my house and has living area above it. So IF I HAVE to set valves on a 90F day, there's a good chance my garage is already only in the 80s at most, and if I leave the door to the house open I can probably get it into the 70s easily enough.
Or we could go to Jay's garage, he's got heat and air.
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If you have a dealer adjust the valves, take it in early, ask them to do the valves after letting the engine cool, like in the afternoon and that should be cool enough to get a good adjustment.
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Or we could go to Jay's garage, he's got heat and air.
:thumb: :grin:
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I don't know Jay but I think he should do a scientific study correlating the change in valve clearance settings for each 5 degree change in cylinder head temperature above and below 70 degrees F. And while he is doing that he could take the exhaust pipes off one of his BMWs and put them on his MG and then he could also answer the "quieter motorcycle" question :-). Seriously, I'm just kidding.
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.... so adjusting them cold in my 40�F garage is not a good idea? (I just did this as I retorqued the head bolts)
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.... so adjusting them cold in my 40�F garage is not a good idea? (I just did this as I retorqued the head bolts)
:laugh: Troublemaker :evil:
Dusty
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How much expansion or contraction of the metal parts could there be between 40 degrees F and 90 degrees F? Has anyone ever checked with feeler gauges to see if the ambient temperature makes a perceptible difference?
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.... so adjusting them cold in my 40�F garage is not a good idea? (I just did this as I retorqued the head bolts)
There is acceptable practice, best practice and unacceptable practice.
There is a gap range and that allows for different temps and such. Stone cold engine is best but that doesn't mean you can't adjust them any other temp such as after sitting for 8 hours and not get a good adjustment or check.
The owner living where they need to adjust the valves and the ambient temps are hovering in the 90s day or night can't get the engine any cooler than that without artificially cooling methods.
Get the engine as cool as ambient temp, it is acceptable or are we all supposed to wait until a cold night to check and adjust valves?
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I believe "cool" just means with the engine not up to normal running temp as in its cool enough to lay your hand on the cylinder heads. Clearances, (specified by the designer) take into account a wide range of temperatures so as not to be critical.
This subject could rival an oil thread.
As Charlie Brown says "good grief".
:-)
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I believe "cool" just means with the engine not up to normal running temp as in its cool enough to lay your hand on the cylinder heads. (Clearances specified by the designer) take into account a wide range of temperatures so as not to be critical.
This subject could rival an oil thread.
As Charlie Brown says "good grief".
:-)
Are you suggesting an oil thread ? We already have the annual ethanol thread going as well as a helmet thread :laugh: All we need now is a counter steering thread ...
Dusty
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The engineers who designed the engine had to deal with the fact that various engine parts are going to expand with heat. Of course the valves are going to get the most heat and the longer the valve the more expansion. All the other valve train parts do the same. It seems to me that it's more important to get an engine down to the ideal temp if you have a long valve train...long valves, long push rods, etc. If the valves are relatively short and the other components are short you are not going to see much difference in material expansion when compared to other designs. My Stelvio has pushrods that are about 2" long. The V7 pushrods are much longer. Based on that alone, I'd be much more concerned about having the V7 totally cooled than the high cam Stelvio. If I'm wrong it won't be the first time!
Peter Y.
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Can any scientographer among us offer any thermal expansion specs? I'll bet there's a slide rule involved, and that gets above my station in life. My gut tells me that there's a negligible difference at best for the normal ambient ranges such as 40 - 85 degrees f . . . and that the expansion characteristics of the head alloy and valve material would only be truly & measurably changed above 150deg and below freezing.
I can't see there being an increasing detrimental effect for adjusting valves for every 10 degree delta +/- a 70 degree atmospheric baseline.
I could be wrong - but I'd be interested to see what science offers to satisfy my curiosity.
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Can any scientographer among us offer any thermal expansion specs? I'll bet there's a slide rule involved, and that gets above my station in life. My gut tells me that there's a negligible difference at best for the normal ambient ranges such as 40 - 85 degrees f . . . and that the expansion characteristics of the head alloy and valve material would only be truly & measurably changed above 150deg and below freezing.
I can't see there being an increasing detrimental effect for adjusting valves for every 10 degree delta +/- a 70 degree atmospheric baseline.
I could be wrong - but I'd be interested to see what science offers to satisfy my curiosity.
If I remember, :rolleyes: I'll look up the coefficient of expansion for various metals in my ancient Machinery's handbook tomorrow. The Kid's coming down to work on his Spot, though, so I'll probably forget..
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just bring back the hydro engine and we can get back to the oil threads.
I'll start it with, had we just used dino 10/40 in the 8 valves would they have failed right away so the Italians would have had to warranty labor in them in the first year OR would they all be running great right now with no failures.
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Are you suggesting an oil thread ? We already have the annual ethanol thread going as well as a helmet thread :laugh: All we need now is a counter steering thread ...
Dusty
How about a tire thread? :laugh:
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A donut thread
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How about a tire thread? :laugh:
A donut thread
Or a donut tire thread :huh: :rolleyes:
Dusty
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Gonna have coffee w/that? How bout a smoke?
You still off that stuff Dusty?
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Gonna have coffee w/that? How bout a smoke?
You still off that stuff Dusty?
Coffee , no , and the occasional cigar . Oh wait , are you asking about my silly sense of humor ? :laugh:
Dusty
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The coefficient of expansion on most common metals is determined and measured at 68 degrees F. Different alloys are rated at this temp and there are
specs given by the producers of the material for that expansion. Different standards organizations produce tolerances allowable for their criteria,
ASTM,SAE, ANSI Etc..
Paul :boozing:
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When you first came on here posting often, you had just quit coffee.
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The coefficient of expansion on most common metals is determined and measured at 68 degrees F. Different alloys are rated at this temp and there are
specs given by the producers of the material for that expansion. Different standards organizations produce tolerances allowable for their criteria,
ASTM,SAE, ANSI Etc..
Paul :boozing:
Yep 40* is too cold
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When you first came on here posting often, you had just quit coffee.
I had ? Oh yeah , to help with the cigarette thing . Damn Steve , you have a great memory :bow:
Dusty
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Yep 40* is too cold
People say that, but is it true? How much variation is there in valve clearance between, say, 40 degrees F and 90 degrees F? Does anyone really know?
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People say that, but is it true? How much variation is there in valve clearance between, say, 40 degrees F and 90 degrees F? Does anyone really know?
Yes they always know! Just like Santa. It is a calculation in microinches based on the material used. So the difference between 70 and 90 would be insignificant.
Paul :boozing:
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If the temperature was that critical between some of the lower temps and the higher temps during different times of year when it comes to adjusting the valves wouldn't there be engines over self destructing themselves because the clearances were either too tight or too loose?
:Beating_A_Dead_Hors e_by_liviu
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I have been oscillating, vacillating and procrastinating because I need to do the clearances on the Breva. Originally I was waiting for the rocker gaskets to arrive, now it is because it is always hot. :grin:
I must admit, I hear the rapid tappets when I first fire it up, but by the time it has warmed up the tappet noise has gone. Hardly scientific I know but it does show me that something tightens up when it is hot.
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If the temperature was that critical between some of the lower temps and the higher temps during different times of year when it comes to adjusting the valves wouldn't there be engines over self destructing themselves because the clearances were either too tight or too loose?
:Beating_A_Dead_Hors e_by_liviu
Short answer, Yes. Thats why engineers that design this stuff have to know what the properties of the materials they plan on using are and consult with metallurgists and suppliers to find the best for their application. Thats why many years ago they filled valves with sodium and utilized stainless because of it's stability under temperature fluctuations.
Paul :boozing:
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People say that, but is it true? How much variation is there in valve clearance between, say, 40 degrees F and 90 degrees F? Does anyone really know?
nail head hit!
From the factory perspective, all concerns are addressed by stating that adjustment be done on a cool 70* engine. I still adjust after the bike has set overnight. I'm curious nonetheless at what temperatures the expansion/contraction really mean something.
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The next time an 8V Norge comes in for service, I'll check the valves after the fans kick on at 125*C . Usually gets there while setting throttle bodies on a warm day.
Interesting to see what they are while you are sitting in traffic boiling your oil and scraping your flat tappets.
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Short answer, Yes. Thats why engineers that design this stuff have to know what the properties of the materials they plan on using are and consult with metallurgists and suppliers to find the best for their application. Thats why many years ago they filled valves with sodium and utilized stainless because of it's stability under temperature fluctuations.
Paul :boozing:
And then any concerns about temps are kind of irrelevant if there is a reasonable cooling off period to get the engine close to ambient temp since temps change throughout the year?
The temp differences between summer and winter could easily be more than 20 degrees and thus so could the valves, even after sitting overnight. It would seem the manufacturer knows this and builds in enough tolerance so that we really don't need to worry about it.
I'd be more concerned that the set of feeler gauges being used were accurate and the piston was at correct TDC than if the engine was at 60 degrees vs 80 degrees because that was the temp of the engine after it cooled to ambient air temp.
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BMW specified 35C in the 70/80s R bikes factory workshop manuals. That converts to 95F.
Ciao,
Dick Casey
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nail head hit!
From the factory perspective, all concerns are addressed by stating that adjustment be done on a cool 70* engine. I still adjust after the bike has set overnight. I'm curious nonetheless at what temperatures the expansion/contraction really mean something.
Well, off the top of my head, I can remember that the thermal coefficient for most steel alloys is right around .000006" per degree Fahrenheit per linear inch, and that the thermal coefficient for most aluminum alloys is approximately twice that at .000012" per degree Fahrenheit per linear inch.
To answer the question at what temperature does the whole expansion/contraction thing makes meaningful difference? I suppose that depends how accurate your instruments are. but if you run the math plus or minus 20 degrees (F.) the change in relationship in the parts is about .00048".
I am not going to sweat checking the valves on a cool 50 degree morning or a hot 90 degree afternoon so long as the bike has been off for at least 8 hours prior.
Skippy