- Thread starter guido
- Start date
Hmmmmm where does it "originate" you ask.
Wellllllllll, since "timing" primarily has to do with when the spark occurs relative to the pistons location (i.e. TDC or 25 BTDC etc) I would say it originates with (per your choices) the crankshaft cuz its location determines the pistons location.
That being said, the rotational adjustment (timing) of the distributor is a function of FIRST the cranks position,,,,,,SECOND the timing chain (if one is used),,,,, THIRD Camshafts position (regardles if chain or direct driven) FOURTH any gears that connect the distributor shaft to the camshaft,,,,,,,,FIFTH the location of the distributor (its timing adjustment) as that determines when the ignition points break open to create the spark to ignite the fuel..
THAT STILL LEAVES ME WITH IT ORIGINATING AT THE CRANKSHAFT AS THAT DETERMIENS THE PISTONS LOCATION.
However, the wear and slop and gear mesh of alllllllll those components such as cam n chains is what determines where the distributor needs located (its rotational timing) in order that the spark occurs at the right time relative to the pistons location (i.e. the ORIGINATING CRANKSHAFT POSITION)
NOTE this is a one size fits all answer and, of course, some engines use a timing chain many a gear to gear cam to crank while the distributor might be driven off different sources like oil pump shafts n camshafts etc etc but regardless, its still the location of the piston thats critical for when the spark occurs adn thats a function of the crankshafts position
THATS MY STORY N IMA STICKIN TO IT LOL
Hey I'm an Engineer and an Attorney my brain likes to over analyze and overword these type questions lol.......
Happy New Year Yall
John T in Indiana
Wellllllllll, since "timing" primarily has to do with when the spark occurs relative to the pistons location (i.e. TDC or 25 BTDC etc) I would say it originates with (per your choices) the crankshaft cuz its location determines the pistons location.
That being said, the rotational adjustment (timing) of the distributor is a function of FIRST the cranks position,,,,,,SECOND the timing chain (if one is used),,,,, THIRD Camshafts position (regardles if chain or direct driven) FOURTH any gears that connect the distributor shaft to the camshaft,,,,,,,,FIFTH the location of the distributor (its timing adjustment) as that determines when the ignition points break open to create the spark to ignite the fuel..
THAT STILL LEAVES ME WITH IT ORIGINATING AT THE CRANKSHAFT AS THAT DETERMIENS THE PISTONS LOCATION.
However, the wear and slop and gear mesh of alllllllll those components such as cam n chains is what determines where the distributor needs located (its rotational timing) in order that the spark occurs at the right time relative to the pistons location (i.e. the ORIGINATING CRANKSHAFT POSITION)
NOTE this is a one size fits all answer and, of course, some engines use a timing chain many a gear to gear cam to crank while the distributor might be driven off different sources like oil pump shafts n camshafts etc etc but regardless, its still the location of the piston thats critical for when the spark occurs adn thats a function of the crankshafts position
THATS MY STORY N IMA STICKIN TO IT LOL
Hey I'm an Engineer and an Attorney my brain likes to over analyze and overword these type questions lol.......
Happy New Year Yall
John T in Indiana
MarkB_MI
Well-known Member
- Location
- Motown USA
Well, on a two-stroke engine it's pretty straight-forward. Timing is based on the crank. I'd say this is true even on engines (such as the Detroit Diesel 2-strokes) that have camshafts.
Now, on a four-stroke engine, it's not so clear. Obviously crank position is the master for timing. Everything is derived from "zero degrees top dead center" on the #1 piston, which is of course crank position. BUT that happens two times in the four-stroke cycle. So to determine the correct timing, you need to know both crank and camshaft position. The camshaft is what determines valve timing, and that is what determines whether you are at TDC on the compression/combustion stroke or at TDC on the exhaust/intake stroke.
Incidentally, since most modern engines determine spark timing off the crankshaft, I believe that most actually fire the spark plug every rotation, both on compression and exhaust.
Now, on a four-stroke engine, it's not so clear. Obviously crank position is the master for timing. Everything is derived from "zero degrees top dead center" on the #1 piston, which is of course crank position. BUT that happens two times in the four-stroke cycle. So to determine the correct timing, you need to know both crank and camshaft position. The camshaft is what determines valve timing, and that is what determines whether you are at TDC on the compression/combustion stroke or at TDC on the exhaust/intake stroke.
Incidentally, since most modern engines determine spark timing off the crankshaft, I believe that most actually fire the spark plug every rotation, both on compression and exhaust.
All engine timing originates at the crankshaft measured in degrees of rotation. Different manufacturers choose the initial piston to begin the timing cycle but it is always measured at the crankshaft in degrees. Valve events are set in relation to crankshaft degrees of rotation,Distributor timing is always in relation to crankshaft degrees of rotation and fuel injection is in relation to crankshaft degrees of rotation
That is a question that is too vague to be answered. Timing of what? Valve opening in relation to piston position, valve closing, static time of ignition, ignition advance curve, diesel injector opening affected by PSI, etc.
All of these things are in relation to the crankshaft degrees .If any of these are out of time in relation to the crankshaft degrees of rotation they will not work properly
All of these things are in relation to the crankshaft degrees .If any of these are out of time in relation to the crankshaft degrees of rotation they will not work properly
Walt Davies
Well-known Member
All timing no matter what, is timed to the front gear on the crankshaft. Most have a timing mark that has to be set with the timing mark on the camshaft which drives the gear for the Distributor. Now don't quote me on this because there is always some guy who designs one that is not always in turn with the rest of us.
Take the Wankel engine for instance it has no camshaft. Also 2 cycle engines don't have cam shafts. Then there is the glow plug engine that is timed by compression. Yes they work very well.
Walt
Take the Wankel engine for instance it has no camshaft. Also 2 cycle engines don't have cam shafts. Then there is the glow plug engine that is timed by compression. Yes they work very well.
Walt
The intial question posted is "WHERE DOES ENGINE TIMING ORIGINATES?"
That question IS too vague. There is NO such thing, or no ONE thing known as "engine timing." I'll add that other factors, not in that list, can cause certain types to timing changes. Just opening pressure of a fuel injector changes timing. So does the length of an injector line in a diesel - which can cause "injection lag."
That question IS too vague. There is NO such thing, or no ONE thing known as "engine timing." I'll add that other factors, not in that list, can cause certain types to timing changes. Just opening pressure of a fuel injector changes timing. So does the length of an injector line in a diesel - which can cause "injection lag."
OP
OP
guido
Well-known Member
Hello John T.
Overanalyzed!!!!!!!!!!! Simple question.
You only needed to pick of of the letters. (CHUCKLE).
By the way what is the difference between a revision and a mistake?
I do have 1 engineer and 3 lawyers in my family and i poke at them as well, all in fun.
Guido.
Overanalyzed!!!!!!!!!!! Simple question.
You only needed to pick of of the letters. (CHUCKLE).
By the way what is the difference between a revision and a mistake?
I do have 1 engineer and 3 lawyers in my family and i poke at them as well, all in fun.
Guido.
The intial question posted is "WHERE DOES ENGINE TIMING ORIGINATES?"
That question IS too vague. There is NO such thing, or no ONE thing known as "engine timing." I"ll add that other factors, not in that list, can cause certain types to timing changes. Just opening pressure of a fuel injector changes timing. So does the length of an injector line in a diesel - which can cause "injection lag."
Exactly "originates" or is relative to what??
REALATIVE PRIMARILY TO CRANKSHAFT ROTATION !!!
These other things you mention only change the relativity to the crankshaft position but all engine timing is in direct relation to the crankshaft. not how you can change the timing you time all engines to the crankshaft where it originates
That question IS too vague. There is NO such thing, or no ONE thing known as "engine timing." I"ll add that other factors, not in that list, can cause certain types to timing changes. Just opening pressure of a fuel injector changes timing. So does the length of an injector line in a diesel - which can cause "injection lag."
Exactly "originates" or is relative to what??
REALATIVE PRIMARILY TO CRANKSHAFT ROTATION !!!
These other things you mention only change the relativity to the crankshaft position but all engine timing is in direct relation to the crankshaft. not how you can change the timing you time all engines to the crankshaft where it originates
Glen D Anderson
Member
Is this your "own" question? Or is it a question found in a text book?
The reason I ask, is that it is too vauge..........
Perhaps a question like:
Which of the following qualifies you as an expert on the theory of operation of the internal combustion engine:
A/ I overhauled a small block Chevy engine in my back-yard when I was in high school.
B/ I regularly watch the television show, Shade Tree Mechanic.
C/ I've got a buddy who is a mechanic.
D/ I stayed at a Holiday Inn last night.
E/ All of the above.
.......would be more appropriate??
BTW, I like to poke fun too
The reason I ask, is that it is too vauge..........
Perhaps a question like:
Which of the following qualifies you as an expert on the theory of operation of the internal combustion engine:
A/ I overhauled a small block Chevy engine in my back-yard when I was in high school.
B/ I regularly watch the television show, Shade Tree Mechanic.
C/ I've got a buddy who is a mechanic.
D/ I stayed at a Holiday Inn last night.
E/ All of the above.
.......would be more appropriate??
BTW, I like to poke fun too
An internal combustion engines uses ignition to light up a fuel charge and make an explosion.
A spark-ignition system uses an electrical spark to start the explosion. Most gas engines work this way. Ignition timing is usually referring to the time-of-spark. Doesn't matter where it occurs since it travels at 186,000 plus miles per second.
A diesel engine uses compressed air to make heat to ignite the fuel-charge, and is usually referred to a compression-ignition engine. Diesel ignition timing is usually referring to the time of fuel injection - but not always. Since fuel does not move at the speed of light there is always diesel-timing-lag. The lag is the time difference between the time of fuel injection, the time it takes for the fuel charge to travel from the injection pump and through the injector, and the actual time of useful combustion. That is why timing diesels can be confusing unless you know, for sure, what the timing specs refer to.
GM and Ford usually give timing specs both ways - for time of injection at the pump, and also for time of combustion that's measured with a luminosity probe.
The glow plug in a conventional diesel is just a starting aid to help the engine start when it lacks combustion heat.
A spark-ignition system uses an electrical spark to start the explosion. Most gas engines work this way. Ignition timing is usually referring to the time-of-spark. Doesn't matter where it occurs since it travels at 186,000 plus miles per second.
A diesel engine uses compressed air to make heat to ignite the fuel-charge, and is usually referred to a compression-ignition engine. Diesel ignition timing is usually referring to the time of fuel injection - but not always. Since fuel does not move at the speed of light there is always diesel-timing-lag. The lag is the time difference between the time of fuel injection, the time it takes for the fuel charge to travel from the injection pump and through the injector, and the actual time of useful combustion. That is why timing diesels can be confusing unless you know, for sure, what the timing specs refer to.
GM and Ford usually give timing specs both ways - for time of injection at the pump, and also for time of combustion that's measured with a luminosity probe.
The glow plug in a conventional diesel is just a starting aid to help the engine start when it lacks combustion heat.
I think with some of these posts, we are getting lost in technical semantics. In the apical/original post, Guido posed a question that is so vague, it cannot be accurately answered. He did not ask "what is the standard reference frame used for valve or ignition timing." If he had, it would make a little more sense. I'm not even sure what timing is in question. Time of ignition? Time of diesel fuel injection? Time of diesel combustion? Time of valve opening in relation to the piston it affects? Time of valve opening as it relates to the flywheel position? Maybe "time to buy a new engine?"
To be technical, a four cylinder engine is basically - four little internal combustion engines all tied together. Each one of those cylinders, individually, can be affected by piston travel as it relates to valve opening, valve closing, time of spark or fuel injection, etc. All of those things can happen differently for each cylinder - and the crankshaft-end will not always work as a common reference point for all. Yes, it IS designed to do so in most cases, but things do NOT always work that way. Measuring each crank throw will work, but that's not usually practical.
I can name a few examples. Bent connecting rods, one throw of a crank a little off, bad cam lobes, looses rocker arms causing late valve timing, tight rocker arms causing early valve timing an in-line injection pump with uneven injection rates, diesel fuel injectors cracking at different pressures that changes firing timing, etc. Note that not all tech manuals for all engines refer to piston position, or time of ignition in reference to the crankshaft-end-marker. They DO often use the crankshaft or flywheel as a marker of general piston position.
Not long ago I had to fix a Deere diesel that had every cylinder getting injection at the proper time when using the crankshaft marks as a rerference. But, one cylinder skipped and smoked worst than the rest. Found out later one piston was not where it was supposed to be - it was late and low. That's one example where a crank-end reference for a muliple cylinder engine does not always work.
Well, now I guess I'm the one wasting a lot of digital hot-air on a question that has no technical meaning anyway.
To be technical, a four cylinder engine is basically - four little internal combustion engines all tied together. Each one of those cylinders, individually, can be affected by piston travel as it relates to valve opening, valve closing, time of spark or fuel injection, etc. All of those things can happen differently for each cylinder - and the crankshaft-end will not always work as a common reference point for all. Yes, it IS designed to do so in most cases, but things do NOT always work that way. Measuring each crank throw will work, but that's not usually practical.
I can name a few examples. Bent connecting rods, one throw of a crank a little off, bad cam lobes, looses rocker arms causing late valve timing, tight rocker arms causing early valve timing an in-line injection pump with uneven injection rates, diesel fuel injectors cracking at different pressures that changes firing timing, etc. Note that not all tech manuals for all engines refer to piston position, or time of ignition in reference to the crankshaft-end-marker. They DO often use the crankshaft or flywheel as a marker of general piston position.
Not long ago I had to fix a Deere diesel that had every cylinder getting injection at the proper time when using the crankshaft marks as a rerference. But, one cylinder skipped and smoked worst than the rest. Found out later one piston was not where it was supposed to be - it was late and low. That's one example where a crank-end reference for a muliple cylinder engine does not always work.
Well, now I guess I'm the one wasting a lot of digital hot-air on a question that has no technical meaning anyway.
Glen D Anderson
Member
So, were you one of the students or the teacher?
I've answered my share of multiple choice questions during my training and I have to say that many of the questions I encountered were more of a "play on words" rather than being a legitimate question intended to find out if the apprentice/student truly understood the subject at hand...................
Have an individual explain, in detail, all four cycles of a four cycle engine AND how all of its main components(crank, piston, cam, & valves)are interacting with each other throughout those cycles and you will have a clear picture of what he or she does or doesn't know!
Multiple choice questions are a poor way of determining an individuals understanding of a given subject due to the "test taker" misinterpreting the intent of the "test maker".............
BTW, my money is with John T and John/Ont BUT I could be misinterpreting your intent...........
As for you having turned a few wrenches, you may very well have BUT I'm absolutely positve jdemaris has too AND he has a valid point!
I've answered my share of multiple choice questions during my training and I have to say that many of the questions I encountered were more of a "play on words" rather than being a legitimate question intended to find out if the apprentice/student truly understood the subject at hand...................
Have an individual explain, in detail, all four cycles of a four cycle engine AND how all of its main components(crank, piston, cam, & valves)are interacting with each other throughout those cycles and you will have a clear picture of what he or she does or doesn't know!
Multiple choice questions are a poor way of determining an individuals understanding of a given subject due to the "test taker" misinterpreting the intent of the "test maker".............
BTW, my money is with John T and John/Ont BUT I could be misinterpreting your intent...........
As for you having turned a few wrenches, you may very well have BUT I'm absolutely positve jdemaris has too AND he has a valid point!
Anonymous-0
Well-known Member
In the examination for Lieutenant in the Army Reserve I was asked..
Can you stand more pain than the next chap?
Answer.. How much pain can the next chap stand?
Smart ar$e said the Sergeant.
The question was incorrectly worded and it got the appropriate reply.
Can you stand more pain than the next chap?
Answer.. How much pain can the next chap stand?
Smart ar$e said the Sergeant.
The question was incorrectly worded and it got the appropriate reply.
This is one of the best forums I have ever entered
For those who would like the correct answer to Guido"s Question
I am a qualified mechanic both automotive and diesel for 30 years.
Guido did not ask a vague question.
Any thing in any internal combustion engine (including Gas or Diesel)when it is timed it is timed right back to the position of the crankshaft. If it is LATE or low it is because it is out of dimension in direct relation to the crankshaft , even if the injection pump or injector sends the charge of fuel too late it is in relation to piston position controled by the crankshaft if the piston is too low then that is caused by damaged or improper parts which is also checked referenced back to crankshaft for proper position .
GUIDO you are right on with this all too popular question in the trade schools and the answers are very similar here as trade school
Glen D Anderson , I think your NOT misinterpreting my intent any way and here is my intent
My intent is to merely add educated answer to this question because of my education and physical practice for 30 years .
Go ahead if you please name me one part of an internal combustion engine that needs to be timed that does not relate back to a crankshaft
For those who would like the correct answer to Guido"s Question
I am a qualified mechanic both automotive and diesel for 30 years.
Guido did not ask a vague question.
Any thing in any internal combustion engine (including Gas or Diesel)when it is timed it is timed right back to the position of the crankshaft. If it is LATE or low it is because it is out of dimension in direct relation to the crankshaft , even if the injection pump or injector sends the charge of fuel too late it is in relation to piston position controled by the crankshaft if the piston is too low then that is caused by damaged or improper parts which is also checked referenced back to crankshaft for proper position .
GUIDO you are right on with this all too popular question in the trade schools and the answers are very similar here as trade school
Glen D Anderson , I think your NOT misinterpreting my intent any way and here is my intent
My intent is to merely add educated answer to this question because of my education and physical practice for 30 years .
Go ahead if you please name me one part of an internal combustion engine that needs to be timed that does not relate back to a crankshaft
Your 30 years do not prove, or disprove a thing. Many here have been turning wrenches a lot longer than that - including me. All I can say is - so what? Some people learn much in short periods of time, and some learn little throughout their lifetimes. We all vary, as do our experiences and interest in learning. I say that as a general statement - not targetted personally at you.
Internal combustion engines with conventional pistons moving in cylinders are engineered with ignition timing and valve timing relating to the position of the piston and it's distance from top or bottom of its travel, NOT the crank or flywheel reference marks. Those crank-marks or flywheel marks are shortcuts to indicate that piston placement and nothing more. They are usually reliable, but not always. Some engines are more precise and give timing specs that relate to direct dial-indicator measurments to indicate piston position.
The plain fact is - the only true constant when it comes to TDC, BTDC, etc. is the piston as it relates to it's position in the cylinder. The other reference markts are just that. Marks that refer to something else. When something calls for TDC, is is assumed that when the piston is at TDC, so will be the crank-throw - but not in all cases.
In response to your " Go ahead if you please name me one part of an internal combustion engine that needs to be timed that does not relate back to a crankshaft . . ."
With a multiple cylinder engine - the crank reference mark does NOT work for all cylinders if all is not perfect. All it takes is one bent connecting rod (that is now shorter than the rest) on a four-cylinder engine, a bent crank with one throw out of wack - and your one crank-mark will lie to you about that particular cylinder. If your crank-mark says - let's say - top-dead-center . . . with a bent rod, it will never get to the engineered point of TDC travel is was designed for - even though the crank or flywheel mark says it is. NOT an uncommon event.
If a crank-throw is not where it is supposed to be - the piston travel timing on that one cylinder can differ from the others - and the crank reference mark will NOT tell you that. I'll add that John Deere had a bunch of three cylinder diesels come through that way in the early 1980s. The Deere flywheel timing mark lied about where #2 piston actually was - on several brand new engines.
Note that even crude tractor engines have their spark ignition timing, or fuel time-of-injection, or time of valve opening - expressed as degrees before, at, or after top-dead-center or bottom-dead-center. Center of what? The crankshaft position? No. It relates to piston position.
Granted that there are a few modern tech manuals that assume crank-throw position has to be the same as piston position - but that is rare -and to be technical - it is incorrect.
Hope you never have to work on a Gnome rotary-cylinder engine. The crank is stationary.
I'll also note, that the term that Guido used - "timing" is indeed vague. It has mutiple connotations, even just within the scope of internal engine mechanics.
Internal combustion engines with conventional pistons moving in cylinders are engineered with ignition timing and valve timing relating to the position of the piston and it's distance from top or bottom of its travel, NOT the crank or flywheel reference marks. Those crank-marks or flywheel marks are shortcuts to indicate that piston placement and nothing more. They are usually reliable, but not always. Some engines are more precise and give timing specs that relate to direct dial-indicator measurments to indicate piston position.
The plain fact is - the only true constant when it comes to TDC, BTDC, etc. is the piston as it relates to it's position in the cylinder. The other reference markts are just that. Marks that refer to something else. When something calls for TDC, is is assumed that when the piston is at TDC, so will be the crank-throw - but not in all cases.
In response to your " Go ahead if you please name me one part of an internal combustion engine that needs to be timed that does not relate back to a crankshaft . . ."
With a multiple cylinder engine - the crank reference mark does NOT work for all cylinders if all is not perfect. All it takes is one bent connecting rod (that is now shorter than the rest) on a four-cylinder engine, a bent crank with one throw out of wack - and your one crank-mark will lie to you about that particular cylinder. If your crank-mark says - let's say - top-dead-center . . . with a bent rod, it will never get to the engineered point of TDC travel is was designed for - even though the crank or flywheel mark says it is. NOT an uncommon event.
If a crank-throw is not where it is supposed to be - the piston travel timing on that one cylinder can differ from the others - and the crank reference mark will NOT tell you that. I'll add that John Deere had a bunch of three cylinder diesels come through that way in the early 1980s. The Deere flywheel timing mark lied about where #2 piston actually was - on several brand new engines.
Note that even crude tractor engines have their spark ignition timing, or fuel time-of-injection, or time of valve opening - expressed as degrees before, at, or after top-dead-center or bottom-dead-center. Center of what? The crankshaft position? No. It relates to piston position.
Granted that there are a few modern tech manuals that assume crank-throw position has to be the same as piston position - but that is rare -and to be technical - it is incorrect.
Hope you never have to work on a Gnome rotary-cylinder engine. The crank is stationary.
I'll also note, that the term that Guido used - "timing" is indeed vague. It has mutiple connotations, even just within the scope of internal engine mechanics.
OP
OP
guido
Well-known Member
Hello Glen D Anderson.
I kept the answer vague about students not having problem understanding where engine timing comes from. I was the one giving the test. Did not write that particular one.
John T said it was a good question and then he also had some negative comments as well.
I did not post the question to have it drag out or be controvertial. Ones the dust settles I'll post the answer.
Guido.
I kept the answer vague about students not having problem understanding where engine timing comes from. I was the one giving the test. Did not write that particular one.
John T said it was a good question and then he also had some negative comments as well.
I did not post the question to have it drag out or be controvertial. Ones the dust settles I'll post the answer.
Guido.
Glen D Anderson
Member
John,
I believe you misunderstood me, I was speaking to Guido about HIS intent of the question he posted:
"BTW, my money is with John T and John/Ont BUT I could be misinterpreting your intent..........."
As for the crankshaft being the origin of engine timing, I agree 100% BUT there are those out there that would say different.........
Multiple choice questions have become so common place in trade schools because they are more convenient for the teacher/instructor than dealing with long answer questions..........Wording a multiple choice question in such a manner that it may be interpreted several different ways with one answer being the BEST is as much of a test of a students grammatical abilities as it is of the students mechanical abilities.................
Ask a student to explain, in detail, all of the four cycles in a four stroke internal combustion engine AND how ALL of the major components are interacting with each other throughout the four cycles and you will have a clear picture of the students understanding of the the subject............
To clarify my point or intentions again, you could take a group of students who have just passed test composed soley of multiple choice questions and re-test them with long answer questions and likley find that 25% of them would NOT have a clear understanding of the subject of the question.........The level of understanding of students taking tests with mutlitple choice questions is inconclusive. People are going to guess and get lucky, it matter of simple mathematics. Not unlike those who win the lottery!
Anyway, no offence intended,
Have a Happy New Year!
Glen
I believe you misunderstood me, I was speaking to Guido about HIS intent of the question he posted:
"BTW, my money is with John T and John/Ont BUT I could be misinterpreting your intent..........."
As for the crankshaft being the origin of engine timing, I agree 100% BUT there are those out there that would say different.........
Multiple choice questions have become so common place in trade schools because they are more convenient for the teacher/instructor than dealing with long answer questions..........Wording a multiple choice question in such a manner that it may be interpreted several different ways with one answer being the BEST is as much of a test of a students grammatical abilities as it is of the students mechanical abilities.................
Ask a student to explain, in detail, all of the four cycles in a four stroke internal combustion engine AND how ALL of the major components are interacting with each other throughout the four cycles and you will have a clear picture of the students understanding of the the subject............
To clarify my point or intentions again, you could take a group of students who have just passed test composed soley of multiple choice questions and re-test them with long answer questions and likley find that 25% of them would NOT have a clear understanding of the subject of the question.........The level of understanding of students taking tests with mutlitple choice questions is inconclusive. People are going to guess and get lucky, it matter of simple mathematics. Not unlike those who win the lottery!
Anyway, no offence intended,
Have a Happy New Year!
Glen
Glen D Anderson
Member
Guido,
Your question may be controversial BUT it is not certainly not offensive.
You are also entitled to your opinions.
My opinions come from being in the mechanics trade for only 15 years BUT having seen MANY other technicians become qualified who have slipped through the cracks by "guessing their way through" the mulitple choice question tests.......That's all!
Anyway, have a Happy New Year!
Glen
Your question may be controversial BUT it is not certainly not offensive.
You are also entitled to your opinions.
My opinions come from being in the mechanics trade for only 15 years BUT having seen MANY other technicians become qualified who have slipped through the cracks by "guessing their way through" the mulitple choice question tests.......That's all!
Anyway, have a Happy New Year!
Glen
at this point as you see it although incorrectly all you have mentioned is things which are able to change piston position. The root of timing in any internal combustion engine be it gasoline, propane, diesel , injector, injector pump or a Gnome Rotary are all termed in degrees of or around the crankshaft rotation .
Spark ignition timing, or fuel time-of-injection, or time of valve opening - expressed as degrees before, at, or after top-dead-center or bottom-dead-center. Center of what? The crankshaft position?
ACTUALLY YES the throw of the crank is supposed to be at the predetermined point before ign or injection . EACH AND EVERY THROW As i said before if they are in the improper place then the part is either damaged
EG.#1-- "The Deere flywheel timing mark lied about where #2 piston actually was = damage
EG#2 -- If a crank-throw is not where it is supposed to be = damaged and that throw is out of time
EG# -- the crank reference mark does NOT work for all cylinders if all is not perfect. All it takes is one bent connecting rod (that is now shorter than the rest)= damaged
Piston travel is not timed it is positioned according to crankshaft throw timing and can safely be assumed that TDC of a piston is Equal to TDC of the crankshaft throw.
Rods are measure in length and weight not degrees
The terms TDC, BTDC, ATDC, BDC, BBDC, ABDC actually refers to the crankshaft throw can be referenced from the manufacturers predetermined position most commonly beginning at #1 cyl and all things being as they are supposed to be each cylinder will fire at the same point (EG 10 deg.BTDC)
DAMAGED OR IMPROPERLY manufactured parts will adversly affect the functionand timing of that part and all those that follow it such as a bent push rod, that valve may be out of time but it is out of time to the crankshaft which put that piston in position .
By using your own quotes I have shown you the difference between close and being correct of which I AM CORRECT
As for my 30 years "Your 30 years do not prove, or disprove a thing." you are WRONG there as well.
They prove I actually have that education and experience. Maybe they don"t mean anything to you but with your attitude which is less than desirable you don"t want to learn you just think you are right
So far you have been unable to name me one part of an internal combustion engine that needs to be timed that does not relate back to a crankshaft
GNOME ENGINE TIMING
To "time" the engine, position the crankshaft with the crankpin at Top Dead Center (TDC) for the right hand cylinder. There will be a timing mark on the the gear of each cam/gear assembly. Position the right hand cam/gear so that the timing mark is closest to the crankshaft -- ie mark "down" in relation to the "up" crank pin. The other gear is set opposite -- ie mark "up" in relation to the "down" crankpin. Now put everything else back together and set the tappet clearence to 0.1mm (0.004") when the valve push rod is at its lowest point. Nothing else requires special attention, assuming you are familiar with engine assembly techniques.
NOTE THAT EVEN THE TIMING FOR THIS ENGINE REFERS BACK TO CRANKSHAFT
So Go ahead you can have the last word I will refrain from any further responses to your comments or this particular subject as you are unwilling to be any further educated
HAPPY NEW YEAR
to YOU and ALL OTHER FORUM PARTICIPANTS
Spark ignition timing, or fuel time-of-injection, or time of valve opening - expressed as degrees before, at, or after top-dead-center or bottom-dead-center. Center of what? The crankshaft position?
ACTUALLY YES the throw of the crank is supposed to be at the predetermined point before ign or injection . EACH AND EVERY THROW As i said before if they are in the improper place then the part is either damaged
EG.#1-- "The Deere flywheel timing mark lied about where #2 piston actually was = damage
EG#2 -- If a crank-throw is not where it is supposed to be = damaged and that throw is out of time
EG# -- the crank reference mark does NOT work for all cylinders if all is not perfect. All it takes is one bent connecting rod (that is now shorter than the rest)= damaged
Piston travel is not timed it is positioned according to crankshaft throw timing and can safely be assumed that TDC of a piston is Equal to TDC of the crankshaft throw.
Rods are measure in length and weight not degrees
The terms TDC, BTDC, ATDC, BDC, BBDC, ABDC actually refers to the crankshaft throw can be referenced from the manufacturers predetermined position most commonly beginning at #1 cyl and all things being as they are supposed to be each cylinder will fire at the same point (EG 10 deg.BTDC)
DAMAGED OR IMPROPERLY manufactured parts will adversly affect the functionand timing of that part and all those that follow it such as a bent push rod, that valve may be out of time but it is out of time to the crankshaft which put that piston in position .
By using your own quotes I have shown you the difference between close and being correct of which I AM CORRECT
As for my 30 years "Your 30 years do not prove, or disprove a thing." you are WRONG there as well.
They prove I actually have that education and experience. Maybe they don"t mean anything to you but with your attitude which is less than desirable you don"t want to learn you just think you are right
So far you have been unable to name me one part of an internal combustion engine that needs to be timed that does not relate back to a crankshaft
GNOME ENGINE TIMING
To "time" the engine, position the crankshaft with the crankpin at Top Dead Center (TDC) for the right hand cylinder. There will be a timing mark on the the gear of each cam/gear assembly. Position the right hand cam/gear so that the timing mark is closest to the crankshaft -- ie mark "down" in relation to the "up" crank pin. The other gear is set opposite -- ie mark "up" in relation to the "down" crankpin. Now put everything else back together and set the tappet clearence to 0.1mm (0.004") when the valve push rod is at its lowest point. Nothing else requires special attention, assuming you are familiar with engine assembly techniques.
NOTE THAT EVEN THE TIMING FOR THIS ENGINE REFERS BACK TO CRANKSHAFT
So Go ahead you can have the last word I will refrain from any further responses to your comments or this particular subject as you are unwilling to be any further educated
HAPPY NEW YEAR
to YOU and ALL OTHER FORUM PARTICIPANTS
OP
OP
guido
Well-known Member
Engine theory of operation is just that.... THEORY. Here is a sequence for timing a 4cycle engine with a distributor type ignition.
First step of timing an engine is to turn the CRANCKSHAFT! to position the piston on the cylinder the engine is timed to, (NOT ALWAYS #1).
Second step is to TIME the camshaft to the CRANCKSHAFT!. If the cam needs to be checked for proper timing the engine heads will have to be installed, and any other componet that may be required to perfom the test,( push rods rocker arms).
The next step, would be to time the distributor to the cylinder that is used for the engine timing driven by the camshaft that is timed to the CRANCKSHAFT!, (NOT ALWAYS #1)
The camshaft will open the engine valves in
sequence/ TIME in respect of piston position controlled by the CRANSHAFT!. It will also controll valve overlap/ openings in degrees of of CRANCKSHAFT rotation.
After the engine is started, the timimg needs to be checked and when you hook up the timing light you point the strobe light at ......................the CRANCKSHAFT!!!!!! If there are any variance in a paricular engine timing,follow the engine manufacturer requirents.
Guido.
First step of timing an engine is to turn the CRANCKSHAFT! to position the piston on the cylinder the engine is timed to, (NOT ALWAYS #1).
Second step is to TIME the camshaft to the CRANCKSHAFT!. If the cam needs to be checked for proper timing the engine heads will have to be installed, and any other componet that may be required to perfom the test,( push rods rocker arms).
The next step, would be to time the distributor to the cylinder that is used for the engine timing driven by the camshaft that is timed to the CRANCKSHAFT!, (NOT ALWAYS #1)
The camshaft will open the engine valves in
sequence/ TIME in respect of piston position controlled by the CRANSHAFT!. It will also controll valve overlap/ openings in degrees of of CRANCKSHAFT rotation.
After the engine is started, the timimg needs to be checked and when you hook up the timing light you point the strobe light at ......................the CRANCKSHAFT!!!!!! If there are any variance in a paricular engine timing,follow the engine manufacturer requirents.
Guido.
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