A few more questions while I'm learning to adjust the valves. It's the stuff they don't say in the book that makes me wonder.
How do I know when a cylinder is ready to have the valve clearance adjusted? Is there some way of knowing EXACTLY when the rockers are at maximum clearance?
It's hard to tell the answers to these questions when I turn the engine over by myself and crawl back in the right side of the engine bay. I think I'm gonna have a friend turn it over while I watch the rockers move. But I appreciate any help before I can do that!
2 stroke
when the injector is fully depressed..the valves are fully closed...
Yes,it is whent the center (injector) rocker is fully compressed. You should do all the valves in only one rotation of the engine.
Yep, but how do I know when the injector is "fully depressed" as opposed to 3/4 depressed? Ha! I can't be helped!
I guess I'll have to have someone else turn the engine over while I watch them move. Then I'll know. I've been trying to do it by myself and I can't tell what's what from behind the engine.
depressesd at all is fine,as in the inj. rocker arm is lower than the valve rocker...pull the fuel at the govenor and get a bumper button...
or bungee the racks...
or drain the fuel filters and plug the air intakes :)
PS. For sure you're setting the injectors...
and your doing this on a hot motor, right ?
No, I'm adjusting the valve clearances. Injector timing will be next. I'm following the manual instructions for setting cold valves then I'll check them hot. Thx.
Ok I think I get it now.
In the cycle of valves and injectors, there is a very short momentary pause when the valves move from open to fully closed before the injectors are pushed down. Then the injector is completely "undepressed" right before the valve bridges are pushed down.
So as long as the injector is depressed, the valves are closed and can be adjusted for clearance. Yah?
And when the valve bridges do not wiggle they are open and the injectors can be timed with the cocktail stick tool, yah?
I'll do all the valves in order in one rotation. Then go through again and do the injectors.
i just do them as i see them...
one bank then the other.
inj or valves which ever is there.
on injectors.. a drop or two of oil on the plunger surface is your friend...
when you twist your timing tool it gives you another reference comparing the "wipe"...
the cocktail stick doesn't hold olives well...the holes are too big, go with onions for Martini's.
ps. the mechanics I know drink Rye whiskey.
ok :)
In tech-speak, a cam has a lobe with a base circle. A full rotation is 360 degrees, and around 200 - 220 degrees of that is base circle. There is a short transition from the base circle called the ramp which takes up clearance smoothly, and then comes the flank. The flank lifts the valve (or closes the injector) until it reaches the nose - the point of maximum lift. Then you get another flank, another ramp, and back onto the base circle. The base circles are ground with an extreme degree of accuracy, so you can set valve clearance or time the injector at any point where the cam follower is on the base circle. There is no special need to find the center point of the base circle, any point 10 or 15 degrees past valve closing is fine. Similarly any point 10 or 15 degrees past the injector finding it's tallest point is fine, but the injectors never have any clearance - they are always under tension from the cam/follower/pushrod. You set the timing by adjusting the height of the injector with the cam lobe on it's base circle. Since you are rotating the engine anyway, it's just as easy to find a good center point on the base circle by setting the valves when the injector is all the way down, and setting the injectors when the valves are fully open, but there is no need to be anal about it - "around" fully down or open is perfectly fine. Remember to lock the engine stop lever in "no-fuel", engine speed lever in idle, and if you use a wrench on the front pulley bolt always turn the engine clockwise as if you were tightening that bolt. Never turn the engine backwards, or you stand a chance of losing torque on that bolt.
Brian
Hint:. Since you have Jakes, you are going to have to bend the injector height tool handle at a 45 degree angle so you can get under the Jake body.
As an aviation mechanic/inspector for 33 years its interesting to note that the FAA requires that a mechanic whom hase'nt performed a task, cannot do so unless he/she performs that task in the presence and under the supervision of one whom has.. It would prevent a lot of goofups by newbe's trying to to technical work for the first time that can have very expensive results.>>>Dan
Quote from: Geoff on March 18, 2018, 09:35:11 AM
Hint:. Since you have Jakes, you are going to have to bend the injector height tool handle at a 45 degree angle so you can get under the Jake body.
Or buy a set made for setting the injectors with Jakes
Quote from: bevans6 on March 18, 2018, 09:14:05 AM
In tech-speak, a cam has a lobe with a base circle. A full rotation is 360 degrees, and around 200 - 220 degrees of that is base circle. There is a short transition from the base circle called the ramp which takes up clearance smoothly, and then comes the flank. The flank lifts the valve (or closes the injector) until it reaches the nose - the point of maximum lift. Then you get another flank, another ramp, and back onto the base circle. The base circles are ground with an extreme degree of accuracy, so you can set valve clearance or time the injector at any point where the cam follower is on the base circle. There is no special need to find the center point of the base circle, any point 10 or 15 degrees past valve closing is fine. Similarly any point 10 or 15 degrees past the injector finding it's tallest point is fine, but the injectors never have any clearance - they are always under tension from the cam/follower/pushrod. You set the timing by adjusting the height of the injector with the cam lobe on it's base circle. Since you are rotating the engine anyway, it's just as easy to find a good center point on the base circle by setting the valves when the injector is all the way down, and setting the injectors when the valves are fully open, but there is no need to be anal about it - "around" fully down or open is perfectly fine. Remember to lock the engine stop lever in "no-fuel", engine speed lever in idle, and if you use a wrench on the front pulley bolt always turn the engine clockwise as if you were tightening that bolt. Never turn the engine backwards, or you stand a chance of losing torque on that bolt.
Brian
Thank you for taking the time to share this. You filled in some of the knowledge I was lacking. I appreciate it!
Quote from: Utahclaimjumper on March 18, 2018, 09:50:31 AM
As an aviation mechanic/inspector for 33 years its interesting to note that the FAA requires that a mechanic whom hase'nt performed a task, cannot do so unless he/she performs that task in the presence and under the supervision of one whom has.. It would prevent a lot of goofups by newbe's trying to to technical work for the first time that can have very expensive results.>>>Dan
I hear that. It isn't easy to learn from a manual that assumes you're generally trained on diesel engines. A lot of basic information is left out. That's why I come here.
Some day I'll have to get to one of these rallies and spend some time learning from you guys in person, but for now, these threads are what I've got. I've resisted the urge to not post threads because eventually someone's gonna tell me if I don't already know the answer then I shouldn't even be doing this. But I figure some newb somewhere might appreciate reading these someday.
Maybe when I come to a rally we can shoot some videos on how to do this kind of maintenance stuff for the bus community. Then people do it the right way and preserve these engines.
I for one applaud your bravery...cool stuff. Keep posting
Sent from my iPhone using Tapatalk Pro
You are doing fine ask for help most are helpful here,use the firing order makes it easier and I mark the the cylinders I do with soap stone so I don't forget where I was last ;D.you were ok like Donald said if the injector is starting on the injection cycle the valves are closed
I was going to say it's no harder than setting the valve lash in an old MGB, or sychronizing the carbs on a motorcycle. then I realized that maybe a lot of people haven't been doing that for 40 years like I have. But every one has a first time for anything, and lots of people figure it out on their own, they don't get taught by a grizzled veteran.
Quote from: bevans6 on March 19, 2018, 05:17:57 AM
I was going to say it's no harder than setting the valve lash in an old MGB, or sychronizing the carbs on a motorcycle. then I realized that maybe a lot of people haven't been doing that for 40 years like I have. But every one has a first time for anything, and lots of people figure it out on their own, they don't get taught by a grizzled veteran.
Lol I owned a 1954 Corvette for 30 years up to 2000 before I sold it,it had a 261 CI inline 6 cylinder with 3 side draft carbs I never did get the hang of adjusting the carbs ;D neither did anyone else
The Blue Flame inline 6? ;D
My first valve adjustment was a 69 VW Bus. I mean... A bus is a bus, right?! ☺
Quote from: luvrbus on March 19, 2018, 06:55:06 AM
Lol I owned a 1954 Corvette for 30 years up to 2000 before I sold it,it had a 261 CI inline 6 cylinder with 3 side draft carbs I never did get the hang of adjusting the carbs ;D neither did anyone else
Pretty rare engine. Generally found in trucks, we had a couple one in a '56 pick-up with a 4 speed hydramatic and one in a dump truck with 4 speed and 2 speed axle vacuum shift.
Quote from: Lee Bradley on March 19, 2018, 08:55:37 AM
Pretty rare engine. Generally found in trucks, we had a couple one in a '56 pick-up with a 4 speed hydramatic and one in a dump truck with 4 speed and 2 speed axle vacuum shift.
Yea it was a truck engine in 1954 the Corvette had a option of the 235 or 261 CI inline 6 both are identical in size even the same valve cover
1954 Corvette was available with only 235 cu. in. engine.
Everything you didn't need to know about the 261:
http://1954advance-design.com/Web%20images/261-engine/index.htm (http://1954advance-design.com/Web%20images/261-engine/index.htm)
Quote from: chessie4905 on March 19, 2018, 01:05:59 PM
1954 Corvette was available with only 235 cu. in. engine.
Everything you didn't need to know about the 261:
http://1954advance-design.com/Web%20images/261-engine/index.htm (http://1954advance-design.com/Web%20images/261-engine/index.htm)
Mine was factory 261 it only had 38,000 miles on it when I sold it
Ok everybody, I finished adjusting the valves and timing the injectors. I really appreciate everyone's helpful words. Now that I understand how the system works it all seems so obvious, heh.
I found that the Snap on 5/16 and 1/2 wrap around wrenches were handy in some cylinders and the stubby wrenches I got at HF were better on others. After a few valves I got better at adjusting them a little before tightening the locknut. Some valves took 10 seconds and others took 10 minutes of back and forth trying to make sure they're just right. I rechecked them a couple rotations to be sure (with the stop lever blocked!).
When I went to fire it up... It sounds about the same but maybe a smidge smoother. :)
Drove 2 hrs today in Nevada on 95 and tested the repaired Jake brakes... But that story is for my other thread!
Here's a few pics to sweeten up the thread. (https://uploads.tapatalk-cdn.com/20180320/f7123d2ddc8909798f1608fb862224c3.jpg)(https://uploads.tapatalk-cdn.com/20180320/6f23d7e2a25cdf3ee8e7cefe5ab2b279.jpg)(https://uploads.tapatalk-cdn.com/20180320/2df8271359d2931f7b83abba4330447f.jpg)
Good job well done! FWIW, the valve clearance tolerance is plus 2 thou, so if (for example) a 12 thou gauge goes in but a 14 thou gauge does not, the clearance is between 12 and 14 thou and within spec.