Very Rough Running
06-28-2009, 01:42 AM
#1
Rennlist Member
Thread Starter
Very Rough Running
Why is it that the simple jobs always seem to go bad
Today, adjusted the tension on the timing belt, and cleaned up the engine bay on the new to me Bleumax (a '78 5spd). The car had been running perfectly prior to today's work. Now it is running very rough and it hardly goes. It feels like it wants to die. Like it isn't getting enough fuel?
The specific jobs I did were remove the airbox and generally clean things up around it and under it. I was careful not to disturb anything, but who knows - maybe I bumped something?
The other job was to adjust the belt tension - it was due (replaced about 2500 miles ago). The belt was very loose. I also noticed that I could not get the cam gear mark to match the top dead center mark on the main shaft.. The cam gear is advanced quite a bit. I did nothing other than turn the crank with a 27 mm socket per the instructions with the Kempf tool ans WSM.
Note - the car has had the cats removed and has an after market muffler. The timing may have been adjusted for that? Also, it ran perfectly before my activities.
Thoughts?
Today, adjusted the tension on the timing belt, and cleaned up the engine bay on the new to me Bleumax (a '78 5spd). The car had been running perfectly prior to today's work. Now it is running very rough and it hardly goes. It feels like it wants to die. Like it isn't getting enough fuel?
The specific jobs I did were remove the airbox and generally clean things up around it and under it. I was careful not to disturb anything, but who knows - maybe I bumped something?
The other job was to adjust the belt tension - it was due (replaced about 2500 miles ago). The belt was very loose. I also noticed that I could not get the cam gear mark to match the top dead center mark on the main shaft.. The cam gear is advanced quite a bit. I did nothing other than turn the crank with a 27 mm socket per the instructions with the Kempf tool ans WSM.
Note - the car has had the cats removed and has an after market muffler. The timing may have been adjusted for that? Also, it ran perfectly before my activities.
Thoughts?
06-28-2009, 01:52 AM
#2
Under the Lift
Lifetime Rennlist
Member
Lifetime Rennlist
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Hi Ed:
Most likely you bumped something. Did you WASH the engine?
The belt should be set on the cam gear within 1/2 a tooth of TDC. If it's within 1/2 tooth, there is nothing you can adjust to get it any closer as the position is determined by the BELT. If it's off more than 1/2 a tooth, the belt should be loosened and the belt moved over on the gear teeth to get it within 1/2 tooth. Initial belt stretch should generally not move the belt tension more than a fraction of the Kempf tool window, like maybe a third or half at most. If the belt stretched more than that, I'd watch that belt more closely. If a belt stretches again outside of the initial post-belt adjustment interval, I replace it.
Most likely you bumped something. Did you WASH the engine?
The belt should be set on the cam gear within 1/2 a tooth of TDC. If it's within 1/2 tooth, there is nothing you can adjust to get it any closer as the position is determined by the BELT. If it's off more than 1/2 a tooth, the belt should be loosened and the belt moved over on the gear teeth to get it within 1/2 tooth. Initial belt stretch should generally not move the belt tension more than a fraction of the Kempf tool window, like maybe a third or half at most. If the belt stretched more than that, I'd watch that belt more closely. If a belt stretches again outside of the initial post-belt adjustment interval, I replace it.
06-28-2009, 09:22 AM
#6
Rennlist Member
Thread Starter
What if I knocked the timing off somehow? How do you reset that? The cam gear was not lined up with TDC at 0. It was off by a pretty wide margin.
note - I couldn't get the crank to turn with the wrench, so I "bumped" the starter a couple of times with the key in the ignition to get it to move more easily - could've thrown off timing by the belt jumping a few teeth? Do I loosen the belt and just line all these marks up by hand?
note - I couldn't get the crank to turn with the wrench, so I "bumped" the starter a couple of times with the key in the ignition to get it to move more easily - could've thrown off timing by the belt jumping a few teeth? Do I loosen the belt and just line all these marks up by hand?
06-28-2009, 09:44 AM
#7
Check the timing marks first and if they are off, it's easy to reset. Turn the engine clockwise with a big wrench or breaker bar since you're fighting compression. With the engine at TDC you will need a wrench on the cams (17mm on mine) to hold them at the timing marks, since they will want to turn with the same compression. Loosen the belt and pull it off the cams (no worries with an early 16v). Then starting with the driver's side cam, turn it until the timing marks line up and then wrap the belt around it, making sure it's tight coming from the crank pulley/oil pump. The belt will hold the cam in place. Then work it tightly around the water pump and idler, and then to the passenger cam. The trick here is to get the cam lined up with the wrench (it will want to turn), and then work the belt over the entire gear at the same time. If you try to get the first few teeth on and then pry it over the gear you'll never get there. Once you have the teeth engaged just a little, the belt will hold the gear and you can release the wrench. Push the belt all the way on and double check all timing marks.
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06-28-2009, 09:45 AM
#8
Rennlist Member
Ed, how far off? You might want to post up some snapshots.
First, the crank markings should be arranged readable from standing in front of engine, text not upside down, so you know that the harmonic balancer is not flipped.
Second, as you know, the crank at TDC will yield cam gear marks either on the refernce marks on the Mickey Mouse ear cam covers, or else 180 degrees off.
Assuming non-interference for the early car, should be OK to rotate cam gears in the direction of normal rotation, independently of each other and crank. Clockwise that is, viewing from in front of the car.
Snapshots would help everybody confirm that no weird mods or wrong cam gears, etc, are used.
I work on 83/4 and 5/6 exclusively, so I don't know what marks are on 78/9 camgears, but suspect they are the tiny little saw marks on the backs of the gear, not front. Are you looking at the right marks?
First, the crank markings should be arranged readable from standing in front of engine, text not upside down, so you know that the harmonic balancer is not flipped.
Second, as you know, the crank at TDC will yield cam gear marks either on the refernce marks on the Mickey Mouse ear cam covers, or else 180 degrees off.
Assuming non-interference for the early car, should be OK to rotate cam gears in the direction of normal rotation, independently of each other and crank. Clockwise that is, viewing from in front of the car.
Snapshots would help everybody confirm that no weird mods or wrong cam gears, etc, are used.
I work on 83/4 and 5/6 exclusively, so I don't know what marks are on 78/9 camgears, but suspect they are the tiny little saw marks on the backs of the gear, not front. Are you looking at the right marks?
06-28-2009, 10:13 AM
#12
Ken posted WSM pics of the timing marks in this thread. I seem to remember that the very early cars had the marks on the front of the cam gears, but I may be mistaken. Either way, make sure they are lined up with the indicators on the cam housing and that the engine is indeed at TDC. BTW also ensure the markings on the harmonic damper are oriented correctly. If you are standing in front and look at the markings, they should be right side up. If not, someone installed the damper backwards and you will be way off. Given the car ran well before, this is probably not the case.
https://rennlist.com/forums/928-foru...ing-marks.html
BTW I'm with Colin, you probably knocked something loose and the engine is getting too much air. But checking the timing is a good idea.
https://rennlist.com/forums/928-foru...ing-marks.html
BTW I'm with Colin, you probably knocked something loose and the engine is getting too much air. But checking the timing is a good idea.
06-28-2009, 10:16 AM
#13
Rennlist Member
Thread Starter
Ed, how far off? You might want to post up some snapshots.
First, the crank markings should be arranged readable from standing in front of engine, text not upside down, so you know that the harmonic balancer is not flipped.
Second, as you know, the crank at TDC will yield cam gear marks either on the refernce marks on the Mickey Mouse ear cam covers, or else 180 degrees off.
Assuming non-interference for the early car, should be OK to rotate cam gears in the direction of normal rotation, independently of each other and crank. Clockwise that is, viewing from in front of the car.
Snapshots would help everybody confirm that no weird mods or wrong cam gears, etc, are used.
I work on 83/4 and 5/6 exclusively, so I don't know what marks are on 78/9 camgears, but suspect they are the tiny little saw marks on the backs of the gear, not front. Are you looking at the right marks?
First, the crank markings should be arranged readable from standing in front of engine, text not upside down, so you know that the harmonic balancer is not flipped.
Second, as you know, the crank at TDC will yield cam gear marks either on the refernce marks on the Mickey Mouse ear cam covers, or else 180 degrees off.
Assuming non-interference for the early car, should be OK to rotate cam gears in the direction of normal rotation, independently of each other and crank. Clockwise that is, viewing from in front of the car.
Snapshots would help everybody confirm that no weird mods or wrong cam gears, etc, are used.
I work on 83/4 and 5/6 exclusively, so I don't know what marks are on 78/9 camgears, but suspect they are the tiny little saw marks on the backs of the gear, not front. Are you looking at the right marks?
06-28-2009, 10:21 AM
#14
Rennlist Member
Thread Starter
Ken posted WSM pics of the timing marks in this thread. I seem to remember that the very early cars had the marks on the front of the cam gears, but I may be mistaken. Either way, make sure they are lined up with the indicators on the cam housing and that the engine is indeed at TDC. BTW also ensure the markings on the harmonic damper are oriented correctly. If you are standing in front and look at the markings, they should be right side up. If not, someone installed the damper backwards and you will be way off. Given the car ran well before, this is probably not the case.
https://rennlist.com/forums/928-foru...ing-marks.html
BTW I'm with Colin, you probably knocked something loose and the engine is getting too much air. But checking the timing is a good idea.
https://rennlist.com/forums/928-foru...ing-marks.html
BTW I'm with Colin, you probably knocked something loose and the engine is getting too much air. But checking the timing is a good idea.
06-28-2009, 12:28 PM
#15
Rennlist Member
Thread Starter
Well, not the easy stuff
I should be so lucky.
Everything is connected properly, no loose vac lines, etc (in fact, there are very few on this old bugger - very different from the later years).
So, it's back into the timing issue. I'll post pics soon.
I should be so lucky. Everything is connected properly, no loose vac lines, etc (in fact, there are very few on this old bugger - very different from the later years).
So, it's back into the timing issue. I'll post pics soon.