magnummopar
Well-Known Member
when 6I and 6 E are opening/closing, check intake #1 at TDC and see what the lifter preload measures at rocker. What was valve guide clearance?
what would be your diagnosis?????
- Thread starter duster360
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I will check the preload later tonight. I don't know the guide clearance, I am assuming my machinist checked it since he pulled the valves to open up the spring seat diameter for spring cups.
Lonewolf3165
Living the Dream!
Zinc additive in the oil during break in? Cam lobes get wiped out real quick if no zinc is in the oil during break in.
It looks like you have at least 1 dead misfire. Have you done a cylinder power balance test to identify what cylinders are affected?
Double check the valve adjustments again.
Make sure the power valve in the carb isn't kaput or the wrong calibration as this would make it run too rich.
It looks like you have at least 1 dead misfire. Have you done a cylinder power balance test to identify what cylinders are affected?
Double check the valve adjustments again.
Make sure the power valve in the carb isn't kaput or the wrong calibration as this would make it run too rich.
KnuckleDuster
Well-Known Member
How does oil get to the backside of the intake valves, loose or tight?
What was the RPM in the video?
What was the RPM in the video?
Tried all kinds of timing. Nothing makes it better. Only thing that makes a change is when I turn it too far one way or the other, then it way out of adjustments. Turned the idle screw in/out, no better.
About 800 rpm idling. The only way it can get to the backside of the valves is through the guides, intake not sealing or rings. I called total seal and the tech guy told me that for oil to get to the backside of the valves because of ring failure it would be smoking like crazy and the plugs would be covered in oil. So it has to be intake or guides. Intake looks like it is sealing, had it off probably 4 times now.
Already done, no difference.
I will be trying that when I get the intake back on. May be monday before I can fire it up.
Marcohotrod
Well-Known Member
1/2 turn on preload should be fine, what is adjuster thread pitch, then do the math. how did it drive, did it have good power? is the engine out of balance and vibrating/shaking??
1967 'cuda
Dropped on Head as a Baby
It sounds as though you've tried to be somewhat methodical in diagnosing the problem with how it's running.
You've said that the (mild) camshaft was degreed in when installed which should make a person believe that the cam timing isn't the issue.
You've tried multiple carbs that you said you knew were good. Even if they weren't perfectly tuned I don't think carburetion would then be the problem.
You inspected the camshaft for noticeable wear and didn't see any. Was the cam run previously in another motor? If it is a used camshaft that hadn't shown an indication of problems in another motor I wouldn't think it's improperly ground. If it is a new camshaft there's always a possibility that the cam grinder screwed up. It's not very likely but without measuring each lobe for lift, timing, and duration you can only assume there's no problem with it.
You've checked the spark plug wires for current carrying capacity and firing order along with the distributor cap and rotor for defects. You've checked the ignition timing and verified it's where it should be. My experience with MSD boxes is usually that they work perfectly or don't work at all. It doesn't sound like you've got an electrical problem.
The presence of oil on the backside of the valves combined with the engine running rough may indicate improper sealing of the intake manifold but I'm inclined to think that your engine hasn't had a chance to run long enough to properly break in the new rings and they're not perfectly seated yet. If I'm wrong that would mean that you've probably got an intake leak that's affecting both oil consumption and air/fuel ratios. I don't think that slight valve seal leaks by themselves would lead to the engine running the way it does.
It still seems to me to likely be valve lash but is there any possibility you've gotten really bad fuel?
You've said that the (mild) camshaft was degreed in when installed which should make a person believe that the cam timing isn't the issue.
You've tried multiple carbs that you said you knew were good. Even if they weren't perfectly tuned I don't think carburetion would then be the problem.
You inspected the camshaft for noticeable wear and didn't see any. Was the cam run previously in another motor? If it is a used camshaft that hadn't shown an indication of problems in another motor I wouldn't think it's improperly ground. If it is a new camshaft there's always a possibility that the cam grinder screwed up. It's not very likely but without measuring each lobe for lift, timing, and duration you can only assume there's no problem with it.
You've checked the spark plug wires for current carrying capacity and firing order along with the distributor cap and rotor for defects. You've checked the ignition timing and verified it's where it should be. My experience with MSD boxes is usually that they work perfectly or don't work at all. It doesn't sound like you've got an electrical problem.
The presence of oil on the backside of the valves combined with the engine running rough may indicate improper sealing of the intake manifold but I'm inclined to think that your engine hasn't had a chance to run long enough to properly break in the new rings and they're not perfectly seated yet. If I'm wrong that would mean that you've probably got an intake leak that's affecting both oil consumption and air/fuel ratios. I don't think that slight valve seal leaks by themselves would lead to the engine running the way it does.
It still seems to me to likely be valve lash but is there any possibility you've gotten really bad fuel?
It has a hesitation when getting into the throttle while cruising and always has a miss to it.
The rotating assembly was balanced.
Cam is new. Put fresh fuel in it a couple times. Had the carb float bowls off checking things. One carb is brand new, the other is used but I put a kit in it.
turbofreek
batcrap crazy racing team
what dampner are you running? if it has an elastomer in the center of it. mark it with a bright white or yellow across from both sides. see if its moving more than an 1/8" to one direction. they do wiggle some but it could have slipped at initial fire and you never knew it.
is it internal or external balanced? u say you had it balanced but is that with the dampner and flexplate?
id suggest swapping out that junk 6al box for a digital 6. common random misfire is the 6al's regular failure flag.
what is plug gap? you can eliminate plug gap by going dowj to .014 and rule out any ignition fire issues. but once again 6al box with the low rpm multi fire delight is also its freddy kruger for these type of problems.
did you check dizzy engagement for full gear contact? is it a tooth off?
those are the things i consider once ive ruled out carb, valve back lash, lower intake leaks, and dizzy damage.
you could also have had the cam bolt if center single bolt cam back out allowing chain deflection for a rough runner.
cam advance sprocket fall out or come lose if adjusting bolt style not incremental spacer designed.
is it internal or external balanced? u say you had it balanced but is that with the dampner and flexplate?
id suggest swapping out that junk 6al box for a digital 6. common random misfire is the 6al's regular failure flag.
what is plug gap? you can eliminate plug gap by going dowj to .014 and rule out any ignition fire issues. but once again 6al box with the low rpm multi fire delight is also its freddy kruger for these type of problems.
did you check dizzy engagement for full gear contact? is it a tooth off?
those are the things i consider once ive ruled out carb, valve back lash, lower intake leaks, and dizzy damage.
you could also have had the cam bolt if center single bolt cam back out allowing chain deflection for a rough runner.
cam advance sprocket fall out or come lose if adjusting bolt style not incremental spacer designed.
SLOPAR72
Well-Known Member
So with your Vacuum reading is telling me that this is a "HOT" street engine. I probably missed it but what exactly is the true static compression of the motor and also what is the stick in it exactly?
When you say good compression and leakdown what are the numbers?
JW
When you say good compression and leakdown what are the numbers?
JW
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I too would be interested to see the numbers.
But, I noticed some clues.
you said;
1)I removed the hose from the PCV valve and the engine idled up but still idled very rough. Plugged it with my finger and it idled back down with the still rough idle. (post #1)
2)Tried all kinds of timing. Nothing makes it better. Only thing that makes a change is when I turn it too far one way or the other, then it way out of adjustments. Turned the idle screw in/out, no better.(post #32)
3)It has a hesitation when getting into the throttle while cruising and always has a miss to it.(post#40)
4)Plug gap is .035"; Dizzy is spot on.(post #45)
5)True static is 9.8:1. Compression is 165 psi roughly all around with one cylinder being 155 psi. In my opinion that is not enough difference to cause this type condition.
6)Leakdown at 90 psi, the gauge drops to 87 psi and that is with the engine stone cold.(post #46)
Ok, that's enough.
Let's start with #6;Your numbers are foreign to me. LD is usuall expressed as a %. If you pressurize to 100 psi, and the gauge reads 90psi, that would be called 10% LD. But if you are saying that you injected at 90 and read 87, that would be 1 minus 87/90 = 3.3% LD; an excellent number, and if they are all about the same, then the valve lash/lifter preload is very likely spot-on. I would move on.
Next is compression-clue #5. The cylinder with 155 definitely has a problem. You can also see that on the vacuum gauge. But the problem (at LD = 3.3%), is not valves nor rings. It is probably a scratch in the cylinder wall in the top half of the ring travel. You can find it by repeating the LD test, at a much reduced pressure, by removing the rocker assy, and beginning the LD test with the piston at the bottom, and slowly moving up and stopping incrementally to see the needle freeze. But, I wouldn't bother yet, cuz I have already come to a diagnostic conclusion, elsewhere.
So next;If you have a performance coil, I would increase the plug gap to in the range of .042 to .045.....I have had good success by forcing the coil to put out.
And finally and the most telling, are clues 1 to 3.
Let's start with clue#2. She does not care much about timing. Once she has enough.This is typical of a cam of this size. Your problem is not in the timing.
Then, clue#1. This is also typical for this cam, but it does tell us one very important thing; the engine wants a little more air, and that takes us to part 2 of this clue; changing the mixture screws is as good as ineffective.And finally
Clue #3. The hesitation.
Taking these clues together, and since you have not yet talked about it, and since changing carbs made no difference;it is my opinion that,You have not yet set the T-port synchronization.
But, I noticed some clues.
you said;
1)I removed the hose from the PCV valve and the engine idled up but still idled very rough. Plugged it with my finger and it idled back down with the still rough idle. (post #1)
2)Tried all kinds of timing. Nothing makes it better. Only thing that makes a change is when I turn it too far one way or the other, then it way out of adjustments. Turned the idle screw in/out, no better.(post #32)
3)It has a hesitation when getting into the throttle while cruising and always has a miss to it.(post#40)
4)Plug gap is .035"; Dizzy is spot on.(post #45)
5)True static is 9.8:1. Compression is 165 psi roughly all around with one cylinder being 155 psi. In my opinion that is not enough difference to cause this type condition.
6)Leakdown at 90 psi, the gauge drops to 87 psi and that is with the engine stone cold.(post #46)
Ok, that's enough.
Let's start with #6;Your numbers are foreign to me. LD is usuall expressed as a %. If you pressurize to 100 psi, and the gauge reads 90psi, that would be called 10% LD. But if you are saying that you injected at 90 and read 87, that would be 1 minus 87/90 = 3.3% LD; an excellent number, and if they are all about the same, then the valve lash/lifter preload is very likely spot-on. I would move on.
Next is compression-clue #5. The cylinder with 155 definitely has a problem. You can also see that on the vacuum gauge. But the problem (at LD = 3.3%), is not valves nor rings. It is probably a scratch in the cylinder wall in the top half of the ring travel. You can find it by repeating the LD test, at a much reduced pressure, by removing the rocker assy, and beginning the LD test with the piston at the bottom, and slowly moving up and stopping incrementally to see the needle freeze. But, I wouldn't bother yet, cuz I have already come to a diagnostic conclusion, elsewhere.
So next;If you have a performance coil, I would increase the plug gap to in the range of .042 to .045.....I have had good success by forcing the coil to put out.
And finally and the most telling, are clues 1 to 3.
Let's start with clue#2. She does not care much about timing. Once she has enough.This is typical of a cam of this size. Your problem is not in the timing.
Then, clue#1. This is also typical for this cam, but it does tell us one very important thing; the engine wants a little more air, and that takes us to part 2 of this clue; changing the mixture screws is as good as ineffective.And finally
Clue #3. The hesitation.
Taking these clues together, and since you have not yet talked about it, and since changing carbs made no difference;it is my opinion that,You have not yet set the T-port synchronization.
1. Brand new Pioneer race balancer.
http://www.summitracing.com/parts/pio-872037/overview/make/dodge
2. Engine was balanced with everthing from the balancer to the pressure plate, but not this balancer. The engine is internally balanced. This balancer is for internally balanced engines.
3. Plug gap is .035"
4. Dizzy is spot on.
1. True static is 9.8:1. Compression is 165 psi roughly all around with one cylinder being 155 psi. In my opinion that is not enough difference to cause this type condition.
2. Leakdown at 90 psi, the gauge drops to 87 psi and that is with the engine stone cold.
3. Cam is comp cams brand XE275HL. Advertised duration I- 275* E- 287* I&E LIFT IS .525". 110* lobe separation 2000 to 6000 power band
I say those things too loosly. There are some slight changes in the engine with the carb and timing but it still runs rough as he$$ no matter where these things are adjusted to.
One thing that pops out at me, you are running an MSD box and plugs at .035. Try opening the gap on the plugs some, maybe .045
rmchrgr
Skate And Destroy
Check the polarity on the distributor pickup wires!
There's a little note about it in the MSD instructions. If the polarity is incorrect, the MSD will advance or retard your timing like 40 degrees or something ridiculous like that.
I had a similar issue when I installed an MSD in my Duster a few years ago. The car would hardly start and when it would, it was missing, running rough, wouldn't stay lit etc. The only thing that was changed was the MSD. It was driving me nuts, everything was right.
I posted a similar question to yours on the Moparts race section and an old racer gave me the tip. Took a while for it to sink in, I did not realize what he was referring to at first. I went back and re-read his reply. Eventually I understood and gave it a shot and switched the polarity of the pickup wires - car fired right up and ran great.
There's a little note about it in the MSD instructions. If the polarity is incorrect, the MSD will advance or retard your timing like 40 degrees or something ridiculous like that.
I had a similar issue when I installed an MSD in my Duster a few years ago. The car would hardly start and when it would, it was missing, running rough, wouldn't stay lit etc. The only thing that was changed was the MSD. It was driving me nuts, everything was right.
I posted a similar question to yours on the Moparts race section and an old racer gave me the tip. Took a while for it to sink in, I did not realize what he was referring to at first. I went back and re-read his reply. Eventually I understood and gave it a shot and switched the polarity of the pickup wires - car fired right up and ran great.
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