Hypothetically Speaking......

[onefast65]

Hypothetically speaking, if one were to run an engine, say a roller 347 stroker, with the valves improperly adjusted - could this damage anything? I have a good idea what may happen if the rocker nuts was overturned during adjustment, but what could happen if the nuts were underturned? Could lifter or cam damage result?

:SNSign:

 

[sweet88gt]

You could bounce a valve off of the piston if the rocker was really loose. Nothing good can come of improper adjustments.

 

[onefast65]

Would this cause any damage that would present itself as an engine miss thereafter, if the engine shows good compression - just likes to miss even after the valves are readjusted properly?

 

[sweet88gt]

Good question, but I would think if this had happened it would have slapped the piston a few times and broke. Maybe it just bent the valve but I would take it back apart and inspect for damage.

 

[onefast65]

I was planning to pull the intake manifold and put a dial gauge on each lifter to check for camshaft damage and then pull and inspect the lifters. I guess that is not too much more work to pull the heads and do an inspection. If a valve has contacted a piston, would you expect to see marks on the piston top?

 

[sweet88gt]

Yes, It should show visible signs of contact. How did you come to the conclusion that this is for sure a loose rocker? I would hate to tear it down for no reason. Did you hear any strange noises at start up?? Have you pulled a valve cover and were any rockers only finger tight??

 

[onefast65]

This is a 'new' engine with only 1000 miles. It is SDS fuel injected and after installing a wideband O2 sensor, I established that the miss and vibrations that I had been feeling all along could not be tuned away. I have since moved injectors, installed new plugs, moved wires around, installed a new coil, etc. I then started thinking about how I adjusted the valves which was taking each piston to TDC and then setting both valves to 1/4 turn after zero lash (don't ask how I came up with this). I have since adjusted the valves 1/2 turn past zero lash while ensure bottom of lobe, i.e. intake at start of exhaust lift and exhause and end of intake lift. This seemed to help somewhat but it still doesn't feel right. Also, some lifters seems kind of squishy when I was adjusting - could turn the nut a full turn past zero lash by hand with almost no resistance.

 

[sweet88gt]

Its been awhile since I adjusted my valves so I cannot give good advice there. I know by doing a search there are tons of threads on how to adjust valves. The slight miss and vibration may not be associated with loose rockers or a valve problem. You may have a lifter thats not pumping up causing a improper adjustment. Someone with more engine knowledge will be able to help. I just dont think you are on the right track just yet. The valve maikng contact with the piston would be very noticeable and there would be no question if that was the problem. More information on what you have done and anything you may feel is of importance.

 

[onefast65]

Here is what I had posted in a separate thread when I first started looking for help on Stangnet. I continue to see some plugs (mostly number 4) turning very black in almost no time. Thus I don't think that it is an overall ignition problem.




I have only 1200 miles on the following all new engine:

347 Stroker
SDS Fuel Injection
30LB Steeda Injectors
Trick Flow Track Heat Heads
Custom Victor Intake Manifold
Mac Long Tube Headers

The problem:
I have always noticed a bit of a vibration that shakes the entire care at 2000 - 2500 RMP. Also, I've recently noticed a miss that is causing number 4 plug to turn black in a very short timeframe. Here is what I have tried so far:

1. Replaced rear rigid muffler hangers with flexible type.
2. Replaced spark plugs.
3. Ran engine without belt.
4. Ran engine without belt and crank pully.
5. Reduced fuel pressure to 30 psi.
6. Increase fuel pressure to 50 psi.
7. Switched number 4 injector with number 6.
8. Checked to make sure coil wire is not grounding out on anything.
9. Replaced the coil.
10. Compression tested number 4. Tested 140 to 150 psi dry and wet test. Tested all since and all good at 150-160.
11. Swapped plug wires 4 and 8.
12. Added rear fuel rail crossover (only had front cross over previously)
13. Swapped injector harness plugs for 3 and 4.
14. Checked valve setting for number 4 - OK.
15. Number 4 rockers appear to be functioning as expected when engine is cranked.
16. Checked rotor phase for SDS system.
17. Checked engine time and advance.
18. Changed engine oil. At same time I swapped 4 plug with a clean one from another cylinder and put a squire of oil into the 4 cylinder.
19. Tried a different distributor cap.

Sorry for the long post but is there anything obvious that I have missed?

 

[sweet88gt]

What is the A/F ratio at idle and at the rpm of the miss?? What about the camshaft and was it installed stright up or was it degreed to ensure proper specs? Everything you listed seems on target but again I am no expert. Others may have some better clues on what to look for. Sorry I wasnt more help.

 

[onefast65]

AFR is manually adjustable from within the car with the SDS controller. Miss/vibration is there at all AFR's but is felt most as a vibration from 1500 to 2500 rpm. I had my engine builder install the cam - I assume they installed it straight up. I guess that that is something else I can check. For now, I have ordered new Ford Racing roller lifters and will also check the cam as previously mentioned when I install the lifters. My money is on the lifters at this point - not sure if I damaged them due to improper valve adjustment or if one or two were bad from day one.

 

[stang8urimport]

Good question, but I would think if this had happened it would have slapped the piston a few times and broke. Maybe it just bent the valve but I would take it back apart and inspect for damage.

Valves usually don't just break... Unless it's catostrophic engine failure. They usually just bend.

If you're getting good compression, and even compression on all cylinders, it's not likely a valve is the problem... as it would leak compression if it was bent. Check all your ignition parts. I had a miss at high RPM, turned out to be a coil putting out weak spark.

 

[postalbunny]

Here is what I had posted in a separate thread when I first started looking for help on Stangnet. I continue to see some plugs (mostly number 4) turning very black in almost no time. Thus I don't think that it is an overall ignition problem.




I have only 1200 miles on the following all new engine:

347 Stroker
SDS Fuel Injection
30LB Steeda Injectors
Trick Flow Track Heat Heads
Custom Victor Intake Manifold
Mac Long Tube Headers

The problem:
I have always noticed a bit of a vibration that shakes the entire care at 2000 - 2500 RMP. Also, I've recently noticed a miss that is causing number 4 plug to turn black in a very short timeframe. Here is what I have tried so far:

1. Replaced rear rigid muffler hangers with flexible type.
2. Replaced spark plugs.
3. Ran engine without belt.
4. Ran engine without belt and crank pully.
5. Reduced fuel pressure to 30 psi.
6. Increase fuel pressure to 50 psi.
7. Switched number 4 injector with number 6.
8. Checked to make sure coil wire is not grounding out on anything.
9. Replaced the coil.
10. Compression tested number 4. Tested 140 to 150 psi dry and wet test. Tested all since and all good at 150-160.
11. Swapped plug wires 4 and 8.
12. Added rear fuel rail crossover (only had front cross over previously)
13. Swapped injector harness plugs for 3 and 4.
14. Checked valve setting for number 4 - OK.
15. Number 4 rockers appear to be functioning as expected when engine is cranked.
16. Checked rotor phase for SDS system.
17. Checked engine time and advance.
18. Changed engine oil. At same time I swapped 4 plug with a clean one from another cylinder and put a squire of oil into the 4 cylinder.
19. Tried a different distributor cap.

Sorry for the long post but is there anything obvious that I have missed?

Did you rotate the engine to TDC and check to make sure the balancer is at 0 deg? I blew my balancer (too high rpm) once, it was a little off and got a vibration at 1k rpm that cleared up by 2k rpm and sounded like a miss at 600-750 rpm (idle). It later spun more and had a horrible shake, didn't have a timeing light at the time so i stuck a screwdriver in #1 and rotated it by hand... 23 deg off according to the balancer.

 

[ninety15.0]

I dont understand where everyone gets their valve adjustment info from. Were your lifters pumped up when you adjusted the valves. How did you check clearence? or did u just tighten down to "zero-lash" plus .25 turns? If your lifters were not pumped up then you adjusted the valves improperly and should have checked the stem to guide clearence to be within 0.0015 -- 0.0027.

 

[TheUser]

I assume when you built the engine, you ensured that you had proper piston-to-valve clearance, which I assume would eliminate a valve hitting a piston. I'm not even really sure why anyone would say a loose rocker would make the valve hit the piston. If your rockers are very loose, it'll run like complete garbage, make almost no power, especially over 2000 rpm or so and you'll definately know something is wrong.

I do agree with Poopdog that if a valve was bent, you would not have good compression as the pressure would leak out of the bad valve's seat.

If you can turn your rocker nuts a more than a full turn past zero lash, I do believe you'll need to shim. I think you want to keep it to one full turn or less. I think each shim is equal to like 1/4 turn or so, but search for that info. You can get the shims at the auto parts store.

If you're getting a miss, try checking your timing, plugs, wires, cap, rotor, coil, etc again. That's the easiest way to start I'd say.

What is your timing set at?

 

[JChalfan]

My morning coffee hasn't kicked in yet, so excuse me if I say something dumb...

I also don't see how having rockers too loose will make the valve hit the piston.

A vibration between 1500 and 2500 rpm's sounds to me like one cylinder is not firing. With #4 plug having problems, it leads me to beleive #4 cylinder may not be firing properly.

Looking at the list of 19 things that have been done to try to fix the problem, it looks like it would cover all the likely culprits, like a bad plug, wire, or injector.

I don't know anything about the SDS injection. Is it possible it's fouled up somehow and not operating the #4 injector properly?

Just some thoughts.

Jeff

 

[Woodrow]

I also don't see how having rockers too loose will make the valve hit the piston.

It can't the only way the valve is going to hit the piston is with to long of a push rod, a higher ratio rocker arm, or if the retainers/spring broke. If you take the rocker arms off one cylinder and crank the motor are the valves going to magicly open and hit the piston? NO The only other way is odvious pv clearance but I would hope who ever built it clayed the pstions if things were going to be tight. If the rockers were lose 95% of the time the only thing it damages is the arm itself, sometimes it will get the push rod just depends on how long you run it like that

 

[onefast65]

Photos

OK - I have now removed the intake, rockers, push rods and lifters. I can see nothing obviously wrong with any of the components but the number 4 cylinder intake port is absolutely black. All others are clean. As everything compression tested good, I don't think that this could be a head gasket issue. I can see two possibilities:
1. the intake valve is not closing - maybe a lifter is hanging up.
2. the exhaust valve is not opening properly and letting the burnt gases out the exhaust - possibly a bad lifter on the exhaust valve. Is there anyway to check a lifter or do I simply have to replace it, reassemble the engine and hope for the best.

To answer a few of the questions above:
1. The SDS could not be causing this because if fires the right bank all at once and then the left bank. I have swapped injector harness plugs 3 and 4, and also left to right. Number 4 continues to miss.
2. I did not assemble the short block and I had the shop install the heads. If there were valve-piston clearance problems this should show up on all cylinders, not just one I assume.
3. I will check TDC tomorrow but again, don't know that this would affect one cylinder only. Still a good idea to check though.

Here is a photo showing the black number 4.

 

[onefast65]

Lets try the photo again.

 

[06stangtyme]

Check the ohms on #4 plug wire and compare it to the others...or just change # 4 wire.