Major timing corrections, super knock & misfires

[Msport335]

Update.. the issue is not running 100% meth or the nozzle size. Before this started happening I was running 2x 1000cc nozzles and it ran without issue or corrections.... put down 670 with that setup.

Last night I pulled the intake off ...ports still look really clean so its not carbon related either. I went ahead and swapped out the knock sensors for another pair which I had and also put in my original hpfp which had no problems. Took it for a rip today on the same tune and no dice.... still getting major correction up to -8 deg ( mainly in cyl 2 &5.

I guess all that's left is to get a leakdown done. If that check out okay the only thing I can think of is the tq converter , trans and /or driveahaft. Maybe something unbalanced which the knock sensors are picking up.

 

[SlowE93]

Update.. the issue is not running 100% meth or the nozzle size. Before this started happening I was running 2x 1000cc nozzles and it ran without issue or corrections.... put down 670 with that setup.

Last night I pulled the intake off ...ports still look really clean so its not carbon related either. I went ahead and swapped out the knock sensors for another pair which I had and also put in my original hpfp which had no problems. Took it for a rip today on the same tune and no dice.... still getting major correction up to -8 deg ( mainly in cyl 2 &5.

I guess all that's left is to get a leakdown done. If that check out okay the only thing I can think of is the tq converter , trans and /or driveahaft. Maybe something unbalanced which the knock sensors are picking up.

Does it ever do a clean pull ? Since the issues cropped up, every single pull is "ugly" or do you get an occasional clean log on high boost ?

 

[Msport335]

Does it ever do a clean pull ? Since the issues cropped up, every single pull is "ugly" or do you get an occasional clean log on high boost ?

Every pull is ugly ... pulls hard but never clean.

 

[SlowE93]

Every pull is ugly ... pulls hard but never clean.

Strange indeed. I go through similar things with my car, but can pull some very clean logs at times. I have different tunes and revisions. All act the same (gets tempermental and get timing drops), some (tune and revisions) worse than others, but all can eventually pull a clean log.
Let us know what u find !

 

[Slowagon54]

I guess we have all been there. I remember i had loose spark plugs. I replaced my old plugs with new ones, and torqued them to spec (18NM). A week later 4 out of 6 were loose... and of course i had corrections on high boost.

 

[Jeffman]

Just a reminder - make sure your spark plug shafts are clean before installing new plugs. I’m taking Filippo’s advice and just purchased the $10 grabbing tool he mentioned in his post above to clean mine.

Call me paranoid but I think everyone should be inspecting the spark plug shafts and cleaning them thoroughly on any plug change. I would not run crush-once aluminum washer spark plugs either, if they come out and need to go back in - the crush washer is used up. One of the reason I went to the 2 step colder plug (NGK 97506) that hard the copper washer. Note the often suggested one-step colder NGK 95770 has the aluminum crush washer.

If I could offer an alternative cleaning approach to @Jeffman's. I tear paper towels into approx 2" x 2" pieces. Soak with brake cleaner. Then use a grab tool - bunch the center of the paper towel and clasp. If you don't own that General grab tool, you will thank me when you've spent the mere $10 and used it the first time. Built-in LED light too. Invaluable. Anyway clean the land area first (where the washer sits) thoroughly. Throw away scrap pieces of paper as they get dirty. When the land is clean, now run a fresh piece of wetted paper into the threads and gently turn to clean the threads. You can run the paper into the chamber and twist your way back out. If the paper falls in, not end of the world - will just burn up and exit the exhaust. Across six cylinders you'll spend 20 minutes cleaning. Time well spent in my opinion.

This ensures that when you torque the spark plug you actually are correctly torqued (with debris you are not) which will prevent plugs backing out or sealing issues. Second with a correct crush washer (not reused aluminum one-use) you will also have proper sealing and torque.

Filippo

 

[Msport335]

Man I wish it was something as simple as torqueing plugs and cleaning but its unfortunately not. I've been through those steps numerous times. I still have this feeling that its being caused by an something no one has seen before and pretty rare .

Just to recap ..the timing corrections are being caused by something OTHER than the following:

Tune
Fuel/octane
Meth system
Hpfp
Injectors
Plugs
Carbon
Pcv
Vanos
Engine compression
Motor mounts
O2's

What else could be causing it? Motor is healthy , pulls hard and does not smoke or burn oil

 

[fmorelli]

Man this is rough. @Msport335 has been working this pretty hard. The above post shows what has been changed along the way. He's also swapped knock sensors. Here's the original log, still representative of major timing retardation. https://datazap.me/u/msport335/e50-meth-v51-0?log=2&data=3-5-6-7-8-9-10-22. I'm just summarizing (ran through the whole thread again). Good compression, leakdown. This motor ran fine with its meth setup for quite some time before the timing correction occurred. Wondering if anyone has suggestions - @martymil @V8bait @Chris@VargasTurboTech ... sorry to tag you guys up here; this poor guy has put in his pound of flesh on this car, and it originally worked fine for quite some time. Something strange is up. Be nice to get some eyes on this and see if we can help @Msport335 out.

Outstanding questions I saw in the thread:
- leakdown not yet done (I doubt the problem is there)
- Could the AT/TQ be having issues that come back to vibration the knock sensors pick up?

 

[Msport335]

Thanks fmorelli ...forgot to add to the list above that I replaced knock sensors as well as new battery.

Your right, the leakdown hasn't been done yet but I dont believe thats the issue. No signs of a hurt motor judging by the power delivery or plugs.

 

[Jeffman]

You’ve ruled out all the usual suspects on engine- so I’d bet money on the AT. When was the last time you changed the AT filter and fluid? Did you ever replace the sleeves and bridge gasket? Did you ever replace the solenoids?

(I’m also now having unexplained timing pulls on an otherwise “clean” engine at high torque in 4th gear. I once changed my ATF and filter at 50K miles 6 years ago - now at 71K miles I’ve had some hard shifting and my Quickcharge pressures and times according to xHP seem to be off-spec, so I’m planning to do a full AT maintenance with filter and sleeves, and maybe also solenoids.)

 

[Msport335]

Car has 150k kms on it and the trans has never been serviced. When things were running smooth I did get slippage going into 4th. My plan was to swap a low km used trans in it along with the tq converter and do a full service on it. But if that doesn't solve this, then it's just me throwing more money at it and still end up suffering with these corrections.

Also forgot to mention my mechanic inspected the drive shaft , center support and guibo and everything looked good. The reason I had him check was that I was concerned the shaft wasn't balanced or put back the right way after we had swapped the engine years ago. There is no noticeable vibration either so assumed all was good there but didn't hurt to give it a once over.

 

[V8bait]

Your timing and boost targets down low are pretty aggressive. I've seen it happen many times, if you are running twins and don't limit torque down low, you'll load up the car in 4th/5th/6th and bend a rod. Timing goes to shit from there out lots of times for no reason. Won't show on compression tests or scopes. If you are making over 650tq anywhere then you're SOL, sometimes happens on 600tq if there's any knock or problems. I try to keep torque down on twins for that reason, not just to save the 6at.

I bet there's a lot of people running around with bent rods.

 

[Msport335]

The only time the car ever saw 650+wtq was on the dyno years ago when it made the following and tq ramped in nice and slow

 

[V8bait]

The only time the car ever saw 650+wtq was on the dyno years ago when it made the following and tq ramped in nice and slow

Maybe, but your targets are 28psi all the way down to 3k rpm, and your timing is aggressive. Dyno's are actually harder to load up than the street. That dyno really just shows you are making more than enough power to have bent your rods, I mean you made 677tq right there which is enough to have bent them during the dyno. These motors take tons of power but pistons don't like knock and break rings lands often, and rods bend north of 650. I mean, maybe it's something else though, I have no idea. But it looks like you've ruled out everything else, so yeah.

I've made over 650tq on my motor. It's just a risk that goes along with it. But nearly every motor teardown I've seen that was making this kind of power has multiple bent rods. Many were torn down for problems like you are explaining, either that or phantom misfires.

 

[Msport335]

Would there be any fairly obvious signs of driving around with bent rods ? Hoping this is not the case but never know. If it was , I would assume by now a rod would have shot out the block but its still pulling damn strong even given the corrections

 

[V8bait]

Would there be any fairly obvious signs of driving around with bent rods ? Hoping this is not the case but never know. If it was , I would assume by now a rod would have shot out the block but its still pulling damn strong even given the corrections

Every motor I've seen with bent rods was torn down for a build and had been driving fine previously, some had blown with cracked pistons/rings, some were just building for more power. A lot of them had random misfires that never showed up in logs, or consistently bad timing corrections that influenced building for safety. Power was usually fine as was drivability and fuel economy etc. Alex at ABR or Tony's builder could probably comment more, if I had to put a number I'd say 10 out of the 15 or so I've seen before/after of in Houston and Florida have had bent anywhere from one to 3 rods. Nobody really talks much about it.

Any of the actual engine builders would have better numbers probably but I think it's pretty common. I will add that building the motor won't fix corrections, it always makes them worse with false knock. Good times lol.

Edit- it can be subtle, like here:

 

[BloodyZ4]

I try to keep torque down on twins for that reason, not just to save the 6at.

I bet there's a lot of people running around with bent rods.

What woudl be a safeish tq limit on twins then? Like 550?

 

[SlowE93]

What woudl be a safeish tq limit on twins then? Like 550?

This is what I have been told. Try and keep it right around 550ish.

 

[V8bait]

What woudl be a safeish tq limit on twins then? Like 550?

I try to target around 550 on 6at cars to keep the trans alive, but with xHP that may be a little conservative now. Keeping torque around 600 is my typical goal since there will always be situation where the car will see more on the street that way in low gears, cold days etc. Singles are a little easier since the torque will hit later in the RPM, but it's also easy to get singles over 700tq so it can be a bit difficult. I mean it's hard to call this a huge concern since people are making this power pretty reliably but it can and does cause problems for some, I don't know if its his problem but he has basically ruled everything else out so that's my out of the box contribution I guess lol. I know it's not good advise but I'd probably just live with the corrections or desensitize the sensors and just plan on maybe needing to throw a motor in over the next few years or build it, I mean my car is 14 years old now, it goes with the territory.

Vibrations can cause corrections and falsely detected misfires. DMFW in 6mt and DCT can cause problems, a bent rod sends the rotating assembly just slightly out of balance and can cause this, a bad dampener could probably do it too.

 

[Jeffman]

Every motor I've seen with bent rods was torn down for a build and had been driving fine previously, some had blown with cracked pistons/rings, some were just building for more power. A lot of them had random misfires that never showed up in logs, or consistently bad timing corrections that influenced building for safety. Power was usually fine as was drivability and fuel economy etc. Alex at ABR or Tony's builder could probably comment more, if I had to put a number I'd say 10 out of the 15 or so I've seen before/after of in Houston and Florida have had bent anywhere from one to 3 rods. Nobody really talks much about it.

Any of the actual engine builders would have better numbers probably but I think it's pretty common. I will add that building the motor won't fix corrections, it always makes them worse with false knock. Good times lol.

Edit- it can be subtle, like here:

Did any of those motors with bent rods have stock turbos?