Once again sorry for the lag, was away for the weekend. Thanks Chuck - PM replied. So finally got it out tonight and logged 3 PL files. I turned the alky system off, and have the AMS 500 set as low as it will go. I'm definitely convinced it's engine/RPM related - not chassis. However I will throw the PL files into a thread on the TT Forum as well. Is it possible to drop the shift RPM down a couple hundred RPM by adjusting the TV Cable back a click or two or is that a bad idea? What's the concensus to quiet down the valve train? Valve springs? Change out the Comp roller lifters?
False Knock Issues driving me nuts...
- Thread starter Justa6MB
- Start date
- Joined
- Feb 18, 2006
Right at 5500-5600 every time. Is it breaking up too? Does it stop pulling? Looks like rpm flat lines.
You said you have scorpion rockers? So you have GN1's with the big valve springs? Do you know what valve springs? Who set up the heads? Any paperwork?
It's not advisable to loosen tv cable. That's how you hurt the trans. Best you can do it lift your foot to let it shift then lay back in.
RL
You said you have scorpion rockers? So you have GN1's with the big valve springs? Do you know what valve springs? Who set up the heads? Any paperwork?
It's not advisable to loosen tv cable. That's how you hurt the trans. Best you can do it lift your foot to let it shift then lay back in.
RL
It doesn't seem to break up at all, but of course when the timing retards 10* - 15* you can feel the power loss. Other than that nothing. Yes the heads are GN1's and came from Champion via Full Throttle and I believe they were shipped direct. I have paperwork on the heads but I can't seem to see anything about the springs? So I suppose I should move over to the engine section now?
- Joined
- May 28, 2001
My GN1 race heads...After a season on the street, [<1000 mi], a few 1/4 runs, [<20], I was seeing the rpms falling off before shifts, [T400 manually shifted at 58-5900] I pulled the springs and found them at <100# at installed hgt. They had lost nearly 80# at full lift.
A set of 26918's, tit retainers, I shifted at 6400. Car picked up from 136mph, to over 141...
A set of 26918's, tit retainers, I shifted at 6400. Car picked up from 136mph, to over 141...
BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
Justa6MB I did notice some odd voltage drop in one of your files, looks like it lost a whole volt. Not sure if that could be a contributor but it is odd.
I am still having some issues with false knock retard sorta similar to yours. I definitely have a tire spin issue which can be handled with the knock ignore features but I also see some intermittent stuff that pops up.
I am still having some issues with false knock retard sorta similar to yours. I definitely have a tire spin issue which can be handled with the knock ignore features but I also see some intermittent stuff that pops up.
Hi, So did you finally figure out your knock problem? I'm having a similar problem. If I let it shift on its own, and that happens at 5k it's all ok but as soon as I shift myself and go over 5000 rpm I get crazy knock. It gets 15 to 19.9 knock retard and then it goes pig rich into the 9's and I usually let of. I've never experienced anything like this. We went through lots of stuff and everything seems ok.
Nick
Nick
Hi Nick, no I still haven't found my problem. I'm thinking of pulling the motor this fall and having a look inside and checking the valvetrain over good. Check cam end thrust, crank end thrust etc... I'm also hoping to get a non lock up converter from Dusty B. I'm wondering if that in itself could help my problem as mine shows up around 5500-5600 rpm. I've heard that one of his converters may hold my rpm's at or below that? Not that I don't want to find the problem. I also have some .060 shims from Tom at Champion to install that may help get rid of any harmonics that are going on. So for now the knock sensor is unplugged and I'm running 110 fuel in it.
Thanks
D
Thanks
D
I see. So basically its not real knock from detonation, just something up with vibrations somewhere. Whether it's engine trans or torque. So I assume you tried some 110 with the knock sensor in place, and knock was still there. I have a 5 gallon of c14 I guess I'll throw it in there and see what happens. If this is real knock in my case, with all these tests I've been doing, the engine must be getting killed. For some reason I strongly feel it's false.
BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
I'm still looking for a false knock source too. Running de-tuned, low timing (18deg) and relatively rich (10.5) until I get it sorted. Also reading the plugs and watching the porcelains very closely to make sure it's not the real deal. Also keeping the sensor plugged in.
I am hearing a "slapping" sound which I think might be the belt. Tensioner seems fine but the belt is quite old and may be slipping and slapping during hard accel. I'm gonna try a new belt next.
I am hearing a "slapping" sound which I think might be the belt. Tensioner seems fine but the belt is quite old and may be slipping and slapping during hard accel. I'm gonna try a new belt next.
So I put the race fuel in and still the same thing. Anything over 5000 rpm and knock retard kicks in. 1st run got about 13 knock retard, 2nd shot it went to 15.? Did a run in drive where it shifts around 5000 and got .7, so it was just starting. This is with the C14 and timing down at 18 degrees in all gears. Air fuel ratio in the low 10's with dual nozzle meth shooting in to. The knock comes up in both 2nd and 3rd gear. Back to the drawing board...
- Joined
- Aug 20, 2001
How does the car run? What kinda converter do you have? I believe my car has a false knock issue, have checked the basics, everything looks fine. The car does have a 5 disc LU, vigilante converter that are known to be noisy. It has 218/212 roller which is noisy too. Going to try race fuel soon, if it does not go away with low boost(22 psi) and race fuel, I am unplugging the knock sensor for now.
May be too much fuel for your boost level.
Recommend you send a note to Eric at TT and see what he has to say. A recording of a run where this occurs should be helpful to him.
Well I am going to try to bring this thread back to life. I pulled the motor and checked cam end thrust, crank end thrust. Piston to head clearances, lifter to cam thrust clearance, valve spring installed height, valve spring pressures, coil bind. Installed .060" valve spring shims, changed back to stock motor mounts, sent my converter back to Dusty to have inspected and tightened up 400 rpm. Installed a Casper voltage booster, changed the ECM, changed upper control arms for downpipe clearance. Dropped the boost to 15# and took it for a spin - hit 5700 rpm and shur as shit - 15* kr 
I posted on TurboTweak Support Forum as suggested but no response yet. Any other suggestions or "work arounds"? Lifters are set to 1/2 turn of preload.
Thanks
D
I posted on TurboTweak Support Forum as suggested but no response yet. Any other suggestions or "work arounds"? Lifters are set to 1/2 turn of preload.Thanks
D
BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
My issue turned out to be valve springs. The slapping sound was some valve float. Spring pressure was around 130 closed and 345ish over the nose. I changed springs to something stronger (PAC 1201) and it cured the problem instantly. Car put down some low 10's at 132 after that.
Are you hearing anything incriminating when the sensor goes crazy? Ticking or popping or slapping? Even intermittently? Windows up or down?
That 210/215 cam is similar to my 215/220 cam. The 215/220 wanted 145lb on the seat and a little over 400lb over the nose. With that spring load it has been happy up over 6000RPM. Maybe even 6200. Got my rev limiter at 6400 and I like to see it shift at around 5850. I can't see how the beehive springs will work with these cams, I haven't found a beehive spring stiff enough. (not sure if you have those or not)
Are you hearing anything incriminating when the sensor goes crazy? Ticking or popping or slapping? Even intermittently? Windows up or down?
That 210/215 cam is similar to my 215/220 cam. The 215/220 wanted 145lb on the seat and a little over 400lb over the nose. With that spring load it has been happy up over 6000RPM. Maybe even 6200. Got my rev limiter at 6400 and I like to see it shift at around 5850. I can't see how the beehive springs will work with these cams, I haven't found a beehive spring stiff enough. (not sure if you have those or not)
- Joined
- May 28, 2001
Have you tried a new knok sensor?
Power Logger files?
Alky on?
Power Logger files?
Alky on?
Yes I did replace the knock sensor. Alky is currently on, I'm logging alky and fuel psi so it can be seen in the logs. Here are a few recent PL files (PLX wideband). I was certain it was valve train related but the valve springs were right were Tom from Champion said they should be which was 380 to 400 at lift. Here are the details on the valve springs. I thought I read something about oil pressure and how certain viscosity oils at high rpm can cause the lifters to over pressure. Any comments on that? I do have fairly high oil pressure - I haven't paid to much attention on a run but at cold start it's 80+ish and hot idle I think it's up around 40? I have heard a certain harmonic that occurs at a certain rpm while driving - but I think it's around 2500 - 3000 and doesn't set of the knock sensor.
3584
Original With .060 Shim
Installed Height Seat Lift Seat Lift
Exhaust 1.725 140 380 162 400
Intake 1.721 144 368 164 402
Intake 1.725 142 376 164 410
Exhaust 1.715 144 378 166 410
Intake 1.725 142 380 170 410
Exhaust 1.721 144 378 164 410
3585
Original With .060 Shim
Exhaust 1.711 142 380 162 410
Intake 1.725 140 372 162 400
Intake 1.722 140 372 164 400
Exhaust 1.711 144 380 174 410
Intake 1.725 140 368 164 400
Exhaust 1.725 140 378 168
408
3584
Original With .060 Shim
Installed Height Seat Lift Seat Lift
Exhaust 1.725 140 380 162 400
Intake 1.721 144 368 164 402
Intake 1.725 142 376 164 410
Exhaust 1.715 144 378 166 410
Intake 1.725 142 380 170 410
Exhaust 1.721 144 378 164 410
3585
Original With .060 Shim
Exhaust 1.711 142 380 162 410
Intake 1.725 140 372 162 400
Intake 1.722 140 372 164 400
Exhaust 1.711 144 380 174 410
Intake 1.725 140 368 164 400
Exhaust 1.725 140 378 168
408
BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
Yes those spring loads do look fine.
Looking at the first log... looks like the KR is happening right at the 1-2 shift. For the boost pressure you are running right now (14psi), I would take the following steps.
retard timing way back, down to 15 degrees. shut off alky and run it on straight gasoline only and lean it out to around 11.0-11.2
running it too rich can also make the knock sensor light up and baby it looks rich at the moment.
I am thinking (hoping) that you have actually fixed the false knock problem and all you need to do is start in the basement with the tune and begin working your way up. It should be clean if you soften the tune that much.
If you pull the tune so far back and it's still giving you shit, then you know.... it's still hiding in there. If it doesn't clean up right away, you can make double sure by throwing a little 100 octane in the tank.
As far as the oil pressure, mine is also pretty similar to yours. I have over 100 on a cold start. At hot idle it's around 25. I wouldn't expect any KR issues from the lifters unless they are having issues staying pumped up at high RPM. When the spring load starts getting up over 400lb it is a concern with the regular roller lifters. I have been OK using the regular Comp 853s so far, but the racing lifters with near zero lash would not be a bad idea especially if getting much over 410lb spring load. I have no experience with morels though, don't know if they can handle it or not.
gonna look at the other files now
Looking at the first log... looks like the KR is happening right at the 1-2 shift. For the boost pressure you are running right now (14psi), I would take the following steps.
retard timing way back, down to 15 degrees. shut off alky and run it on straight gasoline only and lean it out to around 11.0-11.2
running it too rich can also make the knock sensor light up and baby it looks rich at the moment.
I am thinking (hoping) that you have actually fixed the false knock problem and all you need to do is start in the basement with the tune and begin working your way up. It should be clean if you soften the tune that much.
If you pull the tune so far back and it's still giving you shit, then you know.... it's still hiding in there. If it doesn't clean up right away, you can make double sure by throwing a little 100 octane in the tank.
As far as the oil pressure, mine is also pretty similar to yours. I have over 100 on a cold start. At hot idle it's around 25. I wouldn't expect any KR issues from the lifters unless they are having issues staying pumped up at high RPM. When the spring load starts getting up over 400lb it is a concern with the regular roller lifters. I have been OK using the regular Comp 853s so far, but the racing lifters with near zero lash would not be a bad idea especially if getting much over 410lb spring load. I have no experience with morels though, don't know if they can handle it or not.
gonna look at the other files now
