:::RHMT::: Real Home Made Turbo
General Category => Hybrid/Tech => Topic started by: danz on June 08, 2009, 06:06:33 PM
-
i was having an issue where once i hit 7200ish the car would suddenly make no power and seemed to be having ignition problems or maybe valve float? see here: http://www.realhomemadeturbo.com/forum/index.php?topic=2773.0 (http://www.realhomemadeturbo.com/forum/index.php?topic=2773.0)
so last night im heading to costco and decide a nice little 3rd gear highway pull would be proper.
it did the same bullshit it always does at 7200 then just died out.
pistons 3 and 4 were semi melted on the intake side. some major valve to piston interaction.
retainer snapped in number 4 on the intake. i wonder if the retainer snapped from the valve floating and the piston hitting it? hmm
i wonder what order this happened in? valves floated, piston hit valve, retainer broke, the rest is history?
never did figure out for sure why it was stumbling up top but i suspect too much timing or valve float?
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Flh3.ggpht.com%2F_KLU2PrSrd8E%2FSi2GYwSu5zI%2FAAAAAAAAAV4%2FOQ1cCEtn7zU%2Fs800%2FJune%25208%252C%2520piston%25204%2520down%2520007.jpg&hash=f91b058deca9b320981260d7393b16dd05345ab2)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Flh4.ggpht.com%2F_KLU2PrSrd8E%2FSi2GZLlmy7I%2FAAAAAAAAAV8%2FplVhk2K6Niw%2Fs800%2FJune%25208%252C%2520piston%25204%2520down%2520006.jpg&hash=a9f6fe1d40a1bb46198c4e1eecd936212ed43ed8)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Flh6.ggpht.com%2F_KLU2PrSrd8E%2FSi2GYa8LsnI%2FAAAAAAAAAV0%2FLru2spqDMPA%2Fs800%2FJune%25208%252C%2520piston%25204%2520down%2520008.jpg&hash=6c4ff6ff0209d2174f9ab97541cadc83302a9492)
head is junk too
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Flh6.ggpht.com%2F_KLU2PrSrd8E%2FSi2GYFv0P3I%2FAAAAAAAAAVw%2F609fAtLhdZ4%2Fs800%2FJune%25208%252C%2520piston%25204%2520down%2520011.jpg&hash=9e1b785d08d4672383a32be3b3a250d1744b00cc)
-
retainer snapped in number 4 on the intake. i wonder if the retainer snapped from the valve floating and the piston hitting it? hmm
i wonder what order this happened in? valves floated, piston hit valve, retainer broke, the rest is history?
yep...
that head is so fixable/useable... just needs a new guide, easy fix...
-
new larger guide
-
the seat has some damage as well... ill bring it with me to the machine shop and see what they think.
dropping off the new block and pistons for some special love.
what does anyone suggest for ring gaps? my cylinders have some hard core scoring.
i went with upper ring .018 2nd .019 first time.
-
Slightly melted pistons? You tapping the revlimiter in boost with Crome?
.021" top ring and .023" second ring.
-
Slightly melted pistons? You tapping the revlimiter in boost with Crome?
.021" top ring and .023" second ring.
this is why you set it to IGN cut not fuel ?
-
Or, to both.
-
Slightly melted pistons? You tapping the revlimiter in boost with Crome?
.021" top ring and .023" second ring.
using ectune. it wasnt hitting ignition cut or fuel cut but the rpm would not increase past 7200.
never figured that one out.
then again i was running 18-20 degrees of final timing in boost....
-
Did you degree the motor?
-
using ectune. it wasnt hitting ignition cut or fuel cut but the rpm would not increase past 7200.
never figured that one out.
then again i was running 18-20 degrees of final timing in boost....
Did you doublecheck that in the logs? I had some weird shit in ectune and the datalogs showed fuel cut was poping up active and I could never figure out why it was doing it randomly. I think it went away after an uninstall/reinstall but don't remember and my car isn't running right now.
Just asking
-
Did you degree the motor?
degree the motor as in degree the bisi cam? no. i emailed bisi about it and he said not having the cam degree'd wouldnt give me the high rpm problems i was having... (no mention of melted pistons how ever, lol). but i have a degree wheel and dial for next time around. just need a piston stop to find true TDC.
what are you getting at JD? I really would like to know what happened.
cam and crank were timed to each other perfectly.
using ectune. it wasnt hitting ignition cut or fuel cut but the rpm would not increase past 7200.
never figured that one out.
then again i was running 18-20 degrees of final timing in boost....
Did you doublecheck that in the logs? I had some weird shit in ectune and the datalogs showed fuel cut was poping up active and I could never figure out why it was doing it randomly. I think it went away after an uninstall/reinstall but don't remember and my car isn't running right now.
Just asking
yes, verified with datalogs. i tried to lower the fuel and timing cut to double check what it looked like on the graphs and verified they worked when set at 7000rpm.
-
Did you degree the motor?
degree the motor as in degree the bisi cam? no. i emailed bisi about it and he said not having the cam degree'd wouldnt give me the high rpm problems i was having... (no mention of melted pistons how ever, lol). but i have a degree wheel and dial for next time around. just need a piston stop to find true TDC.
what are you getting at JD? I really would like to know what happened.
cam and crank were timed to each other perfectly.
If the deck or the block were ever machined, I'm afraid they very much weren't timed to each other perfectly. For whatever reason, I see 2-3 degrees off as being very common. I've little use for degreeing a motor with a wheel and dial unless it's design dictates their use. Hondas do not. Center the distributor (on non-D16Y cams) like it comes from the factory, lock your timing to whatever your pulley is indexed at, and shine the timing light around. Instead of moving the distributor to get the engine into mechanical time, move the cam gear. This procedure is also applicable to an Evo with a 4G64 block and AEM, among others.
If your cam is too advanced then you hit full boost and mostly full power at 5000-ish rpms, and the power output barely climbs from there becuase the engine is fighting itself. With the cam correctly timed you hit full boost at the same place and the power curve keeps sailing smooth and fluidly and the engine isn't fighting itself. Do I think this caused your valve droppage? No, unless they got super hot and bound up in your guides, but I really doubt that happened. What I have seen is some cars fight themselves on the dyno, and on the street if they are hooking really well in 3rd gear or higher. It's kinda wierd to go through the datalogs and watch the engine decelerate for a quarter second before climbing right back up, something's happening in the combustion chamber and that might be your piston problem.
You want to get pictures up of the pistons, etc? You might have had two mechanical issues going on, the valve dropping and then the pistons. Or a mechanical/tune correlation on the pistons and a mechanical failure on the valve. Or, who knows? A thorough teardown and high res picture thread would help you pinpoint it though.
Uhm, I'm not a huge fan of the two Bisi regrinds I tuned recently, and there's a forum member here not happy with his. Neither made the difference you expect a cam to make, the all motor F23 one I believe to be the vehicle owner's fault as he called up for a performance cam and said the words daily driver and reliability ten times each for every tme he said increase of power, and saddled himself with a stage 1 baby regrind, about as worthwhile as paying $$$ to replace early LS cams with B20 cams. The other was a Y7 turbo cam, Vitara motor, made 280 whp @ 18-19 psi with a T04E compressor and we called it a day as he was out of MAP sensor (2.5 bar). It wanted 14 degrees @ ~12 psi, and 16 degrees at 18 psi (eCtune numbers), kinda wacky if you ask me as I usually find D16 wanting a lot less timing in the upper teens. The only reason I'm even bitching is Bisi told the kid, when asked what sort of power the grind was making, "I don't know, I've sold a couple others but haven't gotten any feedback." :?:
-
hope these help.
let me know if you want some closeups of any specific spots.
(looks like picasa doesnt like what i tried to do... tinypic time)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi43.tinypic.com%2Feriv6w.jpg&hash=a047c56c0c6361f40d15d18b701267a5e9c728ef)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi42.tinypic.com%2F531ldx.jpg&hash=04b24d33b21d8060fe97d56fea24f8dc4d927793)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi39.tinypic.com%2Fv4mc81.jpg&hash=a9509220566ee3cd05df44f2fa51fc2daf7835ed)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi43.tinypic.com%2F66kax4.jpg&hash=986aab4cf5c05807f69aa99609a320f210dbae59)
-
hope these help.
let me know if you want some closeups of any specific spots.
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Flh5.ggpht.com%2F_KLU2PrSrd8E%2FSjCner5GKAI%2FAAAAAAAAAZI%2FQ-NsrfuNUW0%2Fs1152%2FFullscreen%2520capture%25206102009%2520113701%2520PM.jpg&hash=fdccf834d0215ff6fcf095f2bac693b90080acf0)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Flh5.ggpht.com%2F_KLU2PrSrd8E%2FSjCneOX8xHI%2FAAAAAAAAAZE%2Fz0O4-kAiXuQ%2Fs1152%2FFullscreen%2520capture%25206102009%2520113816%2520PM.jpg&hash=a64f035515b9075ed07dfb2e916da467fdda0c64)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Flh6.ggpht.com%2F_KLU2PrSrd8E%2FSjCnfJm9GpI%2FAAAAAAAAAZQ%2FSj5fG0OQd90%2Fs1152%2FFullscreen%2520capture%25206102009%2520113557%2520PM.jpg&hash=76d6542766fa568a140b69ccf6b136290fa75f27)
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Flh3.ggpht.com%2F_KLU2PrSrd8E%2FSjCnfpo0SsI%2FAAAAAAAAAZU%2FwqTRI2nj6KQ%2Fs1152%2FFullscreen%2520capture%25206102009%2520113528%2520PM.jpg&hash=e8bd684a85c8572626d72dec8797ffe2722e6792)
If he's getting the same pictures I'm getting then red X's aren't gonna do much good bub.
-
Daryl, I have an eye for red X's that you apparently do not.
-
picasa eats my asshole but does a piss poor job
-
There's no detonation on those pistons, and the carbon coat looks very good. All I'm seeing, aside from valve dents, is scuffing on the side of the piston, as opposed to the skirt where the piston is widest - the crown is a few thousandths narrower.
Only two things I can think of would be the bore is out of round, and/or the crown got hot very quickly and started to swell. Where or how the valve dropping factors in I dunno.
-
what about the rounded/melted intake reliefs on #4 and #3?
is that kinda shit normal?? :D
-
im gonna say they scuffing/tuning issues and valve death are isolated incidents that coincided that day. a floating intake valve is not in a whole lot of harms way of a piston. valves bounce on the close.. the piston is half way down the bore when an intake will bounce. its the exhaust valve thats getting chased up the bore near TDC that will bounce and contact.
i think the retainer had its day and broke on its own, dropped the valve, killed the piston.
that head is an easy repair.
im no tuner but im gonna say he was leaning into preignition also.. since like you said, the skirts taper.. that wasnt normal bad sizing or the tangs would scuff.. that was a swollen crown from mega heat. a hotspot was likely igniting the incoming fuel charge and the crowns were cooking up on the compression stroke, he said light melting i think. thats all inline with preignition. if it was detonating, hed have a.) heard it b.) see metal transfer c.)blown ring lands d.) cracked rings e.) taco'd bearings f.) all of the above. im not really seeing that at a glance.
-
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi42.tinypic.com%2F531ldx.jpg&hash=04b24d33b21d8060fe97d56fea24f8dc4d927793)
in this pic the arrow dictates a scuffing on the wall that is caused by "slop" of the thrust washers.
To further note.. you're pistons and valves arent burnt.... something unfortunate happened like float, or a miscalculation in timing... the carbon buildup (or lack there-of) on the pistons reflect this.
Sorry dude... Human ERROR
Dr. Mike
-
slop in thrust washers... will check end play next time.
im leaning toward float. sucks but sometimes learning the hard way has to be done
-
Daryl, I have an eye for red X's that you apparently do not.
I recon