valve life
02-11-2010, 05:14 PM
#1
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valve life
when i dug into my 150k engine, i found the valves in terrible shape. all of them, and the exhaust were obviously worse than the intake. the compression was pretty low, as low as 135 in one cylinder. i have new valves in there now, but i've gotten to thinking about what might have caused my valves to get like that, and what i can do to prevent it.
what i've been thinking about is adding an exhaust gas temperature gauge and sensor to let me know how hot it's burning. i'm especially worried about this now because i broke my egr pipe and am deleting the egr during the current project, so acting on the assumption that my worn out valves were due to the combustion chamber getting too hot, i'm just wondering if it's a smart idea to do this install. sorry if this is not so coherent, as i'm pretty much falling asleep right now. i'll revise it in the morning if i have to.
thanks in advance.
what i've been thinking about is adding an exhaust gas temperature gauge and sensor to let me know how hot it's burning. i'm especially worried about this now because i broke my egr pipe and am deleting the egr during the current project, so acting on the assumption that my worn out valves were due to the combustion chamber getting too hot, i'm just wondering if it's a smart idea to do this install. sorry if this is not so coherent, as i'm pretty much falling asleep right now. i'll revise it in the morning if i have to.
thanks in advance.
02-12-2010, 08:29 AM
#3
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great. thanks. the install i was referring to was the EGT gauge.
did a bit of searching and found that you're looking at around $150 to get all the hardware required... owch.
what temp would i be looking for if i installed it?
did a bit of searching and found that you're looking at around $150 to get all the hardware required... owch.
what temp would i be looking for if i installed it?
Last edited by KasbeKZ; 02-12-2010 at 08:35 AM.
02-12-2010, 05:40 PM
#4
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Is that the dual gauge and sensor arrangement?
And it should be 850-900 decrees Celsius at WOT. Ideally, under 870C.
http://www.twinturbo.net/net/viewmsg...orum=technical
http://www.twinturbo.net/net/viewmsg...orum=technical
And something you might find useful:
http://www.twinturbo.net/net/viewmsg...&forum=general
And it should be 850-900 decrees Celsius at WOT. Ideally, under 870C.
http://www.twinturbo.net/net/viewmsg...orum=technical
http://www.twinturbo.net/net/viewmsg...orum=technical
And something you might find useful:
http://www.twinturbo.net/net/viewmsg...&forum=general
02-12-2010, 06:14 PM
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swizeet. thanks. i guess i should have searched longer.
no i'm not planning on going for a dual set up, as i'm not doing a performance build, just being safe i guess. that defi set up is not the only way to go is it? i'm going to get looking into that now though, because that basically looks to me to be a gauge interface that will handle several gauges, and i was also thinking about adding maybe an a/f and oil temperature.
have you ever seen anyone mount gauges in the center console? i really don't want these "safety" gauges as i call them to crowd up my interior. lol, even if you haven't seen it, i'm going to do it.
no i'm not planning on going for a dual set up, as i'm not doing a performance build, just being safe i guess. that defi set up is not the only way to go is it? i'm going to get looking into that now though, because that basically looks to me to be a gauge interface that will handle several gauges, and i was also thinking about adding maybe an a/f and oil temperature.
have you ever seen anyone mount gauges in the center console? i really don't want these "safety" gauges as i call them to crowd up my interior. lol, even if you haven't seen it, i'm going to do it.
Last edited by KasbeKZ; 02-12-2010 at 06:32 PM.
02-12-2010, 06:36 PM
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ahh i don't know about that defi stuff. it looks like i'd be spending a bunch of money for convenience and tuning oriented features. i think i'd be better off getting a gauge or two separately. if the egt looks good and stays good, i probably won't get anymore anyway.
02-12-2010, 08:08 PM
#7
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Two* gauges. One would only tell you half the story. An entire bank of cylinders can be problematic and you'd have a 50% chance of knowing about it with only one gauge.
Gauges in the center console? Bad place for them... look up glovebox panels if you want them hidden.
Gauges in the center console? Bad place for them... look up glovebox panels if you want them hidden.
02-12-2010, 08:38 PM
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yeah one whole bank could be bad, but even with two you could have any one cylinder messing up. don't you think one gauge is still vastly better than none?
and are you saying the console is bad for gauges just for viewing purposes? or are there other reasons? glove box does sound good too though.
and are you saying the console is bad for gauges just for viewing purposes? or are there other reasons? glove box does sound good too though.
02-12-2010, 08:57 PM
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One gauge would be a completely half-assed mod. Do it right or don't bother doing it. And if only one cylinder is running lean, the EGT will show it. But only if you have an EGT gauge for that side... and with one gauge, you're still talking only 50% likelihood. In the world of statistics (remember, I'm a statistician by profession), we would not make any decision based on 50% likelihood... and that's a HUGE risk to be taking with an engine that'll cost thousands to repair. Your options are either double the EGT gauge costs (a few hundred dollars?), or save the cost of the second gauge and risk your entire engine, should something go wrong. Do you really need me to spell out the math? I could do that, but it'll be no less obvious than the simple logic of it. With one gauge, if you have a problem on the other bank, you can blow your engine without seeing it coming. If you have two gauges, you'll be warned by the excessive EGT long before it gets to that point.
And the center console is a bad location because you want to observe EGTs during WOT... I'd hope you don't plan to open the center console and look down at the gauges when your gas pedal is to the floor. Much easier to glance over to the glovebox (and it'd be easier to wire to the glovebox).
Truth be told, though, I forgot you have an NA. While an EGT is never a bad idea, per se, it is really useless on an NA. lol You're not at a high risk of running lean. And it's not unusual for exhaust valves to look a little worse than intake valves. I think you're just being paranoid, but one gauge would be ridiculous.
And the center console is a bad location because you want to observe EGTs during WOT... I'd hope you don't plan to open the center console and look down at the gauges when your gas pedal is to the floor. Much easier to glance over to the glovebox (and it'd be easier to wire to the glovebox).
Truth be told, though, I forgot you have an NA. While an EGT is never a bad idea, per se, it is really useless on an NA. lol You're not at a high risk of running lean. And it's not unusual for exhaust valves to look a little worse than intake valves. I think you're just being paranoid, but one gauge would be ridiculous.
Last edited by ZLover4Life; 02-12-2010 at 09:02 PM.
02-12-2010, 09:39 PM
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i'm pretty sure i am being paranoid lol. well thanks for all the advise there. you've converted me to the glove box idea. i'm not so very nervous about the engine, i really just want to check it once. i don't really trust a pyrometer to get me the reading i want. well, obviously not if i need to check it at WOT. so really for my intentions it wouldn't be crazy to drill both manifolds and cap one and just switch the sensor out every time i'm under there. i'm not expecting an emergency to happen with my stock n/a. or maybe run two sensors and have a switch to select between which one the gauge reads from?
thanks again for all the advise. i do take it quite seriously.
thanks again for all the advise. i do take it quite seriously.
02-12-2010, 09:44 PM
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http://www.glowshiftdirect.com/tinte...%2Bbase%20feed
haha sweet. something like that looks pretty good. though i really like my idea of switching between sensors with one gauge! i don't think i can get just a sensor for that one.
haha sweet. something like that looks pretty good. though i really like my idea of switching between sensors with one gauge! i don't think i can get just a sensor for that one.
03-03-2010, 07:35 PM
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I'm not sure what people do about wideband O2 sensors on the Z32... search. I think, unlike the EGT gauge (which needs to be closer to the engine), you can probably get away with putting one at the X/H-pipe, but don't quote me on that. I just know when my car was dynoed, they didn't see any problem with using only one wideband bung on one exhaust pipe...
Last edited by ZLover4Life; 03-03-2010 at 07:37 PM.
03-03-2010, 10:40 PM
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ALL modern dual exhaust systems have an H or X pipe (or if they're like the 350Z, a Y pipe which has the same effect without the full performance lol).
The vacuum created by exhaust pulses in the opposite pipe is vital for drawing fumes away from the engine between exhaust strokes... without this, it can cause valve problems.
The vacuum created by exhaust pulses in the opposite pipe is vital for drawing fumes away from the engine between exhaust strokes... without this, it can cause valve problems.
