Here we go again
- Thread starter cobra20sc
- Start date
Not much more progress to date but did find the cause of the blowout, well the initial one anyways (continued driving/state of denial of a blown head gasket not recommended).
After disassembly, it was noticed that there was quite a bit of oil/black crap on the intake and exhaust valves and intake runner on the #4 cylinder (same cylinder with blown gasket section). On further inspection, the intake valve seal was pulled off the guide (thanks 96irishcobra for the find). So when I swapped out the AFM hi-rev springs last year, I did note the ID of the inner spring was a tad smaller than the originals (like by 0.01-0.02 if I recall correctly). So at some point in the season, the spring grabbed and yanked the seal off the guide of the intake valve and let lots of oil into the cylinder. I'm guessing the added oil in the chamber taking up volume is like raising the static compression ratio to a point that lowered the threshold for detonation/preignition.
So I'm just specing out parts to buy to put everything back together including valve seals with reduced OD's. The positives are that all of the bores/cylinders/valves look to be in great shape (almost as good as when it was new) and all the surfaces were checked to be flat. Not bad for 6 years at "elevated" power levels. I wonder what the bearings look like.
But most importantly, its good to know that the cause is found and that it was not from too aggressive of a tune (to think I was going to back down on the timing this year, LOL). Will post more pics of the rebuild once I get it restarted.
-Chris
After disassembly, it was noticed that there was quite a bit of oil/black crap on the intake and exhaust valves and intake runner on the #4 cylinder (same cylinder with blown gasket section). On further inspection, the intake valve seal was pulled off the guide (thanks 96irishcobra for the find). So when I swapped out the AFM hi-rev springs last year, I did note the ID of the inner spring was a tad smaller than the originals (like by 0.01-0.02 if I recall correctly). So at some point in the season, the spring grabbed and yanked the seal off the guide of the intake valve and let lots of oil into the cylinder. I'm guessing the added oil in the chamber taking up volume is like raising the static compression ratio to a point that lowered the threshold for detonation/preignition.
So I'm just specing out parts to buy to put everything back together including valve seals with reduced OD's. The positives are that all of the bores/cylinders/valves look to be in great shape (almost as good as when it was new) and all the surfaces were checked to be flat. Not bad for 6 years at "elevated" power levels. I wonder what the bearings look like.
But most importantly, its good to know that the cause is found and that it was not from too aggressive of a tune (to think I was going to back down on the timing this year, LOL). Will post more pics of the rebuild once I get it restarted.
-Chris
Hmm the plan. Well I've been looking to sell the vortech setup so I can go to a single turbo kit. If I can do that, I'll just stay with the 302 motor that I have. If not a 347 shortblock will be next . . .eventually
So for now, replace head gaskets, install reduced od valve seals and run it for another 6 years.
Oh and I'm specing out some of Innovate products to do some better tuning with better instrumentation/data logging. Depending on how that turns out, maybe a larger crank pulley will find its way in, we shall see.
So for now, replace head gaskets, install reduced od valve seals and run it for another 6 years.
Oh and I'm specing out some of Innovate products to do some better tuning with better instrumentation/data logging. Depending on how that turns out, maybe a larger crank pulley will find its way in, we shall see.
What wideband are you using now? You have a twEECer R/T now right? Have you looked at the Zeitronix, NGK AFX, AEM, Dynojet or any other widebands? Alot of guys have switched over to the Moates QH for tuning as it is cheaper and has more flexibility than the twEECer. It seems most of the tuners at shops prefer the AFX with NGK sensor over most others due to the sensor lasting longer. Many say if you cant afford a AFM-1000 or Horiba thats the next best thing. I have not tried one and just installed a Zeitronix in my car but I bought one of those based off alot of research as well.
I'm using a UEGO1000 that I bought from AFM back in 2004. It utilizes a Bosch sensor and seems to still be reading ok but I think its time to replace the sensor and the way prices are these days, I can just get another setup. I don't currentlly have a way to log the readings along with the tweecer RT, was to get the Dataq to interface last year but never did. So I'm thinking of an Innovate LC-1 wideband with the SSI-4 to log along with boost pressure, fuel pressure, at a min. Do you know much about the Innovate products?
I haven't looked at the Moates. How is it more flexible?
I haven't looked at the Moates. How is it more flexible?
Dave
What Zeitronix did you get? The standard ZT-2? These seem to have more features then the Innovate units for a better price.
The Award Winning Zt-2 Model 2010 Wideband Datalogging System
The Zeitronix Wideband Air/Fuel ratio meter and datalogging system is a high quality, stand-alone system for use with carbureted and electronic fuel injection engines. Zt-2 Wideband Kits provide the best bang for your buck delivering unmatched quality, features and capabilities for very reasonable prices. Our system provides the accuracy of a Dyno Air/Fuel reading right in your vehicle as well as multiple engine parameters. Our base system is very easy to install and retails at $279 USD which includes the wideband oxygen sensor, controller, wiring hardware, and the software required to start datalogging and tuning immediately.
Supports Air/Fuel ratio as AFR/Lambda, plus RPM, Vacuum, Boost, Exhaust Gas Temperature, Throttle Position, 0-5 volt sensors, Air/Fluid temperature sensors and Oil/Fuel pressure sensors. Tune fuel injected and carbureted engines.
Very simple installation - connect two wires to +12V and ground and place the O2 sensor in the exhaust stream and you are ready to read AFR! A simple LED indicator displays off, warm-up and running modes.
Cut your tuning time in half!
Click here for recent Zt-2 VIDEO
No matter if you have a stand alone engine management system, a piggy back fuel control or a carbureted engine. The ZT-2 Wideband Air Fuel Ratio Meter is a must for serious tuners! Finally you can tune for more power, closer to the edge, precisely monitoring Air/Fuel ratio Boost, EGT, RPM and throttle position datalogging up to 9 hours of data with a blazing rate of 74 samples per seconds per graph. The ZDL software can be utilized as a real time display when using the standard Zt-2 kit without an LCD, ZR-2 Multi-Gauge or DashDAQ display.
Fully digital, smallest wideband O2 controller and datalogging system in the world!
Zt-2 is about the size of 1" thick business card. Extremely compact design for installation where space is a premium.
Zt-2 Specs
What Zeitronix did you get? The standard ZT-2? These seem to have more features then the Innovate units for a better price.
The Award Winning Zt-2 Model 2010 Wideband Datalogging System
The Zeitronix Wideband Air/Fuel ratio meter and datalogging system is a high quality, stand-alone system for use with carbureted and electronic fuel injection engines. Zt-2 Wideband Kits provide the best bang for your buck delivering unmatched quality, features and capabilities for very reasonable prices. Our system provides the accuracy of a Dyno Air/Fuel reading right in your vehicle as well as multiple engine parameters. Our base system is very easy to install and retails at $279 USD which includes the wideband oxygen sensor, controller, wiring hardware, and the software required to start datalogging and tuning immediately.
Supports Air/Fuel ratio as AFR/Lambda, plus RPM, Vacuum, Boost, Exhaust Gas Temperature, Throttle Position, 0-5 volt sensors, Air/Fluid temperature sensors and Oil/Fuel pressure sensors. Tune fuel injected and carbureted engines.
Very simple installation - connect two wires to +12V and ground and place the O2 sensor in the exhaust stream and you are ready to read AFR! A simple LED indicator displays off, warm-up and running modes.
Click here for recent Zt-2 VIDEO
No matter if you have a stand alone engine management system, a piggy back fuel control or a carbureted engine. The ZT-2 Wideband Air Fuel Ratio Meter is a must for serious tuners! Finally you can tune for more power, closer to the edge, precisely monitoring Air/Fuel ratio Boost, EGT, RPM and throttle position datalogging up to 9 hours of data with a blazing rate of 74 samples per seconds per graph. The ZDL software can be utilized as a real time display when using the standard Zt-2 kit without an LCD, ZR-2 Multi-Gauge or DashDAQ display.
Fully digital, smallest wideband O2 controller and datalogging system in the world!
Zt-2 is about the size of 1" thick business card. Extremely compact design for installation where space is a premium.
Zt-2 Specs
- <LI style="COLOR: #000000">0.1 AFR accuracy<LI style="COLOR: #000000">Operating voltage 10V to 18V<LI style="COLOR: #000000">Switching power supply for oxygen sensor heater<LI style="COLOR: #000000">Precise sensor temperature control<LI style="COLOR: #000000">Reverse polarity protection<LI style="COLOR: #000000">Integrated self resettable fuse<LI style="COLOR: #000000">Positive lock connectors<LI style="COLOR: #000000">Protected inputs and outputs<LI style="COLOR: #000000">Flexible Plug and Play Sensor Harness with a small, easy to route through the fire wall, connector<LI style="COLOR: #000000">Wideband Oxygen Sensor included<LI style="COLOR: #000000">Easy to install plug and play kit<LI style="COLOR: #000000">Adjustable Narrowband Switching Point
- Warning Alarms and Triggers
- Bosch Wideband O2 sensor Input
- Linear Wideband Output AFR = Volts * 2 + 9.6
- Serial data output to the Zeitronix LCD, ZR-1 AFR, and ZR-2 Multi-Gauge Displays
- Serial data output for real time datalogging (PC laptop required)
- RPM Input (tachometer, primary side ignition coil, crank, cam sensor).
The RPM input works in any car and any ignition system. No additional adapters needed!
- Simulated and adjustable Narrowband Output to feed a stock ECU
- Throttle Position Sensor Input
- Boost (MAP) Sensor Input
- Exhaust Gas Temperature (EGT) probe Input
- User1 Input:
- 0-5 volt analog input. Voltage data is viewable on all models of the LCD display.
Software support for the display of Zeitronix pressure sensors.
- Customized data conversions can be entered to match 0-5 volt sensor specifications.
All converted User1 data values are displayed only in the software. - User2 Input:
- 0-5 volt analog input OR configurable to be used with Fuel/Oil/Boost pressure sensors and Air/Water/Oil/Transmission temperature sensors.
- Data is displayed on the 2010 Model LCD and ZR-2 Multi-gauge as a pressure or temperature.
- Zeitronix Data Logger software will display and log data according to sensor type.
- Customized data conversions can be entered to match 0-5 volt sensor specifications.
Customized data conversion values are displayed in the Zeitronix Data Logger software only. - Warning Output for use with ZAVT-1 warning/trigger box
- 5V output for sensors
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