could this be caused by detonation?
03-28-06, 03:02 PM
#1
could this be caused by detonation?
It's been a while since I posted, and when I started up my 7 the other day at my storage facility, i got to thinking about the strange noise that I posted about. A few people suggested spark knock because of my timing being off. Could spark knock cause the insulation around the electrode on my plugs to break? attached is a picture of one of my plugs that I pulled and had to replace.
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03-28-06, 06:00 PM
#8
that's an old shot, i had to pull the electrodes off and file off the rough edges so the ceramic didn't get into my engine and **** my housings. When I was poking around in my engine bay, I bumped my dizzy cap and saw that it moved, so I grabbed it and pulled gently, and it rose ~.5". I'm pretty sure that has something to do with my ignition problem, but i'm not sure ;-). I know that I need a new dizzy cap, rotor, points, etc. I'll see if that fixes what I think is ignition breakup every once in a while at high RPM's under load.
03-28-06, 06:00 PM
#9
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ive seen em do that just from old age too. but preignition (too much timing advance, too lean, too hot) can do it too
03-28-06, 06:03 PM
#10
just as a reference to how bad the ceramic was broken, when I pulled off the electrodes and flipped the plug over, the ceramic fell out w/o any hesitation. It was pretty broken up. If anyone lives in/around Ann Arbor and would like to help troubleshoot my timing (I tried to check the timing, got the light working, but couldn't see any timing marks on my front pulley), i'd be extremely greatful. She's going to stay in storage until I get out of school in May so I can concentrate on my homework, so it'll be a while.
03-28-06, 06:31 PM
#11
Senior Member
I'm a little far from ann arbor, otherwise I would help you out. Here's what I can tell you. The two notches in the pully are very faint and the yellow and red paint is probably long gone by now.
Find a big socket that will fit over the alternator nut, this is your leverage to turn the engine slowly so you can clean the pully well and not miss spotting the marks. Take a rag with hot soapy water and scrub every inch of the eccentric shaft pully. The marks are on the pully lip closest to the engine. Bring the biggest baddest flashlight you can to assist in spottin the marks. re-mark them with a paint pen or paint on a tooth pick, or steal you woman's nail polish, what ever it takes.
Now the engine turns clockwise when you are looking at it from the front of the car so the first mark that passes by the pin is the leading mark, the next of course is the trailing mark.
Don't forget to unplug and cap the vac line to the distributor and try to warm up your engine before adjusting the timing.
Good luck
Find a big socket that will fit over the alternator nut, this is your leverage to turn the engine slowly so you can clean the pully well and not miss spotting the marks. Take a rag with hot soapy water and scrub every inch of the eccentric shaft pully. The marks are on the pully lip closest to the engine. Bring the biggest baddest flashlight you can to assist in spottin the marks. re-mark them with a paint pen or paint on a tooth pick, or steal you woman's nail polish, what ever it takes.
Now the engine turns clockwise when you are looking at it from the front of the car so the first mark that passes by the pin is the leading mark, the next of course is the trailing mark.
Don't forget to unplug and cap the vac line to the distributor and try to warm up your engine before adjusting the timing.
Good luck
03-28-06, 10:50 PM
#12
FB+FC=F-ME
I used to eat up NGK plugs like that with my old MSD direct fire setup.I had to replace leadings at every oilchange because they would start to fall apart the same way.I never lost an engine that way(lucky),and I never heard any detonation either.....not that its very easy to detonate with an N/A rotary.Rotaries have a pretty low comp. ratio and the mixture going into them tends to be on the rich side.Usually,only boosted guys have to worry about detonation....unless your timing is super advanced or your running REALLY bad gas.
I ran the max advance per Paul Yaw's spec,which isnt too wild.Rotaries are hard on plugs,but you should be able to get at least 10K out of them.For the record,I solved my NGK plug failure issue by switching to Nippon Denso plugs.They held up in the same environment 3 times as long as the NGK plugs,and they are OK to run since they are factory recommended right alongside the NGK's.I got the full 10K miles out of them with no insulator issues at all and only moderate electrode wear.
W25EDR14 is the ND part number for 12A leading plugs. 22 and 27 are availible for cold/hot applications.
I ran the max advance per Paul Yaw's spec,which isnt too wild.Rotaries are hard on plugs,but you should be able to get at least 10K out of them.For the record,I solved my NGK plug failure issue by switching to Nippon Denso plugs.They held up in the same environment 3 times as long as the NGK plugs,and they are OK to run since they are factory recommended right alongside the NGK's.I got the full 10K miles out of them with no insulator issues at all and only moderate electrode wear.
W25EDR14 is the ND part number for 12A leading plugs. 22 and 27 are availible for cold/hot applications.
06-23-06, 12:09 PM
#13
Originally Posted by RXBeetle
I'm a little far from ann arbor, otherwise I would help you out. Here's what I can tell you. The two notches in the pully are very faint and the yellow and red paint is probably long gone by now.
Find a big socket that will fit over the alternator nut, this is your leverage to turn the engine slowly so you can clean the pully well and not miss spotting the marks. Take a rag with hot soapy water and scrub every inch of the eccentric shaft pully. The marks are on the pully lip closest to the engine. Bring the biggest baddest flashlight you can to assist in spottin the marks. re-mark them with a paint pen or paint on a tooth pick, or steal you woman's nail polish, what ever it takes.
Now the engine turns clockwise when you are looking at it from the front of the car so the first mark that passes by the pin is the leading mark, the next of course is the trailing mark.
Don't forget to unplug and cap the vac line to the distributor and try to warm up your engine before adjusting the timing.
Good luck
Find a big socket that will fit over the alternator nut, this is your leverage to turn the engine slowly so you can clean the pully well and not miss spotting the marks. Take a rag with hot soapy water and scrub every inch of the eccentric shaft pully. The marks are on the pully lip closest to the engine. Bring the biggest baddest flashlight you can to assist in spottin the marks. re-mark them with a paint pen or paint on a tooth pick, or steal you woman's nail polish, what ever it takes.
Now the engine turns clockwise when you are looking at it from the front of the car so the first mark that passes by the pin is the leading mark, the next of course is the trailing mark.
Don't forget to unplug and cap the vac line to the distributor and try to warm up your engine before adjusting the timing.
Good luck
Where are you located? I'd be willing to drive 2 or 3 hours to get my timing fixed, as it's making my car very very difficult to start this summer. I have an offer from Kentesu from mirotaryclub.com, he's in GR, and i'm seriously considering driving there to have him help me with my timing. Tonight after I work out i'm going to see if I can turn over my engine with the front pulley and find the timing marks. Thanks for the info.
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