Plugs and gap
- Thread starter Sneezy6
- Start date
- Joined
- May 26, 2001
To give you a good recommendation, more info about your build and how it is used would be helpful.
Such items like the heads, iron or alum, ported or not, turbo size, what kind of weather, hot like 110 deg here, 60-90 where you are, intercooler type and so on?
Such items like the heads, iron or alum, ported or not, turbo size, what kind of weather, hot like 110 deg here, 60-90 where you are, intercooler type and so on?
Stock short and long block. Mods are 165* thermostat, DW300 pump, 80lb/hr injectors, TA49 turbo, cold air kit, TT E85 chip, 100lb valve springs, and a hot wire kit. Stock everything else. I am in northern Illinois so the weather is moderate, doesn't get to hot. I drive the car to work occasionaly and the track a few times a year. Have reliable gauges and am trying to tune out of backfires at 22lbs of boost. Ruled out air, fuel, vacuum, exhaust problems. Seems to be a spark issue so I am seeking a plug that has worked for other people running E85.
- Joined
- May 26, 2001
For iron heads I have used Autolite AR133 and AR132 spark plugs at .028" gap.
At 22 psi and a TA49 turbo may be producing so much cylinder pressure the spark may not be strong enough to light off e-85, and also the 100# springs may not be strong enough to close the valves tight?
I had the issue backfiring like a 2-step in one of my street cars with a TE-45A, and the addition of a TR6 ignition then allowed the boost go to over 20 psi instead of 11-15 psi.
By the way, be prepared to change head gaskets if the backfires continue.
At 22 psi and a TA49 turbo may be producing so much cylinder pressure the spark may not be strong enough to light off e-85, and also the 100# springs may not be strong enough to close the valves tight?
I had the issue backfiring like a 2-step in one of my street cars with a TE-45A, and the addition of a TR6 ignition then allowed the boost go to over 20 psi instead of 11-15 psi.
By the way, be prepared to change head gaskets if the backfires continue.
So it turns out my #5 clylinder plug was in really bad shape. The picture attached is it after a solid 30 seconds on the wire bristle bench grinder just so I could see the surface. It was covered in oxidation. I am going to assume this was causing my backfire. I will update after I take it for a ride tomorrow.
Attachments
Rafs-T-Type
Not so Senior Member
- Joined
- Mar 8, 2009
The top part of the plug shouldn't be oxidizing since it shouldn't be getting any air. What do your plug wires look like? Also instead of trying to fix the spark plug, why don't you just spend 2 bucks and get a new one.
I wasn't trying to fix the spark plug, I was trying to asses the severity of the damage so I could figure out why it was oxidizing in the first place. I have new plugs and wires I bought today and will be putting them on shortly. I don't know why the plug did that, the boot appears fine and has no rips, tears, or holes. It might be a worn out end cap, I will cut it open and take a look.
No disintegrations
Well-Known Member
- Joined
- Dec 27, 2015
If the terminal is loose or somehow found a supply of water (car wash?) the electric arc will perform its own "science experiment" and raise hell with that poor piece of metal. you should dab some dielectric grease on them to seal out water.
Solid advice! Thanks. Just sent the wife to autozone for conductive grease. Didn't think of it until seeimg your reply.
Just got it back together and took it for a ride. Not one sputter or hesitation. No knock, quick spool, and holds 22lbs no problem. My problem was obviously the corroded plug and wire on the #5 cylinder. After cutting the plug boot open, there was alot of corrosion from, what appears to be, some sort of improper foriegn grease. The wire was rotted in the boot, clearly been like that a while. Closed the gap on the new plugs from .034 to .028 and added the cunductive grease. I appreciate all the help.
Rafs-T-Type
Not so Senior Member
- Joined
- Mar 8, 2009
Nice. Glad you got her sorted.
