LC9 Spark Plug Cans
06-18-2015, 01:46 PM
#1
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LC9 Spark Plug Cans Spark plug cans
I have a 'connect and cruise' package installed in my 70 C10 chev truck - LC9 and 65e tranny. I have headers installed and 3 plugs had to have the can and 'boot' removed because they kit the headers.
I am having loss of power at high altitudes and stumbling - above 3000' or so.
Chevy dealer claims its because the cans are missing, spark is jumping to headers. The is at least .5 inch between the wire and header. Since the plug gap is maybe .060 inches this doesn't seen possible to me. They claim the load on the engine is causing the spark to jump.
Does anybody know the real purpose of the cans and boots? I have heard radio interference suppression and wire insulators because of heat.
Hope I'm not duplicating -tried to post yesterday but couldn't find it.
Thanks
I have a 'connect and cruise' package installed in my 70 C10 chev truck - LC9 and 65e tranny. I have headers installed and 3 plugs had to have the can and 'boot' removed because they kit the headers.
I am having loss of power at high altitudes and stumbling - above 3000' or so.
Chevy dealer claims its because the cans are missing, spark is jumping to headers. The is at least .5 inch between the wire and header. Since the plug gap is maybe .060 inches this doesn't seen possible to me. They claim the load on the engine is causing the spark to jump.
Does anybody know the real purpose of the cans and boots? I have heard radio interference suppression and wire insulators because of heat.
Hope I'm not duplicating -tried to post yesterday but couldn't find it.
Thanks
06-18-2015, 05:20 PM
#2
Well, let's acknowledge you will lose power above 3000' in any gas engine and a "good enough" fuel & spark setup can show faults and weird drivability issues when you start pushing a mile up. (Years back, I moved to an area about 5,500' higher in altitude.)
Where are you starting and how high are you going? Are you running 87 octane the whole time? 93? 85? Are there are any codes being set? How about live data logs of misfires or timing pulled? On the spark, does it noticeably jump spark in the dark?
I'd start by bending or trimming the cans to see if they work. Or aftermarket wires.
To be honest, it's probably simpler to go with good aftermarket wires with 90deg. or bendable boots at the plug and never look back. The OEM straights have never been the hot ticket with headers.
Where are you starting and how high are you going? Are you running 87 octane the whole time? 93? 85? Are there are any codes being set? How about live data logs of misfires or timing pulled? On the spark, does it noticeably jump spark in the dark?
I'd start by bending or trimming the cans to see if they work. Or aftermarket wires.
To be honest, it's probably simpler to go with good aftermarket wires with 90deg. or bendable boots at the plug and never look back. The OEM straights have never been the hot ticket with headers.
06-19-2015, 11:30 AM
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The LC9 is the truck engine with variable cam timing up front. I installed 'connect and cruise' GM performance package. Specs call for 87 gas.
Problem first appeared when running the blue ridge parkway - around 5000'. Hadn't had truck running long and it would fairly leap up the hills. I was going down a long grade and then back up another. Fairly cold weather. When I started back up there was a major loss of power and stumbling - not skipping. Moving gas petal make very little difference.
Kinda concerning - almost no cars at time of year and no cell coverage. I have experienced same kind of problem at lower ells 3000'-3800' but not as severe.
I had truck in for service and on this issue they said it was caused by spark jump and an exhaust leak at collector which threw off o2 sensor. I just don't buy their answer. Package is covered for 2 year and 50,000 miles.
Where can I get angled plug wires for LS?
Thanks
The LC9 is the truck engine with variable cam timing up front. I installed 'connect and cruise' GM performance package. Specs call for 87 gas.
Problem first appeared when running the blue ridge parkway - around 5000'. Hadn't had truck running long and it would fairly leap up the hills. I was going down a long grade and then back up another. Fairly cold weather. When I started back up there was a major loss of power and stumbling - not skipping. Moving gas petal make very little difference.
Kinda concerning - almost no cars at time of year and no cell coverage. I have experienced same kind of problem at lower ells 3000'-3800' but not as severe.
I had truck in for service and on this issue they said it was caused by spark jump and an exhaust leak at collector which threw off o2 sensor. I just don't buy their answer. Package is covered for 2 year and 50,000 miles.
Where can I get angled plug wires for LS?
Thanks