Spark Plug Gap and stuff - ZR-1 Net Registry Forums

QMCMSS · 05-05-2015

So last week I was a newbie and this week after reading and rereading. I've made a few decisions and raised a few questions for myself based on what I've read here and the Hailbeck site. Hopefully by sharing them I can help the next newbie. Also included here are some of my own discoveries.

First the car 1991 ZR1 with the following changes. K&N filter setup Corsa Cat Back Exhaust, Hailbeck Chip, Top end ported and polished. I bought the car about 10 days ago and it has 51k original it would not pass California Smog because of high NOx . The end of that saga was to change both O2 sensors NOx went from 699 to 385 and the car passed max allowable is 545. The car also has a high RPM miss around 5500rpm under a heavy foot which seems to sound ignition related rather than fuel. Other than that life is seems pretty good.

My next plan is to create a baseline of the simple stuff Oil, Plugs, and fluids. and here is what I have concluded based on the great info available here.

Plugs I'm going with the NGK part # 3690 which is one step cooler than OE. After reading the spark plug debate between the less expensive AC Delco and NGK my reason for choosing the NGK was Marc's recommendation that this was the best plug. Couldn't find them at any of the local parts house's so I wound up ordering them from Rock Auto just under $60 for the set including shipping. Hopefully they will help with the high RPM miss. Spark plug gap seems to be open for debate with a split between 40 and 50 I'm thinking of going with 45 and am interested in your thoughts. I'm sure it's a small thing but my curiosity needs to know.

Oil debate a very good one between Amsoil and Mobil 1. Marc gives a pretty good explanation which is way to Scientific for me to understand but boy it sounded good so I'm going with Amsoil I had some difficulty locating it locally so got it direct from AMSOIL about $120 for a twelve pack. Free shipping for orders over $100. Using the Bosch oil filter seems to get a lot of props and it's black.

Coolant not much debate here everyone seems the good old green stuff is the way to go. But what I'm still puzzled about is whether or not the good old 50/50 ratio is right for the aluminum block. Marc has an interesting article on how to refill the system but I couldn't locate any info on how to get all the old stuff out. Any help here would be great.

I know this is small stuff but my philosophy is that a few small things can make a big difference plus these are "DISCUSSION FORUMS" so thanks in advance for your help and input. It's off to the dyno next week to see what this baby's got.

bradley · 05-05-2015

how I change the fluid is to get 5 gallons of distilled water . drain the old fluid and then fill with the distilled water and run the motor till fully hot . then shut it off drain .let it cool for 1/2 hr and fill again with the distilled water . I do it 3 times then drain and fill with a 70%distilled water and 30 green in the summer and 50/50 in the winter .I use mobil 1 high mileage. I use the napa gold filters . I change the filter every 2 k miles and the oil every 6 k miles . I use autolite 3923 plugs but keep the gaps @35 thou. my car seems to like the smaller gaps .the compression on our cars is 11/to1 which to me is high enough to maybe cause a misfire with the larger gaps due to the compression blowing out the flame . but that is just me .mark knows a lot more than I do about our motors .

05-05-2015	#1
QMCMSS Join Date: May 2015 Location: Benicia, CA Posts: 28	Spark Plug Gap and stuff So last week I was a newbie and this week after reading and rereading. I've made a few decisions and raised a few questions for myself based on what I've read here and the Hailbeck site. Hopefully by sharing them I can help the next newbie. Also included here are some of my own discoveries. First the car 1991 ZR1 with the following changes. K&N filter setup Corsa Cat Back Exhaust, Hailbeck Chip, Top end ported and polished. I bought the car about 10 days ago and it has 51k original it would not pass California Smog because of high NOx . The end of that saga was to change both O2 sensors NOx went from 699 to 385 and the car passed max allowable is 545. The car also has a high RPM miss around 5500rpm under a heavy foot which seems to sound ignition related rather than fuel. Other than that life is seems pretty good. My next plan is to create a baseline of the simple stuff Oil, Plugs, and fluids. and here is what I have concluded based on the great info available here. Plugs I'm going with the NGK part # 3690 which is one step cooler than OE. After reading the spark plug debate between the less expensive AC Delco and NGK my reason for choosing the NGK was Marc's recommendation that this was the best plug. Couldn't find them at any of the local parts house's so I wound up ordering them from Rock Auto just under $60 for the set including shipping. Hopefully they will help with the high RPM miss. Spark plug gap seems to be open for debate with a split between 40 and 50 I'm thinking of going with 45 and am interested in your thoughts. I'm sure it's a small thing but my curiosity needs to know. Oil debate a very good one between Amsoil and Mobil 1. Marc gives a pretty good explanation which is way to Scientific for me to understand but boy it sounded good so I'm going with Amsoil I had some difficulty locating it locally so got it direct from AMSOIL about $120 for a twelve pack. Free shipping for orders over $100. Using the Bosch oil filter seems to get a lot of props and it's black. Coolant not much debate here everyone seems the good old green stuff is the way to go. But what I'm still puzzled about is whether or not the good old 50/50 ratio is right for the aluminum block. Marc has an interesting article on how to refill the system but I couldn't locate any info on how to get all the old stuff out. Any help here would be great. I know this is small stuff but my philosophy is that a few small things can make a big difference plus these are "DISCUSSION FORUMS" so thanks in advance for your help and input. It's off to the dyno next week to see what this baby's got. Last edited by QMCMSS; 05-05-2015 at 12:19 PM.

05-05-2015	#2
bradley Join Date: Aug 2013 Location: ridgecrest ca Posts: 104	Re: Spark Plug Gap and stuff how I change the fluid is to get 5 gallons of distilled water . drain the old fluid and then fill with the distilled water and run the motor till fully hot . then shut it off drain .let it cool for 1/2 hr and fill again with the distilled water . I do it 3 times then drain and fill with a 70%distilled water and 30 green in the summer and 50/50 in the winter .I use mobil 1 high mileage. I use the napa gold filters . I change the filter every 2 k miles and the oil every 6 k miles . I use autolite 3923 plugs but keep the gaps @35 thou. my car seems to like the smaller gaps .the compression on our cars is 11/to1 which to me is high enough to maybe cause a misfire with the larger gaps due to the compression blowing out the flame . but that is just me .mark knows a lot more than I do about our motors .