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Strap on the JATO
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305 Posts
Discussion Starter #1
I'm having trouble reading my plugs & wanted to ask you guys
a couple questions. My Engine's freshly re-built & the 800dp
Holley 9022 carb re-built w/ a holley kit. I have no problems
what so ever, no hesitation & the throttle response is perfect.
My holley has stock jetting, squirters, cam's etc. But I cannot
get any color on the plugs? I have a Victor Jr. Intake & I put
Splitfire plugs in it(SF2E), I think that's the #? I know these are
not setup for a Marine app. Is there another plug that works
better for reading? How about a NGK BR6FS? I did some searching,
but couldn't find anything for my setup. Here's my build;

Chevy 454 .030 9.5/1comp
990 heads
Crane Hyd roller 226/236 ZHR-288
Rewarder OT headers
Petronix HEI

Since this is a high rise/ air gap style single plain intake does that
necesitate more jetting? I thought Holley's were a little rich in stock
form?

Thanks Guys in advance!:)hand
 

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3,859 Posts
Question everyone will ask! OR SHOULD. How much idle time and how much WOT time before checking plugs? (WOT) wide open throttle.
 

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Strap on the JATO
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305 Posts
Discussion Starter #4
Question everyone will ask! OR SHOULD. How much idle time and how much WOT time before checking plugs? (WOT) wide open throttle.
There's a long wide open shoot before entering the marina w/ a
short idle in before docking. I pulled the plugs after & the porcelain
was white w/ a small spot(1/8")wide or so that was tan at the
very top. I'm getting no color changing on the threads also, so
i'm sure I need a hotter plug?
 

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steelcomp was here
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26,512 Posts
First thing to do is learn to read a plug. The NGK's are a good place to start. They're about the easiest plug to read, IMO. Next would be Autolite. I've never tried to read a splitfire, but I'm guessing you can't very well.
Idling isn't going to help you read plugs. You really need to shut the engine off at WOT with no idling, and you need new plugs to get a true reading. You don't read porcelain color either. Ground strap, electrode, and carbon ring (way down inside the plug) are the three places to read a plug correctly. You need a good lighted inspection scope to do this correctly, and not just a $40.00 cheapo. You also need to know where your timing is.
HTH
 

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Premium Member
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First thing to do is learn to read a plug. The NGK's are a good place to start. They're about the easiest plug to read, IMO. Next would be Autolite. I've never tried to read a splitfire, but I'm guessing you can't very well.
Idling isn't going to help you read plugs. You really need to shut the engine off at WOT with no idling, and you need new plugs to get a true reading. You don't read porcelain color either. Ground strap, electrode, and carbon ring (way down inside the plug) are the three places to read a plug correctly. You need a good lighted inspection scope to do this correctly, and not just a $40.00 cheapo. You also need to know where your timing is.
HTH

Steelcomp is 100% spot on here. Not only is it totally impossible to teach someone how to read a plug verbally, it is even more impossible to read a plug for jetting, timing, or heat range by having them describe the plug to you. Also, unleaded fuel and more so, gas/ethanol don't leave a very obvious carbon ring compared to leaded fuel, and seem to take longer to color. These sites have some very usefull info and I highly recommend that you read them. http://members.uia.net/pkelley2/sparkplugreading.html
http://www.4secondsflat.com/Spark_plug_reading.html



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Strap on the JATO
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305 Posts
Discussion Starter #7
Thanks Guys! I appreciate the help. I think I might go
buy a wide band O2 setup after I figure this out &
learn both ways. I'm just making sure I don't hurt the
motor this early. I'm thinking the jetting is close because
I have no driveability issues, but the no color on the plugs
has me a little nervous. I've been going 2jets up at a time to get some color. Does a Victor Jr usually lean the A/F out from a stock
jetted carb?
 

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FYI, going up two jets at a time may not always be going up at all. Holley does lots of neat things including overlapping jet sizes. Not all, but quite a few. For example, jet #'s 80, 81 and 82 are all .093. 88, 89 and 90 are all .104. There are several more sizes that do this as well. This information can be found in the back pages of most Holley carb books.
 

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Bouncing off rocks
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holley sizes jets on flow, not on hole diameter. go by jet number, not hole size when using holley jets
 

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You really need to shut the engine off at WOT with no idling, and you need new plugs to get a true reading. You don't read porcelain color either. Ground strap, electrode, and carbon ring (way down inside the plug) are the three places to read a plug correctly. You need a good lighted inspection scope to do this correctly, and not just a $40.00 cheapo. You also need to know where your timing is.
HTH
He has a jet boat...cannot shut it off at WOT without getting wet. :D:D
(just kidding...had to get a shot in)
I am with Comp...tellling someone how to read plugs is like telling someone how to screw. Not very easy. Pictures will help, better yet, find someone to spend 10 minutes with you, explain why and how, look at plugs, and go for it.
Wags
 

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You know what I like about these boards? Damn near everytime I post something, I learn something in return. It's a great place to further ones education.:)devil
 

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Resident Ford Nut
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Thanks Guys! I appreciate the help. I think I might go
buy a wide band O2 setup after I figure this out &
learn both ways. I'm just making sure I don't hurt the
motor this early. I'm thinking the jetting is close because
I have no driveability issues, but the no color on the plugs
has me a little nervous. I've been going 2jets up at a time to get some color. Does a Victor Jr usually lean the A/F out from a stock
jetted carb?
I use a wide-band lambda sensor for tuning. The only problem with them for recreational boats is that you can't use your water injection in your exhausts - the water will ruin the O2 sensors. For racers, the problem is the lead in the race fuel - it ruins the O2 sensors, too. The rate of decay with leaded fuel is slow enough that you can get away with it by replacing the sensor often. That being said, there is no better way to tune your motor throughout the entire range of operation - not just WOT.

Here's the one I use:
http://www.innovatemotorsports.com/products/lm1.php
 
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