I'd try a RN12YC Champion
massive reconfiguration time again.
- Thread starter j par
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j par
Well-hung Member
right now I'm trying to kind of work on the combination here as I wasn't aware I was running so much compression. How to deal with that on the street and still have good performance is what I'm trying to figure out? I was just looking at my distributor curve...
j par
Well-hung Member
This is what I'm running now, I think...
j par
Well-hung Member
I was actually trying to find a cross reference for a champion. I don't know if I'd be stepping up or down in heat range with the one you're recommending?
up. it will be a little hotter burning plug. More porcelain will show.
Your car will start better, idle better, perform better.
j par
Well-hung Member
A few years ago when I had my heads off with the old cam I was getting just a wee bit of detonation on the tops of a few of the Pistons. I brought a spark plug into the machine shop and it was way too hot and I'm pretty sure the AR 3934 s are what he sold me or that was the heat range and I changed brand but I don't think so. But I did now LOL... 220 lb of cranking compression, I may be dealing with a combustion chamber heat issue?
When your cranking compression is that high, you will need to pull a few degrees of total timing out of it, unless you are running high octane fuel. I'd put thicker head gaskets on it next time you have it apart. My opinion, of course
j par
Well-hung Member
Pretty much all of the above. Pulling timing, adding race fuel, and cold plugs...
are your heads milled?
j par
Well-hung Member
The next time I have those heads off I'm going for way bigger head gaskets as I'll probably have closed chamber heads.
I'm hoping somebody with some nice Edelbrock heads gets trick flow fever...
Uggggh! I'm only going to say this once and I'll not argue about it. Get the open chambered heads. Open chambers flow better and you DON'T need the bump in compression.
j par
Well-hung Member
Maybe a little bit for cleanup purposes but nothing beyond that. The 596 open chamber heads were gasket matched with a slight countersink because I'm.005-.010 out of the hole...
j par
Well-hung Member
LOL... NO obviously I'm not looking for a bump in compressions I have plenty of that. I have open chamber heads. It's just if I go to an aluminum head likely I'll end up with a closed chamber and special made Ultra thick head gaskets LOL...
j par
Well-hung Member
Well I'm hoping the dying battery thing was an anomaly. It was down to 11.99. I charged it up to 14 volts for about 3 hours. I can tell there's a small drain when I turn the battery switch on. But it never brought it down past 12.7 on its own. After we got done doing all the compression test it was down to 12.4. after turning the battery switch off for the night it's at about 12.9. I think I'm safe I've never really had any other problem with it but if it does give up the ghost I have had five good years with it. But for now I feel confident...
j par
Well-hung Member
Seemed to run pretty good. Seems hard to figure that I would have a detonation problem and carbon build-up LOL... A new plug with 15 - 20 miles..
j par
Well-hung Member
^^^^LOL... by lookin' at the picture of your plug you posted, you might have an issue or two yourself... eddy related??????
j par
Well-hung Member
Now I feel I've backed off the timing to much? New plugs, 100 freeway miles, 3k rpm's...
That is pretty white..
That is pretty white..
j par
Well-hung Member
The water temp was 170.. no fans on...
j par
Well-hung Member
Oil 65, volts 14, water 170...
I'm not expert but the timing shows up on the ground strap.
color starts at the bottom of the bend of your ground strap. At Least the best i can see from that picture angle.
Do you have a o2 to watch your air fuel ratio. Is it possible that it's getting to lean at cruising speed.
If you add timing the ground strap burn mark get longer, if you add fuel the same burn mark gets shorter. and less would make it longer.
In my opinion the white is only for reading detonation.
Did you go to a colder spark plug???? the length of the ground burn mark will also change with a colder plug. pulls more heat out of the plug, aka ground strap doesn't get as hot.
I'm just a amiture at plug reading so open to be educated.
color starts at the bottom of the bend of your ground strap. At Least the best i can see from that picture angle.
Do you have a o2 to watch your air fuel ratio. Is it possible that it's getting to lean at cruising speed.
If you add timing the ground strap burn mark get longer, if you add fuel the same burn mark gets shorter. and less would make it longer.
In my opinion the white is only for reading detonation.
Did you go to a colder spark plug???? the length of the ground burn mark will also change with a colder plug. pulls more heat out of the plug, aka ground strap doesn't get as hot.
I'm just a amiture at plug reading so open to be educated.
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Ok so here is the theory that i have been told(May not be accurate for a highway vehicle.)
You should have burn or discolor down 3 threads if you have the right heat range spark plug in.
If the timing is right, should be starting around the ground bend......to about were it is now.
Fuel curve should have a light gray(depending on fuel grade) color all the way around the base ring(were the ground strap is welded on) If you don't have a fuel ring all the way around the base, you could be getting lean.
So with that said......Its to cold of a spark plug
Timing is to high and its running rich..............
The problem with a street eng is everything affects everything.
Does your mechanical curve ramp to fast(compression with a street car i say yes)
do you have too much advance in the vac canister, advance???
To much initial timing???..... need to take more out of the mechanical curve????
The problem is that plug is showing idle, cruise (fuel tranfer slot) to hill climbing(running thru the main booster), to full throttle (main boost and power valve inrichment(If it s a holley or metering rods if its not.)
I'm not the one to tell any one, how to tune a street car........but that's what i see/read on your plug......But it's for full throttle, cut clean drag racing.
You should have burn or discolor down 3 threads if you have the right heat range spark plug in.
If the timing is right, should be starting around the ground bend......to about were it is now.
Fuel curve should have a light gray(depending on fuel grade) color all the way around the base ring(were the ground strap is welded on) If you don't have a fuel ring all the way around the base, you could be getting lean.
So with that said......Its to cold of a spark plug
Timing is to high and its running rich..............
The problem with a street eng is everything affects everything.
Does your mechanical curve ramp to fast(compression with a street car i say yes)
do you have too much advance in the vac canister, advance???
To much initial timing???..... need to take more out of the mechanical curve????
The problem is that plug is showing idle, cruise (fuel tranfer slot) to hill climbing(running thru the main booster), to full throttle (main boost and power valve inrichment(If it s a holley or metering rods if its not.)
I'm not the one to tell any one, how to tune a street car........but that's what i see/read on your plug......But it's for full throttle, cut clean drag racing.
It might be time to give YR a call. lol looks like you are close, just a little fine tuning and a hotter plug.
j par
Well-hung Member
Let me say this first and it keeps swirling in my head that after the first year of just basically drag racing only I took the heads off and put 202 valves instead of the 188''s. At that time there was a little bit of detonation on the tops of the Pistons but just very very start of something. I showed the Machine Shop my plugs with the porcelain sticking out about a quarter of an inch LOL and he said well this is way too hot. And recommended the ones that I'm using now. Back when I had an average cranking pressure of 190.
I sure appreciate you taking the time because I'm getting a little bit lost with all these things for some reason. It's always ran at about 35 36 degrees of advance with my old cam. It was used a lot for drag racing but a lot of putting as well. I always seemed to be burning rich and have black plugs.
Now I've changed the cam and my compression is higher so I backed the timing off to 34 right out of the gate. I've been putting smaller and smaller Jets and larger metering rods to lean the carbs to stop having such a rich condition. but here I am reading the plugs and seeing some speckling on the porcelain thinking I'm back to getting detonation. But still seeming to run very rich as you can see from the plug that I just pulled out the other day. All these plug reading things I'm trying as well LOL.. I'm constantly watching my AF gauge. It runs down my driver side header. It was burning about 14.2 on the freeway which I thought was a little high for cruise at 28 to 3000 RPMs. About 68 miles an hour. I have no vacuum advance canister. I would think what timing curve was probably about 3/4 open at the time. On post #1028 I'm showing my timing curve.
This is a side-by-side comparison of the number 2 spark plug. I believe they're the same heat range that's why I bought the NGK. The one on the right is the one that I've been running for a while and it's in Autolite ar3934. The one on the left has a hundred miles on it mostly freeway and it's the NGK 4554.
That was what really the first time I've ever took it on the freeway and had it like that for 45 minutes at a time. It's mostly driving around town and short verse of yeehaw... I thought it was the timing because I dropped it down 2 about 32 degrees total. a good Lord I was reading somewhere just recently were too low of timing was the cause of too much heat in the combustion chamber. It was running 170 cool-as-a-cucumber the whole time outside the combustion chamber...
j par
Well-hung Member
Your funny..
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