Re: any Thermoquad experts here?
[Re: B1MAXX]
#2878133
01/21/21 10:40 PM
01/21/21 10:40 PM
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Joined: Jan 2003
Posts: 2,863 middle Tennessee
mopower440
OP
master
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OP
master
Joined: Jan 2003
Posts: 2,863
middle Tennessee
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Have you tried driving (flooring) it without the vacuum advance hooked up? Did it ping? If not, disconnect it, set the total timing to 34* Then take it out for a pounding. Did it ping? If yes you need more octane. Red deposits on the plug are usually from fuel additives/ octane boosters. The plugs look fine to me. yes, even with the vacuum unhooked it still pings, BUT, i believe i have figured this out. The builder i bought the distributor from built it to my specs but something happened between him shipping it to me and me installing it because when i watched it with my timing light, it was advancing into the 50's WITHOUT the vacuum hooked up and into the 60's with the vacuum hooked up! Im actually surprised it didnt ping even more! Its a shame because it liked all that advance as far as performance besides the pinging.. So anyways, he had me send it back to him to put it back on his distributor machine and see wth happened..
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Re: any Thermoquad experts here?
[Re: mopower440]
#2878178
01/22/21 12:27 AM
01/22/21 12:27 AM
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Joined: May 2012
Posts: 1,849 South Bend
John Brown
top fuel
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top fuel
Joined: May 2012
Posts: 1,849
South Bend
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You have a MSD ignition box? Have seen some that were wonky and added lots of advance on their own.
July 19th should be "Drive Like Rockford Day". R.I.P. Jimmie.
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Re: any Thermoquad experts here?
[Re: BSB67]
#2878224
01/22/21 09:13 AM
01/22/21 09:13 AM
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Joined: Jan 2003
Posts: 2,863 middle Tennessee
mopower440
OP
master
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OP
master
Joined: Jan 2003
Posts: 2,863
middle Tennessee
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Maybe I missed it.
What is your cranking cylinder pressure? What spark plug are you using? ok, the spark plug is an NGK XR4. I didnt think that was the actual number but looking it up, it actually is, just XR4..also lists as 5858. I cant find a chart that shows what the next colder NGK plugs are.. Also, what other things will happen with going with a colder plug? it wont run too rich will it?
Last edited by mopower440; 01/22/21 12:50 PM.
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Re: any Thermoquad experts here?
[Re: mopower440]
#2878576
01/22/21 07:48 PM
01/22/21 07:48 PM
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Joined: Jan 2003
Posts: 1,767 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,767
Windsor, ON, Canada
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Like the others have pointed out, that TOTAL MECHANICAL advance is WAY too big!!! I'm a small-block guy, and with 21 initial I aim for about 35 deg. TOTAL mechanical. The VAC can is configured to toss another 15 in at cruise, and since at WOT it gets no vacum signal that keeps it safely out of contributing any advance. Take the distributor apart and see what's going on with the advance mechanism. It could be one of two types: 1) Old Mopar OEM thing 2) More recent (and Aftermarket only???) version which allows a much easler adjustability to BOTH the TOTAL advance as well as the actual CURVE Here is what that distributor looks like:
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Re: any Thermoquad experts here?
[Re: BSB67]
#2878658
01/22/21 10:48 PM
01/22/21 10:48 PM
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Joined: Jan 2003
Posts: 2,863 middle Tennessee
mopower440
OP
master
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OP
master
Joined: Jan 2003
Posts: 2,863
middle Tennessee
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That's a hot plug. It will add to your detonation problem.
The last digit specifies where the plug is in its heat range. XR4 is a plug that cross references to a JY12 to JY14. This plug would be on the hot side for a 7.5:1 motor with a 2.76 gear in a 5000 lb Imperial that almost never sees more that 2000 rpm.
I would not put anything hotter than a -6, like a NGK r5670-6, and would consider a -7.
And I also agree with what folks are saying about your full advance timing (>50°) being too high, and possibly being too lean. Plugs is the easy first step.
A few questions..if i go to a 7 heat range, it wont start sooting up the plugs? It already stinks like hell at idle, but looking at the plugs, they look good. like correct mixture..Also, Looking at the NGK R5670-7, they are 7.00 each compared to the 3.00 each of the XR4, can you tell me of a cheaper alternative with the same heat range as the R5670-7 being this is experimental, dont want to spend that much if i dont have too.. crossing the R5670-7 that you recommended crosses to the champion J12Y, which you said also crosses to the XR4 i already have..? confusing
Last edited by mopower440; 01/22/21 11:13 PM.
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Re: any Thermoquad experts here?
[Re: mopower440]
#2878770
01/23/21 08:53 AM
01/23/21 08:53 AM
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Joined: May 2019
Posts: 6,324 nowhere
Sniper
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master
Joined: May 2019
Posts: 6,324
nowhere
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That's a hot plug. It will add to your detonation problem.
The last digit specifies where the plug is in its heat range. XR4 is a plug that cross references to a JY12 to JY14. This plug would be on the hot side for a 7.5:1 motor with a 2.76 gear in a 5000 lb Imperial that almost never sees more that 2000 rpm.
I would not put anything hotter than a -6, like a NGK r5670-6, and would consider a -7.
And I also agree with what folks are saying about your full advance timing (>50°) being too high, and possibly being too lean. Plugs is the easy first step.
A few questions..if i go to a 7 heat range, it wont start sooting up the plugs? It already stinks like hell at idle, but looking at the plugs, they look good. like correct mixture..Also, Looking at the NGK R5670-7, they are 7.00 each compared to the 3.00 each of the XR4, can you tell me of a cheaper alternative with the same heat range as the R5670-7 being this is experimental, dont want to spend that much if i dont have too.. crossing the R5670-7 that you recommended crosses to the champion J12Y, which you said also crosses to the XR4 i already have..? confusing If you are running a hot plug it will look cleaner with a rich mixture than a colder plug will. IOW, your hotter plug might be crutching your rich mixture. An O2 sensor will be if use sorting that out.
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Re: any Thermoquad experts here?
[Re: BSB67]
#2881834
01/29/21 08:28 PM
01/29/21 08:28 PM
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Joined: Jan 2003
Posts: 2,863 middle Tennessee
mopower440
OP
master
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OP
master
Joined: Jan 2003
Posts: 2,863
middle Tennessee
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That's a hot plug. It will add to your detonation problem.
The last digit specifies where the plug is in its heat range. XR4 is a plug that cross references to a JY12 to JY14. This plug would be on the hot side for a 7.5:1 motor with a 2.76 gear in a 5000 lb Imperial that almost never sees more that 2000 rpm.
I would not put anything hotter than a -6, like a NGK r5670-6, and would consider a -7.
And I also agree with what folks are saying about your full advance timing (>50°) being too high, and possibly being too lean. Plugs is the easy first step.
so do i need to go 1 or 2 steps colder on the plugs? Would 1 step be enough to help with the pinging?
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Re: any Thermoquad experts here?
[Re: mopower440]
#2882883
02/01/21 07:34 PM
02/01/21 07:34 PM
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Joined: Jan 2003
Posts: 20,212 Park Forest, IL
slantzilla
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 20,212
Park Forest, IL
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I would get the timing issues fixed before I worry about plugs. With the timing right you could be fine.
"Everybody funny, now you funny too."
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