When does an engine go from needing a range plug to a hot range plug?
My engine is a 2600s bored, head work, 32/72 cam, ww2 carb and headers.
I hand a brain freeze when buying plugs and bought cold range...consequently they keep fouling. They all look like there covered with soot but a quick wipe with wire brush and its all good.
So my thinking now is that the cam and head means more fuel thus needing hot plugs to burn it ??
hot plugs vs cold plugs
Started by
_gtr161s_
, Mar 13 2009 07:37 PM
20 replies to this topic
#2
FastEHHolden
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Posted 13 March 2009 - 07:42 PM
your combo seems mildish...how many stages colder did you go? I would have thought one off STD would be OK....but I'm thinking STD plugs would be the go.
#3
_gtr161s_
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Posted 13 March 2009 - 07:57 PM
I should have a look at what Ive got but when i went the auto pro they offered just "hot or "cold' so dumb me was thinking weather at the time and I said cold!
#4
_memorylane-spare-parts_
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Posted 13 March 2009 - 08:09 PM
i think you need a hotter plug have a look a this and let me know i sell
them from $4.25 each+fr
www.ngkspark.com.au
them from $4.25 each+fr
www.ngkspark.com.au
#5
LXCHEV
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Posted 13 March 2009 - 08:23 PM
A general rule of thumb is something like this:
Use standard heat-range spark plugs for standard and mildly worked engines.
For every extra 100 HP you make, go one heat range colder in the spark plug.
We really need some more details though of what you're running - find out the numbers on the plugs you fitted, and compare them to standard ones to see how much colder you have gone - hopefully it was only one range colder. But if they're fouling already, I'd say it's a sign to go back to standard, especially if it's just for street driving.
Use standard heat-range spark plugs for standard and mildly worked engines.
For every extra 100 HP you make, go one heat range colder in the spark plug.
We really need some more details though of what you're running - find out the numbers on the plugs you fitted, and compare them to standard ones to see how much colder you have gone - hopefully it was only one range colder. But if they're fouling already, I'd say it's a sign to go back to standard, especially if it's just for street driving.
#6
_gtr161s_
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Posted 13 March 2009 - 08:33 PM
Ok just checked..Ive got NKG BP5ES, the NKG site recommends BP6ES for xu1 engines.
My engine is a 161 + 0.60, balanced, yella terra head, ww2 carb but will run 3 x cd 150s, 32/72 hyd crow cam, 2 piece headers.
At this stage Ive only had a chance to run in cam as car can't be driven so I have been guilty of running it for a couple of 15min times
My engine is a 161 + 0.60, balanced, yella terra head, ww2 carb but will run 3 x cd 150s, 32/72 hyd crow cam, 2 piece headers.
At this stage Ive only had a chance to run in cam as car can't be driven so I have been guilty of running it for a couple of 15min times
#7
_gtr161s_
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Posted 13 March 2009 - 08:35 PM
Just did a comparison on the nkg site for a stock 6cyl and it recommends the BP5ES so maybe I be running the BP6ES
#8
_gtr161s_
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Posted 13 March 2009 - 08:37 PM
Just did a comparison on the nkg site for a stock 6cyl and it recommends the BP5ES so maybe I be running the BP6ES
When the heat rating is too high:
The spark plug temperature remains too low and causes deposits to build up on the firing end; the deposits offer an electrical leakage path that gives rise to loss of sparks.
When the heat rating is too low:
The spark plug temperature rises too high and induces abnormal combustion (pre-ignition): this leads to melting of the spark plug electrodes as well as piston seizure and erosion.
NGK Spark Plugs pioneered the use of a copper cored electrode in 1958, which enables a spark plug to heat up quickly and also dissipate heat quickly giving an ultra wide heat range. It is essential to use a spark plug that fits a specific engine and its conditions of use.
As spark plugs are positioned in the head of an engine, their analysis can give a good indication of how your engine is operating.
#9
_torbirdie_
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Posted 14 March 2009 - 12:53 AM
The five rated plug in the ngk, as described ^ should be the go in your application. What were you using before?, were they okay, perhaps go back and look what they were.
There is absolutely no benefit in trying to use a colder plug, unless you are convinced that your motor was suffering from preignition.
There is absolutely no benefit in trying to use a colder plug, unless you are convinced that your motor was suffering from preignition.
#10
_NZ Toranaman_
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Posted 14 March 2009 - 05:31 AM
LXChev summed it up perfectly.
The more modified the engine generally you go colder plug.
Read the plugs for your "normal" use, run the car as you would normally drive and in the normal operating temperature.
Too white a colour you need colder, too black a colour you need hotter but make sure your car is in tune before doing a plug read as it may cause variances to this.
As you found:
NGK the lower the number = hotter plug
An example is my Webers run dark (over fueling) around town but burn cleaner down the quarter mile!
The more modified the engine generally you go colder plug.
Read the plugs for your "normal" use, run the car as you would normally drive and in the normal operating temperature.
Too white a colour you need colder, too black a colour you need hotter but make sure your car is in tune before doing a plug read as it may cause variances to this.
As you found:
NGK the lower the number = hotter plug
An example is my Webers run dark (over fueling) around town but burn cleaner down the quarter mile!
#11
_gtr161s_
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Posted 14 March 2009 - 05:17 PM
Going on the nkg site the 5's suit a stock motor and the 6's suit xu1.
Carby has been rebuilt and tuned but I did get the dizzy regraphed so Im still not 100% sure on the setting of 12-14o.
I'll try a set of 6's
Carby has been rebuilt and tuned but I did get the dizzy regraphed so Im still not 100% sure on the setting of 12-14o.
I'll try a set of 6's
#12
_memorylane-spare-parts_
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Posted 14 March 2009 - 05:42 PM
Hi what dizzy are you running try a NGK BPR6FS or BPR6FS-15 just to open the gap 1.5
Edited by memorylane-spare-parts, 14 March 2009 - 05:42 PM.
#13
_gtr161s_
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Posted 14 March 2009 - 07:36 PM
Hi what dizzy are you running try a NGK BPR6FS or BPR6FS-15 just to open the gap 1.5
Id say your right with those part numbers...will be getting a set on sunday
#14
_memorylane-spare-parts_
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Posted 14 March 2009 - 07:54 PM
i sell
them from $4.25 each+fr
them from $4.25 each+fr
#15
_torbirdie_
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Posted 15 March 2009 - 04:55 AM
Sorry, didnt read this bit before replying last time.Ok just checked..Ive got NKG BP5ES, the NKG site recommends BP6ES for xu1 engines.
My engine is a 161 + 0.60, balanced, yella terra head, ww2 carb but will run 3 x cd 150s, 32/72 hyd crow cam, 2 piece headers.
At this stage Ive only had a chance to run in cam as car can't be driven so I have been guilty of running it for a couple of 15min times
If you now have the 5 rated plug, that is standard. Going to a 6 rated plug is going to make matters worse in terms of fouling, its colder.
sounds like you have a fuel mixture problem. I dont think you want to try and put hotter plugs in it to solve this problem!
Even if you decide you have a xu1 spec setup, would still use 5 rated plug unless you were doing serious stuff like time trials or racing etc. Changing the dizzy setup shouldnt make a colder plug necessary.
Did it foul the set of plugs you had before?
In terms of gaps, do you have the standard dizzy or hei unit. The standard distributor cap isnt designed for setting the spark gap to 1.5mm.
Edited by torbirdie, 15 March 2009 - 05:01 AM.
#16
_gtr161s_
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Posted 16 March 2009 - 07:36 PM
Put in a new set of NKG bp6es plugs and it runs perfectly.
So without putting the mocker on myself it now revs smoother, the cam has a nice even sound and its no where near as fumey as before.
The dizzy is basically brand new, regraghed 2600s points type, the plug gap is 0.8mm.
The motor is all new so the bp5es plugs where new and had only done about 1hr running time.
I'll give it a couple more starts then check the plugs...fingers crossed its all good now
So without putting the mocker on myself it now revs smoother, the cam has a nice even sound and its no where near as fumey as before.
The dizzy is basically brand new, regraghed 2600s points type, the plug gap is 0.8mm.
The motor is all new so the bp5es plugs where new and had only done about 1hr running time.
I'll give it a couple more starts then check the plugs...fingers crossed its all good now
#17
_torbirdie_
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Posted 17 March 2009 - 03:15 AM
You might have mentioned this when asked about what plugs you had been using or have included that in your initial post due to it being somewhat important.The motor is all new so the bp5es plugs where new and had only done about 1hr running time.
Oh, I do see in one of the replies you made that you have run in the cam, missed that. Possibly the plugs got badly fouled from the very 1st startup and unless very well cleaned never recover. Hopefully things will bed in quickly and you wont be pushing any more oil into the cylinders and/or you get the mixtures checked.
It will be more to do with the plugs actually being clean, colder plugs will not make it run any better, they will only prevent preignition which is the remotest of possibilities under heavy load in your motor and not something you'll possibly doing in the running in process.Put in a new set of NKG bp6es plugs and it runs perfectly.
So without putting the mocker on myself it now revs smoother, the cam has a nice even sound and its no where near as fumey as before.
Replacing plugs that fouled with a colder plug at this stage is hardly a move in the right direction, hope it turns out okay for you.
Edited by torbirdie, 17 March 2009 - 03:19 AM.
#18
_gtr161s_
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Posted 17 March 2009 - 08:17 PM
Thanks "torbirdie"
When i first suspected it may be the plugs I gave then a wire brush clean and It was enought o make it run smooth but that was only short lived.
Since i cant drive the car at the moment I've given it 2 starts with these new plugs and all is still ok....revs quick, smooth and very responsive - never did this with the previous plugs.
Something that has got me curious is why does the nkg site recommend bp5's for stock engine and bp6's for xu1 (lc & lj)?
When i first suspected it may be the plugs I gave then a wire brush clean and It was enought o make it run smooth but that was only short lived.
Since i cant drive the car at the moment I've given it 2 starts with these new plugs and all is still ok....revs quick, smooth and very responsive - never did this with the previous plugs.
Something that has got me curious is why does the nkg site recommend bp5's for stock engine and bp6's for xu1 (lc & lj)?
#19
_NZ Toranaman_
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Posted 17 March 2009 - 08:22 PM
Thanks "torbirdie"
When i first suspected it may be the plugs I gave then a wire brush clean and It was enought o make it run smooth but that was only short lived.
Since i cant drive the car at the moment I've given it 2 starts with these new plugs and all is still ok....revs quick, smooth and very responsive - never did this with the previous plugs.
Something that has got me curious is why does the nkg site recommend bp5's for stock engine and bp6's for xu1 (lc & lj)?
Hi mate,
6's are colder than 5's and as said before "generally" you run colder with a more modified engine.
BTW I was always told never use a wire brush on spark plugs as you can damage them, don;'t tell anyone though as I still do when I can't use my mates sand blaster
Graham
#20
_gtr161s_
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Posted 18 March 2009 - 11:11 AM
Hi mate,
6's are colder than 5's and as said before "generally" you run colder with a more modified engine.
BTW I was always told never use a wire brush on spark plugs as you can damage them, don;'t tell anyone though as I still do when I can't use my mates sand blaster
Graham
Nice tip Graham
6's are colder than 5's and as said before "generally" you run colder with a more modified engine.
BTW I was always told never use a wire brush on spark plugs as you can damage them, don;'t tell anyone though as I still do when I can't use my mates sand blaster
Graham
Nice tip Graham
#21
_Terrible One_
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Posted 18 March 2009 - 04:46 PM
I had some plug related problems with my turbo 202, under boost it would ping even with timing pulled back, I went to a colder plug and it stopped doing it. I was using a standard style plug to start with, didn't come to think it would have been a problem. I thought initially maybe a carbon build up but the motor was only a couple thousand KM old!
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