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Spark Plug In J-Head Question #1321127
10/15/12 09:01 PM
10/15/12 09:01 PM
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I decided to pull a few plugs tonight and while they were out, I noticed that a couple of them had oil laying around the outside of the spark plug hex. After looking a little more, it almost looks like the spark plug hex is bottoming out on the j-head casting diameter and not allowing the plug to seat all the way. In this picture, you can see around the hex and down into where the threaded portion of the plug enters the head.
Is there a chance that my spark plugs are too short on the threaded side of the plug?
Is it normal to be able to see down around the hex on the plug?
I am just trying to figure out why there is oil puddling around the outside of the plug when I always torque them to 35ft/lbs. It just seams like the sealing rings on some of the plugs are not sealing.

Thanks

7422331-10-15-12.png (95 downloads)

1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321128
10/15/12 09:06 PM
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Another picture which might show the gap better.

7422346-10-15-12_1.png (75 downloads)

1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321129
10/15/12 09:15 PM
10/15/12 09:15 PM
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you have the right plug.correct?

I run autolite 65( or maybe it is 85? I have to look) in all my SB engines,they have at least 3/4" reach into the cyl head. no short thred plugs.

I allways make sure the seal rings are all faceing the same way,small side down. and I change them often.

oil puddle around plug hex is not from the plugs/cyls. it is from a oil leak elswhere.IMO

you should never have that much oil coming from the combustion chambers past the plug.

clean it with brake clean,airdry,throw a hand full of baby powder around the plugs. this will show where the oil is wicking from as it travels to the plug cavity.


Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321130
10/15/12 09:18 PM
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Quote:

Another picture which might show the gap better.




the gap is for socket clearance.

on a magnum head,they have tubes to press down in those pockets and use a 5/8" hex plug. remove them to use a LA plug for a wider heat range on magnums.


Re: Spark Plug In J-Head Question [Re: scratchnfotraction] #1321131
10/15/12 09:36 PM
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My plugs have around an inch or so of thread, so they should be correct.
I just replaced my valve cover gaskets due to them leaking. I will keep an eye on the oil puddling, maybe it was from the old gaskets.

Thanks


1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: scratchnfotraction] #1321132
10/15/12 09:37 PM
10/15/12 09:37 PM
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Quote:

Quote:

Another picture which might show the gap better.




the gap is for socket clearance.

on a magnum head,they have tubes to press down in those pockets and use a 5/8" hex plug. remove them to use a LA plug for a wider heat range on magnums.




I go the other direction and only run the 5/8 hex plug in everything. To the op, the pic kinda looks like the seat area is tapered? I'm thinking its an illusion and the seating area is flat? correct? It should be. Autolite 3923 should work fine for most mild street engines.

Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321133
10/15/12 09:38 PM
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Quote:

My plugs have around an inch or so of thread, so they should be correct.
I just replaced my valve cover gaskets due to them leaking. I will keep an eye on the oil puddling, maybe it was from the old gaskets.

Thanks


This sounds logical,there's no way oil would travel up the treads without some real issues!

Re: Spark Plug In J-Head Question [Re: goldmember] #1321134
10/15/12 09:44 PM
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Gold,
The outer diameter is definitely a countersink that leads
Down into the hole. The second picture, left side
Is my best shot of the c'sink.
Is this an issue? If so, can I use a soft washers help
Seal it?
The second picture makes it appear that I can see down past the hex of the plug. This might just be a optical allusion.


1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321135
10/15/12 10:04 PM
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Quote:

Gold,
The outer diameter is definitely a countersink that leads
Down into the hole. The second picture, left side
Is my best shot of the c'sink.
Is this an issue? If so, can I use a soft washers help
Seal it?
The second picture makes it appear that I can see down past the hex of the plug. This might just be a optical allusion.


Looks like you need a tapered seat plug,no gasket needed or wanted in that application. My memory might be fuzzy as it's been years since I built anything with a J type head but I thought they used a gasket type plug??? I'm guessing you need a 3/4" reach tapered seat plug?? I'll do a little research and hopefully someone will come along and give us a hand.LOL

Re: Spark Plug In J-Head Question [Re: goldmember] #1321136
10/15/12 10:21 PM
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I am not familiar with a tapered seat plug, but it does have the taper on each hole. I had these heads machined about 6 years ago and that shop must have added the taper. I have been running the standard type of plug with the gasket ever since. Are tapered plugs easy to find? These are -7 NGK's.

Thanks allot for your replies.


1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321137
10/15/12 10:32 PM
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looking at the 360 heads in the shed that taper is there and the autolight 65 plug has the washers to seal it.

I have never saw a stock SB head use a taper plug.

now my 452 440 heeads use the small peanut plug with a taperd seat.

I have saw a lot of them have oil at the plug and in the threds but has always been from from other oil leaks,windage, yrs of no cleaning.

dont overthink it.

if you think they are leaking,mix some dish soap with water and fill the gap around the plug,run engine and look for bubbles.

chase the oil leak with baby powder. same on a trans leaks.

Last edited by scratchnfotraction; 10/15/12 10:34 PM.
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321138
10/15/12 11:04 PM
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Quote:

I am not familiar with a tapered seat plug, but it does have the taper on each hole. I had these heads machined about 6 years ago and that shop must have added the taper. I have been running the standard type of plug with the gasket ever since. Are tapered plugs easy to find? These are -7 NGK's.

Thanks allot for your replies.


Don't listen to me.LOL I just looked again at your pics and was looking at the wrong area. Sorry for getting this off track. A 3/4" reach gasket type plug is fine,I'd choose autolite 3923's but what you have if it's 3/4" reach will be ok as well.

Re: Spark Plug In J-Head Question [Re: goldmember] #1321139
10/16/12 08:06 AM
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The attached shows the four plugs that I pulled from the head. They each have the standard washer. I will put them back and and go forward and I will keep an eye on the new valve cover gaskets to see if they are the reason for the oil at the base of the plug.

I thought that the "orange-ish" color on the number #1 plug was odd. I am assuming that it is from the E10.

My ground straps are showing two plugs in the middle of the bend, one at the beginning of the bend and one at the end of the bend. I assume that this is due to the dual plane intake?

Thanks again for the replies.

EDIT:
I have been reading up on the taper spark plugs and it appears that if the "iron" head has a taper, then a taper plug should be used to make sure the cylinder is sealed.

Something else that makes me rethink this is, I have been chasing a "ticking" noise which is an exhaust sound. I have gone over each of my exhaust pipe connections a few time each and I can not find the issue. I have also just replaced my header gaskets and the ticking noise is still there. After rethinking this, I am looking at finding a direct replacement for my existing NGK -7 plugs for a taper plug to test out because two of my plugs appear to have the hex head scraping against the taper in the head as they get tight. I am wondering if the ticking exhaust noise that I am hearing is a couple of the spark plugs not sealing correctly.

7422983-10-15-12_3.JPG (59 downloads)
Last edited by YO7_A66; 10/16/12 09:22 AM.

1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321140
10/16/12 09:35 AM
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do the water soap around the plug while it idles,if it leaks it will bubble around the plug.

never saw a machine shop change the stock SB plug hole. even the new magnum heads use the same seal,the 5/8 hex is all that changed.

are the air injection holes on the heads blocked off,or are they non emission J heads that were not drill for air injection? with headers they are not coved and sealed by gasket. the need to be filled or blocked.

I dont see anything different on yours that my 88 360 heads does not have. same taper,same hole,same long reach plug. mine ar on the bench so I can see them very well.

try another plug like an autolite 65 in the hole,the NGK could have different plug body specs.

compair the 2 plugs together and see if they look the same.

I dont see any taper plugs crossing over to a SB myself.hard enuff to get the peanut plugs for my BB,they all stock the 13/16 short reach plug.

Re: Spark Plug In J-Head Question [Re: scratchnfotraction] #1321141
10/16/12 10:24 AM
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I called my local NAPA store and they show this head requiring a washer type plug. I will check down inside of the socket relief to see if there is any signs of leakage (black trails) around the plugs. If not, then I will put my existing plugs back in.
I do have some old Autolites that I used to use and I will check against my existing NGK's for any size differences.

Thanks again to all.


1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321142
10/16/12 04:26 PM
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Yes those J heads should be washer plugs 7's may be a bit too cold unless you are at 13 to 1 try Champion RN12YC always worked perfect for me!

Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321143
10/24/12 09:02 AM
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After I pulled the plugs for a general reading, I wiped out the spark plug pockets (oil/dirt) and then re-torqued all of the plugs. I then started up the car to make sure that I had all of the wires connected properly. After a few minutes of idling, I shut it down.

Then a few days later, I decided to re-gap my plugs. After only a few minutes of idling a couple of days before, I already had oil puddling up in the #7 spark plug well again. The attached picture is of #5 & #7 plugs. I do not have any oil leaking from my valve covers. It appears (you can see it in the picture) that my #7 spark plug hex (bottom side) is scraping against the chamfer in the spark plug hole as I am torquing down the plug. I am now wondering if my spark plug seat is not getting down low enough to seal off the hole due to the spark plug hex rubbing against the chamfer which is allowing oil to come up and out of the spark plug hole.
I am considering adding an indexing washer to this plug to see if I can gain some clearance below the spark plug hex to allow the plug to achieve the correct torque on the spark plug seal ring. #7 was the only plug that had oil puddling this time after the short idle time.

Thanks

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1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321144
10/24/12 01:12 PM
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like what was posted before,if you have that amount of oil coming from the combustion chamber past the plug you have bigger issues.

clean well with brake clean to remove all trace of oil,then throw some baby powder around the spark plug,give it some run time,shut down and wait till you see where the oil is wicking from.

if it did it this time it should do it again.

i would wager the VC is still weeping oil. oil son the inside of VC above the lower VC rail above the plugs till the head drains back to head. some spots would just hold oil till enuff moves it to a drain hole.

it would be hard to see a real thin coat of oil on nice bright orange paint. but the baby poweder will show the oil leak in a jiffy.

also the water around the plug in the pocket would bubble if it is leaking comp by the plug seal.

I would deff be swaping to an autolite set of plug just to rule out a machining problem with the NGKs. they are cheap enuff anyways.

I repete the baby powder/water thing as you did not say if you did or not do this test.

sounds silly I know. but I have found lots of leaks on engines and trans that I THOUGHT would not be the cause of the leaks.

remember,windage from the fan will make the oil travel.the baby powder shows the path it takes.


Re: Spark Plug In J-Head Question [Re: scratchnfotraction] #1321145
10/24/12 02:02 PM
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I have not, but I will try the powder trick. It may not be until this weekend though.

What issues in the head would cause oil to go past the plug? Cracked plug thread?

Thanks


1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
Re: Spark Plug In J-Head Question [Re: YO7_A66] #1321146
10/24/12 04:35 PM
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I dont think there would be anyway to get that much oil from a combustion chamber blowing past a plug. how would it get into a cyl and not smoke out the tail pipe?

why is there no ash build up on the plugs from burnt oil?

if it did have a crack in the threds it should still only push compression by the plug.

if it had a crack from an oil passage to the threds. if it had a crack from the crankcase area of the heads to the outside of head along VC rail.

when oil puddles around the intake bolts/pockets, the oil is wicking up the threds. this is because the intake bolts go into the open area of the oil crankcase. r&r of the bolts adding rtv and re-torque to specs it stops the leaks.

you could try some brush on antisieze on the plug threds to see if that stops oil from puddling up around the plug.

IMHO, I just think the oil is from the VC rail above the plug pocket.

or it could be from the intake end rails and windage blows it around and back down the side of head to plug area.

looking at the plugs there seems to NOT be that much oil in the cyls to blow up the threds.

I have found loose plugs that where blowing bubbles in the mud truck when it had been in the deep water,i just torqued them down some more to stop it.

see what the baby powder shows, be sure to clean it down good with brake clean to remove all oil traces.

do as before. run engine a while then let it sit a while with the powder around the plugs and side of heads above plugs.

do the water test for bubbles when you wash the powder off.

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