Spark Plugs

First verify what series of plugs the head manufacturer says the heads use. Then you need to determine the heat range. In Motorcraft the heat range will be either a 32 as in bf32 or af 32. the next hotter will be a 42.

In Champion the heat range would be a 9y or a 11y (hotter).

Steet engines need an extended tip plug.

It's possible that the "original" plug you just removed is entirely wrong. Talk to the head manufacturer.

Since you are installing new plugs, you might want to take the extra time & effort to "index" the spark plugs...Mark

https://www.youtube.com/watch?v=Ys4GnIk_YC0

I have no clue about the manufacturer of the heads. I could not find any stamp or label. I have attached a photo of the heads and somebody might know....
Brgds
Hartwig

Was the engine running and running well with those plugs already? If so just get a new set of what was in there. The plugs you posted in the picture are obviously two different lengths. The danger would be if they are too long and the threads are projecting into the combustion chambers.

If that were so, sometimes IF YOU ARE LUCKY, the piston doesn't get hurt but pushes the tip of the electrode closed.

With Clevelands though, because of the big intake valves and they are canted on an angle, with a high lift cam it is possible with too long of a plug that the plug will catch the edge of the valves.



The picture of the engine shows heads and intake manifold that look like the Ford Motorsport "high port" aluminum heads.
The Ford intake manifold will have identification on top of one of the intake runners, towards the back of the engine. There will be a number cast into such as M-9436-A341.

Inside under the rocker arms, the head will have an identification cast into it. It will say A3, B351, C302, or D302. There will also be a date code and a stamped in serial number.

I am using BP5ES NGK plugs in my car which is using the A3 heads. In Champion (which I use to calibrate, then switch to a better quaility plug) the N-8, 9, 10, 11 will fit. The problem with them is they are not a projected tip plug and as a result run too cold, even with the right heat range. The NGK plug is the one that works right.

It is the right length, is a projected tip and is the right heat range for my engine with the Webers. It is on the hotter side of the chart, much like the Champion 11 is. The Champion 8 is the cold side. In my case fouls up almost immediately at idle.

It is time for you to remove your valve coves to identify your heads once and for all. You can't do this without knowing that.


Mark is correct in that you can index these plugs with that type of seat. IT IS worthwhile on this engine and seems to be worth about 25hp or so. Not that you are gaining 25hp, it's just that you aren't loosing that power because the plug is pointing the wrong way.

The important thing now is to get the right plug in the car. Worry about indexing later.


Incidentally let me just add again, IF you are having issues with the engine fouling the spark plugs AND you do have the correct heat range AND HAVE the projected tip spark plug then there is an additional item that you need. First thing to do is take out the MSD ignition and throw it as far away as you can and never, ever think about MSD again.

Get a Pantera-Electronics Ignition Controller and install according to Jon's instructions. It 1) will fire a fouled plug 2) will clean the plug while running.

MSD ignitions will not fire fouled plugs. Unless you are a racer and need the contingency money from MSD, forget about them. They belong back in the '70s with platform shoes and disco music.


Make sure you put the vacuum plug back on the vacuum tube at the back of the Holley carb. It is missing in this picture. Looks like a 4779 from here. If it is, it has a heavy idle that is built into the carb and it will like a hotter plug better than a cold one.

I will remove the valve covers this weekend and look for some numbers. The engine is not running well with the autolite spark plugs but I also found the ignition cables in poor status which I will also change this week end.I keep you updated.
Brgds

Hartwig

I can't see the detail of the tip of the Autolite plug in the picture. It looks dark (as in black...not good). If the temp range is right, it should be a dark brown but you should be able to see the white porcelain on it. There should be virtually no carbon on the threaded part of the plug.

Just right would be the porcelain is stained brownish like a person who smokes and his teeth are stained from the cigarettes. About that color is right plus or minus.

I think it is just the wrong series plug for those heads?

The spark plugs are dark black and clearly indicate that there is something wrong with the engine. This afternoon I have started replacing the ignition wires and found them quite degraded (high resistance and partially disconnected). I removed one of the valve covers and found following number on the head
"E2ZM 6049 A3". Does this help identifying the correct spark plug type? Thanks for any help.
Brgds
Hartwig

quote:

Originally posted by SIG:
The spark plugs are dark black and clearly indicate that there is something wrong with the engine. This afternoon I have started replacing the ignition wires and found them quite degraded (high resistance and partially disconnected). I removed one of the valve covers and found following number on the head
"E2ZM 6049 A3". Does this help identifying the correct spark plug type? Thanks for any help.
Brgds
Hartwig

It sure does. They are "A3" heads. That's what I am using.

I found that the NGK BP5ES plug runs nicely. I would recommend that you try a set.

You COULD cross that number over to another brand and use their equivelent.



I think that it is in the Champion F11y heat range? Maybe a little hotter? In US production that would be for a 2v 351w vs a 4v 351w which would be colder and be a F9y.

I have found that this A3 head needs to run a hotter plug then the equivalent IRON head would need. Especially with the Webers.



If that is a Holley 750cfm double pump, mechanical secondary carb, Holley number 4779, then it has a very heavy idle and certainly would benefit from using this NGK plug.

To index the plugs, the tip of the electrode needs to point at the intake valve.

You need a spark plug shim assortment. I think three different sizes come in the kit from Moroso.

Mark the plug on the outside porcelen where the tip of the electrode is pointing with a black felt tip marker pen. Screw the plug in and snug it up.

Record where it is pointing if it isn't pointing at the intake valve.

Remove it and place one of the thinest shims on the plug first and reinstall it. Notice that you black mark has moved. Keep doing this until that mark points at the valve.

The cylinder head that you have, the "A3", is sensitive to this indexing and will give you positive results. It's worth the effort.



Check the float levels in the carb. With the engine running, fuel should be at the bottom edge of the examination port opening and should not run out.

The intake manifold that you have (I know which one it is) was not angle cut from Ford Motorsport, but some people mill the top of the carburetor pad to 17 degrees because they are going to use it in a car like a Mustang and the engine in that car (as well as most other US production vehicles) is set in at an angle.

It is important that the carb sits level. If your carb is not sitting level, then I guaranty that the float levels are wrong and that could be contributing to an idle mixture that is too rich.



With the Holley double pumper series of carburetors, the air / fuel ratio of the idle circuit is already built into it. When you turn the "idle adjustment" screws, you are not changing that ratio, you are changing the VOLUME of atomized mixture the engine is getting at idle.

Those carburetors have a VERY HEAVY idle and the fumes from the exhaust normally will smart you eyes (make them burn).

They are "race calibrated" carburetors and are set that way at the factory because they presume the engine will be run with race headers that tend to lean out the carburetor right off of idle, at sudden throttle opening.

That carburetor all by itself can blacken the plugs.



This all goes back to getting the heat range of the spark plugs right. When you have those "settings" correct, that is an exceptional engine. It makes power.

Most Ford SVO/Motorsport heads take a 5/8" or 3/4" reach spark plug. I use easy-to locate aluminum-head Corvette plugs in my A-3s. Too long a threaded area protrudes steel threads into the chamber, which accumulate carbon and then strips aluminum when you try removing them. Too short will recess the plug electrodes up into the threaded hole and changes the way the plug fires. They actually act like retarded timing.

With some aluminum heads (Edelbrock models in particular), the aluminum around the threaded plug boss in the combustion chamber is contoured very thin on one side. This section often breaks away in use, exposing steel plug threads on one side. Which may act like a diesel glow-plug, causing pre-ignition. The fix involves removing the heads and dressing the broken area with a grinder. And then using a shorter reach plug. If the heads are in fact Edelbrock and this fix has already been done, the mfgr's 'spec' for plugs will be wrong, and if the area is cracked and has NOT been fixed, poor running can result. This may need expert diagnosis not possible by long-distance. A video inspection device thru the intake port might show something 'interesting' without major disassembly. But the FIRST move is to find out what heads you have maybe by pulling the rocker covers. Have a new set of gaskets nearby- some will break during removal.

quote:

Originally posted by Bosswrench:
Most Ford SVO/Motorsport heads take a 5/8" or 3/4" reach spark plug. I use easy-to locate aluminum-head Corvette plugs in my A-3s. Too long a threaded area protrudes steel threads into the chamber, which accumulate carbon and then strips aluminum when you try removing them. Too short will recess the plug electrodes up into the threaded hole and changes the way the plug fires. They actually act like retarded timing.

With some aluminum heads (Edelbrock models in particular), the aluminum around the threaded plug boss in the combustion chamber is contoured very thin on one side. This section often breaks away in use, exposing steel plug threads on one side. Which may act like a diesel glow-plug, causing pre-ignition. The fix involves removing the heads and dressing the broken area with a grinder. And then using a shorter reach plug. If the heads are in fact Edelbrock and this fix has already been done, the mfgr's 'spec' for plugs will be wrong, and if the area is cracked and has NOT been fixed, poor running can result. This may need expert diagnosis not possible by long-distance. A video inspection device thru the intake port might show something 'interesting' without major disassembly. But the FIRST move is to find out what heads you have maybe by pulling the rocker covers. Have a new set of gaskets nearby- some will break during removal.

Yes. The correct length plug is the N series Champion. The electrode reach is too short on it.

Threw most of them out (about three sets), can't go measure them.

Try the NGK above. It is an extended tip plug. Runs much cleaner than the N's. Even the hotter N's will foul on you unless you are running flat out constantly.

The tip is out in the open and as a result runs much cleaner. The electrode just show a transparent tan color. I call it "golden oak" like the MinWax wood stains?

Morning,
I just bought a set of NGK BP5ES and they don't really fit (photo). The srew part of the spark plug is bigger than the installed autolite. In the head there is just not enough space to fit the NGK plus the tool......

Hello gentlemen
Interesting infos here ... What would you think for my stock 351ci engine (10/1 cr, performance cams, 180deg headers ...)
Regards
Philippe
And wish you all a happy new Year

quote:

Originally posted by SIG:
Morning,
I just bought a set of NGK BP5ES and they don't really fit (photo). The srew part of the spark plug is bigger than the installed autolite. In the head there is just not enough space to fit the NGK plus the tool......

This IS VERY STRANGE! I have that exact plug. I have that head, and they ARE installed in the head WITH NO PROBLEMS AT ALL?

What I do know about MY heads is that on the A3 heads the bolt pattern on the exhausts have two slightly different patterns.
Ford moved one of the bolts, the bottom one, "outward" to allow engine builders to enlarge the exhaust port more. about 1/2".
I have the early pattern.
I went through that because the header flange needed to be modified to bolt the headers up.
I'm the one who had to do that.
The builder of the headers bought the flanges from Ford and was in California. He bought the wrong ones, the late pattern flanges.

He wasn't going to pay for shipping back and forth again. These headers weren't cheap to ship.
I wound up having to put them in a drill press to redrill the flanges, which is another story altogether that I don't need to get into again.

Now I'm thinking that there may be differences in the spark plug hole location ALSO? Either the casting itself or the machining of it?

My heads were not new when I bought them. They had been on a circle track race car. I am very sure there are no machining marks around the spark plugs. There must be a difference in the casting at that point?

I bought them from the engine builder at his shop. All he said was that the spark plugs my heads use are the Champion N-8s. I may have some of those in my shop and will look for them later.

Bosswrench has the same A3 heads on his car. He did not comment specifically on which plug he uses by part number. Lets ask him what part number he is using?

It is entirely possible that it is my heads that are out of the common and are the b ast ards? They do have the two hash marks on the ends of the heads so they technically are not the "phase 1-1/2" heads Dan Jones refers to.

Dan Jones refers to the differences here but he doesn't mention spark plug machining differences?

http://www.panteraplace.com/page35.htm

I'm stumped on this one?

Here's the Autolite 3926 cross reference chart.

http://www.sparkplug-crossrefe...onvert/AUTOLITE/3926

quote:

Originally posted by "72 GTS:
Hello gentlemen
Interesting infos here ... What would you think for my stock 351ci engine (10/1 cr, performance cams, 180deg headers ...)
Regards
Philippe
And wish you all a happy new Year

Yours are easy. Motorcraft AF32 is what it should use. If they are fouling up some, then use the hotter plug, the AF42. Either should work with no problems on an iron 4v Ford head.

If you can't get those there, the Champion is the easiest to get worldwide. Don't remember the numbers on them though at the moment.

I have a cross reference chart in the computer, if I can remember what file I put it in, I will post it up.

Here's one from online.

http://www.sparkplug-crossrefe...vert/MTRCRFT_PN/AF32

quote:

BP5ES

Here is a crossover chart for the NGK I am using.

http://www.sparkplug-crossrefe...convert/NGK_PN/BP5ES

I would like to find a NGK spark plug equivalent with NGK BP5ES but having only a smaller screw part. Is there somebody understanding the NGK numbering logic who could advice?
Brgds
Hartwig

sparkplugs.com has a very useful tool for finding what you need

http://www.sparkplugs.com/Search.aspx?ptn=Spark+Plug

The question really here to me is what plug physically needs to fit that head. It is different than mine.

I couldn't tell for sure unless the head was off and on the bench so I could see the length needed of the thread, and the projection.

There isn't enough of this type of technical information available to tell me what the head was originally machined to take and if there was a change over to another size at a certain date.

For all I know, my heads were re-machined to take the Champion N series plugs? I would have no way of knowing that.

We need more people that have the A3 heads that can say for sure what THEIR set is using.

You CAN measure that with the head installed. Did you ever see the movie "Oceans 11" with George Cloney? They used a small Chinese acrobat. Maybe he is available?

I found in the NGK specification that BCP5ES is identical with BP5ES except of the hex size which is 16mm instead of 20.8mm. Could it be a mistake to install BCP5ES?
Brgds
Hartwig

sounds like a job for a paperclip and a Sharpie, if a decent inspection light isn't enough to get a good look

quote:

Originally posted by SIG:
I found in the NGK specification that BCP5ES is identical with BP5ES except of the hex size which is 16mm instead of 20.8mm. Could it be a mistake to install BCP5ES?
Brgds
Hartwig

Just make sure that the length of the thread doesn't project past the inner part of the casting. If you are going to index the plugs your shim probably most often will be a 10, so that is about the allowable amount the plug can project past the inner casting without a shim.

As long as that is ok, then that plug that you found, as far as I understand, should be ok and the one to use?

Thanks for all your comments.
Brgds
Hartwig