32 replies to this topic

[Ando]

Does anyone know what spark plug is used in the Bathurst 6000 head?

The casting date & numbers are milled off but the head looks to be a 149 going by the exhaust post casting. It definitely isn't the standard type 9 port plug.

Going by the plug hole machined in the head, the plug would look like a short thread length (10-12mm) then a longish shank before the hex nut (10-14mm) approximately. 

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Edited by Ando, 20 November 2024 - 09:01 AM.

[warrenm]

Can you show the spark plug hole, so the plug type can be determined.

[claysummers]

Also a photo of the front of the head where the thermostat housing bolts on will confirm if it is 149 or 161.


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[claysummers]

Assuming it is a small chamber head that is?


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[Ando]

G'day Clay. The head is at my local engine builder. I'll drop in there & get a couple photos as requested.

[LCK186]

hi looks like its a low comp head, with yt valves and duel springs, why do u think that its a 6000 head,

[I'm a Red Motor fiend]

It's a 149 hi comp head that's been f*cked by having the chambers machined.

[Dr Terry]

It's a 149 hi comp head that's been f*cked by having the chambers machined.

How do you know it's not a 161 head ?

 

Dr Terry

[I'm a Red Motor fiend]

How do you know it's not a 161 head ?

Dr Terry

The exhaust ports

[Ando]

The engine shop sent some pics of the spark plug hole plus a couple more. He's work on one of these heads a long time ago but he can't remember the type or brand spark plug that suits the hole bore. Any clues?

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[LCK186]

Hi it still looks like a low comp head, why would u open the chambers, the whole idea is to get higher comp, unless you were building a turbo engine,which is lower the com the better

[Ando]

Hi it still looks like a low comp head, why would u open the chambers, the whole idea is to get higher comp, unless you were building a turbo engine,which is lower the com the better

 

The engine build is to take a Strata turbo. 

[LCK186]

Hi  i thought so, so its a low comp head,set op for turbo,so its not a bath 6000 head,

[Ando]

Hi  i thought so, so its a low comp head,set op for turbo,so its not a bath 6000 head,

 

I didn't think it was Bathurst 6000 head but my engine builder reckons it is. Personally I don't care but trying to find the right spark plug to suit it.

[Bruiser]

I have seen that machined chamber before, I think yt sold them done
like that for turbo’d motors
149 waternecks only used 2 bolts, but did the head face still have 3?
If you have any Ngk bp5es / Bosch w8dc / champion n11yc laying around
give one of those a try
I thought they fit in all red heads twitch the square machined
plug sealing face

[LCK186]

Nando hi how sloppy is a normal spark plug, many moons ago i was running a garret turbo on my 202 by memory the plugs were enlarged, if u want to get answers i would ring Eddy woods in melbourne he is the gurru on heads, ill try and find his number for you, i hope this helps u,  by the way that head u have is a profesionaly built head, a lot of money was spent to get it like that,

[Ando]

Thanks. I was hoping for an easy answer but happy to contact Eddy or start trying different type plugs. 

My engine builder is going to run the cam in with single valve springs before finishing the motor & getting it back to me before Xmas.

He's got me chasing the spark plug information as he's pushed for time.

[Ando]

Here's my sketch of what the spark plug should look like according to the spark plug hole in this head. Hoping this will trigger someone's memory bank.

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[S pack]

Std production GMH Red 6 14mm flat seat spark plug hole. Use any 14mm spark plug with the flat washer recommended to fit a 138, 149, 161, 179, 186.

[Bruiser]

My head is on the bench so easy to take this snap for you
 IMG_0864.jpeg   164.87K   1 downloads
To my eye looks the same as yours, I use bp5ey in those holes

Also took a snap of a black carbed 12 port 3.3 with the tapered plugs
The picture was too bloody big to upload for computery reasons
It didn’t really show the tapered mating face too well anyway, but it was
fairly easy to see actually looking at it from the right angle.
Although not as big a chamfer as I expected to find, maybe 1 to 1.5mm ish across
and around 45 degrees
The plugs in that one were bp6efs - both plugs 14mm thread diameter

[claysummers]

Stretching my memory, but I think that thermo mounting identifies it as 186/161. Adam probably knows better. What is the difference in the exhaust ports? I thought the chambers looked pretty unusual.


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[RallyRed]

Bomber ...oh where are you?

[Ando]

My head is on the bench so easy to take this snap for you
IMG_0864.jpeg
To my eye looks the same as yours, I use bp5ey in those holes

Also took a snap of a black carbed 12 port 3.3 with the tapered plugs
The picture was too bloody big to upload for computery reasons
It didn’t really show the tapered mating face too well anyway, but it was
fairly easy to see actually looking at it from the right angle.
Although not as big a chamfer as I expected to find, maybe 1 to 1.5mm ish across
and around 45 degrees
The plugs in that one were bp6efs - both plugs 14mm thread diameter

 

Thanks Bruce. That's a better pic & looks the same.

I should've realised to think of a plug with a full thread up to the seat.

Must be old age lol Reckon I'm on the right track now.

[S pack]

Stretching my memory, but I think that thermo mounting identifies it as 186/161. Adam probably knows better. What is the difference in the exhaust ports? I thought the chambers looked pretty unusual.


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Agree Bruce, I reckon it started life as a 161 high comp head. Looks to me like the chambers have been machined to make it low comp to suit turbo charging. As others have already stated in previous posts.
 

[I'm a Red Motor fiend]

Stretching my memory, but I think that thermo mounting identifies it as 186/161. Adam probably knows better. What is the difference in the exhaust ports? I thought the chambers looked pretty unusual.


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I certainly don't know better Clay. I actually don't know what is is definitively now I've seen the front of the head.
The fact that it takes a 3 bolt lower thermo housing throws a curve ball.
Ando also mentioned the exhaust ports in his OP.
All 149 heads I've encountered have the exhaust port divider set back from the manifold face if that makes sense?
All 161 heads I've seen have the divider flush and flat with the manifold face.
I don't think it's a later head because it looks to have press in studs and takes the larger earlier style plug.
I don't have a clue what it is now.