Grey motor cylinder head identification

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Harv
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Grey motor cylinder head identification

Post by Harv »

Ladies and gents,

As I get more serious about the Normans, I have started getting the FB ready to act as a test-bed for the finished product. The motor has been re-ringed not long ago, but the head was a little sad. I ended up biting the bullet and getting the spare head done up... no rush job, but will be interesting to see how it goes. Head will get ported out, chamber relieved and some red motor valves thrown in. No head shaving, as I don't need any extra squeeeeze once the Norman is in place. There will however be a time when I will run this head in naturally aspirated form (at least until the Norman is ready :D ). Given that the chambers are being relieved, I'm starting to wonder what the compression ratio is going to end up at... will be interesting to calculate once the heads are CCd.

All this mucking around with cylinder heads made me have a bit more of a think about what I started with. All the engine parts I have are a mad mixture of vintages... the cylinder head could be anything from FX-EJ. When I go through the data from the Workshop Manuals though, it is clear that a number of head changes were made.

Model/ Bore (")/ Stroke (")/ CR/ Capacity (ci)/ Cylinder capacity (ci)/ Clearance Volume (ci)

FX/ 3/ 3.125/ 6.5/ 132.5/ 22.09/ 4.016
FJ/ 3/ 3.125/ 6.5/ 132.5/ 22.09/ 4.016
FE/ 3/ 3.125/ 6.8/ 132.5/ 22.09/ 3.809
FC/ 3/ 3.125/ 7/ 132.5/ 22.09/ 3.682
FB/ 3.062/ 3.125/ 7.25/ 138.1/ 23.01/ 3.682
EK/ 3.062/ 3.125/ 7.25/ 138.1/ 23.01/ 3.682
EJ/ 3.062/ 3.125/ 7.25/ 138.1/ 23.01/ 3.682

It looks like FX and FJ had the same cylinder head, whilst the FE had a head with a reduced chamber volume (clearnace volume) to increase comrpession ratio. The same change (smaller chamber again) was made at FC. FC-EJ seem to have the same head - whilst the compression ration went up for FB, this was done by increasing bore size rather than playing with the head. This would infer there are (at least) three distinct grey motor heads: FX-FJ, FE and FC-EJ.

My question for today - does anyone know how to positively identify these three cylinder head types (other than pulling them down and CC'ing them)?

Cheers,
Harv (aprentice cylinder head thinkerer).
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
fingers
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Re: Grey motor cylinder head identification

Post by fingers »

FYI Harv ....I know its not what your looking for but it could help identify how much is already gone from a head ...so you can pick the lowest comp ratio head at your disposal ....
Cant offer you any more info on the ID,ing of these heads but I did do some research and got some answers how to tell how much has been machined already and how much more to go .....heres a part of that text from the forum some time ago ...........
the standard holden grey head is measured for total thickness from the surface on top of the head where the rocker cover gasket sits and the bottom surface that bolts to the block the standard measurement is 3.250 inches .. Repco recommend the a minimum thickness to be 3.190 inches so 60thou is the maximum that should be shaved from the head surface according to them ...it seems that from what I have been told the thumb print is approx 60 thou deep but this varies on different castings ...so the important measurement is the 3.250 inches total thickness ...I have heard of heads being shaved up to 125 thou ....but this seems a little dodgey by todays quality of heads with them being 50 years old the inner water jackets are getting thinner with rust and scale build up so 100 thou would be suspicious at the best ...also the surface deck gets thin at this amount of machining and sealing between the head and block can be compromised and fail as a result ............Maximum compression ratio of around 8.5 to 1 will be acheived machining 60.to 80 thou off ..this can vary with any work on the combustion chambers ..this figure will still allow the motor to run on 91 unleaded fuel and have good performance figures... well as good as can be expected from Grey...I guess if it were about performance then you wouldnt be messing around with a grey motors .....For me its about a lumpy idle , carbys hanging off it everywhere and that distinctive grey motor note ... ....oooooohhhhh yeah .............Fingers
ps ..I ended up shaving 80 thou off the head and also zero decked the blocked the comp ratio was around 9 :to 1 maybe a tad over .we also used 3 and 3/16th pistons
a man of great knowledge all things to do with grey heads would be Edddy Wood from Headstud Development in Moorabbin he has grey heads laying around everywhere in his workshop that have been cut , sectioned and layered ....he has research grey heads since he developed the Yella Terra greys heads in the 50s and 60s working for Yella Terra at the time ...... :thumbsup: :thumbsup:
Don’t you find it Funny that after Monday(M) and Tuesday(T), the rest of the week says WTF?
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Harv
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Re: Grey motor cylinder head identification

Post by Harv »

Thanks Fingers - appreciated.

Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
FB search
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Location: Brisbane

Re: Grey motor cylinder head identification

Post by FB search »

G'day Harv,

Did you ever find a way of identifying heads?
I thought I read somewhere once that there were tell tale signs but I can't find that thread anymore.

I have an EJ block in an FB but I'd like to know what the head is. Do they all have the same part number - 7412811?

cheers

P.S. I'm doing a bit of research into bending pushrods and broken rockers, your threads make for great reading. Thanks. :thumbsup:
The search continues...
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Harv
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Re: Grey motor cylinder head identification

Post by Harv »

No, didn't get too far down the path of identifying the various heads.

The MasterParts lists a single number for the head assembly (7406681) so is not too helpful.

Early FX (up to engine number 37831) had a 1.25" and 1 9/32" welsh plugs. This changed to 1 5/8" and 1 11/16" for the later greys.

Cylinder heads from FB onwards had the second hole (one for the idiot light switch, one for the heater) with a 1/2" square head pipe plug fitted if the heater was absent.

Two idiot light switches are used - one for engines prior to FE L388857, and one for the later greys. Suspect they are two different threads.

Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
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Harv
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Re: Grey motor cylinder head identification

Post by Harv »

Was trawling through some of my old photos and ran across the one below - though I'd post it for interest. The combustion chamber on the left is the standard grey motor one. The one on the right is from the head prepared for me by Superflow heads - ported, relieved, double valve springs, titanium retainers/collets, bigger valves. Didn't shave the head, as I was intending to use it for the blown meth monster project (no need for increased compression with the Norman huffer). The head made a hell of a difference when I put it onto the FB a few years back.
Optimized-Old versus SuperFlow grey motor combustion chambers.jpg
Optimized-Old versus SuperFlow grey motor combustion chambers.jpg (393.71 KiB) Viewed 1482 times
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
ardiesse
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Re: Grey motor cylinder head identification

Post by ardiesse »

Harv,

I've just taken a look at what's cast onto various cylinder heads -

The FX carries part number 7400646.
I don't have an FJ head easily available.
I have a '58 single-hole head - 7409457.
The FB-EJ two-hole heads are, I think, 7412811.

Can't type, eating. Bye.

Rob
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