Crossflow alloy head casting numbers

[Valvebouncer 2,389]

Hey all,

 

I'm after a bit of advice with crossflow alloy head.

 

I have 3 heads with casting numbers c1,c2 and e2. From what I can gather there are some differences between the heads but what are they?

 

Is either of these heads better than the others? If so, why?

[slydog 7,873]

C2 is the highest comp...C1 has a high comp but not as much as the C2 it also flows well.E2 is a low comp EFI head.

[Valvebouncer 2,389]

Cool, thanks Slydog. So do all these heads flow the same?

[slydog 7,873]

Nope...but all flow good realisticly.The C2 has a high swirl chamber but can be prone to detonation.For all round I like the C1A or the old HF1

[ando76 4,354]

I'm sure the E2 has a larger inlet valve than the C1 or the C2. I have achieved good flow numbers out of the E2 but as mentioned it does have a more open chamber. It really depends on what you are chasing and what comp ratio you want. I am fan of the C1 as I got one to flow within 4cfm of my E2 and that was with a few basic mods and a crappy single seat cut.

 

As Sly has mentioned the C2 and C1 both require chamber mods in high comp and high performance use as the sharp point where the inlet and exhaust swirl creates a big hot spot.

[Thom 6,650]

I'm sure the E2 has a larger inlet valve than the C1 or the C2. I have achieved good flow numbers out of the E2 but as mentioned it does have a more open chamber. It really depends on what you are chasing and what comp ratio you want. I am fan of the C1 as I got one to flow within 4cfm of my E2 and that was with a few basic mods and a crappy single seat cut.

 

As Sly has mentioned the C2 and C1 both require chamber mods in high comp and high performance use as the sharp point where the inlet and exhaust swirl creates a big hot spot.

Ea heads have a similar.problem with creating a hot spot

[slydog 7,873]

I'm sure the E2 has a larger inlet valve than the C1 or the C2. I have achieved good flow numbers out of the E2 but as mentioned it does have a more open chamber. It really depends on what you are chasing and what comp ratio you want. I am fan of the C1 as I got one to flow within 4cfm of my E2 and that was with a few basic mods and a crappy single seat cut.

 

As Sly has mentioned the C2 and C1 both require chamber mods in high comp and high performance use as the sharp point where the inlet and exhaust swirl creates a big hot spot.

 

On the money there Ando,here's my modified C1A

 

 

 

You can see how and why it was modded based on the chamber mods alone.

[ando76 4,354]

Yeah very interesting chambers on that c1 head Sly, barely recognisable as a c1 head anymore. Would love to see the inlet flow figures from that head. Shame its all bolted down to that roller cam monster. Oh well as a wise man once said "I've never seen a flow bench win a race yet!".

[Valvebouncer 2,389]

Thanks for your replies guys, awesome amount of info. Your a wealth of knowledge!!

[matt_lamb_160 252]

E2 is still pretty high comp ~50cc. It is similar to C1. E1 heads are low comp ~57cc.

 

Correct me if I am wrong, but I am reasonably confident.

[n00bus m@x1mus 465]

Ive measured most of them but cant remember all of them. But the E1 and E2 are esentially the same. 57cc & 58cc. The C2 i have hear is 48cc and D heads are 49-50cc. I beleive the C1s where 52cc?

[ando76 4,354]

E2 with .040 off measures at 47cc with no chamber mods. E2 has a lovely chamber shape. See below 

 

 

 

 

C1 with .040 off and a lay back of the inlet swirl to 60 degrees measures at 49cc

 

C2 (D) with .040 off and laid back inlet swirl is 47cc

C2 (D) with nothing off measures at 42cc

 

E1 has a real open chamber like the early unmarked heads.  Never measured one but they would be up at 56cc

 

 

[matt_lamb_160 252]

What Ando has said sounds right to me.

 

I have C2 heads at 42cc, C1 heads at 49-50, E1 at 57cc and E2 at 50cc. These numbers may not be exact, but E1 and E2 heads I am sure are very different.

[ando76 4,354]

I've got an E1 head in my shed in town.  I'll grab a chamber shot when I'm in there next. 

 

I have a cylinder here at home that has a chamber like I have never seen before.  It came off a HM Gem engine and the casting number had been ground.  It sort of looks like a C1 but with less of a rise.  I'll clean up the chamber when I have time and post a pic.  It is truly weird.

 

Since I have all the head castings I should really take pictures of each chamber and post them up.  Hmm time.....

[matt_lamb_160 252]

Pictures would be good.

[ando76 4,354]

Leave it with me Matt. I have a pretty full on week this week but I will try and make time.

[matt_lamb_160 252]

Thanks ando.

[ando76 4,354]

C2 Head chamber with laid back inlet swirl. (D,C2A are the same)

 

Note how the chamber shaping goes all the way to the head gasket face.

 

C1(C1A) Head chamber with laid back inlet swirl and reduced sharp point where exhaust and inlet meet.

 

 

Similar to C2 but note how the chamber shaping stops short of the head gasket face.

 

I believe that these heads have the best inlet flow potential and best initial chamber shape. With additional shaping on the opposite side to raised inlet swirl area and a bigger valve I reckon low lift flow figures would go through the roof. Cam and I are playing with this idea on my new speedway head.

 

I'll get an E1 snap and then an unmarked head and we have pretty much got them all covered.

[n00bus m@x1mus 465]

You sure the C1 head hasnt been modified? Looks a lot different to the C1 ive seen, looks like its been mill cut on an angle right across the top face of the chamber there

[ando76 4,354]

I don't think so Clint. I have just laid back the inlet swirl. Here is another C1 head chamber - no where near as clean LOL and no laying back on the inlet swirl.

 

[ando76 4,354]

Early unmarked head chamber

 

 

 

 

and now the mystery head chamber.  The raised casting section has been dieground back, but dead set looks like C2 but this is no C2 chamber.  Can anyone identify it?

 

 

 

 

 

 

 

[Valvebouncer 2,389]

Here is a pick of my E1 head, sort of looks similar( sorry thought I had an E2 not E1)

[ando76 4,354]

saves me going into town and snapping a photo of my E1. thanks. 

[n00bus m@x1mus 465]

I don't think so Clint. I have just laid back the inlet swirl. Here is another C1 head chamber - no where near as clean LOL and no laying back on the inlet swirl.

While they are the same shape they still look different to me LOL The old crusty one looks just like mine does but the first one does not. You can see in the second pic the exhaust valve is shrouded by a bullnose edge that tapers up to the outer perimeter of the chamber with a bevel at the outer edge, the inlet has a sharp bevel also.

Where as the first picture shows a sharp bevel on both vlaves and a definate shoulder on the top edge of that chamber, a step down rather than a bevel.

And that unmarked head looks like the E1s ive seen, that other one WTF! LOL..... Maybe some real early dedicated gas design?

Just a thought... any chance nissan went out on a limb with their XFN and commissioned honda to design a different head just for them?

[Valvebouncer 2,389]

I would have thought a dedicated lpg head would have a more of a closed chamber to give it a bit more comp?

 

Probably an early alloy head, there were so many variants in engine specs for XD and XE. High comp/low comp, 3.3, 4.1 etc etc and for some reason ( guessing emissions) there were NSW spec engines too.