JMC L6 Head Project

[240ZBUILTBYME]

Hi all

Thought I would start a thread topic on the JMC head project as from what I can tell no one has done so already. 

would be interested to know if anyone in Australia is planning a build with one of these. 

for those living under a rock JMC designed and manufactured a brand new L28 head with various improvements over the oem N42 head.

- larger intake/exhaust ports with a uniform 2.5mm thickness between ports

- reshaped combustion chamber designed for higher compression 

- redesigned water jackets to improve cooling 

Overall aiming for a better flowing and more durable head for tuning the L28

Website supplying the US:

http://bluemoonperformance.com/project-l6/

has spec sheets and pricing chart

video of the head in action

Video where they CT scan a worked genuine L series head and found a port wall thickness of 1.2mm 

The price for a head is around the $7-8k AUD mark. So a significant investment.

I haven’t seen any testing or performance/dyno figures with and without the head for example. 

discuss.

 

[gav240z]

I think what they are doing is a great idea, given that OEM cylinder heads are getting harder to source and often in poor shape by this time. I also like the idea of a head you can bolt on that will straight away flow better than anything else. I am eager to see results also, given cost of porting a head and prepping it, the $7-8k is actually not a bad deal.

[gav240z]

Anyone ordered 1 yet?

[cracker]

11 hours ago, gav240z said:

Anyone ordered 1 yet?

The first batch was sold out months ago I think - have they offered another allocation?

[240ZBUILTBYME]

On 11/14/2022 at 7:59 PM, gav240z said:

Anyone ordered 1 yet?

in terms of exchange rate to the yen there's probably no better time. Id love to get one but really want to see some solid numbers and testing come back from a western source. 

[C.A.R.]

On 11/19/2022 at 5:50 PM, 240ZBUILTBYME said:

in terms of exchange rate to the yen there's probably no better time. Id love to get one but really want to see some solid numbers and testing come back from a western source. 

Are you intending on building an all out competition engine?

[240ZBUILTBYME]

6 hours ago, C.A.R. said:

Are you intending on building an all out competition engine?

No, i just like shiny things…. I haven’t made any final decisions about my engine build. And you could argue it’s unnecessary to spend that amount on a street car head. 

[NickF]

Might find it better to complete body work before considering mechanicals.

Many a build falters in body restoration.

[240ZBUILTBYME]

19 minutes ago, NickF said:

Might find it better to complete body work before considering mechanicals.

Many a build falters in body restoration.

I agree with you, but if the 240z is cactus I have a 280zx that the worked engine will fit in perfectly…..

[hmd]

My vote is to stay with an L6 with carbies. Just a rebuilt L24 but nicely tune.

Unless you want to do restomod with big flares etc.. then RB26 it.

[240ZBUILTBYME]

On 11/22/2022 at 6:48 AM, hmd said:

My vote is to stay with an L6 with carbies. Just a rebuilt L24 but nicely tune.

Unless you want to do restomod with big flares etc.. then RB26 it.

L6 was always the plan, I never had an original L24, only a L20, so I have a L28 head and block for the build, Ive always planned to go with carbies but lately i have been toying with the idea of doing FI wit ITBs, combined with stroking it makes a pretty potent package. 

[hmd]

ITB are greats but the cost is huge for what it gains over a professionally tuned carbs.

Get webbers and go to Steve Boyle in Perth to get it tuned. He's a guru with carbs.