Twin cam head

[24TZ]

Has anyone read this over at hybridz? Will be interesting to see the progress.

 

http://forums.hybridz.org/topic/119641-twin-cam-head-for-the-l6-from-derek-at-datsunworks/

[luvemfast]

VERY interesting.

But one has to ask.........

What are the gains for all this?

And dollar for power. How does it compare to the Les Collins / PMC strokers? 

[gav240z]

I hope this doesn't die like many other attempts before it. Would be great to see this make it to production and I do wonder what kind of price it will be all up.

 

I'd love the O.S Giken set up, that seems a bit out of reach along with an S20 so this could be viable depending on cost.

 

Then again I agree with what Alan has said regarding reproduction of the LY heads. I'd love to see that done.

[Riceburner]

Wow. The time, effort and money that must go into this is amazing. I'd love to see it completed!

 

Price will be the make or break. Surely RB or V8 power is cheaper/better and Isn't the Giken head 30K (unattainable to every Datsun enthusiast) ? So this at a guess could be (10K), who would pay that for a twin cam head to suit an L-series bottom end that is not eligible for classic racing and is limited by the ancient L28 short block.   

[NZeder]

When some of the local zclub here in NZ visited my place a few weekends back one member said he knew someone with the means to cast up new heads or copy an existing head.

 

He was talking about a new head design but again I would say why make something that you can't use for classic racing. Why not as Alan and Gavin have pointed out the LY or FIA Safari heads. I would purchase one of those.

[NZeder]

Oops double post.

[24TZ]

It will definitely be interesting to see it's progress and see what gains they get out of it. I think I would still prefer a les Colin's, peter mc stroker. I think the cost will be up there, they have obviously put a lot of thought into it and it's gonna take a lot of trial and error to get right.

It's still great to see people doing these things

[1600dave]

Surely RB or V8 power is cheaper/better

 

And dollar for power. How does it compare to the Les Collins / PMC strokers?

 

I used to ride a 1954 BSA 250cc bike. A postie bike would have been cheaper/faster/ etc.

 

Bur that wasn't the point.

 

I see where you guys are coming from, but the potential purchaser for stuff like these exotic heads isn't doing a cost/benefit analysis before plonking their money down, they are buying simply because they want something different / unusual / etc / etc.

[PB260Z]

I used to ride a 1954 BSA 250cc bike. A postie bike would have been cheaper/faster/ etc.

 

Bur that wasn't the point.

 

I see where you guys are coming from, but the potential purchaser for stuff like these exotic heads isn't doing a cost/benefit analysis before plonking their money down, they are buying simply because they want something different / unusual / etc / etc.

 

So true, if we did a cost/benefit anaylsis before choosing a car, none of us would be in Z's

We would all be driving some cheap hatchback, or similar soulless mode of transport 

[gav240z]

Why not as Alan and Gavin have pointed out the LY or FIA Safari heads. I would purchase one of those.

 

I have to say that in all the years of learning about S30z's these heads are something I know very little about and don't really understand all that well. Are the FIA Safari heads the same as the LY head in terms of concept and design? Perhaps I should start a new thread but I'd love to see detailed photos of these heads and the differences etc..

[ZAZ]

Page 59 of

How to Modify your Nissan/Datsun OHC engine has an exploded view of the TC24-B Twin cam cross flow L series 6 cylinder head made by

O Giken in Japan.

Page 60 has exploded view

 

Page 59 talks about FIA Group 2 heads but they don't seem to be twin cam just four valves

 

Early 11041-22010

Intake 45mm

Ex 35mm

 

Late 11041-N7120

Intake 44mm

Ex 36mm

 

Parts numbers

Cylinder head Early 11041-22010 Late 11041-N7120

 

 

Editorial goes on to say..

Optional two valve cross flow was n/a Nissan USA

The reason is that it was not allowed in racing class.

 

But it only gave 4-6%v improvement according to the text

 

The cross flow twin cam head it says was a private designby OS Giken and were sent to USA for RALLYE 280ZX

by Japanese team

The car was SCCA RENO entry but car was sent back to JAPAN.

 

The TC24B1 head is available from OS GIKEN in japan for $12,000 if youw ant

 

call them at 464 Okimoto Okayama Japan

 

Hope this helps

 

 

 

 

 

[dat2kman]

I have to say that in all the years of learning about S30z's these heads are something I know very little about and don't really understand all that well. Are the FIA Safari heads the same as the LY head in terms of concept and design? Perhaps I should start a new thread but I'd love to see detailed photos of these heads and the differences etc..

LY head is crossflow single cam

FIA are in/out same side ( normal) single cam, used different intakes and exhausts. In both 6 and 4 cyl

FIA heads were also done for U20.

It was from U20 FIA was born L Series FIA,

It was from U series alloy head design that L series head design originated.

 

 

Funny to see everyone jizzing pants over very expensive Unobtainium, or Makitnewium.

[gav240z]

Editorial goes on to say..

Optional two valve cross flow was n/a Nissan USA

The reason is that it was not allowed in racing class.

 

But it only gave 4-6%v improvement according to the text

 

Ok sorry I perhaps wasn't clear, and that submissive 4-6% improvement is 1 of those things that I feel is often mis-quoted. I think to look at it from that perspective is to totally miss the point. I'm talking about the author of that out-dated book - not you ZAZ. I know what the LY head was. However what I don't know much about is it's history..and it's eligibility in competition.

 

So I did some digging and came across this.

 

http://www.viczcar.com/forum/index.php/topic,8835.msg85373.html#msg85373

 

As Alan mentions it wasn't just about a cylinder head, it was a complete package.  What I'd like to know more about is the usage of the head and package and why Nissan was allowed to use these specialty cast heads in certain competitions. The 240ZR designation also appears to have been used in relation to some cars using this motor.

 

However not all the rally cars were fitted with these motors and that's what I'd like to understand better. I guess I don't understand as much as I'd like to about racing sanctioning bodies and their rules of the time etc..

 

Everything I know about them I'm sure has come from a comment that Alan has posted on a forum somewhere at some point.

 

It looks like the RB30 SOHC engine can derive it's origins and design back to the LY head. However I don't know much about the LY or RB30s so not sure how similar they are and how much was changed between them.

[HS30-H]

Page 59 talks about FIA Group 2 heads but they don't seem to be twin cam just four valves

 

Parts numbers

Cylinder head Early 11041-22010 Late 11041-N7120

 

I think you mean four cylinder? The FIA Group 2 heads for the L4 (22010 and N7120 mentioned above) were SOHC, two valve, non-crossflow type. Their advantage was that they were completely different castings (and individually sand cast, by the way) in comparison to the 'heads seen on stock production models. They moved the coolant passages to an external log on the inlet manifold, allowing them to dramatically increase port sizes and improve their shape. These heads were designed with electronic fuel injection in mind.

 

The E4621 'Safari' head (ironically never used on the East African Safari Rally...) was the six-cylinder cousin to the above. It was used occasionally in international rallying, Japanese domestic circuit racing and some - limited - excursions in international circuit racing (in FIA Group 4 and FIA Group 5 classes). Always used by the factory Works race cars with their ECGI (Electronic Control Gas Injection) individual throttle-bodied system.   

 

Editorial goes on to say..

Optional two valve cross flow was n/a Nissan USA

The reason is that it was not allowed in racing class.

 

But it only gave 4-6%v improvement according to the text

 

This is often repeated, but is quite wrong. Frank Honsowetz obviously knew very little about Nissan's 'LY' crossflow 'head, and the "4-6% improvement" quote is nonsense. Four to six percent more than what exactly?

 

The point about the 'LY' was that it was about so much more than just peak power. It was conceived, designed and engineered to work within a particular framework of rules and with some specific (mainly endurance-related) types of racing in mind. It would have led on to further interesting developments had it not been for the 'Oil Shock' of 1973 and Nissan all but putting a lid on six-banger related racing... 

 

 

 

 

[HS30-H]

It was from U series alloy head design that L series head design originated.

 

Not true. L-gata architecture and design predated U-gata by years.

 

This line of thinking appears to originate from USA. It's all about what 'they' saw first: Hence we see L6 being talked about as "L4 with two extra cylinders added on" etc etc.