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OS Giken twin cam 4 valve head


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Glad you're all so impressed with it. You guys on HybridZ seem to like these turboed dinosaurs ( I'm more of an Old School lover ). I'll have to dig out some other pics from the past too ( seem to remember an LY28 "Crossflow" head with a single turbo conversion too ). Really busy with work at the moment - so not at the computer very often. Might take me a few days to hunt the pics out. Bear with me...............

 

Sorry - don't remember any HP or performance figures off the top of my head for the Twin turboed O.S. Giken TC24-B1. I'll have to have a dig around in my archives and see what I can find on it. It was featured in a Japanese tuning magazine when it was first built - so maybe that might have reported some figures.

 

Let me look into it.

 

Ron - those turbines were KKK "K26-3664G" ( If I remember correctly they came from a Japanese truck ). They were blowing through three 50mm OER carburettors, and it also had 6 injectors in the inlet manifold which were controlled by an SK D-Fit injection unit.

 

Best regards,

Alan T.

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man that thing is tough, yeah plumbing and stuff could be neater, but still, that thing looks ready to rumble. ive heard that the sideflow head of the "normal" L motor is a 15% off the bat loss compared to a crossflow head, and were losing like 1000 rpm top end because of it as well, although we can gain some of it back with forced induction ;) we are still losing that 15% right off the bat, man we here in the US never get the good stuff.

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I sooo want one. My desktop wallpaper has been the OSG brochure for this head for ages. It's about to be replaced.... :D

 

My (under contruction) L31ETT just doesn't quite make the grade when compared to this thing. frown.gif

 

BUT, I am managing to squeeze it all in the original engine bay! smile.gif

 

Top work Alan (again)

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It's currently getting an L28 single turbo setup for use as an 'in-the-meantime' engine.

 

I've been gathering parts for the TT setup for quite some time now & I expect that it won't be finished for around a year.

twinmanifold.jpgttmanifold.jpg

 

The current setup (not quite running): DSC01398.JPG

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  • 3 years later...

I know this thread is older than my niece, but I came across it while reading this thread: http://forums.hybridz.org/showthread.php?t=105972 here about the S20 engine. Anyway, I was intrigued by Alan's (HS30-H) mention of having a picture of an LY turbo engine, because it sounded like there was some good story to go along with it. I sent him a PM asking about it, and he suggested I post on this thread so he could put the picture up with some explanation, that way there would be some context to go along with the image. So, here it is. How 'bout it Alan?

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Single turbo blowing through triple Weber DCOE carbs, built and used ( although rather limited experimental use, it has to be said ) in Group 4 and Group 5 European racing by JANSPEED - based in Salisbury, UK - during the mid to late 1970s.

 

janspeedsingleturboly1zp0.jpg

 

janspeedsingleturboly2eu6.jpg

 

JANSPEED obtained this particular 'LY' engine as something of a leftover from Nissan's rallying activities here in the UK, and did a little of their own experimentation with it. However, by all accounts the blow-through turbo setup was not all that satisfactory and was not pursued further.

 

The JANSPEED 'LY' passed into the hands of others, and lives on in a road car here in the UK ( with a normal aspiration setup and Weber 48DCOEs ).

 

We actually have two running 'LY' engines here in the UK, and I have just spent a few days with the people from 'Nostalgic Hero' magazine of Japan who are doing a feature on one of them - amongst other interesting cars here in the UK.

 

There's at least one twin-turboed 'LY' still running around in Japan too. I took some photos of it at one of the Sagamiko meetings. I'll see if I can dig them out.

 

Alan T.

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Wow, great pictures! I don't know why I always imagined the LY to have the exhaust on the right side (must be cultural biasing-my car is LHD, so everybody else's must be too?), I guess it would make more sense from a right hand drive point of view to keep it on the left. It's easy to look back now and notice things like the drier tube intake duct and the less than ideal wastegate placement (look at the size of that wastegate!), but I still love to see the pioneers, and how they solved the problems they came across with what was available. Thanks Alan!

 

I'm still holding my breath for the LYTT!

 

*edit* Would that engine have been laid over a little bit for clearance? I'm guessing that pump assembly driven off the crank is for a dry sump, but is that tube on the right a fabricated motor mount?

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I guess it would make more sense from a right hand drive point of view to keep it on the left.

 

Just about everything on an early S30-series Z makes 'more sense' in RHD configuration. That's just natural when you consider the source of much of the mechanical componentry ( Nissan's home-market sedans ), and the fact that Japan is an RHD market.

 

Would that engine have been laid over a little bit for clearance?

 

Different engine mounts and a completely different bellhousing were part of the 'kit' for the 'LY', and these combined to sit the engine block at a quite different angle to the stock non-crossflow engines. The 'S20' too sat at a different angle, which was achieved with another ( different again ) bellhousing and a completely different front crossmember. I've just been through all that for my 432R replica project.

 

I'm guessing that pump assembly driven off the crank is for a dry sump, but is that tube on the right a fabricated motor mount?

 

Yes that's a dry sump pump, but I think the tube you can see is part of an engine stand similar to the one on the engine in the background ( except that the 'LY' has a super trick piece of 4x2 under it too .... :wink: ).

 

I'm still holding my breath for the LYTT!

 

Breathe out now:

 

071103035xe0.jpg

 

071103038dj3.jpg

 

071103041lk5.jpg

 

071103037ou3.jpg

 

Alan T.

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So a lot of people reference the "how to modify" claim of 4-6% hp gain that this head made, but obviously in a situation like this that wouldn't really apply. If nothing else, you just removed a huge heat source from your intake track, so in a turbo application, I would guess this would make a much more dramatic difference, right?

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Good to see you here Alan :-)

 

Hello Andy ( waving ).

I'm not here, I'm working. You haven't seen me, right?

 

So a lot of people reference the "how to modify" claim of 4-6% hp gain that this head made........

 

Max,

As I have mentioned many times in the past, my opinion is that Honsowetz's quote should be disregarded because it is completely unsubstantiated, and was probably second or third-hand opinion from somebody with an axe to grind in the first place.

 

Think a little about the politics that might be involved between a USA-based race shop ( assuming such a concern was the origin of the "4~6% gain" quote ) and a Japanese manufacturer. I've lost count of the number of times I've seen quotes that imply that the Japanese had no idea what they were doing when it came to race-prepping the L-gata engine. Much of this stems from ignorance mixed with some kind of jealousy, and in almost all cases these comments overlook the fact that Nissan were most actively engaged in completely different types of racing to the likes of BRE and BSR et al. I've even read that BRE were supposed to have "discovered" the crank harmonics issues with the earliest L24s, and "told" Nissan "how to cure" them - even though Nissan knew the problem and were working on the crank re-design long before BRE had received their first Z. It just illustrates the gulf that existed - and indeed arguably still exists - between Japan and the rest of the world.

 

I have no idea how anybody would go about making a fair and honest like-for-like comparison between the 'normal' L-gata engine ( in what state of tune, and for what type of race? ) and a full 'LY' engine ( what capacity, what induction system, and again for what type of race? ). To offer up the quote of "4~6%" gain without any mention of parameters or variables is farcical. To sum it up, he was pretty much saying "We can't get it over here anyway guys, so best forget about it..........".

 

Alan T.

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