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Derek

Twin cam head for the L6 from Derek at Datsunworks

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If only you knew someone with a Rottler Valve Machine and the index reference points for the K20.

 

If one (Number 1 or Number 6) is in the same relative position as it is on a K20 that Rottler can sink guides, valve seats per factory specs and then moving on from there is pretty easy rather than starting from scratch.

 

Boy, would it suck right now if the site crashed and we lost this thread...hahaha

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After talking with Jeff about his testing on coolant flow I decided to get the most out of the 3D sand printing process as I could. I designed a water jacket that would be pretty hard to duplicate traditionally. There is a lot of surface area so hopefully there will be large improvements in cooling.

 

Some computerized flow analysis seems like a good idea.  I thought that the big problem with the L6 head is the flow, not so much the surface area.

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I thought that the big problem with the L6 head is the flow, not so much the surface area.

I believe you are correct. Tony pointed this out to me but it was too late in the process as the molds were already printed. Version 2 will have access to the water jacket above each exhaust port. If you want to get to it you mill through the head. This way if you have a high heat turbo build you can exit the water at each port tied to a single tube with thermostat. Personally I won't need it for my NA build but it will be there for those that need it. The OS Giken is this way.

 

 

 

Boy, would it suck right now if the site crashed and we lost this thread...hahaha

 

Yea that would suck. I thought about that a few times. I hope they are actually getting the backup service now.

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If you are considering this modification... a few bucks goes out the window just as fast as 1,000!

For this intake port design, it's not uncommon to find ITB's in the 56-62mm range being used in N/A Applications...

 

When you put lift to these valves, you are close to 400 cfm port flow! 

 

One thing Jenvey has going for them that most of the others don't is that they have selections OTHER than the standard 109mm flange-to-flange distance. On a DOHC head, space to the right shock tower, no matter what you are in, will be at a premium. Competition Torquer Plenums for this intake have 9 to 12" runners to give performance in the 3,000 to 8,200 rpm range. If you think about trumpets and intake tuning, then that's the length you will want on ITB's as well (trumpets) and that will get tricky. 

 

Using Discarded RB26 T/B's might be an idea..

 

Or as Alan T has reminded us: JECS ECGI (Japan Engine Control Systems Electronic Controlled Gasoline Injection) was available in late 1971...

 

post-380-0-66396000-1411531972_thumb.jpg

Edited by Tony D

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Or as Alan T has reminded us: JECS ECGI (Japan Engine Control Systems Electronic Controlled Gasoline Injection) was available in late 1971...

 

attachicon.gifLY-24-on-ECGI-pre-73-RAC-12.jpg

 

Nissan's ECGI was made by (HItachi-affiliated) Nissan subsidiary Diesel KiKi, and used Bosch-licensed electronics as their starting point. The throttle bodies themselves were manufactured by Denso. 

 

JECS was formed in 1973, uniting Diesel KiKi, Unisia, Nissan and Robert Bosch Japan with Hitachi as nominated parent company.

 

 

Now back to our usual programming...

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The work of the indomitable MITI... The later cars had "JECS" decals on the side, I don't know what that particular one had on it...since it said 73 I was assuming the later, even though the identification was "ECGI"...

 

The MAP sensor on the firewall is a dead giveaway, identical to First Generation BOSCH in the TypIII VW, and the Isuzu Bellet.

 

I've got half a dozen of them at home from my VW Days... Would make a nice looking period-correct 'cheater' system for those at the car shows to argue about...

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Went and picked up the casting yesterday. Looks great. No surprises. I checked the shrink rate when I got back and my edumicated guess appears to have been good. I was off by .015" or so on the total length which for this size casting is not too bad. keep in mind trying to measure a casting is like trying to measure a rock.

 

Just to give you an idea how cool 3D sand printing is here is a shot of the part number and name.

20170707041249-a59884e4-me.jpg

 

 

Unfortunately that's the only one you'll see like that as that area is going to be where the new water outlets will be. 

Not a lot of clear exterior area for branding!

 

 

Met with the shop yesterday that will be doing the automotive end of the machining. He didn't see any obvious issues which was good news.

 

I should have some rough pricing soon. I'm waiting for cam core prices. That will give you a more complete picture.

 

So the next step is to make a plastic mockup of the head. I'll machine it as far as I need to to feel comfortable with the strategy. Which at this point will be most of the way.

 

The worst part is I only have one 4th axis and it's making money for the next few days so I'm on severe hold :(  I hate when work gets in the way of fun.

Edited by Derek

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Head casting pricing.

 

Some will be happy.

Some will be sad.

And so it goes:)

 

Well I was trying to get a more complete picture for you but unfortunately I don't have cam pricing yet. And I'm not a big enough fish to push.

 

The head casting, valve cover and front cover UN-MACINED is going to be $4500.00. 

 

My ESTIMATE for machining the parts to the point that an automotive machinist can finish it is going to be in the $500.00 range. I'm counting on being able to fire and forget on the machining. This should be doable based on the fact I'm printing the cores. If I have to stand over it the whole time it will double for sure. I'll have a handle on that after I machine the first one.

 

Every head casting will be X-rayed and impregnated. Impregnation is a processes where the casting is put under a vacuum and a sealant leaches into the pores. 

 

Not in this is the intake manifold. I'll obviously be offering one but I haven't had time to draw it up to get pricing.

 

 

If you think you are going to want one of these then by all means PM me. The more people we have on board in the beginning the better.

 

Thanks

Derek

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This is fascinating and I hope it works.  But is it really that simple to draw up a head on a computer, cast it, machine it, and have it work correctly right off the bat?  A scan of the exterior of an existing head doesn't show internals that may have been designed to distribute and accommodate loads, in use and cooling/heating cycling.  I would imagine that in the automotive world, there would be many trials, tests, failures, and redesigns before the final product was locked in.  Seems like someone's going to need to offer up a test engine, and break a few heads before this is done.

 

Eeyore

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But is it really that simple to draw up a head on a computer, cast it, machine it, and have it work correctly right off the bat?

Nope:)

But it is what I do for a living. So there's that. The internals are very close to the K20 with extra meat in a few areas. Honda tries to save every gram for production costs as well as vehicle weight. Me, not so much. Thicker combustion chamber, thicker bottom surface, larger radius on the fillets, every head x-rayed, every head impregnated, etc etc. 

 

But you certainly bring up a valid point so don't think I'm dismissing you. All I can do is bring everyone along every step of the way and it's a journey we'll take together. The one that goes on my car may be the last and that's ok too!

 

 

Derek

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