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Twin cam head for the L6 from Derek at Datsunworks


Derek

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Little update on the headers here, I had today off work so I have finish welded the front three tubes.

 

KIMG0061_zps65y98vx8.jpg

 

Close up of some of the welds:

 

KIMG0059_zpscpfssyxo.jpg

 

Some people think headers are easy. I'm one of them...but stainless headers *are* a bit more trouble sometimes...

 

That tube fit there two minutes previously...as the welds cooled it squrimed around quite a bit. By the time it was totally cool, it slipped right in.

 

KIMG0060_zpstoinrp5c.jpg

 

Plan is to have the back three cylinders tacked up this week, and be ready for finish welding.

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This is what I call an "Epic Build", the one thing that has truely perplexed me with my 25 year love affair with S30 2 seaters is why would they make a car with styling that is timeless, physical dimentions that make it handle like no other car can equiped with MacPherson struts at the front and Chapman struts at the rear (yes most people think that they have MacPherson struts all round but there is a difference!).

 

And then equip it with an engine that is serverely let down by the design of the head? Single overhead cam is one thing, but it's not even a cross flow?!!! When so much of the car is a forward design for it's time (even though strut suspension was a compromise), why would they settle for a head design that is way behind the rest.

 

The '432' was cool to say the least, and yes the American market would need a larger capacity engine, but to restrict it in such a way was just incredibly short sighted.

 

Thank god Derek is doing something about it because I don't have the 'conections' or the '$$$' to get an S20 engine or an OS Giken exravagance.

 

I was seriously considering an RB26 build and if power and performance was all that I cared about then that is probably the way I would go, but it is my honest opinion that the best engine for an S30 is a Nissan L2X, twin cam 24v crossflow head with a modern 4vcc design.

 

Keep up the brilliant work Derek, I can't wait to see this in action, and I know I'm not the only one.

Edited by zedric
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No Problem! You just had the bad luck to drunk post when not a lot was going on:) And then it just sat there reminding you of all your poor choices you've made in life.

 

I figured someone would respond but I think at the time they were pretty decently powered for what they were up against. Tony and others would know better than I but I'm sure the L6 was chosen for budgetary reasons as much as anything else.

 

 

Not much happening on the head. I'm dealing with all of the small issues that crop up during a prototype build like this. I'm pretty sure I have reached the point where fabrication on the head is done and I can start assembling. Without cams though I'm going to grind (pun intended) to a halt. I still have one major design issue to work out and that's the adjustable hubs for the cam gears. The KA24 cam gears are tiny so any kind of slotting arrangement is out. On the KA they drill holes in the gear to get their offset but I think that may be restrictive on this build.

 

I did start the design work on KN20 Rev_2 though.   I've got the new exhaust port designed and I'm reworking the water jacket. I'm going to stick with the current intake port design. 

 

This is the point in a project where my McMaster Carr bill goes through the roof:)

 

 

Derek

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This is what I call an "Epic Build", the one thing that has truely perplexed me with my 25 year love affair with S30 2 seaters is why would they make a car with styling that is timeless, physical dimentions that make it handle like no other car can equiped with MacPherson struts at the front and Chapman struts at the rear (yes most people think that they have MacPherson struts all round but there is a difference!).

 

And then equip it with an engine that is serverely let down by the design of the head? Single overhead cam is one thing, but it's not even a cross flow?!!! When so much of the car is a forward design for it's time (even though strut suspension was a compromise), why would they settle for a head design that is way behind the rest.

 

The '432' was cool to say the least, and yes the American market would need a larger capacity engine, but to restrict it in such a way was just incredibly short sighted.

 

Thank god Derek is doing something about it because I don't have the 'conections' or the '$$$' to get an S20 engine or an OS Giken exravagance.

 

I was seriously considering an RB26 build and if power and performance was all that I cared about then that is probably the way I would go, but it is my honest opinion that the best engine for an S30 is a Nissan L2X, twin cam 24v crossflow head with a modern 4vcc design.

 

Keep up the brilliant work Derek, I can't wait to see this in action, and I know I'm not the only one.

To be blunt, Nissan correctly assessed market conditions in the USA and realized that outside of the turnabout on emissions, the US Service Network was not set up nor capable to service the engine. Toyota nixed their DOHC 1600 for similar reasons. 

 

There were problems with 2 carbs like the simple SU being properly tuned, three? HAH! Not a chance! Remember, the triple Mikuni 44's fit so well, and had such a nice manifold because Nissan ran them as a production option in the 240Z Sports (165hp) with the SU's as a downmarket stripper version...all that went away for the same reasons.

 

They did have a crossflow (LY) head which made a marginal amount of power more than the non-crossflow head. In the end the added complexity was not necessary, nor was it supportable in the USA Dealership network due to a serious lack of skills. Learn well the lesson of the 2000GT: Add Complexity, Add Cost, and kill the product.

 

The head beat the world. It was in no way "severely let down" by that head design, which made over 1100HP in Turbocharged Form... Knocking it for it's design is really, really foolish. Especially in light of the fact that the valvetrain on this new head was designed 50 years later, from a company with that much time building F1 Engines. 

Edited by Tony D
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Good news, I get sunday, monday, and tuesday off work-so I should get some good time in on the headers. I hope to get them fitted in my personal Z Monday so I can get the collector location locked down. (I belive in options...so there are two tuned lengths available here...Datsun style or BMW style)

 

More photos monday, when I can get them actually down in the car for the first time in months.

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I may be nitpicking here, but I would have used some red scotch-brite sanding belts and a couple of squirts of elbow grease to wipe the mandrel bending lines/marks from the tubing before welding them up. It ends up looking 10 times better, and prevents it from looking like it is made out of mild-steel exhaust tubing. I know it can be done post-weld, but then you lose the colouring at the weld joint- which is attractive to most people looking at welds and manifolds in particular.

 

Eventually the tubing will end up looking a somewhat uniform brown colour across the entire length of the manifold if it's 304SS due to intergranular corrosion- but the process of treating the tubes to some belt sanding will make it look reeeeeeeeal nice for photos. you could try putting some tape over the welds and do it afterwards if you think I'm on to something. Or not. I'm a block of text on a forum, not a cop!

 

Some 321 tubing would make 'em look real right n' purdy for a lot longer if it's not going turbo :-)

 

However, K motors respond amazingly to turbo- so I expect this manifold to change at some point... right, Derek? :-D

 

 

Little update on the headers here, I had today off work so I have finish welded the front three tubes.

 

KIMG0061_zps65y98vx8.jpg

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The head beat the world. It was in no way "severely let down" by that head design, which made over 1100HP in Turbocharged Form..

 

which head are we talking about here? 1100HP LY Datsun head?

 

not questioning truth/existence. would genuinely like to read about its applications where 1000hp would be necessary in racing for whatever class it was in.

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The 1100HP modified standard production L-head...wasn't an LY.

 

It will take about ten minutes after the first startup to wipe the color from the welds, and intergranular corrosion occurs at carbide inclusion sites, not over the whole surface. It's just normal oxidation corrosion that causes the brown color. The first 6-8" will show considerable coloring after a week of driving, excluding the first inch or so from the flange...that should stay bright a while longer.

 

Not to mention those weld colors are actually detriminal to weld life...in industrial use they get acid washed to prevent corrosion and then the tube just looks like a single piece with a swirl in it.

 

Examples:

 

760_428_csupload_57488396.jpg?u=13230919

 

Will get acid washed to look like this, removing the corrosion.

 

760_428_csupload_57488365.jpg?u=91980745

 

321 won't look "better" any longer, it'll just last longer when it's glowing dull red in a high vibration environment. And 321 will always look better because it's hard to justify a 58$ U-bend over a 21$ U-bend on your street car if you can't at least say it looks better...321 is over double the price of 304 and really isn't needed until you go turbo/nitrous. Even moderate supercharged engines can run 304 without major incident.

Edited by Xnke
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Being as I was the one signing the check for materials I was happy to use 304:)

 

As XNKE pointed out welds in stainless will corrode unless mechanically or chemically polished up. I used to do a lot of marine work when I was still fabricating. Miss the slightest bit of weld cleanup and you have problems. My favorite line to my customers was "it's stainLESS not stain proof" That stopped most of their carping.

 

Derek

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Being as I was the one signing the check for materials I was happy to use 304:)

 

Derek

Hey! There are other guys who will help with that! But of course, my application is of course Turbo.

 

They didn't hang "Turbotony" on me back in the 80's because I was singing Wango Tango verses....

Edited by Tony D
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Hey! There are other guys who will help with that! But of course, my application is of course Turbo.

 

 

 

You'll get your chance to participate soon enough. Of course your head will sit in a container un-machined in the desert for years until you get time to build it:) 

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TonyD is probably referring to the Electromotive 280ZX turbo race car with 1100hp in the 80's. Impressive to say the least.

He is, indeed. It's pretty well known.

Read Tony A to Z's notes on driving the car at Riverside.

 

By "beat the world" though, I was really talking 10 years earlier in places like Kenya, Acropolis, and Monte-Carlo.

When the East African Safari was put back to the original rules "nobody but the driver and navigator touch the car between maintenance stages" the 240 jumped back into the lead. It works, is rugged, and that's what you need.

 

The difference in power will merely be at which boost level it occurs at, but with an L30 making 750 to the rear wheels below 20psi you start getting into the "useable horsepower" question.

 

At which point you do the Tony A to Z: crank it in to get the lead you need, then back it off and just cruise to the finish line...

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You'll get your chance to participate soon enough. Of course your head will sit in a container un-machined in the desert for years until you get time to build it:)

 

I know people, who know things... I actually am involved in a 3.0 build here in the PI. Imagine that, I found probably one of three S30's in a 3 to 4 hour driving radius, and the guy wants help with the engine. It's already turning into a Mini-JeffP: "Every time we talk, you make me spend money!"

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