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Twin cam head for the L6 from Derek at Datsunworks


Derek

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Thanks for that. I'll contact them. I talked to someone who was highly recommended and had a sit down meeting with the head. Unfortunately they seem to be as busy as I am and haven't worked up pricing. Called twice with no call back so that's my cut off so I'm on the hunt again. Too busy to call me back... Too busy to do the work.  I'll contact Mazworx when I have more info on the cams. 

 

 

I may hold you to that:)

 

it seems have spent the money for the head one of my UK cars in going from 410 to 460 hp.... 4.3L NA and the 3.1 in the datsun is running fine but if this thing is putting out near 350 hp in standard setup below 10K i would be interessted too ;)

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Any interest in making a manifold that works with say Weber or Mikuni triple carbs as well?  I wonder if everyone would want to run ITB's and fuel injection or not...then again if thats where the power is.....

Incredible thread, very interested to see where it goes.  If I thought I could have a 300WHP L28 that was streetable (91 octane, dont really care if the idle is lumpy) I would probably forgo the idea of a LS swap in which case 10 grand really seems like a steal for something so unique and still ultimately very fast :) 

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Any interest in making a manifold that works with say Weber or Mikuni triple carbs as well?  I wonder if everyone would want to run ITB's and fuel injection or not...then again if thats where the power is.....

 

Well that was my first plan. Make a manifold that would accept a DCOE pattern. After further research in that department it seems 52mm ITB's are the bare minimum for a stock K20. That kind of leaves out all the DCOE style and puts you right into the DCO. I may be interpreting this wrong but that's the conclusion I've drawn at this point. 

 

I'm going with ITB's because I want them. From a tuning and drivability stand point a plenum with a single throttle body would probably be better.

 

But I don't care:)

 

Derek

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Meeting with Mazworks tomorrow to see if we can come to terms with the machining. My big sticking point is finding someone to line bore the cam towers. At least someone semi locally.

 

I really think the cam towers should be bored especially since we are custom grinding cams. Might as well take advantage of that. They are 29.5mm right now and finding someone with a bar that small has been problematic. Mazworks doesn't have one.

Edited by Derek
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Why line bore them? Are they split caps? If not split caps, jig bore them. You have CNC capabilities...there is no need to line-bore the cam towers if you can repeatably set up sets of cam towers in a jig designed to hold them all on a plane during the boring.

 

The cam towers bolt to the head. If the cam towers are uniform, and the top face of the cylinder head is uniform, then the existing bores will be uniform. Just like removing and replacing the cam towers on a standard L6 head. They could have been done by bolting to a jig, line boring or jig boring, removed from that jig, and placed onto the milled-flat, dowel pin aligned surface of the cylinder head, and would STILL be in alignment.

 

Don't make it harder than it has to be!

 

Oh, and the ITBs...they're not hard on N/A engines! I will gladly make a drive if you need/want help tuning them.

Edited by Xnke
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Why line bore them? Are they split caps? If not split caps, jig bore them. You have CNC capabilities...there is no need to line-bore the cam towers if you can repeatably set up sets of cam towers in a jig designed to hold them all on a plane during the boring.

 

The cam towers bolt to the head. If the cam towers are uniform, and the top face of the cylinder head is uniform, then the existing bores will be uniform. Just like removing and replacing the cam towers on a standard L6 head. They could have been done by bolting to a jig, line boring or jig boring, removed from that jig, and placed onto the milled-flat, dowel pin aligned surface of the cylinder head, and would STILL be in alignment.

 

They are split caps

My fear is inaccuracies between the sets of caps being as they are coming from different motors. For the price of a line bore and considering how hard getting cams are it seems it would be good insurance. And a lot easier than me setting up a jig and boring them. Actually I would mount them to mandrels and face the mounting surfaces but that's still more work than I want to do. I prefer "And line bore the cam towers while you're at it" approach.

 

I don't think I'll have much trouble with the tune. I managed to get that contraption of a manifold running really well. I was just pointing out that it can be tricky. 

Although when your design mantra is;

Look cool

Look really cool

Actually run

Then there is a lot of room for definition of "drivability" :)

 

I think the honda guys have problems because they are still using the honda ecu. With megasquirt (and others) the ability to get a decent tune makes it pretty easy. Of course if you're looking for every bit of power that's a different story.

 

 

Derek

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I'm with Xnke in this one - same as the L-Engine. I've grabbed towers from a box where they were all mixed (4 & 6 cylinder sets just thrown together) with a mandrel to assemble them, they go together fine if the head is flat. The issue comes from guys who warp a head and ONLY mill the HG Surface...and not the top side. I was planning on mandrel assembly. The SPC Machining tolerances on Honda Parts are insane. You have a 0.003" oiling clearance, with a line-to-line fit on the split towers it will be more than tight enough. The issue is parallelism and square to all valve stems. You could even make an assembly mandrel to locate that, as well. Then match mark and pin them.

 

IMO, line boring will screw up the Honda tolerance and require an expensive machine.

 

If you are considering a poorman's line-boring setup like they use on VW Type 1 cases that locates on front and rear towers as a sliding bearing, with the remaining caps cut at the parting line and then cut to match the end two bearings....you could run that with a 1/2" air drill.

 

But given Honda Tolerances....I'd mandrel assemble them.

Edited by Tony D
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To me, it really looks like they locate with a single hollow dowel on the outside cam tower bolt...is that really all they locate with?

 

Honda guys seem to have no trouble pulling and placing the cam towers, so I think Tony is got the idea, using a mandrel to align them.

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Derek. I have been out of the Z world for a few years now and last time I saw what you where doing it was finishing up your ITB's  I come back on the board and i find this. Ive just wasted my lunch hour plus 30 min reading this thread(well wasted is not the right term) and I'm amazed. Im amazed at what your doing. Keep it up.  Ill be around to keep tabs on this. 

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Just got back from meeting with Mazworx. Went very well. Nice clean facility. Plus they do have a boring bar that will do the cam towers.

I hear what you guys are saying about the cam towers but it just seems to me that one clean bore through the towers and a cam ground to fit is the way to go. Of course when I get the price I may be of a different mind. 

I just checked and I can get 29mm drill rod. I could use that to check the alignment of the cam towers. If it locks up solid then I have a problem. If it doesn't then I'm good to go.

The bottom line is I have options and I like options.

 

They were just finishing up one of these bad boys for a 2JZ

IMG-0037-2.jpg?lr=t&bw=550&w=550&bh=550&

 

That's a big ol block of aluminum!

 

Well at this point everything is in place to get it to the next level. I'm bringing a second mill online to do the head as my main mill is just too busy. I don't want to be rushed on the machining and I don't want to have to keep yanking it out of the mill. 

Edited by Derek
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Derek. I have been out of the Z world for a few years now and last time I saw what you where doing it was finishing up your ITB's  I come back on the board and i find this. Ive just wasted my lunch hour plus 30 min reading this thread(well wasted is not the right term) and I'm amazed. Im amazed at what your doing. Keep it up.  Ill be around to keep tabs on this. 

Hey Jeff long time!

Yea this thread is pulling people out of the woodwork. 

 

The good stuff is about to begin!

 

Derek

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On the cams note, something I have considered while dreaming up stuff in my head that I have no money for.... How about a modular camshaft like Ford used on the 4.6s?  cut the lobes and bearings out of whatever material you want and use an EDM to slice them like loaves of bread.  Maybe an indexing keyway cut into the cam and lobes to make sure everything lines up right, bingo.  

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