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Twin cam head for the L6 from Derek at Datsunworks


Derek

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Derek, this is amazing work. This is one of the most exciting developments for the Z in many years. Hopefully it will bring back some of the lost interest in the L series motors. My only concern is if there is a sufficient market of actual buyers to make this economically viable. Thanks for taking the risk and doing such great work for all of us Z'ers.

Thanks Tim

Well if everyone is going to see how much ultimate power it will make then it may fail as I don't have the time and the resources available for that. But since it's based on a known design and if this head has decent longevity I think it may work out.

Who knows. I'm having a blast and that's what counts. For others it may be a leap of faith.

 

Found time to map out the exhaust ports. They were all within .005" or .006" of where they should have been. A lot of that may have been the toughness of the casting affecting my touch probe accuracy. I can tell you that is pretty accurate for a sand casting.

 

Here is a shot of me taking a skim pass for port matching to the flange.

You can see I have a little hand work to do on a couple of the combustion chambers.

 

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Exhaust side all done

 

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Tomorrow I start on the valve guide bores.

Edited by Derek
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I just returned from a visit to the largest casting supplier in Germany. Amazing stuff going on there, investment castings down to .4mm thick, 3 x 3 meter cnc'd sand castings, custom alloys mixed on site....but this project still blows me away. Derek thanks for taking us through the steps so people can see just how ambitious this really is. It definitely makes a statement to your skills and capabilities.

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I just returned from a visit to the largest casting supplier in Germany. Amazing stuff going on there, investment castings down to .4mm thick, 3 x 3 meter cnc'd sand castings, custom alloys mixed on site....but this project still blows me away. Derek thanks for taking us through the steps so people can see just how ambitious this really is. It definitely makes a statement to your skills and capabilities.

Thanks.

I feel like people need to realize just how much work it is to bring projects like this to fruition. Of course if it wasn't for the sand printing none of this would be happening.

I also look at it like I have a bunch of eye's on it that may spot potential problems. 

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Well today was a big and stressful day. I got all of the exhaust valve work done. Drilled and reamed the valve guide holes and machined the valve spring bosses.

 

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Everything seems to be working out as I planned. 

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This is the best part. The bores came through right where I needed them to. After I had printed the sand molds I realized my valve angle was off by half a degree. That's why the bore of the valve guide is not centered on the boss. Future heads won't even have that boss on there. I'm not really sure why I put it in  as there is plenty of support for the guide without it.

 

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So far so good. Tomorrow is the intake valves and Wednesday should finish off the intake side of the head.

Edited by Derek
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What's the plan to keep oil out of the spark plug area? Is there enough meat left over in the spark plug boss for a counterbore for tubes or something? On your plastic mock-up, it looks like you left enough material to counterbore for tubes, but after threading the real casting, it looks tight. Maybe you're planning to finish the OD of the boss and seal on the outside?

 

Also, what type of plug are you planning to use? Taper seat or crush washer? I don't see the machined feature for sealing the plug to the head.

 

Awesome project! I'll never be able to afford one, but kudos to you and those who can!   :)

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Here's your daily fix :)

 

Got all the intake valve work done.

 

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Got a little carried away with the machine allowance on the intake side! Had to take it down almost .375".  I had to leave that wall around it because the mill was hitting the side of the head. You can see where it nicked the intake bolt boss.

 

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Every port looks just like this. Man I like digital mold making. The accuracy is just amazing.

 

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I should have the rest of the machine work on the four sides done tomorrow. Then it goes to get radiology testing. I would normally do that before machining but I was going to machine it regardless of the outcome. I don't foresee any problems and it's mainly an insurance policy at this point. After that I will send it to get impregnation and then it's off to Mazworx for the headwork.

 

Cam design, cam core pattern and cast cam cores are next on the list. 

Edited by Derek
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Your going to run cast cams?  Why?  I would definitly recomend making cam blanks out of 8620 or 9310 and carborize them.  I have made quite a few blanks, and this is by far they best way to do it. 

 

Where were you about 160 posts ago :)

 

Basically although I could do it with the equipment I have it would be a stretch. Out of all the cam companies out there very few make their own cores and those that do had an attitude like "go away kid you bother me". The pricing I got pushed the overall price of the head out past where people could justify it.

 

I'm having them cast out of 8625 so from a chemical (or metallurgical ???) sense it's close. I know it's not as strong as cold rolled but it will probably do for the lower HP units like mine. Ron Iskenderian will be taking the cast cores all the way from the rough state to final grind including hardening and straightening. 

 

NOW if you are interested in producing cores then I'm more than happy to talk to you about it. So much so that I'm going to PM you on it.

 

Derek 

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Ill have to PM  you the Buick straight 8 head I am building out of billet.  I dont own a casting shop, so I just make heads out of billet  :)  .

Please do. Preferably in the mill you're using for the work. Must be a huge!

Edited by Derek
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What other automotive communities have people making their own heads...

 

This is amazing...

 

Quite a few actually. Just off the top of my head I can cite aftermarket performance 'heads for MGs, Austin Healeys, Aston Martins, Jaguars, ALFAs, even Abarths.

 

All commercial propositions, and usually - to be expected - not 'cheap'...

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