Derek

This is all Tony D’s fault:) Hi everyone. Some of you know me from my DIY EFI manifold project http://forums.hybridz.org/topic/63445-making-my-own-efi-intake-the-first-casting/ Well now I’m tackling a DOHC head. Some history: I get a PM from Tony D in September of 2012 about the Goerz-Paeco DOHC L6 Head coming up for air.http://forums.hybridz.org/index.php/topic/109116-dohc-l6-was-somebody-looking-for-the-goerz-paeco-dohc-l6-head/?&gopid=1020596 Which led to a brief discussion about what would be involved in producing a head. And that was the end of it... Or so you thought. Tony and I started trading emails about the feasibility of producing it and what kind of heads we could use as a donor for the valve train. Tony suggested bringing Jeff P on board because of his work with cooling the L6 head. Tony and I kicked around RB and KA motors for a while and then Tony suggested checking out the Honda K20. Bingo. Removable cam towers, factory roller rockers and a plethora of aftermarket parts. I called one oh my clients that is big in the import drag market and procured an old K20 head. I did some quick measurements and decided that it was probably workable. And so the journey began. The idea is to use the cam towers and valve train from a K20. I grabbed a quick scan with my white light scanner of the exterior. It’s dirty because I’m only using it as a reference scan to design against. I imported the scan into my solids program and then proceed to replace the mesh with solids. Jeff provided me with a great CAD drawing of his head gasket to work from. I decided to take a module approach to model the head. I made a single cylinder complete and the copied and offset it for the other cylinders. I then pulled the solids together to create a single model. At this point I was at a standstill until I could figure out what to do about the timing chain. Jeff and I had a long conversation about pros an cons of various designs. The preference would be a single chain so I ordered up a K20 set to see if it was workable. NOPE. Lower timing gear is too small to bore out to fit the L6 crank. Back to the drawing board. I decided to give the KA set a try. I decided the Altima set would be a good choice as it’s only a single row chain up top. With the roller rockers I don’t think you need a double row. I did a rough mockup on a piece of wood mounting all the pieces. Then I machined a chunk of plastic so I could actually mount it to the block. You can see I’m trying to incorporate the KA guides and lower tensioner but that won’t happen without a new lower timing cover. Here is the lower section with stock modified L6 components. The only tricky bit is I need to remove one link from the chain. I think this is a workable solution. Now I could finish modeling the front and back of the head. Next the front timing cover. The water outlet exits the head in the front and makes a 90 degree turn through the timing cover where the thermostat housing will mount. Now the valve cover. The K20 cam towers kind of dictated the overall size but I was still able to get the styling I was looking for. I was trying to have the flavor of the S20. I’m still tweaking the design but so far I’m pretty happy. The “NISSAN” and “3000” will be machined in so they are kind of placeholders for now. 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. Here is a nice shot of the intake and exhaust cores, water core, and upper tensioner. You can see where the cross drilling will go to supply oil to the head, tensioner and idler gear lube. There will have to be additional oil supplied to the last three cam towers as the single feed in the front won’t cut it. Here is a cross section of the head. The cut plane is through the center of one of the intake valves so the ports look a bit off. There is machine allowance on the bottom so the combustion chamber is a little larger than it will be after surfacing. Well like I said in the original Goerz-Paeco post I think this is a very viable approach to producing DOHC head. Should make for an interesting conversation. Derek Oh and one more thing. What good would a thread about casting a head be without....... / / / / / / / / / / / / / / / / / / / An actual casting. We poured this Monday and I just got these pics from the foundry today. I haven't seen the head personally but we're pretty sure it is good enough to move forward with. Still lots to do but you can't imagine how happy I am to get the first one right. As long as things proceed as planned I will be selling these. There is still a lot to figure out. I have the foundry working up some pricing for me and I'll post that as soon as I can. Thanks for looking Derek EDIT: I now have a blog about this head on my site. I'm going to continue to post here but the blog is a condensed version of what you see here. There is a FAQ on the left side bar that has a lot of data. If you are new to this build you may want to come up to speed there and then start following it here as there is a lot of great back and forth that isn't on the blog. http://www.datsunworks.com/Blog/

Listen I'll be the first to admit this is still and will probably be a pipe dream. But as technology advanced things that were previously absurd become feasible. The only way i would consider getting involved in this is if it used off the shelf components. That just makes sense. Also keep in mind what I'm pushing is being done right now by ford, chevy etcetera. This is how they are prototyping their stuff. When ever I quote out manifold or head work this is how I propose it. By printing the cores you can keep tweaking things until you get it the way you want it. Then after you have a workable design in both performance and cast ability you commit to traditional core boxes for production. By 3D sand printing the cores the combustion chamber and ports can be tailored to each head. As long as it fits inside the outer shell your good to go. The thing I like about this design is it looks right for the car. So if you can design an exterior patten that looks period correct and custom print the internals what's not to like! Derek

Maybe because I'm a pattern maker the casting seems to be the least of the problems. Cams,timing chain and gears, lifters etc are all going to be harder to come up with. Also people qualified to bring a raw head casting to a finished product probably aren't looking for any hobby projects. And thanks to Tony instead of concentrating on the bid I should be working on i've given the casting approach some more thought. And I really think this is feasible. Acquire a copy of the prints. Develop the 3D model. Carve a traditional cope and drag pattern for air set sand for the exterior of the head. This will cut down enormously on the cost of the 3D printed sand and shipping. Have the water cores and air passage cores 3D printed. The benefits to printing the cores are huge. first and foremost your not constrained by the limitations of a traditional core box. Since each core is printed separately any changes are just a matter of redrawing the model. Also because it's a continuous 3D print there are no part lines and the sand is super smooth. To put this into perspective I would design the intake, exhaust and combustion chamber as one continuous chunk of sand. The finish and precision of this method can only be matched by investment casting. Also this gives you tons of freedom to individually design each heads internals. Here is a shot of a sample of some sand I had printed. I was doing some restoration work for the King Lunalilo Tomb in Hawaii and was curious how the sand would look. I sent them a STL file of the crown scan and they printed this. I was really blown away by the detail it picked up. So you can see the possibilities for this. First step get the prints. Second step find a machinist. Preferably one that want's a twin cam L6 head Third step source cams and assorted hardware. Fourth step develop 3D model for casting. (me) Fifth step have machining model and prints developed from casting model with proper tolerances and such. Step six patterns and castings (me) Step seven Machine castings So fill in all the steps except for four and six and this could happen. There's makers and takers in a deal like this. Makers donate labor takers donate cash. Derek

I finally got this crap out of my head and you had to wave this in front of me Yes a copy of the prints are a good starting point. Often times though the prints are way off from the final castings. I do a lot of parts for a kit helicopter based on an old Sikorsky. The prints I get are from the 50's and were hand drawn by the the draftsman at sikorsky. Most times if I build to the prints he part wont fit. If I work from an original part it fit's every time. If someone came to me with this project this is how I would do it. 3D scan the original with my structured light scanner. Develop a solid model based on the exterior scan. Design the water core, intake, and exhaust system based on observation of the original casting and print. Make any changes to the design deemed necessary for use in modern machining and usage. Rig the model with the necessary gating, core prints risers etc. Have the sand mold and cores 3D printed at exone in texas. Ship the printed sand to the foundry and pour. Hope like hell your gating is right and you get a good pour as you only get one chance. Bask in the glory that technology can afford. Then fap Derek

Hi Yes I do and I have them in stock 100.00 plus 5.00 shipping. PM me your paypal address if you want a set. Derek

I bought my paint from SPI. I heard about them on one of the hot rod boards and people were very positive about the quality. They have a basic red that was pretty reasonable.

I used panel adhesive on all my rust repair panels and haven't had a problem. Expensive but worth every penny. Derek

32 years for me. Bought it in 1980. At the time I had a 1968 Firebird and a 1970 Maverick. The 240 then replaced the Maverick that was my daily driver. And now after all these years the Z is my daily again. Funny how things work out like that! Here's a shot of the Firebird. This was probably in 1979. Derek

Hey I can see my car from here! The red one with the hood up. I called bill. They're from Reaction Research I'm sure if you call them and say I want bills fenders he'll probably know which ones. Derek

Well since we're talking castings, patterns and production I feel qualified to weigh in on this one. I usually agree with Tony on stuff as he seems to have a firm handle on this kind of thing. This time he has a death grip. bringing a head like this into production is incredibly costly. The last head pattern I bid on was hitting $25,000.00 and they had all the 3D modeling done. Anything over $200.00 and your market dies right off with most Z owners. At least in the kind of numbers you need to get to justify bringing an item into production. The only thing I've made that has paid off the development costs are the speaker panels I sell. That's why I have to want what ever it is I'm developing. I seriously have well over $25,000.00 in R&D and production on my manifold. When I finally came up with a price on them ( I think it was around $3500.00) I didn't get a single nibble. Which is ok because I did it to get the attention of future pattern customers. And it has more than paid off for that. Now having said that I'm working with a product that is going to change everything. Seriously. I've been too lazy to post about this but this is probably a good time. There is a company in Texas that has equipment that 3D prints bonded foundry sand right from a 3D model. I'm currently working on a few projects with it and it's AMAZING. No patterns. Although this will make me irrelevant in some jobs I'm learning and using the technology so I don't get run over by it. Here is a link to the web site. printed sand It's expensive and you only get one shot with the sand but it's still way cheaper than doing patterns.And you're not tied to a design. I'll be putting together a separate post in a few days with my thoughts on this stuff and a few pics and how I think it's going to change everything. OK I admit it I'm a fan boi but it's just so freaking cool. I never would have done patterns for my manifold I just would have printed the sand and poured it. Derek

Hi Bill Looks great! I think just about everyone (including me) found it easier to cut the tops off. Derek

Personally I don't care for the look. Plus since it's mostly popular with the younger crowd it's done on a shoe string budget. As a fabricator I always enjoy looking at good fab work but that's not always the case. It's more like how fast and cheap can I get this done because I have to drive it to work on Monday style of fabrication. My gut feeling is they would be more comfortable on a site that is dedicated to stance type cars. I can take nuggets of knowledge from any forum on Hybridz and apply it to my car. I'm not sure what I would apply from a stance topic. Just hold fast to the "no texting" style of posting and any problem child will just fade away Derek Get off my yard you punks (said in my best geezer impression)

That's the stuff. Great work on your car. Looks awesome. Derek

The 3M grey acrylic double stick tape is the stuff. It's a little pricy but well worth it. Make sure you get it right the first time because there is no repositioning! Derek

That assumes I know that a 280 is wired differently than a 73 240. I put out what I knew and qualified it with a year and application. But I do apologize if it lead you astray. Derek

Hence my qualifier "The route on the factory wiring on my 73".

One thing I just ran into. I put a 90 amp maxima alternator in a couple of years ago. My charging during the summer was always marginal. I'd have to thow a charger on it at least once a week. This summer I decided to do some checking. To make a long story short you cant run 90 amps of power through a system built for 45 amps. The route on the factory wiring on my 73 is alternator, amp gauge, fuse box, Fusable link, starter, battery. I added an extra 10 gauge wire from the alternator to the battery and the problem has gone away. Obviously the amp gauge isn't accurate anymore and at some point soon I'll be doing a major rewire job. Derek

And that fixed it. Thanks Daniel you may have saved my life I guess I should get off of my but and do a proper tune. Thanks again everyone for the help Derek

Thanks for the info guys. I'll check it out tomorrow and post back. Derek

Simultaneous 2 squirt. Map based fuel. TPS based acceleration. I think I'll start data logging and then go out in the parking lot and keep trying to make it happen. I was kind of hoping that someone would be like "yep had the same thing happen to me try XXX" Hey a guy can dream right! I'll post the log when I get something worth looking at. Derek

Ok Maybe it's not that dramatic. I've had this problem since I first set up my megasquirt. My car is a little touchy rolling off of idle. If I release the clutch a little to aggressively the car starts to die and then goes into a full lean condition. Pressing the throttle makes no difference. the only recovery is to restart if it died or shut it down and restart. It has only happened 4 or 5 times but it could be really a problem if I jump out a little to quickly into traffic and the car dies. It seems like it jumps into flood clear mode. Unfortunately it never happens when I'm logging. Has anyone got any ideas on this? Thanks Derek

Not on the radar right now as I have a bunch of pattern commitments. Derek

I think the only lead is the seam between the roof and 1/4 panel and the roof and A pillar. Derek

Crap you beat me to it Foiled again

That must be some kind of magnet!