Derek Posted April 5, 2015 Author Share Posted April 5, 2015 (edited) 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. Exhaust side all done Tomorrow I start on the valve guide bores. Edited July 7, 2017 by Derek Quote Link to comment Share on other sites More sharing options...
clarkspeed Posted April 6, 2015 Share Posted April 6, 2015 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. Quote Link to comment Share on other sites More sharing options...
Derek Posted April 6, 2015 Author Share Posted April 6, 2015 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. Quote Link to comment Share on other sites More sharing options...
Derek Posted April 6, 2015 Author Share Posted April 6, 2015 (edited) 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. Everything seems to be working out as I planned. 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. So far so good. Tomorrow is the intake valves and Wednesday should finish off the intake side of the head. Edited July 7, 2017 by Derek Quote Link to comment Share on other sites More sharing options...
Xnke Posted April 7, 2015 Share Posted April 7, 2015 Looking fantastic! Looks like that flange will be pretty easy to work with too. Quote Link to comment Share on other sites More sharing options...
Derek Posted April 7, 2015 Author Share Posted April 7, 2015 yea you won't be lacking in surface area! Quote Link to comment Share on other sites More sharing options...
JoshuA Posted April 7, 2015 Share Posted April 7, 2015 Can almost see the light from here. Still a good amount to do though, I suppose. It's pretty exciting to see this come together. When do you anticipate you'll have the cams ground for this? https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpa1/t31.0-8/11101222_955102757863556_5975098830518405437_o.jpg Quote Link to comment Share on other sites More sharing options...
Professor Threadkiller Posted April 7, 2015 Share Posted April 7, 2015 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! Quote Link to comment Share on other sites More sharing options...
HybridHydra Posted April 7, 2015 Share Posted April 7, 2015 If you plan on mass producing the DOHC L28 head, what price ( or price range) are you aiming for? A DOHC L28 head previously sold on eBay for 10k. Quote Link to comment Share on other sites More sharing options...
Xnke Posted April 7, 2015 Share Posted April 7, 2015 The pricing is layed out early in this thread. The threads you see in the spark plug bosses are for the tubes...the plug threads themselves are down in the hole. Quote Link to comment Share on other sites More sharing options...
Professor Threadkiller Posted April 7, 2015 Share Posted April 7, 2015 Got it. I see 'em now. Was a little dark down in them holes. Thanks for clearing that up! Quote Link to comment Share on other sites More sharing options...
Derek Posted April 7, 2015 Author Share Posted April 7, 2015 (edited) Here's your daily fix Got all the intake valve work done. 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. Every port looks just like this. Man I like digital mold making. The accuracy is just amazing. 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 July 7, 2017 by Derek Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted April 8, 2015 Share Posted April 8, 2015 What other automotive communities have people making their own heads... This is amazing... Quote Link to comment Share on other sites More sharing options...
Xnke Posted April 8, 2015 Share Posted April 8, 2015 What kind of headwork is Mazworx doing? Just guides/seats/valvejob? Quote Link to comment Share on other sites More sharing options...
Derek Posted April 8, 2015 Author Share Posted April 8, 2015 Surface the top and bottom. Install the valve guides. Cut the pockets for the valve seats and install them. multi angle valve job. Line bore the cam towers if necessary. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted April 8, 2015 Share Posted April 8, 2015 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. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted April 8, 2015 Share Posted April 8, 2015 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 . Quote Link to comment Share on other sites More sharing options...
Derek Posted April 8, 2015 Author Share Posted April 8, 2015 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 Quote Link to comment Share on other sites More sharing options...
Derek Posted April 8, 2015 Author Share Posted April 8, 2015 (edited) 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 April 8, 2015 by Derek Quote Link to comment Share on other sites More sharing options...
HS30-H Posted April 8, 2015 Share Posted April 8, 2015 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'... Quote Link to comment Share on other sites More sharing options...
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