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Twin cam head for the L6 from Derek at Datsunworks


Derek

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Fantastic read from page 1, but I will need to re-read and digest all this engine terminology, I'm a   :newbie:  get's my head working lol  Awesome work Derek thanks for sharing! I look forward to your updates!

 

New guy here, first post on this forum too lol

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Derek,

I am wondering what thermostat you are planning on using with v2. I know inline but my concern is getting circulation around the t-stat to heat it. Without a bypassing t-stat it seems you would get a temp spike before the thermostat heated the water around the t-stat enough to open it. I thing casting enough meat in the ft of the new water manifold to machine a t-stat right into it would be better. I am running a -4an bypass from one of the old sensor holes in my t-stat housing back into the inlet of the water pump to circulate around the t-stat. If you look at all l6's I can think of they always have some water coming out of the housing to circulate. Like with the fuel injected cars they had the heater under the aux air valve.

 

For v2 you might look at the old bmw 4cyl. Thermostats. They were reliable and are a cheap inline with bypass. They came in a variety of temps too.

 

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I am definitely seriously considering getting on the list for one of these. Like I said before I would want to do a tall block 3.0L so I could get some rod ratio to turn this thing like it need to be turned. Seems fitting to do a 3.0 with the rod ratio Nissan would have wanted given the l20b was done this way.

 

Would it be difficult to relocate the oil cap to the rear over one of the cams? This would give extra clearance to the hood. Also I would want coil on plug. Could we cast some meat in the valve cover for a hold down bolt or make sure the diameter fits a push in coil like the VW or BMW ones.

 

Coming home from vacation today I told my wife I thought I was going to sell my 911 turbo. I told her I like playing with my Datsun more. This is why. I could build a serious motor, rotisserie it & still have money left over.

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Here is my water bypass hose to the water pump. You would need something much larger for that BMW t-stat and most of the inline ones I have seen. I think a built in t-stat with at least two or three casting bosses for temp sensors & a bypass like this. I would think you would want the stock temp sensor for the gauge & a second for the fuel system.

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Most serious coolant systems are "bypass to cooler" setups. If you search the available external thermostats you will find those readily available.

 

You will run full circulation from outlet to to inlet (and into the bottom of the radiator) until the thermostat heats up, at which time an exceedingly small portion of flow is sent to the radiator...consequently radiator cooled fluid will be admitted into the water pump inlet.

 

Likely a 5/8" restrictor will be necessary to hold pressure when cold and ultimately restrict recycled flow when below thermostat opening temperature, but it is easily done.

 

A simple 1/2" line out the end of the V2 water manifold casting would easily provide more than enough recirculating flow before warmup, and when equipped with a reverse-acting thermostat as discussed previously, could have that passage fully closed off by 170F insuring FULL pump capacity to the engine with no recirculating losses...and a simple inline thermostat in the upper radiator hose!

 

Hope that makes sense the way I explained it. I think the old BMW stat was an example Imused on "junkyard sourcing" for people looking to source parts for their build that way ( or to order proven OEM items of known good quality )

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I am wondering what thermostat you are planning on using with v2.

 

Right now it's going to be an inline. I don't know the exact config yet but I've tapped the the outlet 1-1/4 NPT. I may end up welding something to it or using the threads.

 

There is a 3/4 NPT boss at the front that could be utilized as a bypass. 

 

 

 

I thing casting enough meat in the ft of the new water manifold to machine a t-stat right into it would be better.

 

Right now as it's designed so you can surface the top of the head without dodging anything. I couldn't fit the thermostat housing in there without it being above the plane. Tony and I agreed having a round boss would offer the most versatility. I'm tapping it now because it's in the machine.  One area I'm a little shy on is real estate for temp switches. I may have to weld a couple bosses on. 

 

With the OSG head (i'm not dissing it) You build according to the head you are given. With the KN20 the head is tailored to the build you are doing.  

 

 

 

Would it be difficult to relocate the oil cap to the rear over one of the cams? This would give extra clearance to the hood. Also I would want coil on plug. Could we cast some meat in the valve cover for a hold down bolt or make sure the diameter fits a push in coil like the VW or BMW ones. 

 

It wouldn't be impossible. Especially if you are going to powdercoat the valve cover. If the K20 coils will work electronically then they would be the best choice as they will fit physically. There would need to be a boss added to the valve cover at each plug but that isn't a big deal.

 

 

Derek

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Why not put the thermostat in from the front like the OSG TC-24. You could do a ft outlet housing cover like they did (but may be harder to find a hose that fits) or just match the bolt pattern of the stock thermostat housing cover and have it point to the drivers side (left) then a 90* upper house would work. This would seem to keep it from interfering with surfacing top or bottom.

 

I can easily run any coil with an igniter built in so k20 would be fine.

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Tony,

 

The throttle bodies are jenvey. I really like them. They are much slimmer than most of the others. The hardware, levers and fuel rail are very nice and clean.

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Edited by tioga
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Why not put the thermostat in from the front like the OSG TC-24. You could do a ft outlet housing cover like they did (but may be harder to find a hose that fits) or just match the bolt pattern of the stock thermostat housing cover and have it point to the drivers side (left) then a 90* upper house would work. This would seem to keep it from interfering with surfacing top or bottom.

 

I can easily run any coil with an igniter built in so k20 would be fine.

 

The OSG is above the head plane but it's an add on so it's not a problem. Even if I could easily incorporate it into the casting I wouldn't as it may not be right for certain builds or layouts. For this build I may machine a housing that screws into the 1 1/4" npt that will hold the thermostat and 2 temp sensors. I'll use the 3/4" NPT bung at the front for the bypass.  

 

This build is getting the Jenvey THS52i 52mm throttle bodies. I'm glad to hear you like yours. Can you post or PM me some pics of your linkage setup?  I'm using the same basic manifold as I have on mine but I'm making a new top pattern without injector bosses. 

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Have you bought them yet? Strong dollar right now. I just ordered a mangoletsi intake for 150.00 dollars less than last week.

One thing that I did wrong was use all right hand lever interconnects. What I should have done is on the center body put a right and left master lever on. Then the center body would open the left and right body. As I have it I open number one body with a link and it opens #2 and #3 this puts the load of two return springs on one interconnect tab. I think during rapid throttle opening it flexes.

 

You should order light weight return springs with the bodies. The ones they come with once you tie three together plus the cable return spring are heavier than necessary.

 

Does the fuel-rail overhang the inlet of the body with the short body THS52i?

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That's funny. I just sent an email to my client a couple of hours ago that he should be looking at pulling the trigger soon on the ITB's because of the exchange rate:)

 

I don't know about the fuel rail overhanging the inlets. 

 

Do you have any comparison of a standard cross bar style linkage vs the cable bell crank style you are using now? Cross bar is the type most triple setups run. 

 

Thanks for the info on the levers and springs.

 

Derek

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Looks like if you run the short 37mm o-ring to o-ring injectors it will not interfere with the air box. I have the Bosch ev14 short in mine.

What fuel system will this be running? I have been extremely happy with the AEM Infinity I am running. The tuning softwhere is extremely easy to use. When you drag the timeline through a log it highlights the cell or cells responsible for that moment in time and will suggest a new VE to correct. It should also have auto-tune within the next update or two and correct for you.

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Probably going to make up air filters like I'm running on mine so there won't be a traditional air box.

 

We are going with Megasquirt. I've been really happy with my system and the tuner I hooked up with is really good with them. He's going to take care of all of it as I don't have time to mess with that end of it.

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I liked the clean hidden look of the interconnects. It seems to be how the manufactures do it like the M motors and old Mercedes. I have had it both ways and don't think one is better than the other as long as your links and rose joints are tight. It would seem the number of joints in a crossbar setup would be more susceptible to slop. Some manifolds with only two crossbar supports and oddly placed ones at that bother me. The TWM manifold on my car now is guilty of that. Shorty before I did my itb's I did a set of Weber's for a customer and did a interconnect setup and liked it so I did the same on mine. Seems easy to get balanced and have not changed over time.

Edited by tioga
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Are you line boring the cam towers once the head decks are machined? I can see why you would not have with your head using the old Honda cam towers but with the new machined towers you made it would make since to do that when the rest of the head work was getting done as a final step. You post that you had to turn your cams with a wrench worries me. Maybe it took no effort and was a 2" wrench but it did make me wonder. With no rockers I would want the cams to turn easily by hand.

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The towers were used and I think one was bured a bit. It loosened up during the course of assembly. With the new towers it remains to be seen. I'm hoping that my machining method will be true enough but I won't know for sure until I get the cams back and the head surfaced.

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  • 2 weeks later...

Derek I hope you plan to sell these heads for a while, I'm already getting a fund aside for one (although school is slowing it down a little bit, more motivation to finish faster!  :lol: )

 

I have not yet read through the 54 pages in the thread so far, but have people been talking about doing turbo setups with this head? I assume its all theoretical at the moment but still so exciting :D

 

 

Worst case just save me one :P 

Edited by heyitsrama
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  • 2 weeks later...

hey Derek!

 

Any progress on v2?  or on other copies of v2?  any new changes?

 

actually, how's v1 doing?  still going strong?

 

I'm curious to see what's happening.  

 

also, do you have any other build post?  your work is so amazing i'd love to check it all out.

 

thanks!

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Derek I hope you plan to sell these heads for a while, I'm already getting a fund aside for one (although school is slowing it down a little bit, more motivation to finish faster!  :lol: )

 

I have not yet read through the 54 pages in the thread so far, but have people been talking about doing turbo setups with this head? I assume its all theoretical at the moment but still so exciting :D

 

 

Worst case just save me one :P

 

The plan all along for me was to make this available for a long time. 

There are people planning turbo builds with the head but who knows when that will happen. 

 

hey Derek!

 

Any progress on v2?  or on other copies of v2?  any new changes?

 

actually, how's v1 doing?  still going strong?

 

I'm curious to see what's happening.  

 

also, do you have any other build post?  your work is so amazing i'd love to check it all out.

 

thanks!

 

There has been progress and other than this all consuming build I don't have a lot going on.

 

Lots of regular work though so that's nice.

 

I'm uploading new pics now so stay tuned.

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