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Rebuilding my L20B


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#41 banzai510(hainz)

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Posted 01 May 2017 - 07:46 AM

reliable is close to stock

 

personally I like the 38/38 and they are new

 

question really is do you have at least $ 3 K in the Bank. if yes then go with the bigger better stuff.

If NOOOOOOOOOOO your living on the edge in a apt with no garage and tools

then go 38/38 on a L 20 get e Elelctric ignition. call it good.  Its a L motor.  spending $2000 on a L motor might get you 15hp. $800 on block and then rest on carbs cam valavle train misc....


Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#42 ErickwithnoK

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Posted 01 May 2017 - 02:48 PM

Depends on the gas station around here.  91-93.  at  roughly 1000' altitude.  Keep in mind I build distributors for a living, so timing setup is easy to avoid pinging.  The motor in our race truck is over 15:1.  

 

Erick, stop looking to buy someone else's problems.  By the time you give up tuning, you will have spent more than buying new.  The 38/38 won't give you timing issues like the 40's or 45's.  

 

I'm interested in tuning, I'm not interested in bolting on a 38/38. I want side drafts so I have a toy to play with. I understand that the 38/38 is simpler to deal with, cheaper, and probably would even perform better since it would be better tuned. I am not interested in a 32/36, 38/38 or hitachi. They just aren't very interesting. 

 

If I do end up buying someone else's problems, I will not "give up" tuning, I will enjoy it! That's the plan at least. I have a company vehicle for work, so my datsun is a fun project and not my daily, so it's OK if I get a pair of side drafts and tune them for months before it's drivable. That being said, I'll wait till after Canby so I can show up in my 620.

 

In what way does a dcoe carb cause timing issues?



#43 ErickwithnoK

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Posted 01 May 2017 - 02:53 PM

reliable is close to stock

 

personally I like the 38/38 and they are new

 

question really is do you have at least $ 3 K in the Bank. if yes then go with the bigger better stuff.

If NOOOOOOOOOOO your living on the edge in a apt with no garage and tools

then go 38/38 on a L 20 get e Elelctric ignition. call it good.  Its a L motor.  spending $2000 on a L motor might get you 15hp. $800 on block and then rest on carbs cam valavle train misc....

 

I love a lot of stuff to be stock, but stock-ish is even better.

 

I am not gonna spend 3k on my motor, but I'm not living on the edge in an apartment with no garage or tools. I think I'll go somewhere in between and risk side drafts (weber or dellorto or solex). At the same time I'll go electronic distributor. I'm glad you all are keeping me from going completely overboard, I don't expect to spend money and gain 50HP. I just want a driveable modified l20 that has some interest and is a fun project. 



#44 flatcat19

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Posted 01 May 2017 - 03:54 PM

From horror stories I have heard/read...don't buy used side drafts.


If they worked properly...they probably wouldn't be for sale.

You can't hang if your nuts haven't dropped...it's physics


#45 datzenmike

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Posted 01 May 2017 - 04:07 PM

And they call the Hitachi a complex carb. 


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#46 distributorguy

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Posted 01 May 2017 - 04:18 PM

From horror stories I have heard/read...don't buy used side drafts.


If they worked properly...they probably wouldn't be for sale.

 

Exactly!!!



#47 ErickwithnoK

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Posted 01 May 2017 - 04:32 PM

From horror stories I have heard/read...don't buy used side drafts.


If they worked properly...they probably wouldn't be for sale.

 

Maybe I'll shell out the cash for some new 40 dcoe's if that's really true. Is it an extra $600 true or just a caution? 

 

And they call the Hitachi a complex carb. 

 

The hitachi seems complex but it's also a stock downdraft carb which makes it boring to me



#48 flatcat19

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Posted 01 May 2017 - 04:57 PM

New carbs kick ass. Nothing quite like minimal fuss when you're dying to get your car running.

You can't hang if your nuts haven't dropped...it's physics


#49 ErickwithnoK

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Posted 01 May 2017 - 04:59 PM

New carbs kick ass. Nothing quite like minimal fuss when you're dying to get your car running.

 

Are you enabling me to spend a lot of money right now?



#50 flatcat19

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Posted 01 May 2017 - 05:12 PM

You have my permission.

Might as well get a new manifold too.

You can't hang if your nuts haven't dropped...it's physics


#51 ErickwithnoK

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Posted 01 May 2017 - 05:28 PM

You have my permission.

Might as well get a new manifold too.

 

I've legitimately never seen a used L series dual dcoe manifold for sale...would love to buy that part used.



#52 datzenmike

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Posted 01 May 2017 - 05:47 PM

Maybe I'll shell out the cash for some new 40 dcoe's if that's really true. Is it an extra $600 true or just a caution? 

 

 

The hitachi seems complex but it's also a stock downdraft carb which makes it boring to me

 

Yeah double the complexity, ... at least double, plus tuning them with jets and air bleeds then syncing them. I might be wrong but there is no vacuum advance for them and shitty mileage. Unless you also add a cam most of this upgrade is a waste.... and it's a truck. You won't be bored.

 

Get a KA24DE and trans from a 2wd Hardbody and it will run circles around this for half or less. You won't be bored.


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#53 ErickwithnoK

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Posted 01 May 2017 - 05:51 PM

Yeah double the complexity, ... at least double, plus tuning them with jets and air bleeds then syncing them. I might be wrong but there is no vacuum advance for them and shitty mileage. Unless you also add a cam most of this upgrade is a waste. You won't be bored.

 

What is considered adding a cam? An l18 cam?



#54 Crashtd420

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Posted 01 May 2017 - 05:54 PM

Just step into the rabbit hole and enjoy the ride.... build it how you want but build it right..

#55 datzenmike

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Posted 01 May 2017 - 05:55 PM

No the L18 cam is the same as the L16. The L20B is the same cam as the L16/18 SSS and while a good cam for a 2bbl is not going to allow the engine to make use of multiple carbs. You would want something that opens the valves wider and for longer.


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#56 Crashtd420

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Posted 01 May 2017 - 05:59 PM

It means regrinding your cam to a different profile... usually holds the valves open longer and other technical stuff I don't know...

#57 ErickwithnoK

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Posted 01 May 2017 - 06:08 PM

No the L18 cam is the same as the L16. The L20B is the same cam as the L16/18 SSS and while a good cam for a 2bbl is not going to allow the engine to make use of multiple carbs. You would want something that opens the valves wider and for longer.

 

It means regrinding your cam to a different profile... usually holds the valves open longer and other technical stuff I don't know...

 

This is probably in my Datsun bible "How to modify your datsun OHC engine", there are probably specs in there I could bring to a shop that would do the cam work for me. Someone mentioned earlier in this thread there's a datsun head guru in eugene? What about a shop in oregon/washington that any of you have used and liked for your stuff



#58 datzenmike

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Posted 01 May 2017 - 06:14 PM

Engine strength is in the block. Engine power is made by the head. If the carb(s) intake, ports, valves, exhaust system is a symphony.... the cam is the conductor that brings it all together.

 

There are probably dozens of after market cam grinds available to choose from. From mild to wild. Keep in mind that the wilder the cam the less derivable it is at low speeds and idle. You will always be happier wanting more cam than have too much and wish you had less.


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#59 ErickwithnoK

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Posted 01 May 2017 - 06:39 PM

Engine strength is in the block. Engine power is made by the head. If the carb(s) intake, ports, valves, exhaust system is a symphony.... the cam is the conductor that brings it all together.

 

There are probably dozens of after market cam grinds available to choose from. From mild to wild. Keep in mind that the wilder the cam the less derivable it is at low speeds and idle. You will always be happier wanting more cam than have too much and wish you had less.

 

So I should go with something mild and reap some small benefits of my side drafts? That sounds right up my alley, thanks Mike. I'll do some googling and see what comes up in terms of cams for sale.



#60 ErickwithnoK

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Posted 01 May 2017 - 06:50 PM

My manual says Camshaft lobe lift is 0.276, what is the duration?