tuning

[bonvo]

what is the best tuning for power with a completly stock l20b timing? carb settings? valve settings? cam timing?

[zerow]

what is the best tuning for power with a completly stock l20b timing? carb settings? valve settings? cam timing?

 

You still have to smog your 610, otherwise I would start with the carb and work my way back into the motor. And for those of us who don't have to smog...

 

1) Weber 32/36

2) Cam (then valves)

3) Header (at the very least, one without all the smog plumbing)/Exhaust

4) Ignition upgrades (at least there is one you could do without smog being an issue, run an Electonic Distributor, not your remote black box kind).

 

Then tune as necessary.

[racerx]

don't even try to mess with smog. You can only do so much. If you advance your timing, it will fail smog test, if you change your carb, strong likelihood it will fail, if add header, more than likely it will fail, unless you get smog legal type.

 

That's why I stay away from 76 and up cars in Calif...I also heard that there are certain areas in Calif. that don't need smog test.

 

 

RacerX

[banzai510(hainz)]

http://www.olddatsuns.com/620tech.htm

 

this should have everything you need to know.

 

L20s cam from factory cam sprocket setting on #2 for emission reasons. Doesnt mean it cant run On #1 either

[bonvo]

i know i have smog but thats also once every 2 years what im looking for is what i can set it at for that 2 year time period to get more power out of it then when its time for smog set it back to factory specs (works every time) for smog

[hogboy52]

The simplest and most effective way to icrease HP is by raising the commpression. And upping the normal 8.5 to say 10.0 would give an almost linear increase in power throughout the range.

It would also need the more expensive grades of gas but I think a boost to a 9.0 CR with modern ignition would work fine.

[ppeters914]

"Just raise the CR.." C'mon, the man is on a budget. Might as well swap an LZ or KA to get more ponies and FI and those smog checks can kiss his butt. :fu:

[ggzilla]

Going from 8.5 to 10 compression ratio will give you about 5% improvement across the board (about 5 hp)

 

And it is usually cheap: What does it cost, about $75 to mill the head?

[datzenmike]

And pull up to the premium pump from then on.$$$

[bonvo]

yes ive considered a compression ratio change but there are a few things holding me back

 

1: will it still pass smog this is after all not just a project its my daily driver so it passing is manditory

 

2: that kinda kills one of my ideas for the future the compression is low enough that it can run boost im considering later down the road throwing a 4 bbl on it and a paxton super charger it would make good power and be original

 

as ppeters914 said i am on a budget im disabled and only get a certan amount of cash a month

 

ggzilla: according to my factory service manual the compression on the 76 datsun 610 with the l20B is 8.1:1

 

and on the subjects of motor swaps (i know its way off subject but its my thread :fu:) is a motor swap smog legal? i know that a newer motor should blow cleaner numbers and if i leave all the smog equipment hooked up i should be good to go the only issue i see is there would be no way in hell i would pass visual with a ca18det between the strut towers :D

[racerx]

tell you what call DMV or go on their website...yep, your right as far as passing visual...again I tell people, specially if living in Cal. stay away from cars made after 1975...

 

why make it harder on yourself. Get a 1975 and you can do whatever you want, put a V-8, SR motor, FJ, KA or whatever you want.....at this point with all of that stuff you will do, there aint not guarantee that it will pass. And from the sound of it you want "assurance" that it will pass smog...and I don't think nobody on this site will and can give you that only DMV, so go straigth to the horses mouth as they say and call DMV

[bonvo]

im working on it lol im just asking if anyone had any ideas and i know that a 75 would be best but my 610 was given to me for free and it has been in the family forever it has sentimental value

[zerow]

You can swap a motor from the same model into the car, as long as the motor is as new or newer than the car. For example: You have a 1976 Datsun 610. You can swap in the motor from another 1976 Datsun 610, or a 1977 Datsun 610, or a 1978 Datsun 610...you catch my drift. You could argue for a model that the engine crosses over, i.e. a 1979 Datsun 510, or a 1979 Datsun 200SX, but you would have to install all the smog equipment from your car onto that engine. That is why most of us back in the '90s here in CA would get a L20B from a '74 or later 610 and slap it in our '73 610s, '72 510s, '72 521s, etc, etc. The smog tech didn't know a L20B from a L18, and as long as the air cleaner stayed on by itself, we were good.

 

Now you are in a situation where some of had faced: Before 1998, those of us with 1973 models were fretting smog checks, but the State passed that the cars with a 1973 MODEL year were now smog exempt. The angels sang and we all danced (even us white folk...), then the 1974 cars became exempt in 2004, 1975 cars became smog exempt in 2005...Then the clock stopped. You are stuck in a smog "Groundhog Day". No word, if any, if 1976 model year cars are to become exempt, if ever. Too many people anticipated this change. Also, many smog polluting models still exist from 1976. Think about it: 1976 Continentals, 1976 El Dorados, 1976 Cordobas, etc. who pound for pound pollute more than any 610 are still around, waiting to be driven once again. You get punked because of the model year of your vehicle? And top it all off, we all know that you're going to put something on the car that is bound to cause more pollution, one way or another.

 

I agree, it's BS, but you have no choice. What would I do? Build a motor for 23 months out of the year, run the crap out of it and swap for smog check time. At least you know the motor passed the "last time it ran".

[bonvo]

the problem with that bro is then the seals and such in the carb and other places go bad (excel pump in carb in perticular) im seriously considering fighting it considering the car was maufactured in 75 my dad did that back in the arly 90s when his 66 mustang didnt pass(at the time the smog year was 65) and got away with it i wonder if i could do the same:rolleyes:

[racerx]

yes you can give that a try as far as figthing the year thing but more than likely they will not buy that...did you say that car came from your dad. I may be wrong but heard that if it's from a direct family member you don't need to smog. Again check DMV website or call them. The other you can do is see if you have any friends or relatives that live in certain cal. counties or cities that don't require smog. I am hearing this more often through the grapevine as well.

 

You can also find a shop that will perform some questionable smog check adn you pay, heard that going price is $250, I don't recommend this, if caught, then it's crime and it will not be worth it. If you really don't want to part it, then just keep it stock and do your best to pass smog. You see, people here will make all kinds of recommendations because they want you car to perform but they don't realize how strict cal. smog laws are. Yes, people thought that smog inspection was going to creep up every year, like for instance 1976 will not be required..again people had wishful thinking and their empotions got the best of them...so people started buying cars that were made 1976 and "ASSUMED" that eventually they will not be required to be smogged, WRONG!....as a matter of fact, maybe 3 - 6 mos. ago, some congressman or legislator tried to go back to the old senate bill where only 1966 cars and below did not require smog..boy this sent SEMA, collectors and other ol skool car hobbyist, including Shelby and the likes panicking, calling their politicians to stop this. Luckily it did...

 

The bottom line is..1) don't do a whole lot to that car (mod) - even a 32/36 weber& exhaust, knowing that it may not pass smog 2). get the skinny from DMV, should you change the engine to a newer one 3). make sure all of your smog devices are there, don't advance the timing, fixed that carb 4). do a complete tune - up including adjusting your valves...I mean what else can you do, since you really want to keep the car for "nostalgiac" purposes, right?

[bonvo]

well i wanna keep it cause i love the car it passes smog without an issue its just i want more power unfortunatly i cant get that with smog and exhaust from the manifold back shouldnt effect it

[thisismatt]

Swap in an SR20, swap the L back in when it needs smog...problem sol...err

[racerx]

for some swapping engines is as easy as 1.2.3 but for others this is a serious challenge. If it passes smog, leave it the way it is...if you have some extra scratch buy another one and now you can do whatever you want..btw, even if you install a 32/36, exhaust to an L series engine, you are not going to get the power you think you will (maybe 15 hp), so you have spent like $800 (assuming you buy brnad new 32/36 and exhaust) to get 15 hp?....that's why most people will do an SR or KA swap. Even if you change the heads on the L series engine and go side drafts, you will get maybe 120-130 hp, maybe more, depending on your money.....it's good that your asking a lot of questions cuz most people will think with their hearts and not their wallet.

 

Hope you don't think I bursting your bubble, it's just I've seen this too many times where people will build their L-series engine and 6 mos. later, they were dissapointment or did not see the results they expected and after several thousands of dollars later they opt for an SR or KA or a VG motor.

 

Modifying our cars or any car is a very expensive hobby and I remember this 510 on Ebay and he was like trying to get like $25 K and evethough he spent like $38K on the car, he did not even come close to getting $20 K for it. So a word to the wise, be careful about these little projects that can turn into a "stay the course", you know what I mean...each little project becomes compounds itself...

 

 

RacerX

[bonvo]

yeah i understand im not looking for sr or ka power here just a little more umph you know i need to redo the exhaust anyway it leaks like a stuck pig so i figure while im at it might as well step up to 2 1/2 insted of the 1 ?/? thats on it now later in life when it no longer has to pass smog im looking at a chevy 4.3 v6 but for now i just was wondering if there was some settings i could play with to make it go a little better

[racerx]

Unless the legislators pass a new smog law its 1975 and below...awhile back people thought that it will roll over but Cal. state killed that idea. I heard that 2.25 exhaust is better. If you do go this route, what muffler and header will you use?

[bonvo]

im looking at making a custom header that still has the fittings for the smog pump and such and im thinking a flowmaster 40 series

[hogboy52]

..

Don't throw money away on a fat exaust, it will add nothing. The subject was what can you tweek to get some extra power from a stock smog motor. The answer is almost nothing. Run as much timing advance as you can get away with, say at least 35deg. at 3000rpm.

If your motor really has only an 8.1 CR, that is so retro-grade, like a side-valve iron head of the 40's. If you should pull the head, have it shaved to a 9.0 and gain a near equal % in both HP and MPG.

[racerx]

I agree with Hogboy....the original post was how to tune our car to get max out of stock L20B and you can't do much, plain and simple...if you want to change exhaust then make it 2.25 from header and get a muffler like a magnaflow or dynamax...I heard practically of the mufflers that's out on the market and these 2 sound the best. magnaflows are only $60, with header maybe $200 new, used maybe $100 and piping from header to tip maybe $200 - $300, this price goes up if you want stainless steel. So a set-up will be about $600 for a gain of maybe 10 hp. Again if you advance your timing, it will not pass and if you put header, unless it's smog legal, which is still questionable since you will have to make sure that the smog stuff is connected to the header...

 

It boils down to:

 

1). how much HP do you want? if you want to 50% more power then a whole engine swap or a complete L20B rebuild is another option.

 

2). How much do you have to spend? Like I said $600 for an exhaust set-up. This varies with size of piping and 2.5 is too big for a 4 cylinder, 2.25 is just right.

 

3). What's you long term plan for this car?

 

Good luck....

[bonvo]

1). how much HP do you want? if you want to 50% more power then a whole engine swap or a complete L20B rebuild is another option.

 

im not looking for really more power im looking for what settings on stock carb and timing such as cam timeing and general timing im looking for the most out of the stock motor so when its time to run it on the smog dyno i reset it back to stock to pass then bump the timing back up excetera

 

2). How much do you have to spend? Like I said $600 for an exhaust set-up. This varies with size of piping and 2.5 is too big for a 4 cylinder, 2.25 is just right.

 

i was quotes $250 for a 2.5 system from the manifold back and why would 2.5 be to big?

3). What's you long term plan for this car?

 

long term plans are after it no longer has to be smoged (ill find a way if the year isnt moved) im gonna drop eather a ka or a chevy 4.3 vortec v6

 

what im really asking with thius post is this: what settings in terms of timing, carb settings and cam timing will allow me to get the most power with stock componants that way when its time for somg i set it all back pass smog then set it to the "performance" settings

 

[racerx]

As I said before you can advance the timing and then when you smog turn in back to stock. Advance timing till it starts pinging. As faras 2.5 vs 2.25, I gone on line and did research, spoke to exhaust shops andons of Toyota and Datsun owners. As far as carbs, if it's stock you can't do much. You can put bigger jets but this will offset something else.....if you add 32/36 weber, be careful since smog will be an issue unless you get smog legal ones but 2 problems 1). they are hard to come by 2). even the ones who have smog legal ones the reviews are mixed as far as passing and not passing.

 

Why don;t you just keep this one stock and find another Datsun 1975 and below so that you don't have to worry about smog, then you can install a V-8, V-6, KA, SR, F20 and the list goes on but being a vehicle that is registered as a 76 then you have limited options and that's the bottom line.