cannon manifold 821

[yoloSun]

Hey guys, does a "cannon manifold 821" fit an L20B head?

Scoured the net but came up empty. 

[Charlie69]

Call Pierce Manifolds they would be able to tell you.  I do not remeber the number on my Cannon on my L20B.

 

Pierce Manifolds

 

I believe Pierce Manifolds sells new Cannon Manifolds for the L20B.

Edited April 15, 2019 by Charlie69

[Crashtd420]

On 4/14/2019 at 2:26 AM, yoloSun said:

Hey guys, does a "cannon manifold 821" fit an L20B head?

Scoured the net but came up empty. 

Isn't that the single sidedraft intake?

 

If so search for a lynx intake if you wanna use a single sidedraft....

 

The problem with the cannon intake is it pairs 1/2 and 3/4.... 

 

The lynx pairs 1/4 and 2/3.... allows for better induction pulses... 

Look at the firing order and you will understand what I am saying.....

 

I have read many complaints about running a single side draft on the cannon intake.....  

Edited April 15, 2019 by Crashtd420

[Stoffregen Motorsports]

...many complaints of a single side draft, period. I have never like the single setup, no matter which intake is used.

[Crashtd420]

28 minutes ago, Stoffregen Motorsports said:

...many complaints of a single side draft, period. I have never like the single setup, no matter which intake is used.

I'm actually doing really well getting my single 40dcoe with the lynx intake tuned....

Yes it's a pain but doable....

[yoloSun]

Thanks guys I'll check with Pierce; the firing order thing makes sense, definitely something to consider. As for complaints, I don't know what they would be - though I read here that the single side draft carb is the most fun pennywise. 

 

I am in the process of changing the manifold gasket, previously the engine would not idle and bucked on excelleration, there was an air leak; I went over everything, got frustrated, took the carb on and off probably 15 times, torched a 12 mm wrench and made it custom for the carb bolts.

Then I took the smog equipment off. 

Still to no avail, and that's when I noticed the EGR valve. Cupped it with my hands and the engine settled down, so I blocked it off, tuned the idle vacuum to 22-23 hg, where previous it was...maybe 15 hg. Advanced the timing because I was hearing pre detination, and changed the distributor vacuum advance from the carb to the manifold. The engine ran great, no more bucking or idle issues, excelleration was good, no pinging.

 

Now it's talking to me again, idles a little rough. Tachometer jittering, idle mixture screw all the way out does not kill the engine, but Turning it in does kill it. 

I noticed the manifold is missing a bottom bolt, radiator side. 

So now I'm trying to get the bottom left manifold bolt off without a 12mm shallow swival socket. Fuuuuck.

 

Also it looks like the intake has a coolent line going to it? Wondering what the procedure for that is. 

[Crashtd420]

I'll try to explain what I know... mainly its tuning.... 

As far as cannon vs lynx.... and the firing order.....

 

So with the cannon it intakes fuel from the left barrel of the carburetor sequentially....  from cylinder 2 then 1... then the other from cylinder 4 then 3.... 

With the lynx it alternates the intake pulse... so it take from the left barrel then the right barrel .. back and forth ...

 

As far as the distributor did you get a timing light on it..... ?

I believe the manifold vacuum works a bit backwards from ported vacuum off the carb.... make sure your base timing is good around 12 and then run the motor up to around 3000 rpm and check it there too.... you should see your full advance.. should be around 32....

 

And yes the intake has coolant going through it..... best thing to is drain some out.... you just need the coolant level lower than the head ....

[Crashtd420]

If you do got this route plan on buying extra jets and probably a wideband o2 and air/fuel gauge.....

 

The air/fuel is nice either way... makes tuning easier if you dont have any help.... that's the other problem, finding a shop that can help tune the setup..... 

 

 

[Stoffregen Motorsports]

I am going to suggest swapping out the lower manifold bolts for studs. Studs distribute the load far better than bolts can. Plus, the action of screwing a bolt into the soft aluminum of the cylinder head can weaken the threads over time, making it likely that you'll pull a thread. It is also far easier to get the washers and a nut on a stud than it is to find poke around and find the bolt hole.

[yoloSun]

Thanks guys, tried to check the timing before putting a fresh gaskets, but I couldn't see too well in the day time. 

Putting studs in sounds like a good plan to me, I'll have to look up the thread size.

[Stoffregen Motorsports]

8 x 1.25 thread pitch. Not sure on the length. Studs from a L6 should work.

 

For informational purposes - https://www.thezstore.com/page/TZS/PROD/15-8080

[Str8jacket]

I had a lynx manifold and a single 45 dcoe on my l20b. 36mm chokes.  and i think from memory i went full circle back to almost standard jetting that the new 152g 45s come with. I can find my book with the jetting. The standard emulsions were either f2 or f16 i cant remember now but they are rubbish. I think F8s worked best. There is a guy on side draft central that sells a modified emulsion tube that i wish i had back then, i had a hesitation on transition from idle to mains that  i reckon they would fix. I have a full set for my triples and the quality is top notch. I also would recomend a megajolt ignition or crank fire if you can afford it as it was the best money i spent on the engine. Tuning is much easier if your ignition is top condition. I even have the map i ran. It could be refined  more but it went awesome as it was. 

[yoloSun]

Yeah I'd like to do a single dcoe, with a lynx manifold. I will retroactively wait for good deals, maybe I'll get lucky.

 

But does the lynx come with the coolent plumbing I wonder?

 

I have the w58 head btw. '79 l20b.

 

[Str8jacket]

It blocked the coolant ports off. I had the later head, i cant remebmer which number it is sorry. 

Also look out for either a good quality mechanical high flow low pressure fuel pump or an electric pump designed for webers.

 3psi is all you need, a return to tank regulator worked best for me. 

Edited April 18, 2019 by Str8jacket
Fixed spelling

[Charlie69]

I always have run distributor vacuum from the carb port.

[yoloSun]

2 hours ago, Charlie69 said:

I always have run distributor vacuum from the carb port.

Heres an excerpt from this website :https://www.chevellestuff.net/tech/articles/vacuum/port_or_manifold.htm

This was written by a former GM Engineer.

"Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it.

If you look at the centrifugal advance calibrations for these "ported spark, late-timed" engines, you'll see that instead of having 20 degrees of advance, they had up to 34 degrees of advance in the distributor, in order to get back to the 34-36 degrees "total timing" at high rpm wide-open throttle to get some of the performance back. The vacuum advance still worked at steady-state highway cruise (lean mixture = low emissions), but it was inoperative at idle, which caused all manner of problems - "ported vacuum" was strictly an early, pre-converter crude emissions strategy, and nothing more."

[Charlie69]

That is all well and good but I do not and I bet you do not drive around at WOT.

[yoloSun]

Well, my tach has been saying 4000-5500 above 80Km, or as you yanks say - 40 Miles per hour. I think I may be having some clutch slippage from a slave cylinder malfunction turning it into a hydraulic press and keeping the fork pressed in slightly, or maybe it was the vacuum leak. Take a look at my other post, theres pictures of my intake manifold with the EGR removed.

 

Or do 4-speeds just take a shit ton of revs to go fast?

[Charlie69]

Sounds like you know what might be wrong, not sure why you are not addressing the high RPM problem instead of trying to tune for it.

[yoloSun]

Well I had a rough idle, and the carb wasn't responding to the air/fuel mixture screw being turned all the way out. I was tuning for pinging and top end power at the time of distributor adjustments -  On a slightly inclined highway my speed was dropping to 60 Km, more gas did nothing but make a bogging sound.

 

As for the rpm issue, I was asking a genuine question, what rpm is your engine at in fourth, above, say 80 Km, 40 MPH?

This is the only 4-speed I've owned, so I am unsure. Just feels like the revs are too high without a 5th gear.

[G-Duax]

Ah, 80 kph is 50 mph..... (49.7 actually).

Do you have an actual tachometer ?

My 620 with 4.62 gears, in 4th gear (1:1) is only turning 6000 rpm at 100 mph, so it's only turning 3000 rpm at 80 kph.

 

Have you ever owned an Nissan L4 engine before ?

That is not too high of rpm, in fact they like that type of rpm.

 

[Charlie69]

I have run L16s and L20Bs as high as 7000 RPM on a tac, and have had no problem sustaining that RPM for long periods of time.  These were stock engines with over 100,000 miles on them.

 

I did not realize you were asking a question about the clutch.  Is you 1979 L20B a 720 or a 620?  Short bed or long bed?  Regular cab or King cab.  The 720 had different gear ing than the 620. 

 

G-Daux is correct the L series engines love RPM.

 

Now my later model 720s with the Z24s do not like the higher rpm but will do it if need be.  I drive my trucks like I stole them.  When I buy one the first thing I do is put a down draft DGEV 32/36 Weber on them.  I work the shit out of my trucks and I keep them mechanically sound.  It takes a lot of maintenance when you drive and work them like I do.

 

The other people on Ratsun that I can think of off hand that work their trucks like I do is Wayno and Danial C.

 

These litle trucks were designed to work and last.

[Stoffregen Motorsports]

11 hours ago, yoloSun said:

Well, my tach has been saying 4000-5500 above 80Km, or as you yanks say - 40 Miles per hour. I think I may be having some clutch slippage from a slave cylinder malfunction turning it into a hydraulic press and keeping the fork pressed in slightly, or maybe it was the vacuum leak. Take a look at my other post, theres pictures of my intake manifold with the EGR removed.

 

Or do 4-speeds just take a shit ton of revs to go fast?

If you really so have the clutch hydraulic problem, you better address it soon. Constant pressure on the back of the crank can force the oil away from the thrust bearing and wear a groove in the crank, destroying it in the process.

[vicdat]

Wow - where did G-daux score 4.62 gears? I've only seen 4.38, 4.11 and 3.90's for old datsuns.

 

Vuc dat

[yoloSun]

1979 620 L20b W58, 4-speed, Regular Cab, don't know if it's short or long bed.

I have never owned an l4 engine before, and I have a tachometer that I installed myself.