My '76 710 Goon

[datzenmike]

I'll try that next time, thanks. I just turned it down to low speed and it chatters and stays cleaner. Sort of flicks chips off.

[datzenmike]

I have the '75-'77 L20B with the co-joined intake and exhaust. Not a fan of these as the intake does not have the coolant flow from the head through the runners to warm when it's cold and to cool when it's hot. The later '78-'80 did have this and the engines just run better with a more consistent intake runner air temperature. The co-joined manifolds use exhaust heat to warm the intake but in the summer they get baked by radiant heat. On top of this the L20B exhausts are a simple 4 into 1 pipe jamming the exhaust into a single 2"? down pipe. I like the L16/18 cast iron header which is 4 into 2, keeping adjacent cylinders separated and for almost two feet. In fact the two pipes only join on the down pipe into one and back under the vehicle to the resonator.

 

So I found a two into one down pipe at the scrap yard, no idea what it's off but the flange does not mate to the L16 manifold. It's close but larger. It isn't off a Z24 or a D21? But I held it under the car and it's sort of close.

 

So I cut the flange off and I have one of Mike Klotz's flanges from 5-6 years ago that he gave me. The new down pipe has slightly larger twin down pipes but I wrestled it on into place.

 

Need to get the head on and the L16 exhaust temp. bolted on and test fit. If all goes well I can tack the flange to the two pipes then weld permanently. This will give me the two into one down pipe and bend under the car.

 

 

 

Took my L16 exhaust out and heated and removed the very rusty eroded studs out and replaced them. Cleaned the threads with a tap.

 

 

 

Dremeled the flange to fit the larger twin pipes. Used gear clamp to pull them together for the fit. The protruding ends fit nicely up into the manifold to help the gasket seal.

 

 

 

Roughly how it will fit together. Studs are slightly long but...

 

 

 

The stock L16 twin into one down pipe joins just below the flange. This one stays separate right down to just after the bend under the car. Cylinder 1 & 4 and 2 & 3 travel 18" through the manifold and another 14" through the down pipe before joining. Sort of a long tube header. The head is another 3.5 to 4" so a total of 35.5".

 

Anyone recognize this exhaust down pipe? It visually looks like one from an S13 with KA24E even down to the flange at the back for the cat and those twin tabs in the picture below... ahhh just found out the tabs are for bolting a heat shield to them. The floor may get hot???

 

[datzenmike]

 

Rain all AM. Got 5 hours in this PM.

 

Took the head out and put on and torqued the bolts

thermostat housing on

intake and exhaust on

brake booster hose  on (changed fitting)

Y pipe for the coolant bypass and the intake coolant swapped on with new hoses

fuel pump and fuel rail on

block vent and PCV hose on and secure

 

Needs...

 

coolant added to top it up

carb heat shield

carb

dizzy cap and wires on

valve cover

 

Really needs...

 

the modified 240sx exhaust down pipe test fitted and tack welded, then final weld on the flange.

connect down pipe to the rest of the exhaust system.

 

 

Bottom row of intake/exhaust bolts were a dream to install and tighten with the L16 manifold.

 

BTW... that's a '79 L20B intake without the EGR manifold on or a block off plate. Looks almost like an L16 intake but has larger runner diameter and was port matched to the head.

[datzenmike]

Got the 240sx down pipe fitted and tacked, then welded her up. Got to use my mig welder for the first time in a couple of years. Once under the car the two pipes join into one and there's about a 6" stub. Have to somehow join this to my existing system. They are not aligned very well. Maybe some flex pipe that I can fit, then take somewhere and have a piece bent?

 

Carb can go on after work tomorrow. 

[Eagle_Adam]

Lookn good Mike!!!

[datzenmike]

Carb, cap and wires, valve cover on. Installed the '79 heat shield between the bottom of the intake and the L16 exhaust. Dizzy and carb wired up. Took some measurements on the two exhaust pipes and will try to get a pipe bent that will join them.

[KoHeartsGPA]

Vid of her running soon? :thumbup:

[hobospyder]

One weekend left moke, you gonna make it?

[KoHeartsGPA]

He's gonna have to page Smoke to come help him....

[Draker]

One weekend left moke, you gonna make it?

He already left.. on his bike.

[datzenmike]

Got a pipe bent and installing. NA pipes are different than the Japanese ones. I don't think the exhaust pipe is small enough to slip into the piece I had bent. It's close. I'll get a muffler clamp and crush it multiple times and try.

[datzenmike]

Exhaust done!

 

Engine fired up! Let it warm up. DAMN it's quiet.

 

Idle is a little high.

 

Trans tail is wet so got more oil and a new rear seal.

[datzenmike]

Checked trans and oil ran out, so no worries there.

 

Installed my new HIDs. Will try to get out later tonight to set them. They wouldn't come on and I was very frustrated. Ben explained that low voltage will do this. Once I got my head around them not being at fault, I moved on to my electrical system. Put a relay to run 12 volts directly to the lamps. They now work. The highs are brighter too.

 

The pipe not fitting was simply 40 years of rust on the outside of the pipe. I dremeled it off and bingo, slipped right in hammered it in deeper and added a clamp. Cannot believe how quiet.

 

Three days to get my traveling shit together. 

[datzenmike]

Back from Canby. Stopped off in Calgary and northern BC for total of 3,100 miles. Got 27-28 MPG US gallons and over 32 Imperial.
 
Noticed that my highest mileage numbers were at higher altitudes away from the coast. (31.38 US MPG) As the car is originally from Nevada and the mean altitude is 5,500 feet the carb may be jetted for this? Higher altitude runs richer so a smaller primary jet would be used than if you were at sea level. The carb has a 99 primary jet in it but I have another local L20B carb that has a108 jet. I ran this carb before Canby and it had severe kick ass acceleration compared to the 99... at sea level. I ran the 99 jet for my trip but seriously thinking about swapping it back in for at home use. Picked up a carb at Canby and it has a 103 jet. This carb had a water cooled intake so I thought '78 and up, but checking it also was linkage not cable throttle. Only the '74 and up 610 had this.
 
Only fly in the ointment on the trip was loss of oil pressure. I have a 720 4x4 gauge and at 2K miles it changed from 65 to a totally random low of 20 and high of 40 PSI. Figured the sender and changed it today (not it) pulled the pump and it looks fine. Relief valve is free to move. (not it) Plugged a spare PSI gauge in and that was it. Always do last thing first.
 

 
So the oil pump gasket tore so I made one for it with hole punch and small nail scissors.
 
 

 


 

 
 

 
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[datzenmike]

Last summer I popped the old ones out to clean all the shitty grease out and change the growly wheel bearings and then put them back in. Last spring I ordered two grease seals for the front hubs. Meant to do before trip but.... So took the calipers and hubs off and all the new grease was black around the bearings. Washed them and re-greased them and put the new seals in.

 

Now I noticed that this year I hammered the brakes pretty hard quite a few times (mainly because I don't get to at home and I love how these Maxima brakes stand the car on end!!!) and by the end of the trip there was a slight pedal vibration when braking. Could be a high spot or brake pad transfer from the heat?? Had a good look and the calipers are new and have been to Canby 4? times for about 1,200 miles each plus this one was 3,100 so about 7K miles on them. Does not appear t have ANY wear on them so unlikely a high spot.

 

The rotors look fine but I sanded them to take the mirror finish off. There was a very slight long crescent shaped shadow about 1/3 of the way around on one side on one of them. It sanded off as a black dust. Brake pad transfer??? All together now and will drive it around tomorrow and see. 

 

Might take that carb apart that I got at Canby and clean it.

[datsunfreak]

Now I noticed that this year I hammered the brakes pretty hard quite a few times... by the end of the trip there was a slight pedal vibration when braking...

 

Maybe warped the rotors a bit? 

[datzenmike]

I researched the warped rotor myth. I just doesn't happen. In addition these are vented and quite wide and stable.You can get pad imprint or transfer and the pads grip the pad material that is fused to the rotor better than the cast iron itself. The wheel 'tugs' as it goes round. This can lead to hot spots that harden the metal and end up as high spots as the rotor wears down naturally. The cure in the short term is having the rotor turned down but if the pads are not conditioned, it can happen again on the next panic stop.

 

When I put the Maxima struts on, I did go out and try to bed the pads with repeated hard stops, well not stopped fully, as this is when the transfer takes place. I slowed from 70 to 20 multiple times and then continued on to let them cool down. Probably not enough as on one of my Canby trips I was descending a very steep switchback paved road and at the bottom there was that burned clutch smell. Guess I didn't heat them anywhere near hot enough to condition them.

 

 

That carb I bought from James was torn down today. Man I have to say it was the cleanest inside I have ever seen. Even the cadmium plating is all there and just needs polishing. Maybe it was rebuilt? Decided to put the #108 main jet in as it was on a local L20B truck. On the Canby trip my best mileage was at higher elevations so the #99 jet is probably a bit lean where I am at sea level. (it had a #103 in it)

 

As to the Carb, it's from an L20B and it was mounted on a 'wet' water cooled intake which suggests a '78 and up as earlier ones were dry. It has a linkage set up which none of the later cars have. Mystery solved. It's a first year ('74) L20B from a 610 and was probably on an A87 head which were 'wet'. '75 and on were all U67 which were dry. 

[Lockleaf]

Hub runout also increases high hot spotting on rotors.

[datzenmike]

I was very careful setting the hub. It's tighten the nut to 20 ft lbs and then spin wheel several times both ways. Check the 20 ft lb torque. Now loosen the nut 60 degrees and set the cap over the nut and install cotter pin. Only tighten the nut (if needed) to the next position where a cotter pin can be installed.

[datzenmike]

Put the Canby carb on Sun and spent most of the afternoon trying to get it to run properly. Idles perfectly, has good off idle revving. (probably the slow circuit) In neutral you can rev it to 2,500 fast of slow but if you try to go above this it quits unless you release the throttle. No gas comes out the primary venture and there should be. By pumping the gas (accelerator pump) you can force it above this point and when gas starts to come out the venturi you can hear the change in power. Reset the fuel bowl height and didn't help. Seems like there is a problem drawing fuel into the venturi. Once revved up it's fine.

 

Will remove and check the primary air bleed and emulsion tube.

[Grahem]

hey i picked this up at a swap meet last weekend i think its a 710 side marker is it of any use to you?

[datzenmike]

Sure I'll take it. Next time I roll through :lol:

[Grahem]

Perfect I will put it somewhere safe lol

[datsunfreak]

Hey. This is what the classifieds are for. Noob.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

:rofl:

[datzenmike]

Work sure cuts into Datsun time.

 

Back story: I had the stock '76 710 Nevada carb, then a '79 local 620 carb, now a Canby carb that I believe is from a '74 610. All taken apart and cleaned and adjusted. Stock one ran slightly better but I put the '79 on and there was an improvement. Used it for the Canby trip averaged 32 MPG or 28 MPG US. Both have just off idle stutter as clutch engages otherwise they run ok.

 

Cleaned the Canby carb and it won't rev up as described in the previous post. Does, however have good off idle throttle response.

 

Took off this week and took completely apart. Worked on it for about 3 hours. Ground down a screwdriver so I could get at a couple of bleeds that I simply blew out before. I always thought there was a primary a secondary and an idle system. Forget the choke and the accelerator pump for now.

 

Turns out there is a slow system for above idle throttle using the same gas as the idle mixture screw. Both are shut off by the idle cut solenoid. The slow system is like a carb within a carb and gets the air flowing in the primary so it can produce enough vacuum at the venturi to draw it's own gas in. Just like the primary and secondary it has it's own air bleed and it won't work without it. I guess mine must have been plugged. I poked a couple of strands of twisted copper wire down the hole and it came out with carbon on it. Now that it's open a carb cleaner spray can flush anything else out. Carb went on yesterday and ran perfectly. Really stable idle, you can pull away from stops without any gas. No stumble as gas is added. Accelerated very well, smooth and strong pull. About  half an hour and it quits but restarts, idles fine and I limp home. Feels like plugged jet.

 

Took carb off and there was a speck in the primary jet, all together and running perfectly. I guess this is to be expected carb on an off and apart so many times. This one on off on off on, hopefully for the last time.

 

So take note. If you have poor idle or even a good idle but as soon as you start to give it throttle it stumbles or balks. If this stumble really interferes with clutch engagement and you have to rev it higher to engage smoothly... it could be your slow speed circuit. Probably one of the two air bleeds. Yes there are two.