My '76 710 Goon

[datzenmike]

Not sure if I could pull off connecting all the runners properly or neatly.  Hoses might blow off in a backfire. Also it might end up a one piece manifold while at the moment it's two pieces. A one piece might not align on the head or the carburetors but with two pieces there's some wiggle room. Manifold vacuum is usually around 22 Hg but the pump pulls over 25 so maybe a slight increase in braking performance. Maybe.

 

With the new battery and only side posts now, my electric fans need to be somehow connected to a non switched source. So does my stereo and because my digital oil pressure gauge drops 15 pounds when the headlights are on, it could use a good solid power source too. Then there's the O₂ gauge....

[datzenmike]

Well I couldn't find anything wrong with Carburetor #2 so I  made a gasket for it and traced out 4 more so I have one extra. The tiny O ring gaskets are flattened so I'll just put thee right on top.

 

[datzenmike]

Pulled the rear two runners off, drilled and tapped for a brass fitting so I can connect the coolant line to the rear carb. The front carb will outlet back into the thermostat by-pass line. Found some EFI fuel hose that should do the trick. Installed the rear manifold. It's to rain tomorrow so wanted this done before that. Tonight or in the rain I'll finish cutting the gaskets I traced out the other night and install them.

 

While the fuel bowl covers are off I will drill out the mains to 1.8mm

 

 

A 1.8mm drill would be 0.07092" This is a No. 50 drill which is 0.07000 Close enough.

[datzenmike]

Didn't rain so I sat outside and cut the gaskets and put them on.

 

 

Stock 1,000cc engine jet is a 1.46mm

 

 

Drilled to 1.8 for a 2 liter engine. Went through like butter.

 

Carburetors assembled and on the manifold. Connected the rear coolant line and the front using EFI fuel lines and leftover hoses from a KA intake. Tomorrow electrical. The battery has side terminals now so no easy connections to tap into the positive. I have an inline fuse and some relays. The electric fans need connecting also.

[datzenmike]

Electrical cobbled together. Carburetors on and throttle connected. Fired up and gas still dripping. Sanded down the casting slightly and put two gaskets on same thing. (sigh) The fuel inlet pipe is right at this carburetor also. Hose is on and hose clamp tight. I'll try another clamp.

 

I don't think it's flooding. Maybe leaking at the fuel inlet? Need to watch while engine is cranking with coil wire off. See where the wetness starts.

[datzenmike]

Carburetors off (again) and pulled the cover off the leaking #2 that I used two gaskets on and there is a good solid imprint on both sides so no way it can be a bad seal. The fuel inlet is brass pushed up into the casting. It seems tight fitting but (for lack of anything else) one side has a very slight separation, like it may have been bumped. So out with the JB weld. Cleaned with screwdriver blade and carpet knife, roughing up the surface after using carb spray and Q-tips to clean and de-grease. 

 

 

Fuck it was hot today and warm biking home, didn't really feel like working on it. Cold shower and sit around and it's cooled off slightly and everything came off with no problems. Gets easier every time.

 

I started it up cold 3 times this weekend, but very briefly with the fuel leak. Amazed that it idled at 400, though roughly, no time to turn the idle speed up when I see the gas dripping. No way would a Hitachi 2bbl do this without the choke on for a few minutes. What a difference a carburetor for each cylinder is!!!

[datzenmike]

All together and it ran but the leak is actually higher up on the carb where it feeds left and right to the carburetors on each side. All I could see before was it dripping on or at the inlet pipe. I was using a mirror and I think it's to the front carb but I will remove, drain spray clean and JB both sides just to be sure. Maybe this is why these R-1 carbs were for sale. Happy I'm on the right track and I'll get this.... 

[datzenmike]

OK last night I JB welded the, for lack of a better word... fuel rail, that moves fuel from the #2 carb left and right to the others. I guess one of the little pipes was leaking, nice and dry now. It's sort of like the tube on the old Hollys that feeds fuel to the rear fuel bowl on a 4 bbl. Let it cure all day today and installed, fired up and it works! Will fuck with it on the weekend. Too hot and too tired now. Have to adjust the idle fuel mix. 

[datzenmike]

Got the O₂ gauge in, wired up and calibrated. Ran a thicker power wire from the battery through a fuse to a relay that lets it through with the ignition on. Idle is 14.8/9 to 15.1. I haven't messed with the idle mix screws yet. Could be a little richer.

 

Had it out today, just got back. Full throttle it drops through 11 down to 9.8 which seems kind of rich to me. All I've done is drill the mains out to 1.8mm. It pulls really well but will sometimes let out a pop through the exhaust wen over 4.500. Lots of exhaust rumbling popping on deceleration, but there's no vacuum advance and again maybe a slightly richer idle setting would help this.

 

The SOUND it makes!!! No air filter. It roars.

 

How do you start these R-1 carbs when starting up cold???

[datzenmike]

Only way to really get at the idle mix screws is to take the carburetors back off. I did and bottomed them and turned out exactly 3 turns. Idle mix is now low 13s and high 12s but much much smoother. This week after work I'll take them off and close them 1/2 turn and check the reading. If too much then 1/8 turn back, too little and 1/8 turn forward.

[datzenmike]

Still will not start by itself. I pull the enrich lever all the way out but no start. I know this does something because when started and you shut it off the idle drops to normal. Squirt gas down each carburetor and away it goes. Idle is good. Pull away from a stop is insane! The old Hitachi carb seemed to transition badly from idle to primary. This set up leaps away, will try not giving it the gas and just let the clutch out. Lugged it down to 1,000 in 5th and stepped on it.... smooth pull away. SLOW... but smooth.

 

Cruise with barely any throttle is high 14 and even 15.3 but as soon as you touch the gas it drops into the 12s.

 

Floor it and will even go down to 9.6. I did drill the jets out to 1.8mm as recommended. Haven't moved the long tapered needles yet. Maybe lower them? s less fuel?? It drives just great!!! smooth with no lag or slow spots. 

[datzenmike]

Bought a GM vacuum pump for the brake booster and it works just fine but the pump runs continuously and gets HOT. This can't be right, it should only come on to maintain vacuum. Tried to modify a 720 vacuum switch with a stringer spring and it turns on and off continually... so fuck it. I already have four little vacuum lines fitted to the individual pipes on the flange. Will try to join them all together with vinyl tubing for a vacuum source. Gotta get out on the road to get these carbs tuned just right for mixture.

[Crashtd420]

5 hours ago, datzenmike said:

Bought a GM vacuum pump for the brake booster and it works just fine but the pump runs continuously and gets HOT. This can't be right, it should only come on to maintain vacuum. Tried to modify a 720 vacuum switch with a stringer spring and it turns on and off continually... so fuck it. I already have four little vacuum lines fitted to the individual pipes on the flange. Will try to join them all together with vinyl tubing for a vacuum source. Gotta get out on the road to get these carbs tuned just right for mixture.

 

What you using the switch off the brake pedal?

the minute you touch the brakes it would activate the pump..... 

 

Might need to be a separate switch not sure.... or if that would activate quick enough..... just an idea....

[datzenmike]

I don't know. Sounds awesome but no assist at start and you have to think worst case scenario. 

[Crashtd420]

9 minutes ago, datzenmike said:

I don't know. Sounds awesome but no assist at start and you have to think worst case scenario. 

I wasn't sure how quick it built vacuum or not..... 

I never really messed with a brake booster or looked at what it needs, i was just trying to think of a way to keep the pump from constantly running but still be there when you want brakes.....

 

[datzenmike]

I thought about this all day at work and your idea is genius. There is a one way valve on the line to the booster, so vacuum is held even if you're driving and the engine quits. You have at least one good press on the brakes before it's all used up. Just don't pump the brakes. So your idea of the brake light switch will work. It does build very fast, but not fast enough for using it alone. But if the booster still has vacuum in it anyway it should easily catch up. The only problem is sitting for long times with the brakes on. Maybe I can make something that turns the pump on for only 5 seconds at a time.

[datzenmike]

Connected the brake light switch to the relay that controls the vacuum pump and it works quite well. Thank you Crashtd.

 

On the highway at 50 and level.... high 13s and low 14s, but as soon as you give any throttle it drops., moderate throttle 11s and full throttle 9.6  Once she cools down I'm going to try lowering the needles.... perhaps the bike owner ran them rich. 

 

After a long run I turned the idle down below 800 and it's showing 19/20 and doesn't sound smooth. I did turn the screws 1/2 turn lean from 3 turns out. Might look at this.

[Crashtd420]

I knew you needed something more like the relay and/or vacuum switch, without being there to play with the set up the most I was hoping for was to spark an idea..... Glad that worked out.....

[datzenmike]

Zactly.  Just needed to be outside the box.

[datzenmike]

Was out yesterday for a drive and level cruise was in the 14s but just touch the gas and it drops. Any throttle drops it and the higher the revs the more it drops. Down to 9.8 when really wrung out. Hot idle was 19-20 and running not so smooth. Now this may be from turning the idle jets in from 3 to 2 1/2 turns.

 

So this morning I removed the slides and needles and moved the E clips up one notch so the needles are sitting deeper and allowing less fuel at any throttle position. What I have now is low/mid 14s at cruise and slight hill climb. I can still get it down to 9.8 but it takes longer to get there and at higher revs. On the way home it's several miles all down hill to my driveway, foot off the gas. So I pulled the plugs and they are cream color so definitely lean at 16/17.

 

Will move the idle screws back to 3 turns out as this gave a warmed up 14.8/15.1 before. Then check if this has changed anything when driving. Would like to see it stop at low 12s when floored. If it hasn't changed other than the idle mixture I may try moving up one more notch on the jets just to see what happens. 

 

For starting cold I have a small plastic water bottle of fuel that I drilled a 1.8mm hole in the cap. Hold over each carb opening and squeeze lightly, fires right up.  

 

 

[datzenmike]

Took for a drive Sunday out on the highway and the transmission started growling badly on deceleration. Really loud out of gear coasting. It's quiet below 50/60. Well this transmission was in a crushed '79 280zx and was in my 620 for over 10 years and now in my 710. Lord knows the mileage on her. I had it apart last summer to replace the oil trough and all the bearings looked good so I'm at a loss. I'll get the car in the air and check the mount and engine mounting bolts are tight. But it may have to come out.

 

I have a later '81-'83 280zx with the big over drive. I started taking it apart as I could only turn it in 1st. It's increasingly tighter as I go up the gears and need a clutch disc on the splines to turn it. A few times I couldn't turn it backwards so this would seem to be a bad bearing that acts like a sprag clutch. I think it's in the rear case, the front looks ok. If fucked I'll have the front case machined for the larger 62mm counter bearing and fit it to my CA18ET 5 speed. Dying to try this 'almost 71C transmission'. Has weird synchros and huge shift forks and the larger 62mm bearing. It is a wide ratio though.

[datzenmike]

Found the '85 CA18ET 5 speed. Power washed the 280zx L case and the CA tail and got them clean.  The L case has to be machined out to 2.4428" so went to the machine shop but it was closed. Will drive to work Monday, and check on the way home. I traded the CA 'bell' for a KA-E head (sucker) but the front cover went with it (idiot) so I pulled my 720 shorty out and I believe it's for a 62mm bearing. Failing that I did have an '85 diesel 5 speed just have to burrow through all my junk to find it.

 

After the machine shop I took the 710 out on the highway and only at high speed is there noise from somewhere under the car. It's right when you let of and coast and really loud in neutral. Seems to go away down at 50/60. Totally quiet in town. Later I will check the drive shaft, the trans and diff oil levels. If not this then I'll continue with the trans from the CA18ET. I had the zx trans out last summer and checked all the bearings so I can see how this would be making noise.

 

Highway cruise at 70 reads 15 on the air fuel so good enough. Will slowly drop into the 11s when floored and above 4k keeps dropping to 9.8. Pulls very well and on entry to the freeway in third a long hard pull the speedo keeps climbing where with the carb, acceleration would noticeably drop off above 3,500 and take forever to get to 5k. Also there is a slight hesitation off idle transitioning to primary with the Hitachi... that's gone. These are much smoother and no slight bog. Still don't have the vacuum advance worked out but it runs so good I can't see it being any better....

[datzenmike]

Pulled the tail off the 280zx 5 speed and.... the counter bearing on the adapter plate is the problem. The counter gear cluster actually wobbles. Probably why the transmission was removed and traded, oh well. It's not at all destroyed and totally fixable.

 

I have the CA18ET 5 speed and have the original tail for it and a 62mm cover plate for the L front case when it gets machined.  

 

Also found a long dogleg with front case missing.

 

Also found a mid ratio Z series.  Front and rear cases off

 

By putting the front main and counter driven gears on the CA18ET wide ratio, it can become a mid ratio but with a 280zx 25% over drive 5th! What a concept!

[datzenmike]

Found a spare shifter to mess with. I did this mod last summer but was conservative, This time I'm maxing out the fulcrum height to get the shortest throw but retain the same shifter height. Looks like 7/8" higher and a 23/64" drill

 

 

Cut and weld.

 

 

 

Tried to put the CA18ET tail onto the zx box to check the shift length, and whada ya know... the striking rod width was increased so it won't fit into the hole on the adapter plate. Well that's one more thing different on the '85 and up 71Bs. Larger 1st 2nd shift rod, larger counter bearing, and larger diameter striking rod..

 

So it has to go on the CA gears anyway so I fit it and got it on the first try. It's on loosely so when I'm ready I'll crack the rear case and squirt some Honda Bond or w/e it's called in when I mount the modified L series front.

 

Shifter travel is now 3.5" between 1,3,5 and 2,4 R.

 

Shift effort is minimal in every gear but 5th and reverse. I tried everything to make it easier but it requires a hefty tug to get it out of 5th or reverse. The last thing was to remove the plug covering the detente ball on the 5th/rev shift rail and suddenly it was free to move. I settled for trimming the spring till it was just like the other 4 gears. If this turns out to be a bad idea I have plenty of 71B springs and can replace it. Maybe it just needs to be driven. The other thing is mechanical advantage id lost by raising the fulcrum point so I may have to live with it.

[datzenmike]

OK milling the case is a problem as there isn't anyone near me capable of it... so, I have a new in the box 56mm Nachi 'Made in Japan' bearing. This is more than enough for now.

 

 

Pulled off the 62mm and saved it. The 56mm tapped on with a 4 lb mallet with little effort. Then switch to a suitable pipe and driven home. Had to clean up the 280zx cover plate and swapped the less rusty clutch arm pivot onto it. I guess a home made gasket is in order.

 

Still to do is drill out the first/second shift rod to 16mm or 0.6304". A 5/8" is 0.625" I imagine it will wobble a bit and be oversize 5 thou anyway.

 

I ordered a new rear transmission seal and a front cover seal.... they should be in by Friday. This is a long weekend with Canada Day holiday Monday. I don't see why I can't get this bad boy swapped in.