L20B Hitachi secondary issues and overheating

[ninjabortion]

The car ran fine when i first got it up and going after the PO had ripped all the guts out of it. I replaced some rigged electric fuel pump with a mechanical one, put the stock fuel rails back on, set the timing, and it ran pretty well. The car ran at just over the halfway point on the temp gauge, which seemed good enough for me.

 

A couple weeks later I readjusted the valves(they were way off and tightened by the hulk i think) set the timing at idle to 12 deg btdc at 750 rpm's per the manual, and it seemed to run fine. I discovered the secondaries have been stuck the entire time and had dead leaves on em, so i got a rebuild kit and went to work on it. Everything worked pretty well at that point except the thing bogs baddddd when i floor it enough for the secondaries to kick in, like just bucks instead of going. Before it had no balls, but at least i could still floor it. It also seems to run way hotter now, though i did also install an h4 conversion setup so bright that the idle drops a bit when i turn the lows on so maybe the gauge reads different now?

 

 

First step was thermostat, so i got a nice one that fails to the open position, drilled a 1/8" hole per another thread i read about, got the air out of the system, and everything seemed fine. I can let it idle and it hovers around 2/3 on the gauge, but if i start driving it around it climbs up to like 3/4 and a little over, but never into the full hot range of the gauge. I wish i had used my IR temp gun before the work so i would know if my gauge/sender were bad, but at this point the thermostat housing reads around 180-195 depending on if i hit above or below the thermostat. The upper hose reads about 180 and the lower about 130 or so, and the radiator itself reads about 180 +/- 5 degrees across the top fins, and about 130 +/- 5 degrees across the bottom so i don't think it is clogged. I put in half vinegar/water and ran it up to temp, let it sit for 30 minutes, and proceeded to flush the bejesus out of it, still no change in behavior in temp really.

 

The belt was a tad loose so i tightened it up quite a bit, no change. It has always had kind of a weird faint marbley or clicky noise at higher rpm's, so maybe that is a sign of craptastic waterpump bearings meaning possible corrosion and poor flow? Maybe that is a detonation noise and it is staying way retarded up high? My lower radiator hose looks good so i don't think it is collapsing or anything. I read this thread for things i may have missed, and I guess the factory shop manual doesn't mention checking the timing at 3k rpm's with the vac advance disconnected, so i'll look into that. Mine is the california ignition setup which is different, if anyone has any advice there.

 

My fan clutch spins basically freely, but it doesn't seem to overheat really at idle. The only place i can find that carries them in stock has a new GMB model for ac, and for without. Mine originally had a/c, but those parts were off when i got it so i might as well get the 2500rpm one for the non ac cars. Going to go grab that right now in my truck and let the car cool down.

 

Sorry for the novel, coming off a 12 hour night shift and i'm more delirious than usual :P Here are oics of the roof rack setup i got going this weekend to satiate those gods.

 

Where the gauge reads and what the temp gun shows:

 

Annnnnd for making it this far here is a pic of my gf trying on a welding helmet that was in the back of my friend's car :rofl:

[banzai510(hainz)]

Was it just by chance the gas gauge reads same as the fuel gauge? If they move the same amount then its a volt reg on the dash instrumentation.

 

the gauge reads to high if 2/3 temp. But Texas has been hot latley. Could be Normal with a old car

 

Even on Hot days my read will get almost to the half way point.

 

IM thinking if you drive it and the 2ndary wasnt opening it could be lean and run hot. if you found the leaves where locking the 2ndary why rebuilt it ? Just clean it.

Bog when pushing the pedal in is mostl likely a Accel pump. Does it squirt gas In the main barrel whn you cycle the linkage?If Not then accel pump diaphrame

 

H4 conversion? You use a H4 harness if not put the stock lamps back in.Could or will fry a connection one day(BELIEVE ME)

If you have a H4 Harness yes its going to lower the rpm that why you adjust the speed screw on the caqrb to get the idle up as your now using the Low 55watt side(h4) of 2 lamps.

 

I dont know to much about the later clutch fan type water pumps. I know they can lock up but that makes them more like the old type pumping water all the time which still functions OK. One way to ck is run it w/o a termostat and see at the rad if water is flowing. maybe drive it w/o state to hee what gauge reads.

 

next I want to see a photo of your girlfriend!

[ggzilla]

Trust the temperature gun. It's not overheating -- it's only 185 degrees.

[ninjabortion]

Was it just by chance the gas gauge reads same as the fuel gauge? If they move the same amount then its a volt reg on the dash instrumentation. -Nah they move independently

 

the gauge reads to high if 2/3 temp. But Texas has been hot latley. Could be Normal with a old car -Very close to being the worst drought in recorded history, and hottest summer for sure already

 

Even on Hot days my read will get almost to the half way point.

 

IM thinking if you drive it and the 2ndary wasnt opening it could be lean and run hot. if you found the leaves where locking the 2ndary why rebuilt it ? Just clean it.

Bog when pushing the pedal in is mostl likely a Accel pump. Does it squirt gas In the main barrel whn you cycle the linkage?If Not then accel pump diaphrame -Took a looooot of disassembly to get the secondary free. Appears to be squirting fine but i'll look into that a little more closely, thanks

 

H4 conversion? You use a H4 harness if not put the stock lamps back in.Could or will fry a connection one day(BELIEVE ME)

If you have a H4 Harness yes its going to lower the rpm that why you adjust the speed screw on the caqrb to get the idle up as your now using the Low 55watt side(h4) of 2 lamps. -Oh yes, h4 conversion is using 12awg wires straight from battery, using relays connected to one of the old sockets.

 

I dont know to much about the later clutch fan type water pumps. I know they can lock up but that makes them more like the old type pumping water all the time which still functions OK. One way to ck is run it w/o a termostat and see at the rad if water is flowing. maybe drive it w/o state to hee what gauge reads. -New fan clutch has lots of resistance, so maybe it will run a little cooler at idle...

 

next I want to see a photo of your girlfriend! -Haha we'll see how bad my car is messing up next time

Trust the temperature gun. It's not overheating -- it's only 185 degrees.

Yeah that's what i'm thinking as well, but the old one was pretty corroded and shitty looking, and hopefully the source of the weird noise at high rpm's. plus i always feel like i can never throw enough cheap parts at a $100 car :P

 

 

got the new pump in and got sidetracked cleaning the front cover, but it looks way better now at least. i went ahead and filled it, but didn't start it because i also reseated the fuel bowl gasket because it had a slight leak. if i parked more than 12 hours or so it would just empty out and i'd have to crank for 5 seconds til the bowl filled up and then it would run fine. i used some stuff called gasket shellac, hoping it will fill it in perfectly. between that and all the cleaners i figure i'll give it a shot later on after they dry by the time i wake up before work and see how it goes, and see if any coolant has leaked at the same time.

 

No idea why the fsm doesn't say to go ahead and remove the radiator. It is 4 bolts and made things a walk in the park. I would have been done in half the time had i not cleaned, but now maybe i can figure out the source of the oil...

 

Thanks for the replies folks, will keep you guys posted with what may or may not have solved it.

[banzai510(hainz)]

I see your missing to right side front cover bolts? These front covers are not totally flat. so best to find soem bolts

 

The head to the front cover are missing 2 bolts also . The ones that go down. maybe they stripped out? usually a 10mm head like the oil pan bolts. just slightly longer.

 

 

By the pump I see the water bypass plugged off. If you still have a heated intake and have a water passage head(with the holes) this will help in winter to keep the carb from frezzing.

 

I have my head plugged up with pipe plugs as sidedrafts dont need them and used the plugg to prevent water leaks.Your case might not matter as you live in texas where its warm.

 

PS make sure to run 50/50 anti freeze as water or bad antifreeze will cavitate a Datsun front cover.

 

I like this wagon. Mayeb get some better wheels and buff it out and slamm it down! DONE!!!!

[datzenmike]

 

By the pump I see the water bypass plugged off. If you still have a heated intake and have a water passage head(with the holes) this will help in winter to keep the carb from frezzing.

 

 

 

Hainz the outlet from the thermostat housing is plugged too this is why. I think he drilled a 1/8" hole in the thermostat but what it really needs is a hose connected between the two.

[ninjabortion]

Yeah this thing was a hot mess when i got it, so i'm still trying to figure out what all is missing. I've got a nice bolt kit with metric stuff all lined up, i'm assuming those are also m6's like everything else on the front cover but we'll see.

 

I'll look into the intake coolant passages, but i dont think it will be below the 40's but maybe a week a year here so i'm in no rush. PO had those ports cut and pinched off terribly, so i went ahead and got some bolts that fit to block it off. I don't have the heater either, and you can see in the one pic it goes straight from the back of the head to the water inlet, with a water hose flush kit attachment in the middle of course :P

 

As soon as i verify that this thing isn't leaking i'm going to flush it one more time and filler up with 50/50ish, but for now i've been flushing this bastard like once a day almost while i've been troubleshooting it haha

 

Believe it or not i chose these wheels on purpose, got em cheapish from a z guy in town and got some nice new tires put on em to call it good. I'd like to drop it right in the front with a gc coilover kit, but as you can see other things have been needing my attention :P

 

This before pic really makes me want to pull the front bumper off. Gf keeps telling me it looks like a shark, and now i kind of believe her.

 

I'd like to think i've done pretty well considering the mess of a project car i started with

[banzai510(hainz)]

I assume if the heater is hooked up correctly it might be cooler temp wise

 

when it comes to wheels I like Rota RBs. Timeless design

[Buzzbomb]

the timing at idle to 12 deg btdc at 750 rpm's per the manual. It has always had kind of a weird faint marbley or clicky noise at higher rpm's, Maybe that is a detonation noise and it is staying way retarded up high?

 

If you are getting detonation, that comes from too far ADVANCED timing at speed. Too far retarded timing can lead to overheating. If you are wondering if it's possible to have retarded timing at speed due to a sticky or non-functional mechanical advance, YES it is. Same goes for a vacuum can that is leaking, although it may not be as apparent. Conventional wisdom in old car circles is to advance it to the point where it pings, and then back off a few degrees. IT works for other old cars, probably works for Datsuns as well.

 

FWIW, the owners manual in my truck (L20B) states that a needle higher on the scale, or over halfway on teh scale, can come from a long haul up a long hill on a hot day OR from "sustained high speed driving". It also states that when it does that, it's best to idle it and the temp should come down. My truck gets to that reading when I run at highway speeds for a while. It never goes over that point and comes down to half or under when it idles. Lots of this is dependent on outside temp. It used to bug me, but I checked the spot where the sensor is with a probe and I get 205 with a 195 thermostat when the needle is at that point. I don't worry about it anymore, and if you're getting 185 or so, I wouldn't worry about it. I'd trust the temp gun.

[ninjabortion]

I assume if the heater is hooked up correctly it might be cooler temp wise

 

when it comes to wheels I like Rota RBs. Timeless design

if the heater is off i wouldn't see it cooling any better thanks to the bypass valve, i have just simplified the process for now since it is 100+ every single day.

 

yeah i like me some rb's too, but these were cheap and i love old school meshies, so i jumped on em.

 

If you are getting detonation, that comes from too far ADVANCED timing at speed. Too far retarded timing can lead to overheating. If you are wondering if it's possible to have retarded timing at speed due to a sticky or non-functional mechanical advance, YES it is. Same goes for a vacuum can that is leaking, although it may not be as apparent. Conventional wisdom in old car circles is to advance it to the point where it pings, and then back off a few degrees. IT works for other old cars, probably works for Datsuns as well.

 

FWIW, the owners manual in my truck (L20B) states that a needle higher on the scale, or over halfway on teh scale, can come from a long haul up a long hill on a hot day OR from "sustained high speed driving". It also states that when it does that, it's best to idle it and the temp should come down. My truck gets to that reading when I run at highway speeds for a while. It never goes over that point and comes down to half or under when it idles. Lots of this is dependent on outside temp. It used to bug me, but I checked the spot where the sensor is with a probe and I get 205 with a 195 thermostat when the needle is at that point. I don't worry about it anymore, and if you're getting 185 or so, I wouldn't worry about it. I'd trust the temp gun.

i'm not entirely sure i am getting detonation. it is just me at home so i can't tell what sort of advance the timing is doing, but i set it at 10ish at idle and can watch it climb up slowly as i open the throttle, will double check actual rpm vs timing when i've got someone around to help me. i found the source of the marbly noise, turns out there was a screw barely loose on the side of the air cleaner that was rattling just a bit up high. i still have the bogging issue if i try to stomp on the gas at low rpm's.

 

yeah i figured the temp gun was the one to check at this point, but figured it wouldn't hurt to go ahead and get a better working fan and a little piece of mind. Thanks for the tip from the owners manual, definitely puts me at ease.

 

The "indian head" gasket shellac worked great and seems to have stopped my fuel bowl leak issue, it started right up after work. Now to figure out why it bogs when i stomp on the gas pedal more than like 50% or so... Still pulls pretty well, about as well as before i rebuilt it, just the secondaries seem to hate me.

 

 

[banzai510(hainz)]

the BOG

Make sure you get a nice squirt/stream of gas shooting in when you cycle the linkage on carb. Should see it in the main barrel.

 

Im not a stock carb expert but seen once on a Weber DGV. the 2nd barrel has a spring to keep it closed. If spring was missing the 2nd barrfel could open up prematurely and cuase a bog or loss of vacuum.

 

Depending on condition on the 2nd barrel diaphrame or spring this couls also be a cause.

Datzenmike or GGzilla would know more on this.

[ninjabortion]

ah i've got the fsm with me here at work, so i'll look into a return spring or something i might not have. the diaphram on the actuator seemed fine luckily, cause the rebuild kit didn't come with one.i took some cool pics with the FLIR we have at work, will post em up in a bit. no real reason, just for funsies haha

[ninjabortion]

Ok so put some decent coolant in it so that is done. Found out my float was a tad low so i put it up within spec. Now instead of just bogging when i give it more than like half throttle it goes for a bit but backfires through the intake once in awhile. That either means leaning out or busty distributor right? I don't have a helper to rev it to 3k to see if the advance is to spec, but i can see it actively start to advance when i give it a little throttle.

 

I'm running the stock points distributor, wondering how much play is too much play...

http://www.youtube.com/watch?v=4g1_aMS5dpQ

 

Anyone have an electric setup they're looking to get rid of? I've been meaning to swap mine out anyway.

 

Edit: Just checked the plugs and the all are white as shit except for #1, which looks great... Mind you these were on it well before i rebuilt the carb, so it is only recently being able to see the secondaries. Trying to work on my shit after a 12 hour graveyard shift is scrambling my brain. I'm supposed to head to the beach this weekend in it, but unless i can get this problem licked i'll have to take my gf's accord like a chump... If shit is broken and i can't get a part i'm fine with that, but i'd rather get my shit tuned up if at all possible :P

[banzai510(hainz)]

thats not a point dizzy. Its a 1st gen EI dizzy.Be honest it looks fine to me. I would adjust the valve lash then look more at the carb.

 

You could disconnect and plug the vac adv hose and run it and see if it runs beeter or gets worse but Be honest those dizzys are fine. Just the box is inside the car somewhere

[ninjabortion]

ah you are correct, i was reading the non cali section saying i had points. i couldn't find any posts saying how much play is ok, thanks for putting my mind at ease there. i'm going to go grab a new set of plugs so i get a new baseline as far as what color they come out...

 

 

 

 

i swapped out the accel pump with another new one i had and was able to retune it to not backfire on me, but it still bogs a little if i mash on the pedal. i swear the other pump i put in was squirting just fine... if i wait until a few thousand rpm's before giving it some throttle it seems to be doing just fine on the secondaries now. is this how these are supposed to act? i've had mechanical secondaries cars act like that, but the ones i've had with vacuum i could just mash the pedal and it would do the rest for me. i swear this little hitachi feels like voodoo compared to the holleys and autolites that i'm used to :P

[ggzilla]

ocassional backfire through the carb could be caused by spark, fuel or timing.

 

Perhaps the most common cause is bad spark plug wires. If it does it at light throttle, but never at moderate or heavy throttle, that's probably it. Test you wires by inpsection, look for cut, burns, white spots and oxidized wire ends. Then measure the resistance, it should be around 1k or 10k per foot. If one wire measures very different from the others (adjusted for length), then replace that wire.

[ninjabortion]

ocassional backfire through the carb could be caused by spark, fuel or timing.

 

Perhaps the most common cause is bad spark plug wires. If it does it at light throttle, but never at moderate or heavy throttle, that's probably it. Test you wires by inpsection, look for cut, burns, white spots and oxidized wire ends. Then measure the resistance, it should be around 1k or 10k per foot. If one wire measures very different from the others (adjusted for length), then replace that wire.

 

The wires are brand spanking new, as is the cap and rotor. I pulled the plugs and tried out the cheaper copper ones on a whim, and they work wayyyy better than the platinum ones for some reason. They're still showing a little bit white, but i think it should be ok for daily driving, just have to treat the thing like it has mechanical secondaries i guess and lay off the go pedal a bit until upper rpm's. BPR6ES at .040(fsm say 039-044 for cali models) is wayyy better than the BPR6EGP at 040 in this case. Good thing i checked the gap on the new ones before install, one of em was smashed in and no cap at all haha

 

 

I've got a crane hi-6 box and an msd blaster coil laying around from my never ending project car, wondering if i should try tossing that on next weekend to squash the ignition once and for all :P

 

That is enough for one delerious car working session after work. You guys rock all kinds of balls. I'm going to take a nap and try to dream that this thing didn't fight me all day, and hope it still runs well enough when i wake to take to the beach.

[banzai510(hainz)]

I dont think the HI 6 box is needed as you would only be masking a proplem.

The Blaster coil is combatible with the stock coil. Guess you can try it but I highly dought that will be it.

 

It me you got 12deg timming which is good.

 

you could ck the cam timming. Maybe soembody has it too far retarded. Ck to see if the cam sprocket V is lined up under the dash. If the v is too far to the right then cam is retarded.

 

But im thinking is just a worn out carb myself.

[ggzilla]

Platinum plugs don't work any better than copper, they just last longer.

 

BPR6EGP is not the factory specification, is it? I wouldn't expect it to work the same as BPR6ES.