Water temperature fluctuating again

[datzenmike]

Well this applies to all  L series engines. The L20B especially... it's crank is fully counter weighted and good to well in excess of 7K

[josh817]

So for the belt issue, I'm looking at taking KA24 pullies. I haven't head found hard measurements but it's looking like the KA24 front crank snout is smaller than the L20B? The water pumps are different but this pulley bolt pattern appears to be the same. The alternator I can simply upgrade.

 

So, if machining the ID of the front pulley is all that is required, do you suppose this is a viable method of getting a serpentine belt?

 

 

 

Also to avoid the shuttering of the engine on cold days, which causes the belt to initially start to squeal, and also to reduce running full choke for 15-20 minutes of driving until the motor is really warmed up, I'm considering putting a high idle valve on the manifold.

 

1st gen 240Z's had them for the first shipment to the states until they promptly removed them, foreseeing a legal nightmare in the future. It was a lever which I believe pulled on the gas pedal and allowed you to increase the engine speed for quicker warmup without fowling the plugs from full choke (which I have done, idling for 10 minutes in the driveway trying to warm up while I'm getting my shit ready). Instead of opening the throttle, I'd rather have a vacuum bleed.

 

Honestly though, the belt is the root cause of the problem. Increasing the idle speed does reduce the frequency of the belt squealing when I pull away from the light but at this point if I have wipers, blower, headlights, and turn signal going at the same time, the belt will squeal every time I pull away if it isn't already going at idle with all the shit running.

 

I still want a fast idle for these cold days. The Weber DGV has fast idle but it doesn't engage until your choke is all the way closed.

[DanielC]

If the belt is squealing, the belt might need to be a little bit tighter.  

A Datsun engine likes to warm up a bit.  No need for all the electrical accessories to be on for this.  If the engine is cold, the transmission is too.  Push the clutch pedal in when cranking, and starting.   After running for about 30 seconds the engine should be able to warm up with the clutch pedal out.

 

On most carburetors, you typically bend a link between the manual choke linkage, and the throttle shaft to add or subtract more or less throttle for a given amount of choke.

 

Datsun engine are cold blooded.  They like getting warm air off the exhaust manifold when it is cold.  Some people disconnect, or disable the water or exhaust manifold heat to the intake manifold.  This is not a good idea in the winter.  Have a good thermostat in the engine also.   I know it is uncomfortable when it is cold, but turn off the hot water to the heater, to let the engine warn up quicker. 

[datzenmike]

Perhaps a good quality brand name Vee belt is needed. Like over $10.

You're over thinking this. I've had lots of Datsuns and the belts don't squeal. Get a quality belt and tighten properly and you are good to go.

[josh817]

Indeed I agree with both of you. That fluctuating temp this thread was initially about is a bad thermostat in it now. Currently it gets stuck half open so when the headlights are on it warms up a little over the mid-line. If I stop and give the thermostat housing a gentle tap with wrench, you can feel the upper hose get hot again.

 

I don't know the head code for L4's but I'm running the L20B head, no water heat, don't want water heat. Don't want to risk leaking into the intake at the gasket.

 

Tranny lately has been rough shifting until it warms up, like you said. I presume it warms up fast because you're applying that pressure plate force onto the thrust bearing, which is why I typically don't sit on the clutch.

 

Among other things, I have noticed the front cover gasket is taking a shit. Grimey mess in there that's probably getting on the belt every once and a while.

 

I agree with you; I will certainly do the belt before I go any further. My 240 never gave me such problems.

 

 

Poor truck just needs some TLC. Lots of silly little problems that I'm having to just deal with between classes and work. She will get a break from the road in a few months.

[DanielC]

Sorry, a little tough love.

Indeed I agree with both of you. That fluctuating temp this thread was initially about is a bad thermostat in it now. Currently it gets stuck half open so when the headlights are on it warms up a little over the mid-line. If I stop and give the thermostat housing a gentle tap with wrench, you can feel the upper hose get hot again.

Change the thermostat.   Do not write or talk about, CHANGE IT! 

The headlights have nothing to do with the thermostat  The thermostat is simply a mechanical device that opens when it feels hot water under itself, and closes when the water is cold. 

You possibly have a ground problem.  There is a dedicated wire from the headlights to the voltage regulator.  There is also a dedicated wire from the alternator frame to the voltage regulator t

 

I don't know the head code for L4's but I'm running the L20B head, no water heat, don't want water heat. Don't want to risk leaking into the intake at the gasket.

Millions of Datsun L-engines used water manifold heat to vaporize the fuel coming from the carb.  Without intake manifold heat, liquid gasoline puddles in the intake manifold, and only goes into a cylinder at high RPMs.  At low RPM, the engine runs lean, because the gas is not making it into the cylinder, and at high RPMS, the excess gas make the mixture too rich, or worse, the liquid gasoline washes oil off the cylinder walls, and dilutes the oil in the crankcase.  This problem is even worse without hot air from the exhaust manifold into the carb intake.  Cold air, and no intake manifold heat can also lead to the carb actually icing up.

 

Tranny lately has been rough shifting until it warms up, like you said. I presume it warms up fast because you're applying that pressure plate force onto the thrust bearing, which is why I typically don't sit on the clutch.

When was the last time you checked the clutch slave cylinder adjustment.  Adjusting the clutch slave may cure this problem.  Pressure from the throwout bearing does not make the engine warm up faster.  The oil and water are pretty much separated by a cold engine block, and cylinder head.  And without water circulating in the intake manifold, the oil is a long way from warming the intake manifold.

 

Among other things, I have noticed the front cover gasket is taking a shit. Grimey mess in there that's probably getting on the belt every once and a while.

My 521 has a bad front cover seal, and leaks oil.  The belt does have oil on it.   My belt does not squeal with the headlights, heater, and wiper on.

 

I agree with you; I will certainly do the belt before I go any further. My 240 never gave me such problems.

Your 240Z has a bigger alternator, and drags the battery down more when it is cranked.  There should be a tendency for it to squeak the belt more than the 521.

 

Poor truck just needs some TLC. Lots of silly little problems that I'm having to just deal with between classes and work. She will get a break from the road in a few months.  I believe most schools are on winter break until Monday, Jan 5.  45 year old Datsuns needed maintenance every 3000 miles.  This is something you accept when you choose to drive one.  Your new years resolution, give your 521 some attention. 

 

Now, get busy.

 

[datzenmike]

Sorry, a little tough love.

Indeed I agree with both of you. That fluctuating temp this thread was initially about is a bad thermostat in it now. Currently it gets stuck half open so when the headlights are on it warms up a little over the mid-line. If I stop and give the thermostat housing a gentle tap with wrench, you can feel the upper hose get hot again.

Change the thermostat.   Do not write or talk about, CHANGE IT! 

The headlights have nothing to do with the thermostat  The thermostat is simply a mechanical device that opens when it feels hot water under itself, and closes when the water is cold. 

You possibly have a ground problem.  There is a dedicated wire from the headlights to the voltage regulator.  There is also a dedicated wire from the alternator frame to the voltage regulator t

 

I don't know the head code for L4's but I'm running the L20B head, no water heat, don't want water heat. Don't want to risk leaking into the intake at the gasket.

Millions of Datsun L-engines used water manifold heat to vaporize the fuel coming from the carb.  Without intake manifold heat, liquid gasoline puddles in the intake manifold, and only goes into a cylinder at high RPMs.  At low RPM, the engine runs lean, because the gas is not making it into the cylinder, and at high RPMS, the excess gas make the mixture too rich, or worse, the liquid gasoline washes oil off the cylinder walls, and dilutes the oil in the crankcase.  This problem is even worse without hot air from the exhaust manifold into the carb intake.  Cold air, and no intake manifold heat can also lead to the carb actually icing up.

 

Tranny lately has been rough shifting until it warms up, like you said. I presume it warms up fast because you're applying that pressure plate force onto the thrust bearing, which is why I typically don't sit on the clutch.

When was the last time you checked the clutch slave cylinder adjustment.  Adjusting the clutch slave may cure this problem.  Pressure from the throwout bearing does not make the engine warm up faster.  The oil and water are pretty much separated by a cold engine block, and cylinder head.  And without water circulating in the intake manifold, the oil is a long way from warming the intake manifold.

 

Among other things, I have noticed the front cover gasket is taking a shit. Grimey mess in there that's probably getting on the belt every once and a while.

My 521 has a bad front cover seal, and leaks oil.  The belt does have oil on it.   My belt does not squeal with the headlights, heater, and wiper on.

 

I agree with you; I will certainly do the belt before I go any further. My 240 never gave me such problems.

Your 240Z has a bigger alternator, and drags the battery down more when it is cranked.  There should be a tendency for it to squeak the belt more than the 521.

 

Poor truck just needs some TLC. Lots of silly little problems that I'm having to just deal with between classes and work. She will get a break from the road in a few months.  I believe most schools are on winter break until Monday, Jan 5.  45 year old Datsuns needed maintenance every 3000 miles.  This is something you accept when you choose to drive one.  Your new years resolution, give your 521 some attention. 

 

Now, get busy.

 

Yes too much talk, do it.

[banzai510(hainz)]

tighen the front cover boots.

change the stat. maybe 2 months ago would have been good. Use antiseize on the bolts

 

ck the oil in the trans.

 

Datsun require constance mani as these are old.

 

I just swapped out another O rileys cheap Maylasian starter for my 521 (1.5 years). Im tired of doing it also but I do it.

The O Rileys lady says you have a liefetime warrentee. I said, it dont work out in thw woods!!!!!!!!

[josh817]

Sorry guys. Do realize that with a limited budget and time (yes I do work full time along withs school) I want all my ducks in a row before going through with it.

 

That being said, Daniel... I mentioned that I do not have the head with the water ports. I can hook up water to the manifold easy, will it work as it should since there won't be circulation? Think I should just hook it up as is or should I go ahea and get and do the manifold gasket to prevent leaks? This manifold came off of a field truck so I'm not sure if the water passages will be clogged up with mud and all that jive.

[datzenmike]

Only the U67 head didn't have the holes in it that matched the coolant passages in the intake.  Easy enough to use a 1/4" drill and open them up. All intakes have the coolant passages except the one that came with the U67 head. This intake is bolted to the exhaust manifold.. the only ones to do so. I don't know what you have, you'll have to look. If you have replaced your intake and it has coolant passages it will run best if actually working. The outlet from the intake is just below the front of the carb and connects to a Y in the pipe that goes down across the front of the engine to the lower rad hose entry into the timing cover. The other arm of the Y goes to the thermostat housing for the bypass.

[josh817]

Found what looks to be the metal bypass rail for the water from the bottom of the thermostat, manifold, to water pump off the old L16. Also found the L16 front pulley.

 

This means I still haven't fixed the problem. Fixed the squealing belt by tightening her up. Hooked a braided ground strap from the alternator to the block.

 

Here's something that will through a wrench in your wheels. I noticed I was missing a screw on one side of my oil pressure gauge (connected to block via copper tube, has a instrument light in the back). I see it wiggling so I press and hold it up. Blower motor spins faster, lights brighten, water temp gauge starts dropping to the middle line within 10 seconds. I let go, blower motor slows, lights dim, temp increases.

 

I will put another screw in to get the gauge but the question now becomes, why is everything getting improved ground through the gauge when I have the battery to the starter mount, the alternator to the block, grounds on all the lights, and a metal choke cable from the dash to the carb?

 

I've heard of this before in British cars, bad grounds so they ground through the choke cable making it untouchably hot.

 

 

 

 

Just thought I would update you guys.

 

Thanks,

Josh

[banzai510(hainz)]

reseat the instrument panel connector.

maybe cleaning the fuse box might help also.

 

the temp gauge most like would move also with the temp gauge

[DanielC]

These grounds are needed with a 521.   There are more that I do not know about, yet.

Battery negative post to bolt on lifting lug by fuel pump.  That lug has a pigtail that goes down to the alternator frame.

The alternator frame has a second ground wire that goes to the voltage regulator.  If you change to an internally regulated alternator, this wire must still be grounded to the inner fender.  There is a second black wire at the voltage regulator.  This grounds the headlights.  I believe it may also go into the cab, and ground the instrument panel.

 

Those are stock.  I add a ground wire, looping from the engine side to the frame side of one motor mount.

 

Adding a ground wire from the tail light frame to the frame of the truck will go a long way to eliminating problems with the taillights