Guages.....Help...

[laniadude]

I bought a gauge set from Schucks...but the water temp and oil pressure gauges are mechanical...It's it really important to drain the fluids before installing them?? And do they get the same accuracy as electrics??? or are they the same??? thanks...

[datzenmike]

You certainly don't need to drain the oil. However you will need an adapter to connect it to a Datsun block. A 'T' would be good so you can have the stock low pressure oil light still work in the dash. (not totally necessary though) Anyway Datsun uses a 1/8" BSP British Standard Pipe on the pressure sender so you will need an adapter if there isn't one in the kit.

 

If 1/8"seems small that's because that is the inner diameter of the pipe. The threads are on the outside of that. A 1/8" BSP would measure about 0.3 inch across the threads, which seems about right.

 

I assume the gauge has a plastic or copper tube connecting it to the block? I had one on my '64 Dodge. Don't worry if there's air in the tube and not oil. The oil at the engine end will compress the air and the gauge will still read correctly. Mechanical gauges usually respond faster to pressure changes than electric senders.

 

Don't know about a mechanical water temp gauge .

[banzai510(hainz)]

I would just get the oil pressure gauge

Nothing wrong with the stock Datsun one.

 

PS the 1/8 thread in the kit will be close to go in the block but dont use it get the 1/8 BPT adapter from Autometer or in Renton B&B in the brass adapter section they will have it.

(Dont go to the oil line kits,they will not have it)

 

PS do not use the taiwan oil lines either!!!!!!!Get the Autometer brand plastic line ,if your going to use a plastic line and keep the stock sender in the car

 

use a 90deg bend out from the motor also

[DanielC]

The mechanical temp gauge works just like a pressure gauge. There is a fluid inside the bulb on the end of the line, that expands when it gets hot, and the higher pressure pushes the needle in the gauge higher. The bulb must be inside a water jacket somewhere to work. Sometimes you can find an extra hole on a thermostat housing from a different motor that had a different arrangement of pollution control devices on it.

I agree, the stock gauge works pretty good. I am working on my "combination meter" for my 1970 PL-521. With the key on, and the engine off, if you take the wire for the temp sender on the engine and short it to ground, the temp gauge should go to max hot. Disconnecting the wire, and the gauge will go to cold. A 40 ohm resistor connected between the wire and ground will cause the temp gauge to read in the middle. You can get a pack of five ten ohm resistors at Radio Shack, for 99 cents. Solder four of them together in series, and you have a 40 ohm resistor.

[DanielC]

The oil pressure adapter I used on my 1970 PL-521 is made by Edelmann stock number 265220. It is marked 1/8NPTF x 1/8-28BSP. Plumb your oil gauge with a 1/4 id line and it will react much faster.

[laniadude]

cool...well, the reason why I bought aftermarket gauges(water temp), was because the stock one doesn't work....I have no clue on how to fix this...to explain more on the stock gauge, It moves, but only as far as the 2nd line on the meter( which is less than half an inch from the begining)...I know for a fact that the engine gets hotter than that...so I bought an aftermarket one...lol. The whole reason I am doing this is because this is my first "old" vehicle...not to mention my first 4 speed..The engine revs so high on the freeway, I always think its gonna blow...lol or it's over heating or something...It's scary!!!!lol...but then I've read that it can handle 4k rpms cruising...But I don't do that....Well, I'm close...3500 rpms at 70mph is what I do...or so the speedpmeter says...but anyway, If anyone knows the problem with my stock temp gauge, I'll prbrably use it.... Thank for all the replys and help...I Love this forum...!!!!:lol:

 

BTW, is there an actual need for the warning light for the oil press...Is there not a range to indicate the "red" zone or "green" zone??? Cuz right now, mine stays lit...lol the guy who had it before me took the bulb out..so when I changed the bulbs the other day, it remained lit and still does...:confused:

[banzai510(hainz)]

sand the post on the sender and get a good titie crimp on there.

 

one can get a new sender but most times the housing cracks since its been on there for yrs. Most time a new lower housing is needed and the 16mm ring that holds the sender in there. Or get another from a vansing junkyard that is the same and works.

 

Mayb it odes work. Maybe eater reads only at the line near the T of TEMP. In winter it might even be lower(im not drivin it now)

 

But a card board in front of rad and see if it moves in the UPPER range and then youll know its working somewhat.

[DanielC]

RPM ranges:

The Datsun L-series engine is very strong. When the 1968 Datsun 510 first appeared on the scene, many of these cars were used for racing, WITH A TOTALLY STOCK ENGINE! People spent limited budgets on suspension, first.

The difference between a Datsun L-16 engine and a Datsun L-24 engine (240Z) is two less cylinders. The 240Z had a red line of 7000 RPM, Yellow zone started at 6500 RPM. Since the L-16 engine is shorter, there less stresses on the engine than there are with an inline 6 cylinder engine. I have personally held a L-16 engine at 5000 RPM, in second gear, towing a horse trailer down the Columbia gorge, into a very stiff headwind, for over two hours. Speed around 35 miles per hour, Got around 11! miles per gallon doing that.

The torque peak of a L-16 engine is around 3600 RPM. That is where the engine is most efficient. This is way different from a domestic V-8. Let this engine wind up.

Temp Ranges:

The engine will run cool this time of year, at least in the northern hemisphere. I never had a Datsun overheat pulling a horse trailer. Over 90 degrees, climbing Cabbage hill, East of Pendleton, Or, six percent grade. Two horses in the trailer. Second gear, almost wide open, over 5,000 RPM, About 35 miles per hour. Passing loaded semi trucks. I did turn the heater on, to help remove the heat from the engine.

If your Datsun engine is overheating there is something wrong. I have put a piece of cardboard in front of the radiator to help the engine retain heat this time of year. I also have a "fan" that I cut the blades off of, so now it is just a plastic hub, that I have used in the winter.

Check your temp gauge by shorting the wire to ground, should go to hot, disconnecting the wire, it should go back to cold, and get a 40 ohm resistor, and connect it between the wire and ground. This should make the temp gauge go to normal.

Oil pressure ranges:

If the red oil light is on above an idle, find out why. This light should go off around 5 or 7 psi. That is not enough oil pressure to run your engine above idle, or with any load. My Datsun runs about 70 PSI cold, and drops when the engine warms up, to around 40 or 50 psi at idle, more when the engine is revved up. The oil pressure changes with the engine RPM. Your oil pressure should almost follow exactly what your tachometer is doing. My opinion, you need an oil pressure gauge. lack of oil pressure will destroy the crank and rod bearings of your engine. A rod could break, and destroy your engine block.

If you lost a fan belt, and the engine overheats, the steam coming out of the engine will let you know something is wrong, it may warp the cylinder head, but you could probably salvage the block, crank and rods, and pistons.

Get the oil pressure gauge working. That is most important. I would try to get the stock temp gauge working next, that is also important, but not quite as important as oil pressure.

My next item I would get is a voltmeter. it should read from 13.5 volts to around 14 volts with the engine revved up some.

Get a tachometer. Do not put a heavy load on your Datsun L-16 engine below 2500 RPM. A light load is ok, at these RPMS, but if the engine does not really respond to increasing the throttle at the rpm you are running, you probably need to down shift. Do not rev the engine above 6500, for a long period of time. The Datsun L-16 engine is really happy between 3000 and 5000 RPM. Try to keep it there. You can run slightly lower RPMS if you are lightly loaded, or you are trying to get better fuel mileage.

[laniadude]

Ok....Here's what I have right now.....

 

I have a tach....that's how I know that I run 3500 rpms at 70mph....

I have a voltmeter...It reads around the 14 volt when all lights are off...then when I hit the light switch, it drops to about 12 something....I did a thread on this...I'm in the process of the 90 amp saturn swap...(budget)...

I have a triple gauges set...but only the voltmeter is wired...I don't know how to do the oil pressure and water temp...lol

But I will check the sending unit for the light.....By the way, I have an L-18...or so I was told...Where would I find that info?? Thanks...

[hang_510]

...then when I hit the light switch, it drops to about 12 something....

 

at idle? normal.

rev it past 2000 and it should be around 13.6V (lights on, use high beams too)

[hang_510]

I have an L-18...or so I was told...Where would I find that info??

 

stamped on the block, between/below #3 & #4 sparkplugs

[Jester]

Don't worry if there's air in the tube and not oil. The oil at the engine end will compress the air and the gauge will still read correctly. Mechanical gauges usually respond faster to pressure changes than electric senders.

 

This is an easy one. Just don't tighten down the nut at the back of the guage upon install. When everything else is set, put a towel at the end of the tube and start the car. When the oil gets to the end of the tube, tighten the nut.

 

 

Jester

[laniadude]

Ok I got the oil pressure gauge hooked up...thanks jester for the bleeding trick...But now I stumbled on another problem...When I took off the sending unit for the water temp..(the one with the single yellow wire right???) the fittings that I got with my sunpro gauge kit doesn't match the threading on the thermostat housing..anyone know the measurements for the right fitting??? I bought a fitting kit for a different brand gauge but the probe for my gauge did not fit into the fitting itself...not to mention the kit didn't have the right fitting either...:confused::confused: HELP!!!

[Jester]

Take your factory sensor to the shop were you bought your gauges and have them set you up with the adapters you need. That way you don't have to take your gauges back out.

 

Jester