hey guys
im running a L18 with a single weber - it doesnt get alot of running - start it and run for 15 minutes once a week. the head seems to get hot very quickly - like after 10 minutes its too hot to hold your hand on for 5 seconds. i may be a bit dim and this is normal (pls let me know if it is) but just wondering how to measure engine temp (guage is buggered) and what it should be running at?

ta

If your temp. gauge is a non-event, you should really fix him or (my advise) replace it with a mechanical type gauge.
Providing everthing else is OK. the thermostat should regulate the engine temp. at 82degC (180degF).
This of course only applies if the thermo is operating correctly and is rated at 82deg. as specified in the Service Manual.
As a quick check, you could buy an el cheapo digital thermometer from D!ck Smith or such and attach the sensor to the thermo housing to see what gives.
Don't run the engine without a thermostat and added insurance is to use Nissan Long Life coolant to reduce corrosion.

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

you, i agree . my engine was reaally getting hot so i put in an machanical temp gauge and yup , my engine was boiling. Why ? up side down thermo stat . the gauge works great to let me know my temp exactly . GOOD LUCK

Why? Besides the engine never really reaching operating temp, is their a realy disadvantage to not having a thermo?

Its just that I suspect (actually, pretty sure) my L20 doesnt have a thermo and after a fairly long drive (1/2 hour or 45 mins), my head gets pretty bloody hot. Like you cant keep ypur hand on it for longer than 10 seconds?

No Thermostat would make the motor run cooler if anything right?

Well, the theory is that without a thermostat, longer warmup is experienced (I think that is reasonably easy to understand since the water pump will circulate the coolant at max. capacity from startup), and hotter running will result since the coolant doesn't spend enough time in the radiator to shed any heat to the atmosphere.
Believe it or not.
Of course the old adage applies, "if the manufacturer didn't think it useful they wouldn't fit it".
The thermo. regulates temperature and more importantly, coolant flow, to stabilise the operating conditions.

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Spot on there, Graham! If you don't want to run a thermostat (for whatever reason), you'll still need a restrictor to slow the flow of coolant through the radiator so that excess heat can be "radiated".

I've had a "thermally unstable" engine. The temp went up with engine revs. The reason? No thermostat. No sh*t.

Cheers,

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Chris [;-{)>

An other problem associated with not running a thermostat can be water pump cavitation because as already stated the thermostat acts as a restrictor (flow regulator)

It makes sence now but never really thought of that. I always thought that it would be runnning way cool if anything. But my temp gauge is never more than 1 cm from C (cold)? Faulty gauge?

But if I were to install a thermo, does anyone think that I would encounter problems later on down the track........

If what you say is correct i.e. you have no thermo. and the gauge indicates C, then you already have a problem.
Just try using a cheap/simple digital thermometer attached to the thermo. housing to spot check your temp.
I have grown to hate relying on electrical gauges when chasing cooling problems. If the gauge, sender or voltage regulator in the instrument cluster are iffy, you'll see fluctuating readings on fuel, temp. and oil gauges which doesn't help at all
It may be that the previous owner removed the thermo. to mask a clogged radiator or some other problem
At ay rate, in my opinion, the system needs an inspection by a Cooling Specialist to determine WTF

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Yeah. The Temp gauge is pretty dodge as it hardely ever moves. The fuel gauge is pretty dodgy in that its inaccurate but still has some Idea as to the amount of fuel left.

I'll prolly be taking it to a cooling specialist soon when I get the tune up.

Cheers

so if both my fuel and water temp gauges sometimes fluxuate very noticibly....then what would be the problem?
also since re-building my car and putting in my L20B....my fuel gauge doesn't go as low as it used to before running out of gas....hence I've actually run out of gas a few times now because I think theres more in there than there actually is....any ideas...or atrenatives/fixes

My Temp. gauge used to get to H on LH turns and go to C on RH turns.
The fuel gauge wouldn't be too bad but they both get their battery source from an agricultural voltage regulator fitted "somewhere" behind/in the instrument cluster.
I think this device feeds the gauges a reduced voltage of ~8V.
I would suggest talking to an instrument repairer, it may be replaceable.
As for an optomistic fuel gauge, you can pull the sender from the tank and bend the float arm to correct the error.
Don't ask why it has suddenly started reading high
It is far better to read low or accurately for that matter.
Bend it up to make the gauge read lower.
Having been down this road many years ago, I decided to fit mechanical (direct reading) gauges for Oil Pressure and Coolant Temperature.
I barely notice any Fuel gauge fluctuation now.

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Another thing worth checking is your mixtures. A lean burn will increase the engine temperature.

I've seen incorrectly jetted Webers get the exhaust system glowing after about 15 minutes of idling....

You should also check your timing - this will affect your engine temperature too (too retarded will shed lots of combustion heat into the block).

_________________
Ben
Adelaide,
South Australia
L28ET 240Z
RB25DET WGNC34 Stagea RS-FourV

My engine (L20B, with S2 BBird rad and thermal fan) tend to run hot in traffic. Would it help if I put in a lower temp thermostat ?

yeah...I have a mechanical Oils Pressure....but the stock one ( the light ) is still hooked up too
how does a mchanical water temp work?
my temp isn't a problem...it just sometimes moves up and down on the gauge.

I put a 72 degree thermostat in mine.....and it keeps the temp down....it NEVER goes aboves the line on the gauge ( the one on the left of the center )