Choosing oil for cold season ( high miler L series)??

[Rasp933]

Whatsup fellas.

I need advice on what grade of motor oil for my high miler datsun engine in the cooler season.Thanks

[Rasp933]

Seems like its having hard time pumping 10w40 on cold start 

Edited October 6, 2018 by Rasp933

[nl320what]

Something is wrong as 10-40wt is easily rated for less than 0 temps, we are in Cali so it doesnt get below 30degF ever.

 

Oil Filter or passage blocked, bad oil pump, oil pickup/tube blocked, its being restricted when its at its highest viscosity.

 

If all these look ok, try running AutoRX additive to clean the internals out.

[datzenmike]

How are you determining that the oil is having a hard time pumping?

 

If you drive every day there will be more than enough oil still on parts when started. Most oil pressure gauges are electric and if like the ones on the 720 are 8 to 10 seconds behind the actual pressure. If you have the type with the oil line to the block, they pretty much read instantly. You'll see that on the engine side of the filter it jumps up within a second or two and there's nothing to worry about.

 

I run 15w40 Rotella T4 and have driven it for one winter season in snowy conditions dipping just below freezing without any noticeable difference. I do have a gear reduction starter though and a KA high volume oil pump which I highly recommend. Over all running pressures are the same 55-60, but idle and low revs is much higher than the L series pump. My old L20B hot idled at 17 PSI, with no other change than replacing with a wrecking yard KA24E oil pump, it hot idled at 29.

 

I believe Rotella comes in slightly thinner 10w30 T4.

 

 

 

[Rasp933]

In cold start.I hear noise from under valve cover for like 5-10 secs ,so I figured the oil is having hardtime traveling up to the lifters.

Since I just did valve adjustments not to long ago

[Rasp933]

5w30 synthetic oil any good for the situation??

[datzenmike]

5w is for newer cars, It's much thinner and gives better mileage. It's not good for a Datsun above 0 F. I would never run it.

 

Again what is making you think the oil is too thick? You're in California and a thousand miles farther south than me. The average low in Dec and Jan in Modesto is 40F.

 

The coldest day on record for Oct 6th was in 1969. It was 42F.

 

Right now it's 78F

[DanielC]

A Datsun L-16, L-18, or L-20-B does not have hydraulic lifters.  They are adjustable, and must be adjusted for the correct clearance between the heel (low side) of the camshaft lobe, and the pad on the rocker arm, .010 intake, .012 Exhaust, with the engine hot.  Oil pressure does not change valve clearance.  The cam chain tensioner is spring loaded, with an oil pressure assist.  That is the initial noise you hear when first starting the engine.

 

According to the factory service manual, a 30 weight oil is good from 32 degrees F to about 90 degrees F.

The service recommends a 5W-30 oil below a high temperature of 25 degrees F AND COLDER.   In other words, where Datzenmike lives, A 5W-30 oil is still too thin.  If you do not know where DatzenMike lives, he is on Vancouver Island, in Canada.

 

I use 30 weight Valvoline VR-1 racing oil in my Datsuns.  Old engines need old engine oils, with a high level of ZDDP, an anti scuff additive in them.

[Rasp933]

5 hours ago, datzenmike said:

5w is for newer cars, It's much thinner and gives better mileage. It's not good for a Datsun above 0 F. I would never run it.

 

Again what is making you think the oil is too thick? You're in California and a thousand miles farther south than me. The average low in Dec and Jan in Modesto is 40F.

 

The coldest day on record for Oct 6th was in 1969. It was 42F.

 

Right now it's 78F

Ok I got the noise under control.

What I did was I checked the timing. its around 12degs.

Then I opened the fuel mixture screw 1/4 more turn out.

I closed the speed screw say about 2/8 turnd in.engine started to run smooth.98 % of dieselling gone.I even check oil pressure,its around 22psi at idle,

That funny noise coming from under the valve cover is gone..

So my guess is ,my intial adjustments were too lean for the engine causing it to make noises,which had me confused so I started looking at oil,oil pump etc etc.not realizing that the real problem was my carb was way out of tune.

 

Edited October 7, 2018 by Rasp933

[datzenmike]

Rich or lean does not make an engine make noise on cold start up. That would be valve lash or worn timing chain. In some cases very worn rod bearings will chatter on start up. (again the KA pump will help with an older engine)

 

Is this the stock carb?

[Rasp933]

38 /38-weber

[datzenmike]

Right, the dieseling.

[Rasp933]

43 minutes ago, datzenmike said:

Right, the dieseling.

The dieselling is gone .98%is gone.I closed to speed screw aliitle and opened up fuel screw

[nl320what]

Mike is right, at cold start up you have either really loose valve lash clearances, loose chain, and or oil starvation still.

 

You are just masking it by adjusting something else like lowering idle so its not pronounced.

 

At cold startup, all these items can cause your noisy top-end.

[datzenmike]

Set the lash HOT and maybe shave a couple of thou off the factory recommendation, but if you do, keep a close eye on it. Tight lash is to be avoided. The chain... there isn't much you can do but replace it and especially the plastic covered guides. Particularly the slack side. Loose chain and worn plastic = rattle.

 

Take the valve cover off and look on the tension side where the front thermostat housing mounting bolt comes through. It may have been replaced mistakenly with a longer than needed bolt and is riding on or too near the outer side of the timing chain. It's a long shot but an easy fix.

 

 

[banzai510(hainz)]

I do mine .006 and .008 cold

 

good you got it it figured out. personally I would daily drive a nice 510. Buy a beater 510 /or L motor truck to drive and fix and learn about.

buy a good oil filter like Napa(wix) also  Nissan would be better.

 

Edited October 10, 2018 by banzai510(hainz)