Anti-Drain tube back necessity

[Linda]

You can make the tube with an aluminum tube cut to fit, and I think with the shorter filters, same thing.
Home Depot maybe, or Ebay for sure has aluminum tubing.
Just need a measurement.
Linda

[JT68]

Yep shorter tube for shorter filters is fine, but as Curtis pointed out, it needs to be a snug fit in the housing. If oil can leak past the joint, it will. A light press fit is good. Obviously you don't want a very thick walled tube with a small I.d.

[Curtis]

I was taught to assemble engines with a 50-50 mix of Power Punch and oil. I also do the oil pump spin with the Datsun. I suppose as you say it is a good idea with an engine that has been idle too. I have also put oil in through the spark plug holes.

[19692000survivor]

Thanks to all who chimed in on third oil filter tube I plan to install the tube on my U20’s oil change. Anyone noticed a reduction of valve train noise on start up and or any change in oil pressure or anything else after installing the tube? Lastly what filter are you guys using who run the tube? Thanks again for your input. Rick

[Nissanman]

On my SP310 I use the Ryco cartridge element that comes with the required rubber seals which you should replace when fitting a new filter: -







Part R2154P
Inside diameter Top 33.00 mm
Outside diameter Top 73.00 mm
Inside diameter Bottom 33.00 mm
Outside diameter Bottom 73.00 mm
Height Overall 135.00 mm

Still used in a variety of 4WD Nissans and even has the Nissan burger logo printed on it!
NOTE
It is imperative that ALL the bits pictured earlier for the cartridge filter are installed and in correct sequence or the oil filter will not function correctly, if at all

[Curtis]

You can make the tube with an aluminum tube cut to fit, and I think with the shorter filters, same thing.
Home Depot maybe, or Ebay for sure has aluminum tubing.
Just need a measurement.
Linda

The problem is it is 9/16" O.D., not easy to find.

[Nissanman]

From memory, the end is turned down to make a snug fit into the filter base.

[JT68]

Correct, we make them on a lathe from SS tubing rather than AL, but its not a part we typically sell.

[Gregs672000]

The question was asked if having the tube will reduce valve train noise... yes, on start up the valve clatter should clear out much faster. When I ran the Mobile One filter which does not allow the tube to be used it rattled like crazy until the filter was full... the filter anti-drain back valve did not do the trick. I also strongly recommend shimming the chain tensioner. Until oil pressure is up the chain will rattle and mechanical timing (cam to crank) jumps all over the place.

[GeoffM]

The question was asked if having the tube will reduce valve train noise... yes, on start up the valve clatter should clear out much faster. When I ran the Mobile One filter which does not allow the tube to be used it rattled like crazy until the filter was full... the filter anti-drain back valve did not do the trick. I also strongly recommend shimming the chain tensioner. Until oil pressure is up the chain will rattle and mechanical timing (cam to crank) jumps all over the place.

Hey Greg, I'm just wondering if we are perpetuating myth based on our own anecdotes and psudo-engineering based assumptions. Here's a question to think about... How is the tube preventing oil from draining back through the oil pump and back to the sump? It's on the discharge port.
Not a personal attack at all! I'd love to get to the bottom of this as I don't think anyone has really thought through the physics behind it. I have done my share of modeling fluid systems so this is kinda near and dear to my heart...just for curiosity.

[19692000survivor]

Geoff I was wondering the same thing but didn’t want to beat this horse any longer without trying it. I also have a Jeep CJ 258 six that has to have a Wix which has the anti drain back designed in for the same reasons as the U20. I can tell the difference in startup on both when I have run other filters- just common cents - you want a full filter on s/u. My U20 with a Wix rattles on start up for a count to “2 “. I know it’s gonna do it and even if it sits for a few days - same deal. The engine oils great and I have pulled the cam cover after not running it for a while and the rockers & cam are coated not soaked but not dry either. We all hate the rattle but is it more a problem with the chain not lubed entirely until it rotates though the oil in the bottom making the rattle until fully coated on start up ? I am tempted to pull the cover and pour oil over the chain to see if it still rattles to my count to “2” on start up just for fun. I am still going to put a tube in to see if it reduces su rattle but if I don’t improve on my rattle to count to 2 I probably won’t keep it in long term unless Datsun said it belongs there and can explain why as I don’t want to reduce or interrupt my flow through the filtering process. I do think some hard data on pros or cons of tube or no tube would help. Maybe the engine builders here have that?

[JT68]

The ADBV seals off the lower ports. Since the lower ports are sealed, the filter stays full to the top of the tube. Its simple physics.

If you fill a glass with water, seal the top with your hand and turn it over, it will stay totally full.

If you do the same experiment, with a straw through your fingers and into the glass, the water will drain exactly to the top of the straw.

The assumptions are that the ADBV (and your hand) forms a reasonable seal and the tube is also reasonably sealed. If not, the fluid will slowly leak out. I don't see any pseudo engineering.

At the same time, no one needs to get all upset about it, as mentioned previously, all your bearing surfaces have a film of oil on them, so your engine isn't going to self destruct immediately if you don't have the tube. All it does is help keep more oil in the system.

[Curtis]

Well,I look at it this way. Every engine I've taken apart no matter how long it has been sitting is oily and greasy everywhere including all bearing surfaces. Just took apart an engine that has been sitting for probably 35 to 40 years and had to clean oil off all the crank and rods surfaces like it had just run the day before and no tube in the filter.

If you look at the online parts manual the tube is shown in the cartridge filter drawing but not the spin on drawing. It lists the safety valve. Go figure since I know some of the spin on's have the tube.

http://www.carpartsmanual.com/datsun/sp ... oil-filter

http://www.carpartsmanual.com/datsun/sp ... l-filter#2

[JT68]

So, respectfully, carparts manual is not the definitive roadster parts source - highly incomplete. We know they came on many late engines at least from taking apart many dead roadster engines.

With respect to wear, and this is based on probably 50 G,H,R and U engines, bottom end wear is all over the map pristine-to-trainwreck. I would not try to equate that with presence/no presence of the tube...more likely oil quality and maintenance intervals (and how hard it's driven).

If lubrication related wear was a total non-issue, we'd never need to turn cranks or bore cylinders. There are plenty of roadster engines around with lubrication related damage.

I look at it as a penny wise/pound foolish situation. If the tube costs you 10-$25 bucks to source, but saves you from having to turn a vintage crankshaft a couple years from now, that is money well spent. Yes, you can run $3 dollar/quart oil too, probably not the best idea in the long run. Remember, there is about .001" of crankshaft wear that determines whether a crank is usable or requires turning or is scrap.

Honestly, its probably a bigger deal for the U20 camshaft and rockers. That is what will be starved the most from delayed oil pressure/dry rotation. As Curtis pointed out, cranks will typically have a reasonable oil film.

On the other hand R's are famous for throwing the #2 or 3 rod, those bearings can use all the help they can get in the long run.

So you decide..I don't know of any real disadvantage to including the tube and U20 camshafts are cheap? Right?

[Curtis]

Yep, all the different manuals will drive you nuts.

I've been lucky on the thrown rods so far. Never owned a U20 and never will so I plead ignorance.

I do plan to look at the oiling recommendations for my next engine for the crank.