Using super thin oil to start rebuilt engine to prevent filter bypass?

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Cheap 5w30 or 10w30 and a motorcraft FL1A.

Change it after 100 miles.

There's a screen over the oil pickup. It'll catch the rocks. The rest of the drama will lay suspended in the pan's oil until you drain it.

Don't spray brake cleaner where it can get in the oil pan. It's anti-oil. It breaks it down. That's its job. Even if most of it evaporates off it'll do some damage.

I've done head gaskets where I leave the manifolds attached and just reach in the 3/4 inch gap to haphazardly clean what I can. Barely wiggle the new gasket over the locating dowels. Works out fine.
 
Originally Posted by Astro14
In general, if I'm doing a cylinder head - I scrupulously avoid the use of anything abrasive. Abrasive particles in the cylinder bores, or running through the oiling system would be terrible. I scrape, with a razor blade, use a shop vac, and have very possible path for debris blocked with towels or shop rags. When done, it's cleaned with compressed air to get any debris that got past the rags. Bits of head gasket aren't that hard - I don't think they would score a cylinder wall. But carbon, bits of steel, etc. might.

How would the debris get into the oil pan? Did you have the passages blocked/plugged, too? Stuff on top of the rings/pistons is going to be on the cylinder walls until combustion blows it out.


I love this forum! There's so much to respond to I'll just go one at a time. So, Astro14, look at the original picture I posted, next to the pistons there are other openings where the lifters sit about 4 inches lower than the deck surface. Debris in that galley will be washed into the pan. And I was more nervous because I cleaned my piston tops too and I hear that carbon is quite abrasive. So it wasn't just the gasket material I was worried about. I had rags stuffed in the galley, but thinking back, I probably should have put tape over it while I cleaned the pistons.
 
Originally Posted by oil_film_movies
Originally Posted by willistheguy
Now it is my understanding that when the oil is cold, the engine's oil filter bypass can be activated because the oil is still thick.
At the temperature you'll be doing this at, let's assume it's 50 degF, a 5w20 or 5w30 conventional will be fine to not pop the bypass valve. I saw the worst filter at a colder 32 degF out of a group flowed 1.8 GPM at a differential pressure of 15 psi (bypass for a lot of filters) using a conventional 5w30 oil.
Your engine will probably start flowing no more than 2 gpm at start-up, and if you're at a warmer temperature in you garage or shop than 32 degF most likely, very doubtful your oil filter would go into bypass.

Also, coat the cylinder walls with a very thin coat of motor oil. Before you put the head back on. Not much, just smear on some near the piston-cylinder-wall boundary.
Fill the oil filter up before installing a new one.


Your above comment about the filter NOT bypassing in these conditions is supported by the study in the link that Linctex posted above (I think). Yes, it will be at or above 50degF, nothing dramatic. Another note, if you look at the picture I posted, you can see I already coated the cylinder walls with oil (there's some residual on the piston tops). The head is already installed now.
 
Originally Posted by SnowDrifter
Originally Posted by oil_film_movies
Originally Posted by Chris142
Dont forget to put the PH8A size filter on it. More surface so the bypass may not open as soon?
An oversize filter does reduce bypass events. An XG8A fram ultra, if that is the oversized pick, would be the best to get the lowest differential pressure at start-up.

I disagree. The filter's bypass is based on a pressure differential over the media, which is based on viscosity, flow rate, and the media's resistance to flow. Add more media - more surface area, and there's a lower pressure delta.

As to OP, I think you're overthinking this way too hard.

Thing 1. Just because a filter goes into bypass doesn't mean it's not filtering any oil. It just means that some of it isn't being filtered.

Thing 2. Pop off the distributor and drive the oil pump with a drill for a few minutes. That'll cycle the oil through the engine, including the filter, removing the debris you're concerned about.

Thing 3. You can clean the lifter galley with some brake parts cleaner to flush everything into the pan. Make sure to follow up with a few squirts of oil. From there, it'll go through the filter before the rest of the oiling system. Just give enough time for the VOCs to evaporate before adding oil and starting the engine. If this is really a major concern for you, it might be worth your time to drop the pan and clean it, if only for peace of mind.

Thing 4. I'd be more concerned about coolant contamination in the oil than anything. Start it up for a few minutes, change oil. Start it up for another few minutes, change oil again. Done.

Thing 5. Theory vs. practice. In practice, your concerns don't appear to be reflected in the lifespan of engines that have had similar repairs done. There are many a 4.0 that's had a head gasket replaced and continue to run for thousands upon thousands of miles.


Overthinking an oil topic?!?! Yes, that sounds like me!
laugh.gif
My responses to your things below:

1-Why not do something that makes it so ALL the oil is filtered immediately? My original question still stands.

2-This isn't a full rebuild so I probably won't take the time to do that, but I will crank the engine with the ignition disabled for a while.

3-I'll let you into a secret , I already DID spray brake clean into the lifter galley and then followed it up with oil, the whole time with it draining out the drain plug. I just didn't want this discussion to be about that method. Pan doesn't leak so I'm not going to take the time to drop it (I get very little time to work on it, this does not make me less curious about oil questions though).

4-Because this is a straight six, no coolant got into the oil (deck surface is parallel to ground). With the coolant drained on these engines, nothing comes out when you remove the head. So all good there.

5-Yeahhh that's true I'm sure. BUT, maybe all of them didn't clean the pistons like I did (lots of carbon debris), and maybe I happened to get more dirt in there than others. I know that the most common reason engines fail is because of dirt, and I've heard so many stories of people working on engines and then toasting the bearings right after. My original question WAS theoretical, so my specific situation aside, I still want to search for an answer.

Thanks for your post SnowDrifter!
 
Originally Posted by DGXR
Short answer: No. If you are using a thin oil to prevent filter bypass, you'd be better off using an oil filter with better flow and/or a higher bypass pressure.
On a proper rebuild: the assembly lube will protect everything until the oil pressure builds up and complete circulation throughout the oil system. The factory clearances achieved in a proper rebuild will be better lubricated by the correct oil. So use the viscosity spec'd by the engine manufacturer.

On a cylinder head/head gasket only, as another stated, the bottom end is lubricated as much as an everyday cold start. Get a quality oil filter, prime it as much as possible (depending on the base mount/orientation), and use the spec'd viscosity.

In both situations it is common practice (before the valve cover and lifter valley covers are installed) to pour a couple quarts of oil over the rockers, camshafts and lifters so that the valvetrain is lubricated as much as possible during initial start. Then install the valve cover and add the remaining oil. This is not really necessary because again the assembly lube will provide protection, but still it is common to douse everything in oil during final assembly.


I always try and prime my engines as much as possible even for just an oil change. I'll be sure to do that this time as well. And I will use a quality filter.

Smart about pouring a couple quarts of oil over the valvetrain. I forgot about this and will do it before I put the valve cover back on.

Originally Posted by DGXR
Debris small enough to make it through the oil pickup screen will be caught by the oil filter... yes the obvious exception is bypass operation, but the bottom line is you can't do anything about this except run a bypass filter.


THAT is exactly what I am challenging by my original post. I think that is incorrect, from what everyone is saying, it sounds like you CAN do something about the filter bypassing. But the solution doesn't sound complicated, and it may be the case that a quality 5w30 with a quality filter at ambient temp may NOT bypass at all. I am not 100% on this yet but it sounds to be the case.
 
Originally Posted by oil_film_movies
Originally Posted by willistheguy
Now it is my understanding that when the oil is cold, the engine's oil filter bypass can be activated because the oil is still thick.
At the temperature you'll be doing this at, let's assume it's 50 degF, a 5w20 or 5w30 conventional will be fine to not pop the bypass valve. I saw the worst filter at a colder 32 degF out of a group flowed 1.8 GPM at a differential pressure of 15 psi (bypass for a lot of filters) using a conventional 5w30 oil.
Your engine will probably start flowing no more than 2 gpm at start-up, and if you're at a warmer temperature in you garage or shop than 32 degF most likely, very doubtful your oil filter would go into bypass.

To be doubly sure you don't get a bypass event at startup, use a synthetic media oil filter for the least flow resistance and diff pressure, and the cheapest one that's good is a Fram Ultra at ~$9 each at walmart or amazon. Also, a 5w20, or a 5w30 mixed with a pint of SeaFoam or similar thin liquid like kerosene or diesel fuel, would be plenty thin enough to be sure.

Also, coat the cylinder walls with a very thin coat of motor oil. Before you put the head back on. Not much, just smear on some near the piston-cylinder-wall boundary.
Fill the oil filter up before installing a new one.

Was watching a vid on a guy rebuilding a 305 GMC V6, showed him mic'ing all sorts of stuff, seemed like he knew his stuff. He used WD40 for lubing piston rings and cylinder walls. Said that Total Seal said to do that. Worst thing was to use a thick oil that overwhelms the rings at start up, the oil could glaze onto the walls. Thought it interesting.
 
SO, after all that, I'm going to attempt a general conclusion.

Question: if you know there is some debris in the system, what is the best quick method for assuring a healthy/filtered startup:

-Quality oil that is OEM grade @ reasonably warm temperature
-Quality oil filter, primed
-Engine, primed (with starter at least)
-Oil drained and refilled after 100 miles

Now my plan for MY Jeep:
-5w30 semi-synthetic. I'm going to run the sealed jug under hot water for a few minutes to warm it up a little extra before starting the engine. Maybe unnecessary but it won't hurt anything.
-Mopar or ACDelco filter (because I have those in my garage already).
-I will prime the filter and run the starter until I see oil pressure.
-I will drain the oil after 100 miles and exchange it for some real synthetic.

Anyone disagree?
 
If the ambient temp is above 50F and you have a new filter, and you don't rev the motor much over idle at start-up then the filter isn't going to hit bypass.
 
Originally Posted by supton
Originally Posted by oil_film_movies
Also, coat the cylinder walls with a very thin coat of motor oil. Before you put the head back on. Not much, just smear on some near the piston-cylinder-wall boundary.
Fill the oil filter up before installing a new one.
Was watching a vid on a guy rebuilding a 305 GMC V6, showed him mic'ing all sorts of stuff, seemed like he knew his stuff. He used WD40 for lubing piston rings and cylinder walls. Said that Total Seal said to do that. Worst thing was to use a thick oil that overwhelms the rings at start up, the oil could glaze onto the walls. Thought it interesting.

You know, I thought of doing that too, the ease of just grabbing some spray penetrating oil like WD-40 or Super Lube spray (with teflon in it). Maybe better: Grab a can of LiquiMoly MOS2, which is just oil+moly, and just smear a little in the crevice at the piston-wall boundary...... The "glaze" thing I'd not heard of. I had heard that you should use very little oil in the crevice at the piston-wall boundary, just smear some small amount in. Anyway, WD-40 seems fine to use. Discussion at http://www.v8buick.com/index.php?threads/assembly-lube-vs-wd40-on-cyl-walls.135507/ if interested.
 
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Subaru oil filters have abnormally high specced bypass settings, usually around 22psi.

You could always look at the filter they spec for their 3.6L engines.

All subaru threads are m20 x 1.5 if I'm not mistaken, but other than that I'm not sure on the dimensions.
 
WD-40 is not a pre lube for cylinder walls, never do this. I've seen several atv engines ruined by using WD for a cylinder lining lube.

I always use whatever oil I plan on using to lube my pistons/rings before sliding them in the cylinder. Never smoked a set of rings this way in 10 years.

Aa far as oil, a guy we use to drag race with always started fresh rebuilds with Rotella first then switched to the normal fill.
 
I would never use wd-40 on rings for a rebuild or head gasket. If the engine does not fire up quick, you will be cranking on dry cyl walls. Its not that good of a lube. I use 10w 30 mixed with some shaeffers 132.
 
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Engines die from dirt in two ways - bearing failure and piston skirt/bore failure. The easiest way to avoid all this is to use a decent 10W-30 on cold start and an oversized filter. The extra media area will allow cooler thicker oil to pass w/o opening the by-pass.

The piston skirt embedding debris can be offset by not revving a new (or rebuilt engine) over about 2,500 RPM for the first few hours of running. That gives all the debris time to flush into the pan w/o a high revving crank slinging it up the bores as windage pick-up ... The pump and filter will catch it as long as the by-pass never opens
smile.gif
 
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I don't understand all the angst about prelubing an engine. Everything will have oil after a second or 2 of cranking the engine. All that prelube grease just plugs things up.

The pistons and cylinder walls don't need a thing. They can be assembled dry. A couple drops of oil on each bearing shell.
 
Yeah, i guess the lubriplate my dad uses on stuff is going to plug up stuff. What a dumb thing to say. Thats almost as bad as my brother and i using ATF tk hone cylinders or clean cylinder walls up
 
I think a lot of people here are losing sleep over nothing. Put it together, prime the oil pump and filling the oil filter won't hurt, but it's not totally necessary on a simple head gasket change. If you use grease in the engine, use assembly lube, not regular chassis grease. Assembly lube will dissolve into the oil, where chassis grease is stringy and could block small oil passages.
Now as far as lubing the rings with WD40, I wouldn't. The only time WD40 would be used in an engine is when you get the bare block back from the machine shop. You use it to spray on the cylinder walls to get all the foreign material out of the cylinder walls before you assemble the engine. Spray the walls with WD40, use lots of paper towels to rub them until they are clean and then stop. Or you spray a wet distributor cap with WD40 to dry it out. Other than that, keep it out of the engine compartment.
 
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