Yes, I'm sure. I never even heard of a "high pressure" oil pump before until I had my engine rebuilt. I was concerned about that at first, but when my trusted mechanic friend balanced and blueprinted my engine, he took the liberty of installing a standard volume, high pressure oil pump and assured me that it wouldn't hurt and would only help the engine to get the oil pumping quicker on a cold engine. (And maybe that is why he also recommended 5W-30 motor oil? I can't remember now, but what he said sounded good to me, and I have found that the 5W-30 oil is much easier to find around here than 10W-30 oil.) He explained to me that GM guys like to use the "high volume" oil pumps and that Ford engines didn't need them as much. Furthermore, the much larger gear on a high volume oil pump accelerates wear on the distributor and costs horsepower.

Melling Oil Pumps - YouTube

 

Some fair points;

A stock engine has little use for either, originally they size the pump for the original engine and all is good to do that again. Often however changes are made that put more demands on the oiling system, then a higher volume pump is a very good thing, and well better to error on the side of too much oil then too little.

A higher pressure pump will certainly put more strain on the shaft/gears driving it, and a higher volume pump will bypass more wasting energy heating the oil IF the engine doesn't use it.

 

Nice video Lariat.

The only pump there that is not needlessly bypassing oil is the stock replacement pump.

 

Yes and no. Too much is heating the oil needlessly.

Both will bypass and heat the oil more than what is required. Both the high pressure and high volume in the video used high pressure springs. The higher the pressure, the more heat that is imparted to the oil in pumping and more that is bypassed directly to the pan.

 

Not sure if I buy that, Chief. A high-pressure oil pump uses the same gear as stock oil pump. Whereas a high volume oil pump uses a much larger gear, and that puts more strain on the shaft/gears driving it.

Right?

 

You talking to me? See who you quoted...

The high volume and the high pressure pumps in the video both use the same high pressure spring. The difference is the gear height. Both will put a higher load on the distributor gear, etc.

I use stock replacement pumps on my builds and shim the spring only if hot pressures are low.

 

You are using a wrong assumption again. SAE oils get thinner and lose viscocity as they heat up. They tend to be higher viscosity when cold. The Multigrade oils do the exact opposite. This is why multigrade oils were invented in the first place.


I would agree with most of that except the youtube or tv tricks remark, so the question is why did you say this then?

So you are argueing that the fresh cold oil is thicker than what it is when drained hot. Sure fine I agree. What I have the problem with is this...

If you said same thickness at both temps, I would agree that would be ideal. Same viscosity, I highly disagree with. 10w-30 and 10w-40 has the same or near the same exact thickness either when cold and hot, but different viscosity rates when hot for example. 5w-30 has lower viscosity when cold but the same viscosity when hot as 10w-30.

To put it a better way, I'm not arguing about flow rate. The faster it flows the better in most conditions especially when hot, as it cools faster. What the concern with is viscosity or how it lubricates that I do not agree with you on. 5w-30 the viscosity is too low for starting in lets say 90 degrees, the lubricant moves too quickly to do any good, therfore wear happens. This is why the owners manual recommends the viscosity it does as I also exampled with a picture above.

5w-30 does not mean it has a faster flow rate than 10w-30. It means it has a faster viscosity when cold. There are a lot of synthetics that flow twice as fast as dino oils of the same exact viscosity.


Which is explained in the example I gave to you, I suggest everyone here to read it and make up their own minds.

It would be more correct to say same viscosity, rather than thickness when hot. The 5w-30 will still be thinner when hot than the 10w-30.

Think of it more as stickier not as slippery when hot but flows faster, and not as sticky when cold, but flows slower.

Yes, in some ways they are improved and in some ways they are worse for older engines like ours, lack of ZDDP etc. The biggest thing is engine clearances and tolerances and that's why the recommendation for the change in viscosities in oil in the 1980s, compared with newer engines from the '90s up.

With an engine rebuild it changes the dynamics of things. It depends on the clearances used to build the new engine. More than likely if it's a fresh rebuild, you can use the 5w-30 with no problems whatsoever, with use of the Zddp additive, unless it has 1980 era type clearances. Most likely it doesn't, they probably built it to '90s specs. My concern with such low oil viscosities comes with original engines, or engines broke in on 10w30 or 10w40 with original clearances. Using lower than recomended viscosity will do damage at start up, just as much as using too high.

In your case with a brand new rebuild, you can go by your mechanics recommendations. After all he is the one who built it right?

With an older engine, it's not a good idea.


Think of it this way, putting 10w40 in a saturn will kill it's engine quick, because of the clearances being so tight the oil won't flow due to the viscosity. Putting 0w-30 in a truck used to 10w40 oil all it's life will have a similar effect because the oil will not "stick" to the parts when cold.

 

LARIAT, yeah I don't know of any common issues with windsor engines that would suggest the need for a higher volume pump on a rather stock engine and I don't know your engine. FE's though, they need help. High pressure on a windsor, hmmm, I could see a use if there was an added restriction between the pump and the bearings, like for instance a full flow oil cooler. That would ensure that the pressure drop accross the cooler didn't lower the pressure at the bearings too much. But as I said before it's a better safe then sorry thing. However your high pressure pump will do nothing to prevent oil pressure drops from high heat if that is a concern of yours.

 

That makes a whole lot of difference right there in clearances. Forget what I said about '90's clearances, they are even tighter than that.

 

A truely balanced and blueprinted engine would allow a glass of water set on the air cleaner to have no ripples.

My Powerstroke was balanced to within 1/10th of a gram, but I can't say it is blueprinted.

 

Well let's see, the quick answer is BOTH put more strain on the shaft/gears driving it, it's pressure x volume. So the more of either or both the more it takes to turn them. That said the high pressure only pump only takes more to turn when above the pressure at which the stock pumps bypass would open. While the high volume pump always takes more to turn. And pumps with both more volume and higher pressure spings have both issues.
That will do you NO good, shimming or putting in a higher pressure spring will do NOTHING to solve a low oil pressure issue caused by heat. The issue is a lack of volume compared to flow, not that the bypass is opening. This is why I error on the side of more volume on my builds and if worried about the shaft/gears driving it will use a stock/lower pressure bypass spring.


Edit instead of new post: "Blueprinted" is such an overused term, what does it really mean when rebuilding an older engine. The machinist didn't draw up new blueprints for the engine. No if good he just did a good job doing all that was needed to make sure everything had the right clearances, and charged a lot for it. I spent years in machine shops working for grumpy old machinists that really knew what they were doing, and they would all laugh at the term "blueprinted". I've had my grubby hands on and in engines that some are lucky to touch, Don and Josh might if they get around know where there are a few supercharged fuel injected 427 SOHC engines around town. Look closely, they have my fingerprints on and in them.

 

I used to own a completely original 426 Hemi. Sold it for other projects but I do get around. I have played with engines you and the general public will never see.

I still don't think you get the pressure vs volume. None of those builds had bearing issues, just lower "than I like" pressure on the gage at idle/hot. Volume was not an issue.

 

Not exactly. In reference to the Melling pumps in the video, the high pressure and the high volume both use high pressure springs. The high pressure pump with the stock style gears will take less power to turn than the high volume. The high volume will take even more power since it will be bypassing much more oil.

 

Hemi, pffft eveyone has one of those.
What's not to get?
Isn't that what I said? But you can put a lower bypass spring with a high volume pump, better yet you can on some engines have the bypass seperate from the pump. Better yet you can have the bypass go to a bypass filter and/or cooler and/or spray bar and/or accumulator etc, getting the best of it all.