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Hey I know this isn't a "Jetboat" question, but I see alot of good tech talk on these forums in here, do you run a standard or hv oil pump in a jet boat motor...? A guy told me never to run a hv pump, i don't know why, is there a reason? Maybe not with a stock pan, but a 8-10qt pan should you still not...? I have a 468 mild bbc low comp motor in a show truck with a standard m-77 oil pump and it does fine I'd say, this motor for my jet is similar with a Lil more comp itll spin my "a" around 5k or 5.5k im thinking, but I'm curious if your suppose to run hv pumps or not, and when it's ok if so, or is a standard mellings oil pump ok still....?!
 

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I had better luck with a standard flow mellings pump
The hv seems to pump too much too fast at long wot runs and cause too much oil up in the heads even with the 10q pan
As long as you see 10 PSI for every 1k rpm you are good to go
 

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A high volume pump in an application were it's not a necessity is not a good thing. It pumps more oil than is needed, can put too much oil up on top, starve the bearings, draws hp and also causes extra heating of the oil. I've always had better performance out of a stock volume pump that has a little extra pressure. (in a jet boat).

Duane HTP

Read your PM.
 

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Discussion Starter #6
Thanks

Thanks for the info Duane.
 

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Hey I know this isn't a "Jetboat" question, but I see alot of good tech talk on these forums in here, do you run a standard or hv oil pump in a jet boat motor...? A guy told me never to run a hv pump, i don't know why, is there a reason? Maybe not with a stock pan, but a 8-10qt pan should you still not...? I have a 468 mild bbc low comp motor in a show truck with a standard m-77 oil pump and it does fine I'd say, this motor for my jet is similar with a Lil more comp itll spin my "a" around 5k or 5.5k im thinking, but I'm curious if your suppose to run hv pumps or not, and when it's ok if so, or is a standard mellings oil pump ok still....?!
I am going to say that it will depend on how the engine is built, with bearing clearances having a lot to do with which pump you want to run. Larger bearing clearance will bleed off more oil and be happier with the high volume pump.

Also, don't forget that oil not only lubricates, but cools parts. I am building a 427 for the street now that will be getting a standard volume pump (and slightly tighter bearing clearances), but any marine engine I build with clearances that I set gets a high volume pump. That includes jet boats, both recreational and racing, as well as turbo and blown big blocks, flat and roller cams, 14 and 10 qt pans.
 

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AS you can see everyone has an opinion and they all can be different. Depending on your engine build and how you use the boat, they all can be right. If you do not have extremely big brg clearances a HV pump robs Hp, raises oil temps, and increases distributer gear wear with no significant benefit. On the other hand, if your clearances are significantly opened up and you are going to spend significant periods at 5-5500 rpm, the benefit of increased volume will offset the negatives just listed. (Assuming you do not pump all of the oil into the valve covers) If you go the latter route you will need to consider large capacity oil pan and possibly an oil cooler. In my case I have mild 540 that makes about 600Hp, 12 qt pan, standard volume melling pump, no oil cooler. If I run above 4,500 Rpm for 7-8 miles I see about 5 psi drop in oil pressure due to higher oil temps. But I use the boat for pleasure and spend most of the time as lower speeds. Have three seasons on the engine with no problems. For mild engine and recreational use, standard volume pump should be fine. Good luck with your build.
 

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Discussion Starter #10
Thanks

Thanks everyone, I think imma go the more "standard volume* high pressure" route. I believe it to be a 10774 mellings. I run a "m77" standard pump in my street built 468, it works fine, all is appreciated. Thanks again. All the info has helped out. I don't like to run my stuff hard, it'll be at 3500 or so cruising more than anything lol, the 5500 might get touched here and there for fun.
 

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I am going to say that it will depend on how the engine is built...
Without knowing more details about the OP's boat, engine, and application, etc, I think this is the most prudent and wisest reply. The pump selected depends on so many variables.

Moving along: A lot of people claim that HV pumps chew distributor gears and that is a big case of mistaken blame. Oil pressure is oil pressure, meaning that 70 psi is 70 psi regardless of whether the pump is an standard volume pump or an HV pump. The amount of load to turn an oil pump mechanism that has 25% taller gears is inconsequential to the engine's distributor gear--if such a minute change in pump design were so close to the cusp of a distributor gear loading problem then the engine manufacturers wouldn't use the standard pump volume design either. And since oil pressure is the biggest load on the distributor gear, then a high pressure standard pump pushing 80 psi will load/wear the distributor gear more than an HV pump pushing 65 psi, technically speaking. This is why in most cases of recreational engines where longevity and reliability are a big consideration we prefer to build the engine on the loose side and use an HV pump which maintains oil pressure over a wide temperature range, moves more oil when needed which lubricates, cools, cleans, acts as a seal, etc. Also in a given build, contrary to popular belief an HV pump does not move 25% more oil through the engine, it is sending approximately the same amount of oil through the engine but is bypassing more oil until the oil has become so hot and so thin (for example) that when called upon to do so the HV pump will have at its disposal the extra pumping volume to send that needed oil (which was previously being bypassed) through the engine where it is now needed due to the increased bleed-off rate that comes with the increased oil temps, etc.

Thanks everyone, I think imma go the more "standard volume* high pressure" route....I run a "m77" standard pump in my street built 468, it works fine, all is appreciated. ...it'll be at 3500 or so cruising more than anything lol, the 5500 might get touched here and there for fun.
How well a pump maintains oil pressure in a street driven vehicle cannot be a measure for how well it will perform in a jet boat engine that is regularly running at 3500 rpm and above, with looser bearing clearances, higher than typical oil temperatures, probably more oil foaming and whipped up oil, etc. Very generally speaking, an M77 ought to be just fine in a bone stock factory marine engine with clearances tighter than HP builds. If you are currently rebuilding then you might want to provide some specs including engine displacement, bearing clearances, cam type and profile, peak rpm, targeted horsepower, jet pump brand and impeller size, etc. A standard pump might suit you fine; so might an HV pump.

LO
 

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Thanks for the video. Nice. I was answering the question for the thread starter and he stated he had a mild 468 just like in his truck. That would probably be a pretty normal clearanced engine. Same answer use the 10774 Mellings. I also understand the need for the HV in the very high HP and loose clearanced engines. I agree, but that is not what he has. The 10774 will not empty the pan and it will carry about 10lbs. more oil pressure on a hot day when you are running hard. Have used that pump for years and swear by it.

Duane HTP
 

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Thanks for the video. Nice. I was answering the question for the thread starter and he stated he had a mild 468 just like in his truck. That would probably be a pretty normal clearanced engine. Same answer use the 10774 Mellings. I also understand the need for the HV in the very high HP and loose clearanced engines. I agree, but that is not what he has. The 10774 will not empty the pan and it will carry about 10lbs. more oil pressure on a hot day when you are running hard. Have used that pump for years and swear by it.

Duane HTP
The guy says he had a mild 468 in a truck, and goes on to say the boat engine may be similar, but no statement as to how it was built. I specifically did not say that he needs a high volume pump, but that the engines that I build, with the clearances being what they are, do need the high volume pump, and the video clearly illustrates that.
 

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Krazykracker, will the 468 going in your boat be a pretty normal set up on bearing clearances, or will it be set up with extra clearance? I was trying to answer for your engine rather than give a generic answer for the way someone else may build one. Sorry obnoxious, I probably had a little more information on this build from our pm's than you did. I agree with you 100%, if you build his engine, it should have a HV oil pump. Didn't mean to offend anyone.

Duane HTP
 

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Look at the video above obnixious put on. He shows 4 different clearance settings, tells what they are, and shows the difference it makes. Very good video.

The 10774 Melling has a "little" higher than normal pump pressure, not real high pressure. My blown 588 in my lake boat which makes about 1200 hp runs one of the 10774 pumps and goes on a lot of long and sometimes hard runs. It usually carries 60 to 65 lbs running and idles at 40 lbs on a hot day. That's about where I like to run them. In the race boat, we use the 10775 pump. It has the same pressure and volume but has the shaft that goes into the end cap, (best to run with a Pro Mag because of the added drag of the mag). We usually see 70 to 75 lbs at WOT, 7200 rpm. We have had very good luck that way, but, each to his own. It's just what works for me.

Duane HTP

Here are the Melling pump numbers. Don't take my word for it; call Melling Tech line and talk to them about the differences in these pumps. They are very helpful people.

Melling Oil Pump Numbers


10774 – Regular Volume Pump/High Pressure * normal jet boat use!

10775 – Regular Volume Pump/High Pressure/Extended Shaft into Plate

10770 – HV Pump/carries better than normal pressure/no anti cavitation

10778-C – HV Pump/Hi-Press/Anti Cavitation Slots/Extended Shafts HP
 

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Oiling systems need the big picture view
1. a high quality oil pan for intended use
2. oil drain back consideration
3. crankshaft windage
4.oil pick up tubes
5. engine oil flow routing

We use mostly dry sumps to achieve this along with spray bars and a vacuum pump
however, we also have a couple wet sumps set ups
The correct pump is more about your engine set up
 

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Exactly. I might add that for a set up like his, I like to use the Armando 10 Qt Jet Boat oil pan, windage tray, and pick-up along with the recommended oil pump. The dry sump is great, but I don't think the original thread starter is lookinig at the dry sump catagory for his lake boat.

Duane HTP
 

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Recreation vs competition...

DuaneHTP;1872738 10778-[B said:
C[/B] – HV Pump/Hi-Press/Anti Cavitation Slots/Extended Shafts HP
I'm pretty sure the "C" pump is NOT recommended for extending idling, like in or out of 5MPH zones that the recreational boats see.... The 10778, (without the "C") will work fine in a jet boat, and the 10778-C for those engines that don't see a lot of "idle" time....

Ray
 
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