Oil System Plumbing
 

There has been much discussion in regards to what is right and what is wrong in regards to the plumbing of an oil circuit for our performance engines.
The use of 90 degree fittings is considered inappropriate for these systems. The question is, " Can one use a 90 degree swept fitting as in an Aeroquip style hose end"?
I am considering the Aeroquip 90 degree fitting as shown.

The use of 90 degree "drilled" fittings is a no-no but yet Mercury has used them on their HP motor oil circuits. ?????


One more thing to consider is that there are some thermostatically controlled oil coolers available that have an abrupt 90 degree fitting in there design. I would think that this would cause some disturbance in the oil flow as the oil bypasses the cooler and reroutes itself back to the engine.
As always thanks for any replies.
Russ

Re: Oil System Plumbing
 

Russ,if your using -12 hose its not as critical as when lines are marginal,just don't use any more than you have to. Make sure you buy whats called a "full flow fitting",Smitty

Re: Oil System Plumbing
 

Smitty,
I have been in conversation with Stef's Performance and they have done much research in oil line sizing. Their response was that they have tried many combinations of line sizes such as -10 supply and return, -12 supply and return, -10 supply and -12 return, etc.
They felt that -10 was more than adequate except for the highest HP applications (you). I checked out a Mercury Supercat motor at St. Clair and noticed the use of -12 AN exclusively. I am now leaning in the direction of using -10 AN Socketless Aeroquip hose and fittings. As you know my temps and pressures look good now but am looking for a little more volume than the Mercury HP500 setup I am using. I am looking for a little more assurance.
In your case, the -12 lines are warranted. I want to try an upgrade in line size and routing and see the results. My present oil cooler is 2" x 17" with an additional remote PS cooler. I did some searches on OSO and there are some guys using a much larger cooler than what I am running. I don't stay into it for as long as some therefore my temps are not as much as an issue. I see 220-225 at cruise and 250 after WOT. These are return temps after the cooler.
Thanks for your feedback.

Re: Oil System Plumbing
 

With some increased cooling you should be able to get the WOT temps down to 230's.

Re: Oil System Plumbing
 

http://www.hardin-marine.com/product...il-coolers.htm

Dual Tandem Oil Cooler 2" Diameter / 18" Length
This is one of the best designs anywhere. Two coolers and only one water hose connection. Each tube consists of thirty-one 1/4" seamless tubes with displacement baffles so you can be assured you're getting maximum cooling when you need it.

or

"The Ultimate" Hi-Performance Thermostatically Controlled CoolerQuite simply, the ultimate oil cooler on the market today! It maintains oil temperature thermostatically and all in one unit. If you suffer from either high oil temperature or even moisture or condensation in your engine oil this is the answer. The oil thermostat is designed to maintain an oil operating temperature between 190 degrees and 215 degrees. The thermostat bypasses the cooler until operating temperature has been reached and then balances oil flow to maintain optimum oil temperature. This alone can save you from years of damage caused by operating your boat with too cold oil.



Call them Hydro's choices. :D

Re: Oil System Plumbing
 

Hydro, thats exactly what I'm running,it is a little small for my power level but I don't go on poker runs at wot for 45 minutes,works great,Smitty

Re: Oil System Plumbing
 

[QUOTE=RLW]There has been much discussion in regards to what is right and what is wrong in regards to the plumbing of an oil circuit for our performance engines.
The use of 90 degree fittings is considered inappropriate for these systems. The question is, " Can one use a 90 degree swept fitting as in an Aeroquip style hose end"?
I am considering the Aeroquip 90 degree fitting as shown.

The use of 90 degree "drilled" fittings is a no-no but yet Mercury has used them on their HP motor oil circuits. ?????


What specifically are you referring to when you say "drilled" fittings? Are they the 90 degree NPT to AN adapter fittings that many including Aeroquip has to offer?

Re: Oil System Plumbing
 

[QUOTE=Hydrocruiser]http://www.hardin-marine.com/product...il-coolers.htm

Dual Tandem Oil Cooler 2" Diameter / 18" Length
This is one of the best designs anywhere. Two coolers and only one water hose connection. Each tube consists of thirty-one 1/4" seamless tubes with displacement baffles so you can be assured you're getting maximum cooling when you need it.

or

"The Ultimate" Hi-Performance Thermostatically Controlled CoolerQuite simply, the ultimate oil cooler on the market today! It maintains oil temperature thermostatically and all in one unit. If you suffer from either high oil temperature or even moisture or condensation in your engine oil this is the answer. The oil thermostat is designed to maintain an oil operating temperature between 190 degrees and 215 degrees. The thermostat bypasses the cooler until operating temperature has been reached and then balances oil flow to maintain optimum oil temperature. This alone can save you from years of damage caused by operating your boat with too cold oil.



Is what you are saying is the Thermo unit opens at 215 and closes at 190? Just trying to get a handle on the numbers.

Re: Oil System Plumbing
 

Rotax,
When I refer to a drilled fitting I mean something along the order of Item #21 in the below picture.

Re: Oil System Plumbing
 

:drink: Maybe the thermostat controlled cooler is not the right one for you..try the dual set-up. I knew a guy with blown 502 that ran a twin dual set-up...prior was seeing 290*F at WOT for 15 minutes and after was right around 230*F max.

No excuse for oil that is too hot...you just keep plumbing in more surface area...a twin dually always does the trick I am told.

He has a radiator shop plumb the 2 units in a parrallel configuration and essentially have one inlet and outlet. It's all about surface area..temps went down..oil pressure was normal...engine life doubled compared to previous...added extra oil volume as well to the system.

Heat is your engines worst enemy....and oil heat is what they are talking about too...never forget it! :drink:

Re: Oil System Plumbing
 

Then what you are recommending is the straight NPT to #10AN adapter fitting, then screw on the #10AN 90 degree push-on hose fitting. Correct?

Re: Oil System Plumbing
 

The consensus has always been, not to use any 90's regardless of design. If you can use a straight fitting then by all means use that and then sweep the hose to your next connection. I am trying to keep my circuit tight but not cause and disturbance in flow. The use of a swept style 90 versus a drilled 90 is definitely better but to eliminate any 90's is the best.
Cooler size is important as you can read in the above posts.
I still question the 90 degree bypass on the T-stat style cooler pictured above, especially with all this talk of not using 90's.
Bottom line is minimize oil flow disturbances, have adequate flow and size your cooler for maximized cooling without being too cold. Oil T-stats can insure that. Oil temp and oil pressure gauges are a must or you'll never really know what you have.

Re: Oil System Plumbing
 

Hydrocruiser: I like the look of that dual cooler; thanks for the info.

About drilled 90s...if you have to use one because you have no choice due to the installation layout, OK. Ideally when a (Merc) engineer lays out oil plumbing they should/could do a calculation of pressure loss and make sure that the pump can deliver the required volume at that pressure loss.

Big lines, no angle fittings (you can often use a long sweeping section of hose instead), dual coolers; all mean lower pressure loss and therefore more volume. Sufficient cooling of the oil is important, but oil volume flowrate is the other part of the equation for removing heat.

Re: Oil System Plumbing
 

Just something interesting I found. Most oil coolers of this size have 1/2 npt threads to hook up your oil lines. -10 to 1/2 npt adapters have a much larger id than -8 to 1/2 npt adapters. Also, the fitting that RLW is showing in his first post is a full flow fitting. It is much preferred over the ones that look like a block of brass with 2 holes drilled in it.

Re: Oil System Plumbing
 

The dual cooler solves most anyone's problem who have asked me about oil cooling. It's the mother of coolers and can be used in tandem for earthshaking cooling...the thermostat cooler is good up to 400-500 HP...it is a nice design but the big hot running engines seem to not like the T-stat and run hot with the unit I hear.

Re: Oil System Plumbing
 

[QUOTE=ROTAX454]I do believe it allows warm up to 215*F and then is SUPPOSED to be able to cool back down to 190*F. It works great up to a point and that point is when your oil is above the 190-215*F...then you need to add another cooler or go with dually's.

Re: Oil System Plumbing
 

Russ,the bypass on that oil cooler doesn't switch from cooler to bypass like your probably thinking.When its cold oil flows thru the cooler and the bypass,when its warm it only flows thru the cooler. So it really isn't a 3 way valve,it just allows some oil to flow thru the bypass untill warmed up. Its rated to 700 hp too,I am going to install a temp gauge by next season so i can see my actual oil temps when running hard because I have seriously exceeded its rating.I still have great oil pressure though so its not a great concern,there might be some cooling effect or less heat load too from running motor at 100 degrees,Smitty

Re: Oil System Plumbing
 

I ran that cooler (the bypass style) last year with 750hp and .003 rods and mains,its rated for 700 and oil pressure never really dropped much below 75 psi while underway and 60 psi hot idling after long run BUT I don't have temp gauge. This year I've saw oil drop to 45 psi (at Idle) after running 4500-5000 for 15 minutes then full boost at 5900 rp'ms for 3 minutes,the oil pressure came back to 60 psi after idling for a few minutes so I'm thinking it is a little small and oil temp is probably getting up there,Smitty

Re: Oil System Plumbing
 

Go dual :D

Re: Oil System Plumbing
 

I still need some kind of oil thermostat though,my system holds 18 qts of oil and takes ALONG time to come up to enough temp to run boat hard,Smitty

Re: Oil System Plumbing
 

Hey Smitty,
I appreciate the clarification of the oil cooler but figured it worked similar to my Mercury Racing Oil T-Stat Filter mount. I like the design and have not ruled it out as it also helps simplify the oil circuit. I thought it came in different sizes. The dual cooler is interesting. Teague has an oil cooler that is a two pass design and is large by comparison. Pricey though.
Russ

Re: Oil System Plumbing
 

Here's an example of what I am using:

I use dual (2 in 1) oil coolers with several 90* -12 Areoquip fittings. I have GIL 10 quart oil pans with the Kieth Eickert HP-6 size Thermofilters, Mellings HV oil pumps that have about 70-75 pounds of oil pressure at start up, and after a hard run will only go down to about no less than 40 pounds of pressure. During a hard run I have never seen the oil temp ever exceed 230*.