oil coolers
 

Ok!
Got the motor back in and dialed out after THE MELTDOWN, and everything is cool except! The operating temp now runs around 160 & 165, about ten degrees hotter than before the rebuild. I am running a little higher compression about 9:00 to 1, same pistons but just had the deck cut to "0"and then installed a .041 head gaskets. The motor runs great stronger than ever, good plug color etc. My bigger concern is the oil pressure about 70lbs cold at idle, 60lbs warmed up cruising but after a WOT run the pressure will drop to 55lbs running along and drop to about to 30lbs at idle. I have been running the oil cooler from the 7.4L that was originally in the boat and I am concerned that it may not be quite enough now. It was doing this before the rebuild but not to this degree. I was thinking of installing a oil temp gauge along with a large Eddie Marine oil/ps cooler but was wondering what other boaters had experienced in this area. Any input appreciated.:cool:

Those oil pressures don't sound bad to me. And get yourself an oil temp gauge, second most important gauge on my dash. Right after the Tachometer. It might be in your best interest to get the gauge first, check the temp of the oil, and then decide if you need a bigger cooler.

I'll bet after a few minutes at idle speeds (say, 1000 rpm) the pressure comes back up a ways???

Both of mine do just about the same thing.

Last year had same low pressures. This year put big eddie marine cooler & permacool t-stat. Now Oil pressure starts out at 80, & lowest I have ever seen is 70-75 anthing above idle. Do a search on coolers. This has been discussed many times before.

Once I slow down for a 30 to 45 seconds the pressure comes back. I think I'll try a oil temp gauge. I have a port on the remote oil filter pad, is this a good place to install a temp gauge??

Last year I had the same problem with my 406. No oil cooler, just power steering cooler. This year I added the eddie marine cooler and permacool stat, and so far no issue with dropping oil pressure.

Mike

same thing i ran into on my SBC... have a 454 mag cooler on it.. with a perma cool thermostat.. pressure at idle cold is 40 psi.. WOT 58-60 psi.... warmmm i should say hot (280 degrees) its 25 psi at idle and 30 psi at WOT.. So i have the biggest eddie marine cooler coming tommorrow. hopefully that gives me better oil pressure..

Pressures don't sound bad to me either. My two do just about the same. Mine might go down to 25 pounds after a hard run , but like yours in 30-45 second of idling its back to 40. The bad news is the pan is probably the best place for the oil temp sender.:(

I posted this as a question before and did not get an answer to the contrary. Why is the pan a better place than the remote filter when the oil comes directly from the pan, thru the pump out the adapter to the remote oil filter.

Why would the temp be any different at the remote than in the pan other than maybe coolin 1 degree because it goes thru a 2 foot hose to get there:confused: :confused: :confused:

Why I ask you Why :D :D :D

Because I said so :p that's why:D :D :D ! Just kidding! Seriously though , the oil filter location would probably be ok. It would show temp variations as you change speed and load on the engine. But since it is sitting out there in the open with a 1/4 inch of aluminum around it acting like a heat sync , I would imagine it would read a little lower than the pan where you have more volume around it. Even if its 10 degrees off its certainly not going to kill you:D

Mine is in the filter pad. Seems to work fine there. Make sure you ground the pad if you don't have it mounted on the exhaust manifold (stock location). Mine is on the transom and my ground runs back to the block.

Put a temp gauge on it. I'll bet you will be surprised at how hot the oil gets.

I have just experienced this same issue. I swapped out my stock 7.4L with a 21" Mirage Plus for a 502 Mag and a 24" Bravo 1. I used all of the same components except the intake manifold and richer jetting on the 502, including the oil cooler. With the stock cooler I was seeing 230* at just a 3000 rpm cruise. At 4000 rpm or above the temp went to 260 and above. It does take a few minutes for the temps to get that high before they stabilize. IMHO the stock dual cooler on a 7.4L is just too small when any modifications for more horsepower are done.

I went the cheapest and easiest route I could to get the oil temp down. I used a CP Performance 2"X 8" (Actual cooler length is 5",$69.95) power steering cooler and a 2"X16" (Actual cooler length is 12", 89.95) oil cooler plus a permacool T-Stat. (With fittings and extra hose about $80) I went this way because I could make both coolers fit in the stock location and I could use the stock hoses with just a few modifications. The 2X12 cooler fits in the same bracket as the stock dual cooler. With the t-stat rigged onto it, the stock oil lines fit perfect. I installed the 2X5 p.s. cooler on the front of the engine and just cut out a piece of the water hose going up to the t-stat housing. I had to make a bracket out of some 1/8"X3/4" strap iron to hold the p.s. cooler in place. I also had to add some length to the p.s. hoses, too.

Now my oil is 215* at 3000 rpm, about 230* at 4000 rpm and 250* at WOT. I am happy with the results. My oil temp sender is in the remote filter pad, measuring the hot oil before the filter and cooler. I am using 15W-50 Mobil 1.

A large Eddy Marine or CP Performance cooler is probably a better way to go if you have a high HP engine. You will have close to $400 or more invested by the time you add a t-stat, cooler mounting brackets and all new custom made oil lines.

Just my .02, Good luck, Doug

I have a larger cooler coming from Eddie Marine, although it does look a little large! I hope it doesn't cool the oil too much.
I am goung to add a oil temp gauge as well.

Oil Cooler
 

First thing is to be sure to run straight 50 weight oil !!
I had oil pressure of 60-70 - After a hard run , the pressure would drop to 35 at an idle , then come back up after a minute of idling . I installed a HP Keith Eickert 3" cooler with brackets
to mount off rear bellhousng - An excellent location for plumbing
and short oil line plumbing .
Results ;
PRessure of 60-70 @ idle
After hard run , 1-2 minutes WOT , the pressure at idle
drops only to 60 lbs. @ idle
Motors HP500

Good Luck

Who sells the permacool t stat??

Summit or jegs

My thermo coupler is mounted after the
 

Eddie Marine oil cooler. Mine was in the pan and Gary Grimes of Twister Motors (Atlanta) moved it. He located it after my Eddie Marine oil cooler. Gary said it's nice to have it in both locations. If you only have one put it right b-4 going into the engine. He told me to not run hard until I see 180* and it is starting to get hot above 230*. Remember this is after the cooler. You will see much higher temps in the pan.
I have a 540 N/A 683 hp with a Gil 14 qt pan.
My problem I don't have an oil stat. It takes a little while to see good temps to run hard. At 3000 cruise I will see about 200 to 210. Never gets over 225.

umm,,, the cooler only drops it like 15 degrees, so I doubt the hose to the remote and the oil filter block would drop it 10, if so the hose back would drop it another 10 and we wouldn't need a cooler at all. :D

The sender on the remote block sees the oil temp right at the end of the hose from the block before going thru the oil filter etc I would think drop would be 1-2 degrees at most. The pat answer as you have said is "because its better" just wondered if anyone had any real hard data to back this up like "we had a temp sender in the pan and in the remote and saw this difference". I have never talked to anyone builders/owners who has ever had any data to show in the pan is better more accurate.

I am not in favour of the remote over the pan by the Way. Its just much easier to rig this to add a temp guage to an existing installation. If I was dropping in a new engine I would probably install the pan sender.

I typically see 245 WOT 220 cruise with a stock 502 Merc cooler. This is the 13 " cooler ( the 454 mag is 10" and the 7.4L is the small 8" or dual one. The 7.4 one is much to small IMO after upgradeding the engines power to answer the original question