Wes Burmark

My stock oil cooler has 3/8" lines (6.2 MPI - twins in a 29' Fountain Fever).
I replaced the port cooler with one that has 250-300% more area (moved from 9 to 12" length, 2 to 3" diameter)
yet saw little difference in oil temps between port and starboard engines. Is it possible that the 3/8" lines
do not flow enough to take advantage of the larger cooler? The new cooler is set up for 1/2" lines.
I would love to hear comments from those who have actually changed oil line diameters.

Wes Burmark

I have 50+ psi oil pressure hot. Should be plenty of pressure for engines that spend the majority of their time in the 3000 r.p.m. range.

articfriends

iTrader: (1)

I did on a big block and saw immediate difference but small blocks dont need or pump as much oil so not sure? In my case I am positive the bypass relief was opening and pump bypass was prob also opening and oil was never getting to the cooler, Smitty

ezstriper

I know the std BB merc stuff is real restrictive with lines, fittings and adapters, I changed all of mine and ran #10 line

Wes Burmark

BORGIE - Sorry, I now understand your comment. A high volume oil pump might make a difference, correct?

EZSTRIPER - I am leaning towards replacing all stock Mercury plumbing, remote filter adapter, block adapter, and lines with #10.

Wes Burmark

Thanks BORGIE

The new coolers are set up for 1/2" pipe plug. I'm not sure if that would be 8AN or 10AN lines. I will be looking into a block and remote filter adapters that will accept larger lines.
If someone has used a particular brand I would would love to hear about it.

mike tkach

iTrader: (3)

i use -12 for oil lines.i would also add that the pressure releif valve in the oil pump also controles oil pressure.a stiffer spring will raise the pressure .

ezstriper

the bypass relief spring just opens and oil bypasses the filter cooler with the stock stuff, 1/2" is #10 I used aeroquip twist lines

stimleck

borgie my pressure on a stock 502 mag ranges from 20 -40 should I make this modification?