Turbojack

Just found my pictures. Someone on another thread was wondering if the oil came in or out the center. There were answers both way. As you can see from oil pump oil goes to outside of filter.

Turbojack

Here is one of oil filter pad. You can see with wires installed where passages go. See where wire goes thru side hole & center hole on oil filter pad. If you forget to put bypass in or the 11 psi bypass & use a oil cooler the bypass will open up & oil not go thru the cooler or filter.

Turbojack

Last one is to show you if you use the oil cooler passages on the block & do not use the special adapter that GM sells your oil is not going to go thru cooler.

Dork

Excerpt from Speed Reading - GM performance Parts.

Gen V and Gen VI big-block crate engines come with two oil pressure bypass valves installed in the engine blocks. Both of these valves are rated at 11 psi pressure differential. One valve is for the oil filter and the other is for the production oil cooler. If you install an after-market oil cooler or remote oil filter that attaches to the oil filter pad on the engine block, you should be aware that you need to change the oil filter bypass valve in the engine block. When you use an after-market cooler or remote filter that attaches to the filter pad, you are using only one of the bypass valves in the engine block. The after-market oil lines add resistance which will cause the bypass valve to bypass the after-market oil cooler and/or oil filter all the time. Obviously, if the cooler and filter are bypassed the oil will be dirty and hot. Your engine will run hotter and could be damaged by dirt in the oil. If you choose to use an after-market cooler or remote oil filter that attaches to the filter pad, you should change the bypass valve to one with a higher differential pressure rating.
A good choice would be GM # 25161284 which is rated at 30 psi. Remove the valve that is closest to the crankshaft and replace it with the new valve. Press the new valve into the engine block and stake it in three places. You should note that the bypass valves don't need to be changed if you use a production oil cooler which uses the production holes in the engine block and you don't use a remote oil filter. Also, if you use an adapter that just angles the filter for clearance you don't need to change the bypass valves.

Turbojack

Only problem with the "production oil cooler" is it is for automotive/Truck. It is not a marine cooler. Important - DO NOT USE THE FITTINGS IN THE BLOCK FOR YOUR OIL COOLER unless you get the GM hose & adapter

tomcat

Good pictures Turbojack. Scott, there doesn't need to be anything in the center hole unless you are diverting oil to the GM oil cooler holes in the block. Leaving the bypass valve out of the center hole saves the oil from making three turns inside the block. You need to check the bypass valve spring in the off center hole. If you have a 30 psi spring on hand you can easily tell if yours is the right spring by squeezing them.

Scott

Thanks Tomcat
I replaced the spring in the off set hole and yes I could tell the difference in the spring tension.

JaayTeee

Scott,
I remember reading some of you other posts,
and recalled that you broke a lifter in one of your
engines.

Is the motor with the lower oil pressure
the one that puked the lifter ?
One of mine also puked a lifter,
and it will lose about 10 psi after running
above 3500 rpm for a while, the other
engine stays a 65 psi.

I bought oil temp gauges, and connected them
up to the senders installed at the factory,
both engines read identical oil temp (220*
running hard)

It sounds like we may have similar issues.

Am I correct to assume the engine has to
be removed from the boat,
to get the bypass valve out of the
block, or is there some kind of extractor tool ?

jt

Scott

Yes to all of the above! Kinda strange isn't it?
I will edit my post about the valve when I said I could tell the difference I was referring to the spring tension on the bypass valve not my oil pressure.
I shot my remote oil filter pads and oil fittings with a infrared thermometer and got 170* on both engines. What is really strange about all this and if you have been following my posts is that my redline gauge light is starting to come on again after I come down to a idle but the gauge reads about 18 to 20 lbs Soooo I am going to assume I still have some type of electrical problem along with about 10 lbs less oil pressure on that side. I still have no clue why this followed that engine (lifter failure). BTW it also has a new Mellings HV oil pump and still no change

Scott

I pried it out with a screwdriver and yes plan on pulling it out the valve is on the filter pad. I doubt if it will change your pressure I just did it because I was putting in another oil pump and that was a guess Let me know if you come up with anything!