1989 Silverton 34' motorcruiser oil filter

[Mike Thompson]

Recently bought this old boat and trying to bring it up on maintenance. She has two Mercruiser (GMC) 454 inboards, and the existing oil filters are orange can PH8A. [censored]? While these engines have a few mods to make them more marine useful, I can't imagine they would have changed the oil filter type? PH8 are for Fords, no? Since they obviously screwed on, something must be happening that works, so guess I shouldn't be too worried. Anyway any suggestions for the right filter?
**Sidenote
I don't want to start another endless "best" oil thread, but looking at Rotella HDEO 15-40, don't want to spend a fortune on fancy oil. Any reason this won't work? Engines run well, hold 40+ lbs pressure, no cats of course. To be changed once annually, maybe 200-250 hrs.

 

[JayhawkRoy]

PH8A has quite a few applications beyond Ford. Mercruiser applications include 188, 235, 255,555 models of engines. You need to know which model of engine you have, as I see it. I would not assume the PH8A application is incorrect at this point.

You can review all applications on line if you wish. They include quite a few off road applications.

If you don't like Fram, you can cross reference to the filter of your choice.

 

[440Magnum]

PH8A (or equivalent) is probably the most widely used single filter format ever. Ford, GM, Chrysler, AMC all used it. I run it on both my big-block Chryslers, it works on the Jeep 4.0 as an up-size with the same bypass pressure as the factory half-height filter, it was OEM on my smallblock Chryslers in the past, my Ford 302, my folks' old Mercury... LOTS of applications. I'm sure that both Mouse and Rat Chevy blocks used it stock at various times depending on chassis constraints.

 

[AuthorEditor]

Does it have remote oil filters or are the filters on the engines? The PH8 would be replaced by lots of filters. Fram Ultras XG8A is highly respected around here. At the lower cost end of things I have had good service using Motorcraft FL1A filters. I think the Wix number is 51515 or the Napa Gold (same as Wix) is 1515.

 

[Mike Thompson]

Jeez, learn something new everyday. I always thought the PH8A was a ford filter, probably just go with the Motorcrafts. These are just screwed on the block like a car, I think they were running straight 30 or 40 oil, must have been doing something right as the engines have 2700 hrs on them.

 

[CarbonSteel]

Originally Posted By: Mike Thompson
Jeez, learn something new everyday. I always thought the PH8A was a ford filter, probably just go with the Motorcrafts. These are just screwed on the block like a car, I think they were running straight 30 or 40 oil, must have been doing something right as the engines have 2700 hrs on them.
How long will the filters be in service? I would consider using a wire-backed media filter if they are going to be used in a harsh or severe duty environment.

 

[Donald]

Rotella T 15W40 is good oil for a marine engine. The Fram orange filters are OK, but there are better for the money.

I would be more concerned about the gas and gas filters if its been sitting for awhile.

Does it have a genny also.

The big block GM engines are used a lot for larger boats. Bring lots of $$ when you fill it with gas.

Look for duct tape and wire nuts. Both indicate some non professional marine work.

 

[Tuffy1760]

Motors pretty solid... I would run some serious gas conditioner thru it first few tanks... fuel filters gotta be changed asap... I did the proto work on the windows and doors for that boat...

 

[DoubleWasp]

It was quite common at one point in time for external adapters to use the PH8 filter. Probably more PH8 external adapters built than any other type.

Reason is, the PH8 has a bypass. We're they to make the adapters for GM style filters, they'd only be good for GM engines especially, since most GM V8 filters have no bypass (bypass in block). A PH8 adapter can be used on almost anything.

Ultimately, Mercruiser, VP, and others did start using oil filter adapters that use GM style PH5 filters.

Toss on a couple of XG8 Ultra filters and enjoy.

For oil, just use a good 15/40 HDEO for 50 hour OCI's. Feel free to use a synthetic HDEO for 100 hours. Most OEMS approve of syn for 100 hours.