How often do you change your motor oil?
 

I have a 1999 HP500 with about 120 hours on it, I run Mobil 1 15-50 with a Mobil 1 oil filter and have been changing the oil every 25 hrs. We have a 20 minute idle to and from the dock/lift, and I'm concerned about all that idle time, hence I have been changing the oil so often. What do you guys think?
TGIF,
MD

Should be okay with every 25 hours.
I also do it every 20-25 hours.


Another very important thing to remember is not only hours on the motor, but time as well.

Even if you only put like 10 hours in 3 months, you should change it anyway. Engine oil can get very acidy(corrosive) from combustion byproducts.

3 months is about the longest I'll leave oil in any engine.

BD,
Thanks, the last time I changed it was in Aug, so it appears to be working out about right! What oil/filter do you use?
MD

Dean,

I usually just end up using the Merc Tall Filter. I haven't experimented too much yet. It's just too convenient buying it at the marina. :cool:

Changed oil every 20hrs or unless we were doing some unusually high rpm runs like a Poker Run or racing around burning gas at WOT all weekend! Oil was allways still just a couple shades darker then it was when clean but i still felt better changing it......till i switched to RedLine then i changed oil every 30-35 hrs and it was the same as the reg oil.....plus the $8/quart makes me stretch it out a little longer! :D

Oh by the way...I used the AC Delco PF35L filters only but here is a list of the filters that should fit the 454/502 engines:

Oil Filter
FYI:The thread type on the filter is 13/16-16.
Fram:PH5,PH13, HP4
Pureolator: L34631
Purolator Pure One: PL34631
AC: PF1218 AC Delco PF35,PF35L (synthetic) PF1218
Motorcraft: FL-12A
NAPA: 1060
Wix: 51060, 51061
K&N: HP3002
Amsoil: SDF-24
Hastings: LF279
Fleetguard: LF653
Mobil 1: M1-302

HP500s also. Every 20 hours with Merc oil and their "racing" filter.

Change oil every 20-25 hours / use Valvoline 20-50 Racing oil with Wix filter. But like Wally said - It depends on the type of running.

We change once a season or every 20hours, whichever comes first.

500 efi'S

20 Hours Max

Mobile 1 15W-50

Fram HP4

This worked great on my last boat. 200 Trouble free hours.

Thanks guys, great info. I'll be in the bilge this sunday!
MD

It depends on your driving habits and what temp the oil is seeing when run most often. If the oil stays around 220* or less, from my experience, 100hrs is fine. If the oil gets to 260*+ regularly, I would say 20 hrs is appropriate. Oil looses its cushioning effect from contamination and heat. If either one are suspect, more changes are better.

BT :cool:

I change my oil every season or 50 hrs which ever comes first. I use 40 wt Castrol. I've been doing this for longer than I care to admit and never had a problem. Of course I have always had stock motors. Plus I don't run hard. Now I have a 454 mag carb. If I had an hp 500 I would probably go with 20-30 hrs.

I have bone stock SBC's. I change the oil once a season which is about 100 hours. No need to change it more often with these motors and the type of boating I do. If it was a poker run boat I would probably change more frequently.

I always change about every 60 days during the spring-summer. That means I have fresh oil in it when winterized, believe it or not some leave the old stuff in all winter!!:rolleyes:

Every 20-25 hours ,,, Royal Purple straight 40 weight racing synthetic, and a Mobile 1 M1-302 filter.

Jua thought from an "old " filter man!!!!!!!!
When I worked in a manufacturing plant MAKING FILTERS, Our brand name filters that failed our standards that would still pass FRAM's specs became Fram filters.
My 2 $ worth
I wouldn't put Fram filters on my kids go-cart.
Hope I didn't offend anyone but if my rejects would pass another MFG. specs. I wouldn't run anything they made

I use 40 wt VALVOLINE RACING oil and the NAPA racing filter.
I change the oil twice a year. About every 40 hrs. I don't run it that hard.

The March Family and Performance Boating Magazine will have an article on oil filters. There is something that most people don't know about the Chevy automotive filters. Because the Chevy automotive engineers were aware that oil will run out of the filter if the engine sits for a period of time they mounted the oil filter in the vertical position. Almost all other engines have the oil filter mounted at an angle and need an anti drain back valve in the filter. Without an anti drain back valve the engine will have to refill the oil filter with oil every time the engine is restarted (zero oil pressure to the engine while the filter is being refilled). Chevy automotive/truck oil filters do not have an anti drainback. Some Mercruiser engines have the (remote) oil filter mounted upside down and some are on the side. These engines need oil filters with an anti drainback valve. The only Chevy oil filters that I have found with the valve (after cutting open many filters for the magazine article) were the Mercruiser and Fram HP series filters. You should use one of these filters for any Mercruiser that
doesn' t have the filter mounted vertically. Many other things in the March issue that are interesting, be sure and read it!
Sincerely
Dennis Moore
FAMILY AND PERFORMANCE BOATING MAGAZINE

I change mine about every 15-20 hours. stock Mercruiser filter and Valvoline VR-40 synthetic.

Dennis,
I just changed my oil and installed a Fram PH5, which is on a HP500 stock oil thermostat which mounted horizontally as you know. I'm thinking that I'm should go buy a HP4 or HP5 and swap it our before I go boating this weekend. I really don't like the idea of low/no oil pressure until the oil filter refills.
What do you think?
Thanks for the great info. and heads up about this potential problem.
BTW, I loaned my neighbor your book, "Big-Block Chevy Marine Performance" and he loves it.
Dean

Dennis,
From your testing of filters are you saying that the PF25/PF35 don't have anti drain back valves? What about the PF1218.

I cut open a Merc filter and the only thing I saw was a rubber type material that layed across circular series of holes. Is this the anti drain back valve. I believe the PF1218 and PF454 have this as well. Do you agree.

Finally, are you aware of the part # for a filter in the AC line that meets this criteria and is about the same height as the standard Merc filter.

Very informative info., can't wait for that months issue to arrive.

Thanks,
Rick

Interesting,, but rather I would think this makes a case for changing your mount to a vertical style so you can use a decent filter, the FRAM's run 5 degrees hotter oil temp at wot in my experiance

What would be really great is to see a real technical article on something like Oil filters, you know take 10 dif brands cut them open compare a dozen different features , and test them in real world for flow, max oil temp, sensitivity to condensation (does condensation plug them up after idleing thru the channel for 30 min and open the bypass) then send away a sample to analyze the oil for particulates after the 1/2 hour idle and maybe 1 hour hard run.

P.S. the napa Golds also have anti drain back valve. They are made by Wix I think and so the wixs prob do to but I am not sure, anyone ever cut open a WIX can enlighten us maybe?

Can anyone answer this question for me on AC filters.

Does a PF25/PF35 have anti drain back valves? What about the PF1218.

I cut open a Merc filter and the only thing I saw was a rubber type material that layed across circular series of holes. Is this the anti drain back valve. I believe the PF1218 and PF454 have this as well. Do you agree.

Finally, are you aware of the part # for a filter in the AC line that meets this criteria and is about the same height as the standard Merc filter.

RV,
YES...the rubber material covering the holes is the anti-drainback valve. it's not sophisticated and it's not much of a "valve" but it does work!

every 10hrs, HP4 with either Valvoline or Kendell 20w50

Dave,
Thanks for the reply.

Oil Filters
 

RV,
Sorry it took so long to get back to you but I was in Las Vegas at the SEMA show looking at all the latest high performance parts for the magazine.
The PF25, PF35 and PF 932 do not have oil drain back valves and I have yet to find a Chevy filter of any kind other than the Fram HP and the Mercruiser brand filter that have the anti drain back valve.
Don't be so concerned about buying an AC Filter anymore (like I have always been). I recently found out that they are not made by AC Delco anymore but are made by an aftermarket company and are of the exact same quality as everyone elses aftermarket filter. I believe they are made by Champion Labs.
They are identical to many other filters on the market and look exactly like the Mercruiser filter but without an antidrainback valve.
I have always gone out of my way to buy AC Delco products believing them to be the best. I recently read in a trade magazine that AC Delco is now only a wharehouse distributing products that have the AC Delco logo and that they manufacture almost nothing anymore. That was really disappointing for me to read!
Sincerely
Dennis Moore
FAMILY AND PERFORMANCE BOATING MAGAZINE

Why not just buy Mercruiser filters?

Every 20 hrs. Engines & drives...
Kendal 50 racing......HP4 filters....
Merc Hi-Po fluid

Rick,

Yes, the rubber flapper is the drainback valve.

I cut open a Mecury filter and a Sierra filter and they are exactly the same. Manufactured in the same plant, same materials - exactly the same. In fact, one of the mechanics told me that they have even received Mercury boxes with Sierra filters or vice versa. I have not looked at any of the others but I would be willing to cut a few open and check them out. They are only a few bucks a piece.

I think I still have the mecrury filter if you are interested in checking it out.

Steve

I have to agree with Sun. Why try to save a few bucks on something so important. Mercruiser is not going to use oils or filters that could harm their engines and cost thousands in warranty problems. I agree that Mercruiser doesn't make their own oil or filters, but its all made to their specifications.

FYI

As a result of this thread I have done some research of the oil filter topic. I have always used the AC PF-35 with excellent results.

I contacted AC delco via e mail and ask them to explain the difference between the PF-35, PF-35L, & the PF-1218.

Their response was "the only differences are that the PF-35L is a little shorter than the other two, has a higher micron rating and the PF-1218 has an anti - drain valve."

I will more than likely be switching to the PF - 1218 at the next change.

Be safe,
Mark

My next Oil change, I'll be using good ol' Factory Mercruiser

Good Info
 

Thanks for clearing that up!
Dennis Moore

Dennis Moore,

What is your opinion of Kendall GT-1 oils? I have been using straight 40 wt but have had moisture problems (not the oil's fault)

I run straight 40 VR valvoline.

Dr Nautica,

Do I know you? I think that I do. If that is the case when you redid your engine did you eliminate the thermostat and go with a crossover instead? If you did its more than likely a simple fix if you are just getting "condensation" type of moisture problems under the valve covers etc. Had the same problem on my last boat after I "played" with it. Went back to the Merc. thermostat and water pump and problem solved. With the crossover and no thermostat the oil does not get hot enough to evaporate any water out of the engine. My temp guage with the crossover would barely reach the bottom of the scale. Way to cool. If you are the Dr. Nautica I am thinking of then you know that we boat in the same water.

Next step would be to add a spacer between your exhaust manifold and riser to help eliminate any reversion from the exhaust. Don't know your cam specs but it does sound on the healthy side. Where do you have your idle speed set? I would set at 750 min. and more than likely with your set up 800 or so. Higher idle speed will also help eliminate water reversion from the exhaust.

Be Safe,
Mark

I use Valvoline straight 40wt Racing oil. From what I was told the non-racing oil has detergents in it, but I have used that as well. I have oil thermostats, large oil coolers and use the K&N HP-6 oil filters that are mounted vertically on my engines. I usually change out the oil every 15 hours on my engines and drives. My engines have hyd roller cams and see A LOT of idling time.

The K&N oil flters are supposed to have excellent filtering qualities down to so many microns (can't remember how many) and a better tolerance burst rate which means that they're supposed to have excellent flow charactoristics as well. Not sure how well they stack up to other brands though.

Anyone hear or experience anything on the K&N's ?