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GT-40 Oil

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Ajskier View Drop Down
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    Posted: November-03-2017 at 8:06pm
Good Afternoon All,

I am looking for some advice after I have read about as much as I can regarding oil for my baby. I purchased the boat about 3 years ago and I have been using the same oil that the previous owner did in the boat, which he was using the same oil that the original owner was using who was a promo driver.

With that being said the previous two owners were using Mobile 1 Full Synthetic High Mileage 10w-40. I have not had any issues with the boat using that oil, but after reading as much as I could about the proper oil for these motors and contacting PCM directly. I have a few questions that I am hoping that you all could answer for me. I was not really confident in the answers, that I got from the person I spoke with at PCM, she really didn't seem like she knew much about these motors and I am thinking what she was telling me was information for the newer motors,

1) What are you thoughts on the current oil?

2) From the research that I have been able to do, it seems that people are using a few different kinds of oil, but the key thing is to make sure that it has a high ZDDP rating. I looked up the current oil that I am using and it has a ZDDP rating of 900 PPM. Is this to low and what should be the minimum level that I should be looking for?

3) I know that this one is a loaded question, but what best oil I should be running in the motor? I have seen Racing oil or Diesel oil recommend by some.   I have a friend that I ski with that is using Delo 400 SDE 15w 40 in his boat and he swears by, not sure why, but that is what he runs.

4) Is straight weight recommended, which the racing oil comes in or does that aspect not really matter?

5) I have talked to some mencanhics that say to always run the same oil in a motor and to not change from what has always been used. Is there any truth to that or is that a old wives tale?

6) If I do change oil, is there anything that I should do to flush the old oil out?

If there is anything that I should be asking, but didn't, please tell me. I really appreciate all of your help and knowledge.

Thank you,
AJ
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SNobsessed Quote  Post ReplyReply Direct Link To This Post Posted: November-03-2017 at 8:37pm
Many guys here are using Valvoline VR1 20W50.

It has high ZDDP & normal additives.

Oils are pretty much compatible so I wouldn't worry about flushing - but do change filter.

“Beer is proof that God loves us and wants us to be happy.”

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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: November-03-2017 at 8:43pm
Maybe you've just started another oil debate

What I figure is that since you're a Mobil 1 type of guy, why not just put in Mobil 1 15w50.

It has the zinc levels you're looking for (about 1200 PPM)

You'll probably get other recommendations of what to use based on people's personal preference

There's no best oil that everybody will ever agree on
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 63 Skier Quote  Post ReplyReply Direct Link To This Post Posted: November-04-2017 at 1:30pm
Two posts, two good answers. I use the VR1 20W50. Ken's suggestion is excellent. Either is a win, I would suggest changing from current oil to one of those two options. No issues with changing oil, no need to flush out old oil, no need to run straight weight, run a good quality filter.

What do you have for a boat?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Nautiquehunter Quote  Post ReplyReply Direct Link To This Post Posted: November-06-2017 at 11:35am
I checked with Mobil . Mobil 1 15w50 is the only weight they recommends for both flat and roller lifter engines. You still have to change every 50 hours
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: November-06-2017 at 2:36pm
Mobil 1, 15W-50
Available at Walmart for $23 for 5 quarts
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ajskier Quote  Post ReplyReply Direct Link To This Post Posted: November-30-2017 at 2:41pm
Good Afternoon All, I just wanted to pop back in here and let you know what I ended up settling on for oil for the boat. I was able to locate straight 40 Valvoline VR racing oil and that is what I ended up putting in her before I put her to bed for the winter. Again, I really appreciate everyone's help and guidance.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DW SD Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 1:30am
I use straight 40 weight as called out in the manual. I select a reputable brand. Brad penn, Joe Gibbs, redline, royal purple, Delo, Rotella, mobile 1 I also as suggested consider zinc levels given the flat tappet camshaft.
Easy to over think it.

I do have to laugh a bit when folks say “this is working for me.” You really don’t know how well it is working unless it explodes or you tear it down and measure wear.
No offense anyone.
And no I’ve not torn down to measure myself. I think of name brand as insurance. And then apply some blind faith.

Doug
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 1:45am
1200 ppm ZDDP (for the flat tappets) formulated Into any modern oil will probably do the job. Our engines don’t rev high, don’t suffer low temperature starts, and oil is changed frequently—almost wastefully at 50 hours.

If you want to run your boat 3000 plus hours, you probably can on any decent oil, but if you want insurance (I liked that) you’re not going to go wrong with a synthetic. It’s when we let our engines freeze or get too lean or too hot that we kill them before their time. There are soooo many threads here already on this.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DW SD Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 1:48am
One day I will send an oil sample for the GT40 to black stone labs and see what they say about oil change interval at 50 hours.

I am guessing they will suggest trying 100 hours. Even that isn’t long compared to a car’s interval.

Doug
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 2:14am
I’d love to see a ski school send their oil out for trend analysis as it’s probably the only way we will ever get to see Long-term wear. They’d also be in a good spot to run different oils with a fleet of the same boat/engine subjected to the same wear cycle.

I participated in a long-term study using oil trend analysis at a big flying school with a fleet of IO-360’s designed to convince the FAA to extend drain intervals from 100
Hours to 200 and to extend TBMO to a much greater interval. The physical wear evidence was compelling. The duty cycle for training aircraft is pretty tough.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote phatsat67 Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 10:20am
Originally posted by DW SD DW SD wrote:

One day I will send an oil sample for the GT40 to black stone labs and see what they say about oil change interval at 50 hours.

I am guessing they will suggest trying 100 hours. Even that isn’t long compared to a car’s interval.

Doug


I would also be interested in what they have to say. Using Rotella and an FL1A filter is so cheap though it's almost not worth extended intervals. If it was a 100 dollar oil change that may be different.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 10:27am
Originally posted by phatsat67 phatsat67 wrote:

Using Rotella and an FL1A filter is so cheap though it's almost not worth extended intervals. If it was a 100 dollar oil change that may be different.

The extended interval may be worth the savings for those who don't do the service themselves. The marina charges sure aren't like driving your car into one of the quick lube spots!!!   


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Post Options Post Options   Thanks (0) Thanks(0)   Quote phatsat67 Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 10:37am
True Pete. Can I send my impellers to you for extended service interval analysis?! ha.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 63 Skier Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 10:52am
Like most here I change oil/filter each season. Sometimes that's 20 hours, sometimes that's 70 hours. If oil analysis told me I could go 100 hours between changes, I'd still change each season. I really don't want to think about it any more than I do now, not have to put a mark on the wall to tell me which year is the oil change year, or keep a log with my hours. If I was using a boat 200 hours a season I'd be more interested in where I could go with intervals.

Like Zach said, it's pretty cheap and very little effort. Plus, an oil change makes me feel good.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 11:09am
Zach—LOL. Impellers seem like a weak link waiting for a solution! I sure would (no pun intended) like to see an end suction volute with a stainless or bronze impeller as a fix for this but I’m getting better at replacing my impeller now that I’ve marked my pumpw to prevent misassembly! Like an oil change, changing my impeller makes me feel good too.

Trend analysis on an impeller so far; 80 hours and no visible wear but it’s now my backup. Wonder what wears them out faster; Dirty water, sand?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 63 Skier Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 11:19am
Besides the boats, we used to have the same type of jabsco pumps in a factory environment. I'm convinced that 10 seconds of dry running does more damage than running 100 hours in a murky river. Beyond that I think it's just time from manufacture, the rubber impellers degrade over time. When someone has an impeller crack for no apparent reason, short life and no running without water, I always wonder if it was sitting on a supply house shelf for 6 years before being sold.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 11:21am
Originally posted by tryathlete tryathlete wrote:

I sure would (no pun intended) like to see an end suction volute with a stainless or bronze impeller as a fix for this


Trend analysis on an impeller so far; 80 hours and no visible wear but it’s now my backup. Wonder what wears them out faster; Dirty water, sand?

Peter,
You had better start looking at the SPSH ratings on centrifugal pumps.

Yes, sand is bad but I'd say 90% of failures can be attributed to running rubber impeller RWP's dry.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Duane in Indy Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 11:30am
Like Zach said, it's pretty cheap and very little effort. Plus, an oil change makes me feel good.

Another thing to think about:   our engines typically run very cold in comparison to airplanes and auto engines.    Heat burns away the moisture and acids that form in oil. Without that heat (as in our cooler engines) this process will not happen
Bottom line is that oil is cheap, change it often.    Just my theory,    Duane
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Duane in Indy Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 11:34am
Originally posted by 63 Skier 63 Skier wrote:

Besides the boats, we used to have the same type of jabsco pumps in a factory environment. I'm convinced that 10 seconds of dry running does more damage than running 100 hours in a murky river. Beyond that I think it's just time from manufacture, the rubber impellers degrade over time. When someone has an impeller crack for no apparent reason, short life and no running without water, I always wonder if it was sitting on a supply house shelf for 6 years before being sold.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote SNobsessed Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 11:36am
Agree on moisture evaporating with heat, but can't see how heat will neutralize acid.

I thought only an alkali could do that.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote phatsat67 Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 11:56am
If my boat is on a trailer I always dry fire it before I head to the lake. I turn my impeller backwards in the housing in the winter when I remove the belts. I usually get 3 seasons and 200-300 hours of service out of them. They just start to lose pumping abilities and get a little hot after a long hard run then back to idle. Never actually had one come apart not sure how people manage that.

I always turn them by hand before I start in the spring. They can get stuck in the housing and the initial start tends to rip the stuck blade off sometimes (have seen plenty taken apart that way). Hand turning prevents the large amount quicker force from the starter on first turn over dry.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 12:10pm

Peter,
You had better start looking at the SPSH ratings on centrifugal pumps.

Do you mean NPSH?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Duane in Indy Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 12:16pm
Originally posted by tryathlete tryathlete wrote:


Peter,
You had better start looking at the SPSH ratings on centrifugal pumps.
Do you mean NPSH?


I Googled SPSH and found the best Spanish Rice Recipe ever.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gary S Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 12:17pm
Originally posted by 63 Skier 63 Skier wrote:

   When someone has an impeller crack for no apparent reason, short life and no running without water, I always wonder if it was sitting on a supply house shelf for 6 years before being sold.


Genuine Sherwood impellers have a date of manufacture on the package. I'll bet some failures are due to not using oem parts as well. There are people out there that can bend a crow bar in a sandbox
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tryathlete Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 1:12pm
Originally posted by tryathlete tryathlete wrote:


Peter,
You had better start looking at the SPSH ratings on centrifugal pumps.

Do you mean NPSH?


I see what you’re talking about—might need to watch self-priming and cavitation with an end auction volute centrifugal pump. Yeah the neoprene does have a very positive ability to self-prime and draw from negative head pressure.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: December-18-2017 at 1:26pm
Originally posted by tryathlete tryathlete wrote:

Originally posted by tryathlete tryathlete wrote:


Peter,
You had better start looking at the SPSH ratings on centrifugal pumps.

Do you mean NPSH?


I see what you’re talking about—might need to watch self-priming and cavitation with an end auction volute centrifugal pump. Yeah the neoprene does have a very positive ability to self-prime and draw from negative head pressure.

Yup, NPSH - sorry about the typo. Interceptor had an optional RWP centrifugal on their Y blocks. It was meant for deep hulled cruisers where the engines sat well below the water line. I know a friend who ended up with one of them, rebuilt the engine and dropped it into a runabout. He could never keep the pump primed and ended up putting a shaft driven rubber impeller RWP on it.


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