Mercruiser (GM) 4.3l UOA x2 Delvac 1300 11hr and 37hr OCI

[PMT133]

Good morning everyone. This is my first post here but nowhere near my first time here. Been lurking a long time and finally had enough of a reason to sign up. Me? I'm an engineer with experience in labs in chemical industry. Currently a QC guy/operator for a plant. My engineering background is in chemical/petro chemical.

To keep a long story short, this is technically the third iteration of this engine in this boat. I repowered May of last year with what I thought was a good low hour used rebuild. That died of water ingestion due to neglect of the previous guy. (I should've known better) To quote my machinist... "the bores were as rough as the surface of the moon. How this thing made no noise and didn't come flying apart I will never know. It was a fresh rebuild at some point... I guess." Post rebuild it is a vortec roller engine circa 2003 with new internals. I had a problem last year of seeing moisture in the manifolds which has been corrected by installing the correct cooling system configuration for my M.Y. So it is now the third iteration. The water seen was condensation formation best we could tell.

Anyway, I occasionally see some light vapor from the breathers which seems to be normal. I don't get any condensation on the valve covers or oil fill cap. I've attached the UOA for the first two changes below. Some things to note, I can only do an oil change by extraction pump, I have no pan drain due to the dip stick configuration. The extraction pump was new, and could potentially be the reason for the higher silicon levels? Delvac 1300 15w-40 flavor of choice.

First oil change 11 hours:

Note the thinning in the short time...

Second change at 37 hours (48 total):

Some things to note on the second interval. I added a remote oil filter mount in the middle of the interval. Uses a standard pf454 style filter. I replaced the filter bypass spring in the boss in the block. There was a quart of 25w40 quicksilver make up added to it during this interval as well as a splash of delvac... it is what I had laying around. Again with the thinning.

I don't think wear is out of line here being still near a fresh rebuild. I do think my engine doesn't like delvac 1300. My machinist recommended it, I have a ton on hand as I run it in the 33 with the twin diesels but am open to other suggestions. The silicon and sodium stand out to me. Could be from the new extraction pump I suppose or something else lurking. I have pressure tested the block and my machinist tore it down when I found the water and checked it again. Everything seems kosher so we left good enough alone.

Any further insight or interpretation is appreciated.

-Paul

 

[fantastic]

Si is very high & only wear metals that have come down are Pb. Si must be from the work you've done. Yeah, that diesel oil may not like the higher RPM's of your boat, or Si loading, but probably still thicker than what it spec's originally. Just keep at it as you are & congrats for joining or coming out of lurking mode.

 

[PMT133]

Si is very high & only wear metals that have come down are Pb. Si must be from the work you've done. Yeah, that diesel oil may not like the higher RPM's of your boat, or Si loading, but probably still thicker than what it spec's originally. Just keep at it as you are & congrats for joining or coming out of lurking mode.

Thank you sir. And I kind of was figuring that. The higher SI could also be from the small dust left from doing all the glass work on the boat too thinking about it. (Total gut/rebuild) While the flame arrestor cleans some out, it isn't a filter per say. I am running a wix 57099 for this OCI and probably for the foreseeable future.

Also, I believe @LouC is over here. What say you compared to your 88? Similar boats and environment.

 

[LouC]

Ok looked at yours, and yes the SI is high and I think you're right that it may be from all the 'glass work. The other wear metals may really just still be break in, so I'd just monitor it. I also have Blackstone reports on my engine going back to 2011, I had high metals wear and sodium, (salt water cooling) what was happening was the head gaskets were starting to leak but I never saw any water in the oil. Had a bad overheat in 2013, still had the high sodium, and wear metals, then the head gaskets finally really let go in 2016 and I started getting water in a cyl. So took it apart & replaced the cyl heads (cracked from overheat) and new center riser exhaust. Did a few oil analyses after the repairs and the wear metals gradually came down over time and no significant sodium showing up. After the first analysis on this report (2011, used Delo 400 straight 40) I have used Merc oil (25/40 conventional then later on for the last analysis I used the syn blend 25/50) and with all the Merc oils none of them thinned in terms of viscosity. I know the guys on iboats think the Merc oil is a waste of money, but this has been my experience, expensive, yes, but it holds up even in an old engine with the original short block (OE pistons and rings too, from 1988!). Notice also that the Merc 25/50 syn blend has more than average amount of zinc, 1242 ppm vs 937 ppm for the 25/40 conventional. This is a good bit more than any of the other conventional oils I have seen. Since I'm changing the oil once a season, I don't mind spending the money to get good results. Another less expensive but probably very good option is Valvoline VR-1 20/50, this has 1400 ppm zinc.

 

[fantastic]

Ok looked at yours, and yes the SI is high and I think you're right that it may be from all the 'glass work. The other wear metals may really just still be break in, so I'd just monitor it. I also have Blackstone reports on my engine going back to 2011, I had high metals wear and sodium, (salt water cooling) what was happening was the head gaskets were starting to leak but I never saw any water in the oil. Had a bad overheat in 2013, still had the high sodium, and wear metals, then the head gaskets finally really let go in 2016 and I started getting water in a cyl. So took it apart & replaced the cyl heads (cracked from overheat) and new center riser exhaust. Did a few oil analyses after the repairs and the wear metals gradually came down over time and no significant sodium showing up. After the first analysis on this report (2011, used Delo 400 straight 40) I have used Merc oil (25/40 conventional then later on for the last analysis I used the syn blend 25/50) and with all the Merc oils none of them thinned in terms of viscosity. I know the guys on iboats think the Merc oil is a waste of money, but this has been my experience, expensive, yes, but it holds up even in an old engine with the original short block (OE pistons and rings too, from 1988!). Notice also that the Merc 25/50 syn blend has more than average amount of zinc, 1242 ppm vs 937 ppm for the 25/40 conventional. This is a good bit more than any of the other conventional oils I have seen. Since I'm changing the oil once a season, I don't mind spending the money to get good results. Another less expensive but probably very good option is Valvoline VR-1 20/50, this has 1400 ppm zinc.
View attachment 245555

Another great example of UOA showing something not right & the Antifreeze flag smoking gun. I bet you're happy to see all the wear metals go down and everything working well. That Mercruiser looks like some healthy oil. It has viscosity nearing 50 grade.

 

[LouC]

I just did another so I will post it up later today; it’s about the same as the one I did in 2023. Here’s what I learned, it takes a number of seasons for the wear particles to wash out. My engine had sodium in the motor oil as far back as the first analysis I did and after the overheat in 2013, it was more or less the same till I got salt water in 2 cyls from leaky head gaskets. That was repaired in 2017, the boat wasn’t really used till 2019, and each season was only 20-30 hrs. It took till the 2023 season for the results to return to normal probably due to the low yearly accumulation of hours…that’s like 4 seasons 2019-2023. I am liking the results with the expensive Merc/Quicksilver syn blend 25/50. It holds its viscosity well and has more phosphorus and zinc than most oils I have seen. So I’m going to continue using it…
Also did a compression test (all were from 160-170) and scoped the joints between the manifold & elbow with a bore scope camera (still good). In salt/brackish use this is pretty important and it only takes a little while to slide down the exhaust hoses & remove the down pipes. Then you can scope them to see if water is leaking in…..With older boats/engines I think it makes sense to to these checks at the end of each season because then you have time to fix any problems that come up….

 

[LouC]

see below

 

[LouC]