PRM 150 oil change

[Sea Dog]

5 hours ago, catweasel said:

I made a wooden "dip stick" from a piece of dowel.....

 

edit PRM told me to use mineral oil only in this box, never synth or semi.

 

Hmm, food for thought there Catweasel, ta.

 

The edit is particularly interesting since the PRM150 usually takes the same oil as the engine, in my case the ubiquitous Beta 43.  However, Beta have recently cleared the use of semi-synthetic oil in their engines, so there's now a mismatch there.  Since one of the key advantages of synthetic oils is less frequent oil changes which I don't really need, I'll stick with the oil I usually use now rather than switch.  ?

[Flyboy]

5 hours ago, bizzard said:

Yes, but they are helically cut gears so have a lot of teeth rub. From new there would be some ''running in'' fine metal dust from them. The first oil change easpecially would be important. 

I think you have not taken in account that the oil film prevents metal to metal contact.  You are correct that the first oil change is very important though.

[Guest]

1 hour ago, Sea Dog said:

 

Hmm, food for thought there Catweasel, ta.

 

The edit is particularly interesting since the PRM150 usually takes the same oil as the engine, in my case the ubiquitous Beta 43.  However, Beta have recently cleared the use of semi-synthetic oil in their engines, so there's now a mismatch there.  Since one of the key advantages of synthetic oils is less frequent oil changes which I don't really need, I'll stick with the oil I usually use now rather than switch.  ?

Yes I was surprised to see this on the paperwork when I fitted the box a couple of years ago. I emailed PRM and they reiterated the "no synth" thing.  As it happens our genny engine and box all run on the same mineral so no problem here! Our Vetus is OK on synth apparently, but after nearly 15 years on mineral I will leave well alone!

[Boater Sam]

With any box containing bronze parts, Hypoid gear oil is a total no-no.

Perhaps PRM are playing safe by saying no synthetics, mineral only. Good old 20w/50 Rock oil for me and its cheaper.

[john6767]

1 hour ago, Sea Dog said:

 

Hmm, food for thought there Catweasel, ta.

 

The edit is particularly interesting since the PRM150 usually takes the same oil as the engine, in my case the ubiquitous Beta 43.  However, Beta have recently cleared the use of semi-synthetic oil in their engines, so there's now a mismatch there.  Since one of the key advantages of synthetic oils is less frequent oil changes which I don't really need, I'll stick with the oil I usually use now rather than switch.  ?

We have Beta engine with PRM 150 box, and I use mineral oil in both.  Where did you get this from that you can use semi-synthetic in the engine, if it has no downside and increases the engine oils change interval I would be interested in that.  Don’t mind still using mineral in the gearbox.

[blackrose]

46 minutes ago, Flyboy said:

I think you have not taken in account that the oil film prevents metal to metal contact.  You are correct that the first oil change is very important though.

So why does the oil in my gearbox turn black then and where do those bits on my sump nut come from? (See post #21).

 

Does oil really prevent metal to metal contact? Surely it can't do completely? How is engine and gearbox wear caused? I thought oil just reduced contact and friction rather than eliminating contact completely.

[Guest]

8 minutes ago, blackrose said:

So why does the oil in my gearbox turn black then and where do those bits on my sump nut come from? (See post #21).

 

Does oil really prevent metal to metal contact? Surely it can't do completely? How is engine and gearbox wear caused? I thought oil just reduced contact and friction rather than eliminating contact completely.

I'm no expert on engine oil (or anything else) but my understanding is that the oil significantly reduces friction/wear, but will not completely eliminate wear, else engines/boxes would last forever. Stuff like slick 50 has been around for years which is claimed to improve wear reduction. Many discussions around on that subject!
Somewhere on Youtube there is a vid of a geezer who dumped the oil out of a Volvo car and it drove for quite a time before the engine let go. I think it was around 15 mins.

[Sea Dog]

4 hours ago, john6767 said:

Where did you get this from that you can use semi-synthetic in the engine, i

Beta themselves - it's now on their website...somewhere!

[ditchcrawler]

11 hours ago, catweasel said:

I made a wooden "dip stick" from a piece of dowel, two nicks with junior hack saw as per proper dip stick, painted with matt black paint. Self tapping scew through the top in a tee shape to act as a level (looks a bit like a lock handcuff key but smaller.) Works a treat when filling up. For the avoidance of doubt, I put the genuine (unusable) item back in when finished. I did think of using "lolly" sticks meant for freezing lollies but decided to make something more permanent.
I have used the pella pump to good effect, though doubt it gets every last drop out; best to use drain plug if poss.
edit PRM told me to use mineral oil only in this box, never synth or semi.

Take care what you dip in your gearbox to measure the oil level. I was working on a supply vessel in Gt Yarmouth and a chap there used a length of clear pipe planning to put his thumb over the end. It took him all weekend to get it out again while his mates were on shore leave.

[Sea Dog]

3 hours ago, catweasel said:

Somewhere on Youtube there is a vid of a geezer who dumped the oil out of a Volvo car and it drove for quite a time before the engine let go. I think it was around 15 mins.

They used to run an advert for something similar in the 70s: Molyslip - it was great for keeping an engine running without oil for many laps of a track.  Unfortunately, it was discovered that Molybdenum Disulphide eats engine internals over the longer term, so the miracle cure for a problem your car didn't have slowly killed it. 

[Chewbacka]

13 hours ago, blackrose said:

So why does the oil in my gearbox turn black then and where do those bits on my sump nut come from? (See post #21).

 

Does oil really prevent metal to metal contact? Surely it can't do completely? How is engine and gearbox wear caused? I thought oil just reduced contact and friction rather than eliminating contact completely.

It reduces friction by putting a film of oil between the surfaces to ‘eliminate’ metal to metal contact, but in the real world there are tiny areas of highs and lows and the contact area of a ‘high’ is tiny so the pressure on the oil film at that point is greater than the film can withstand resulting in micro metal to metal contact.  So it wears away.

 Added. The ‘better’ the oil film resists pressure the lower the wear rate, so thick, ep gear oils are better from a lubrication view point, but the work required to shift the oil around the system goes up reducing efficiency.  In fact wear may get worse as a very heavy oil may have inadequate flow for the design resulting in oil starvation.

Edited November 12, 2018 by Chewbacka

[bizzard]

Certain old vehicles-cars mainly of pre-war design used a Hi-Press sae160 oil in the rear axles, again large teeth rub with the spiral bevel crownwheel and pinion. In the winter when the oil was cold and thicker its resistance was huge. The car got under way slowly gradually accelerating and if you took your foot off the throttle in neutral it was like putting the brakes on quite hard. Things improved as the oil warmed up.  Most of these old vehicles had differential whine or howl. You can hear it in old films.

[Flyboy]

17 hours ago, blackrose said:

So why does the oil in my gearbox turn black then and where do those bits on my sump nut come from? (See post #21).

 

Does oil really prevent metal to metal contact? Surely it can't do completely? How is engine and gearbox wear caused? I thought oil just reduced contact and friction rather than eliminating contact completely.

I'd be very worried if the oil came out of my PRM 150 gearbox black. It always comes out looking the same colour as it went in on mine.  I assume you change the oil at the correct interval.  Maybe your box is being contaminated by a leaking oil cooler or has run on a very low oil content and is overheating.  Does it have the correct oil type ie engine oil and not EP gear oil. ?

[Guest]

15 hours ago, ditchcrawler said:

Take care what you dip in your gearbox to measure the oil level. I was working on a supply vessel in Gt Yarmouth and a chap there used a length of clear pipe planning to put his thumb over the end. It took him all weekend to get it out again while his mates were on shore leave.

Thanks, yes a good point. I put a screw across the top with this in mind, making it exactly the length of the real dipstick.
Interesting though that he got a clear pipe stuck in there, might make using the Pella a bad idea?

2 hours ago, bizzard said:

Certain old vehicles-cars mainly of pre-war design used a Hi-Press sae160 oil in the rear axles, again large teeth rub with the spiral bevel crownwheel and pinion. In the winter when the oil was cold and thicker its resistance was huge. The car got under way slowly gradually accelerating and if you took your foot off the throttle in neutral it was like putting the brakes on quite hard. Things improved as the oil warmed up.  Most of these old vehicles had differential whine or howl. You can hear it in old films.

Our Seagull outboad box uses (IIRC) 150 hypoy which is also like treacle. According to the Seagull manual, "it will leak until some water gets mixed with the oil!" They don't make 'em like that anymore...

[Boater Sam]

Next time you have the stick out, paint it white.

[john6767]

1 hour ago, Boater Sam said:

Next time you have the stick out, paint it white.

I stick masking tape on the dipstick which helps a bit, but still quite hard to aee

 

 

[ditchcrawler]

2 hours ago, catweasel said:

Thanks, yes a good point. I put a screw across the top with this in mind, making it exactly the length of the real dipstick.
Interesting though that he got a clear pipe stuck in there, might make using the Pella a bad idea?

Our Seagull outboad box uses (IIRC) 150 hypoy which is also like treacle. According to the Seagull manual, "it will leak until some water gets mixed with the oil!" They don't make 'em like that anymore...

It was a big box, about 4 foot tall. it was in something like this https://horizonship.com/ship/84m-offshore-supply-vessel-dwt-4587/

2 hours ago, Boater Sam said:

Next time you have the stick out, paint it white.

I did that to my diesel dipstick and now cant see it so sanded it back down to bear hard wood on one side

[cuthound]

6 hours ago, Flyboy said:

I'd be very worried if the oil came out of my PRM 150 gearbox black. It always comes out looking the same colour as it went in on mine.  I assume you change the oil at the correct interval.  Maybe your box is being contaminated by a leaking oil cooler or has run on a very low oil content and is overheating.  Does it have the correct oil type ie engine oil and not EP gear oil. ?

 

Likewise, the oil in mine is always the same colour as it went in, even after 250 use.

[Cheshire cat]

Quite a few people on this discussion used to be in the shared Ownerships club. Interesting then that Allen Mathews advocated not doing an oil change on the gearbox until the end of the season. This usually meant the box had done 1000 hours plus between oil changes and I don't recall any stories of gearbox failure.

[Guest]

39 minutes ago, Cheshire cat said:

Quite a few people on this discussion used to be in the shared Ownerships club. Interesting then that Allen Mathews advocated not doing an oil change on the gearbox until the end of the season. This usually meant the box had done 1000 hours plus between oil changes and I don't recall any stories of gearbox failure.

 I think oil change intervals on boat engines/boxes are way overkill, but then again oil is comparatively cheap compared to a new engine/box!
I understand some cars have transmission oil for life and it is never changed?

Edited November 12, 2018 by Guest

[WotEver]

29 minutes ago, catweasel said:

I understand some cars have transmission oil for life and it is never changed?

Yeah, about that... Jaguar stated that the gearboxes on the S-Type (among others) were sealed for life and required no oil changes but ask any Jag specialist service centre and they’ll recommend changing it at 60k. Why? Because experience shows that they need it. 

[Guest]

13 minutes ago, WotEver said:

Yeah, about that... Jaguar stated that the gearboxes on the S-Type (among others) were sealed for life and required no oil changes but ask any Jag specialist service centre and they’ll recommend changing it at 60k. Why? Because experience shows that they need it. 

Fair enough. 60K is still very high though compared to the old days. I do wonder if marine oil change intervals have not kept pace with the vast improvements in oil technology?
One example would be that Vetus quote 100 hr oil change interval for my engine. Thorneycroft who used to use the same base engine always said 200 hr interval. Seems odd that one can be double the other whilst using same donkey.
edit: Point of interest, how many running hours would equivalent of 60k be in a boat? 

Edited November 12, 2018 by Guest

[ditchcrawler]

36 minutes ago, catweasel said:

Fair enough. 60K is still very high though compared to the old days. I do wonder if marine oil change intervals have not kept pace with the vast improvements in oil technology?
One example would be that Vetus quote 100 hr oil change interval for my engine. Thorneycroft who used to use the same base engine always said 200 hr interval. Seems odd that one can be double the other whilst using same donkey.
edit: Point of interest, how many running hours would equivalent of 60k be in a boat? 

Well my overall average speed is about 40 mph so  1500 hrs. My engine service is max 12000 miles which would be 300 hrs, running hours.

[Guest]

40 minutes ago, ditchcrawler said:

Well my overall average speed is about 40 mph so  1500 hrs. My engine service is max 12000 miles which would be 300 hrs, running hours.

My car shows a bit less average but similar order of magnitude. That would make my Venus engine/box a 4000 mile oil in car terms or 300 miles in boat terms

[alan_fincher]

On 11/11/2018 at 18:39, blackrose said:

So why does the oil in my gearbox turn black then and where do those bits on my sump nut come from? (See post #21).

 

21 hours ago, Flyboy said:

I'd be very worried if the oil came out of my PRM 150 gearbox black. It always comes out looking the same colour as it went in on mine.  I assume you change the oil at the correct interval.  Maybe your box is being contaminated by a leaking oil cooler or has run on a very low oil content and is overheating.  Does it have the correct oil type ie engine oil and not EP gear oil. ?

^^^^^^^^^^^^^^^^
Exactly this!

Last boat had an ageing PRM Delta, (very similar to a P150).  I didn't change oil that often, but it was always the same colour as when it went in, however long it had been there.

I'd suggest that if oil in a PRM hydraulic box is turning black, there is probably something wrong with it.

In an engine it is the end products of burning the diesel that makes the oil go black.  Nothing should be being burnt in a hydraulic gearbox!