D4 260s low turbo pressure on one engine

[GrahamHR]

I‘m away at the moment, but my props came with instructions.

The torque on the forward hub nut is ”lots”,with lower values for the cone and nut - the instructions have the values.

I'll reply tomorrow re torque.

Use grease or an anti seize compounds on the ( helical) splines. I used a Mercury Quicksilver grease for years. No grease on the threads, or else the torque specs may end up shearing the nuts.

 

[wivsi]

Thanks, no probs. I've got it from the dealer. Your right - forward prop is 'lots'!

 

[papparazzi]

With a DP-H drive, either the props are attached, or they have fallen off.
There is a spiral thread on the shaft: the only way a prop can spin on the shaft is if the hub is knackd.

@SC35 and @volvopaul I read through your comments on this case and wonder if I could have the same situation. Any thoughts would be greatly appreciated.

I just got 2 x DPH-A serviced by a private mechanic (not a Volvo dealer) after the last service was done 2 years ago with estimated less than 50h. Gear Oil was very dark and somewhat milky (greyish) in some parts, according to mechanic water would have entered hence we replaced shaft seals and shift selector seals. Drives was pulled to replace bellows as well, allowed to inspect the u-joint which looked good (only around 630h on the drives).
What wasn't all that great is that I had sourced the wrong oil as it was a Mobil 1 75W90 limited slip and after a ton of research I decided limited slip is to risky to screw with the cone clutch hence we dropped the oil and mechanic filled up with Shell SPIRAX S5 75W-90 which seems to meet the specs but may only be semi-synthetic instead of full synthetic.

I drove the boat back from yard to marina and the first 5NM was great without issues - around 18-20kn at 2500-2600 which was a bit better then before the service / bottom cleaning etc. Whilst pushing the engines higher to 2900 to 3000 and getting above 25kn the drives suddenly felt like loosing power and I throttled back with the initial impression being the props would be slipping. I tried a few times to push the boat out of the hole but the acceleration didn't seem to be there with only some 10kn at 2500 without much forward push.

I am not thinking it might be
- wrongly installed props (but is this even possible in DPH legs? )
- to little oil (maybe they mechanic didn't fill up enough / had air pockets in the drive --> would this result in a slipping cone clutch at higher loads ? )
- wrong oil (semi syntetic) resulting in the cone clutch slipping at higher RPM / loads once the oil is hotter ?
- props damaged (props slipping) --> somewhat strange to assume this given I didn't hit anything ?

Any thoughts ? Thanks

 

[wivsi]

@SC35 and @volvopaul I read through your comments on this case and wonder if I could have the same situation. Any thoughts would be greatly appreciated.

I just got 2 x DPH-A serviced by a private mechanic (not a Volvo dealer) after the last service was done 2 years ago with estimated less than 50h. Gear Oil was very dark and somewhat milky (greyish) in some parts, according to mechanic water would have entered hence we replaced shaft seals and shift selector seals. Drives was pulled to replace bellows as well, allowed to inspect the u-joint which looked good (only around 630h on the drives).
What wasn't all that great is that I had sourced the wrong oil as it was a Mobil 1 75W90 limited slip and after a ton of research I decided limited slip is to risky to screw with the cone clutch hence we dropped the oil and mechanic filled up with Shell SPIRAX S5 75W-90 which seems to meet the specs but may only be semi-synthetic instead of full synthetic.

I drove the boat back from yard to marina and the first 5NM was great without issues - around 18-20kn at 2500-2600 which was a bit better then before the service / bottom cleaning etc. Whilst pushing the engines higher to 2900 to 3000 and getting above 25kn the drives suddenly felt like loosing power and I throttled back with the initial impression being the props would be slipping. I tried a few times to push the boat out of the hole but the acceleration didn't seem to be there with only some 10kn at 2500 without much forward push.

I am not thinking it might be
- wrongly installed props (but is this even possible in DPH legs? )
- to little oil (maybe they mechanic didn't fill up enough / had air pockets in the drive --> would this result in a slipping cone clutch at higher loads ? )
- wrong oil (semi syntetic) resulting in the cone clutch slipping at higher RPM / loads once the oil is hotter ?
- props damaged (props slipping) --> somewhat strange to assume this given I didn't hit anything ?

Any thoughts ? Thanks

Based on my limited experience as per the rest of this thread.... prop slipping is fairly unlikely on both sides, but test it by marking with lipstick and you can easily see (apart from when, in my fortunate case, the props realign after slipping...). I previously had a slipping cone and this became apparent from dark / contaminated oil.

Beyond that .. over to the experts

 

[papparazzi]

thanks @wivsi . I am not quite clear on how to mark the propellers - I believe I would need to remove the propeller cone first (essentially the propeller nut of outer propeller) and mark the hub and propeller itself? To do the same on the internal propeller I would then need to remove the outer one ?

I have another very strange situation I haven't mentioned yet - I got a H4 and G4 propeller mixed up - apparently the old owner replaced one propeller set against the modern h4 (stainless steel) some 2 years ago and didn't swap out the old other propeller set. This would make it more likely that the old one would have failed (12+ years old) which is very likely on the original hub.

I may just have a single prop / set slipping and not both of them, but a single one would be enough to make serious challenges to get the heavy boat (7 ton) on plane. I haven't fully tried out what happens if I just push the engines harder - it may accelerate somewhat more. Will try each drive individually in a few days.

Keen to hear other options, I am now very much narrowed down on the hub instead of a slipping cone (a had no cone issues so far).

 

[wivsi]

Hi - no, no need to remove anything. Just draw a line along the hubs. Give it a little scrub first - line as straight as you can get from front to back. Each hub (should) turn with the prop, and also relative to the cone and the main hub.

But I agree - unlikely to have both slipping! Our symptoms of prop slip were that the boat still planed, but I never really got high turbo pressures on one side ... that side was not doing as much work.

 

[SC35]

Bear in mind that the system tries to “synchronize” the rpm across both engines at speed.
So even if one engine is struggling or has reduced drive, it looks as if both are struggling.

To identify which side has the issue, try powering up using only one engine at a time and see if you get different results.
Monitor rpm, speed, boost pressure each time.
See if that painted line fails to line up afterwards, as above.

A cone clutch problem usually results in slow gear selection or no gear selection at all.
Low oil can cause the upper end to overheat and break, but you’d know about that.

 

[Andyroonot]

What RPM are you getting from each engine when the issue occurs?
Any faults/alarms?
H & G series props shouldn’t be mixed between drives let alone on the same drive, and H require a different prop cone to G, so that should be corrected. Single G series prop sizes are still available, whereas H series are available as single props or a set

 

[papparazzi]

What RPM are you getting from each engine when the issue occurs?
Any faults/alarms?
H & G series props shouldn’t be mixed between drives let alone on the same drive, and H require a different prop cone to G, so that should be corrected. Single G series prop sizes are still available, whereas H series are available as single props or a set

Hi, @Andyroonot I have a twin drive installation, drive 1 has a old G set, drive 2 has a newer H set. This has been done by the older owner, I haven't changed this yet. The cones are different of course.

I haven't done extended testing yet as this only happend yesterday on a 18NM ride from the yard to the marina and I wasn't keen to do the trial and error being far away from the marina. However, what I believe is happening is that once I push above 1600 to 2000 RPM and essentially above 10knots I already have slipping in the propeller and won't be able to get the boat on plane at least not without WOT (not tested yet). I was at far to high RPM of 2500 without getting over 10knots, I assume this was only on one drive but also need to test this.

My boat is fairly heavy, with one drive having a slipping prop I believe I may already struggle to get on plane for that reason.

@SC35 if my gears engage quickly (as always) then this would make the cone clutch problems less likely? Do you think that I would have any clutch issues due to using a semi-synthetic transmission oil instead of full synthetic ?

 

[Andyroonot]

Ok, my apologies I had misread your message about the G & H being on the same drive. To have different sets on either drive is still specifically stated as a no-go by Volvo though

When doing the further tests, see what each RPM engine is able to reach, either together or when only one is operating. If you have slipping props you will likely find the good engine (props) will struggle and the bad side will be achieving much higher, possibly full RPM (3500 or thereabouts)

If neither engine gets close and you have no alarms sounding then it could be your boost temperature sensor feeding the ECU false info and it injecting insufficient fuel. This can be easily checked with Vodia and even with a multimeter if you can get the sensor out

 

[SC35]

My guess is that a G prop is slipping on it's hub, but we shall see.
Boost temperature sensor as above is also possible.

 

[volvopaul]

Hi - props about to arrive, but hoping you can help me with one last thing. Any idea of tightening torques? I can't find a manual! Thanks - Simon

If you have purchased stainless there is a bulletin in the box with the torque settings . You will need the later rear prop cone kit if you have changed to stainless , also if you have the earlier inner shaft you cannot insert the centre locking bolt , you will need a tube of locking liquid . And buy new nuts !

 

[papparazzi]

Hi,
today I went for a 5NM test run as the weather was not very good. Propellers don't seem to slip at all - boat was getting on plane without any challenges, made some 19knots on 2550 rpm similar like it did last time before I experienced the power lost. (what I thought would be slipping clutch or slipping props).

The clutch engages smooth and immediately in all positions of both drives. As stated earlier, I have used a Shell Spirax s5 75W90 which is a GL5 oil but likely only semi-syntetic. I assumed this may result in issues with the clutch at higher drive tempratures but wasn't able to see this effect today at all. Also, based on multiple people input it seems that a clone clutch which would be slipping shows this behavior at low rpm when trying to engage the gear and not once engaged at high rpm. (can someone confirm ? )

I drove WOT on each single drive which resulted in around 10knots at max 2500 rpm (didn't accelerate beyond this point).

I am not clear what else could have resulted in the earlier lost of power which didn't let me get back on plane. Maybe it was related to the air intake temprature sensor / electronics not getting enough diesel into the engine... I will do an extended test in the next days to see more.

 

[papparazzi]

My guess is that a G prop is slipping on it's hub, but we shall see.
Boost temperature sensor as above is also possible.

It doesn't seem to be the prop slipping, I was able to get on plane without problems on my last test ride. I now suspect the sensor. Did you observe issues with the sensor being intermittent before?