Boat Maintenance & Repair Forum

Latest issue / ongoing problem

by shibbs » 24 Nov 2016, 19:57

Evening all.
I spent the day servicing and putting the boat to bed for the winter on Saturday. All was going well until the oil change when i noticed (again) some emulsified oil in the rocker cover filling cap thread.
Some may remember i discovered this last year and assumed it was caused by condensation / the problem i had with my head valve seats...
Well this year it was considerably worse!!
I will add a couple of pictures in a moment,
i checked the oil in the sump and it was absolutely fine, no water at all. Checked the compression of all cylinders, once again fine. The emulsification was serious on the port rocker but still present (but to a far less level) in the stbd.

Does anyone have any idea what could be causing this? I put a new head gasket on when i did the valves on the port, but dont think this could be the issue as i have no issue with the sump oil and good compression all round.

I was thinking down the lines of manifolds... does anyone have any knowledge of possible causes of this or experience with manifolds giving up?

Image
Image
Image
Image
As you can see in one of the pictures, there seems to be some serious levels of water in there!!

I can only assume that this must be connected to the problem i had on the final run prior to removing from the water, what appeared to be serious mis fire and complete loss of any power.. - Which i at the time thought might be water in fuel separator / moisture in the distributor.. both checked and nothing out of place.

Why is there always something??? :roll:

I cleaned the whole rocker spaces of much, sprayed with storage oil and re filled with fresh oil. hopefully this will leave it in a decent condition over the winter..

Anyone have any ideas? :idea:
Stu

Draco 2500 Crystal - Mercruiser 5.7, Alpha one - Chin Chin
User avatar
shibbs
 
Posts: 616
Joined: 25 Nov 2014, 20:28
Location: Hampshire

by Ianfs » 24 Nov 2016, 22:21

How did you take the old oil out Stu?
Ianfs
 
Posts: 1427
Joined: 24 Nov 2014, 18:40
Location: Hampshire, by the Sea

by shibbs » 24 Nov 2016, 22:24

With a sump oil extractor pump...
Stu

Draco 2500 Crystal - Mercruiser 5.7, Alpha one - Chin Chin
User avatar
shibbs
 
Posts: 616
Joined: 25 Nov 2014, 20:28
Location: Hampshire

by Ianfs » 25 Nov 2016, 08:08

Ok thanks. As we all know oil floats on water. I know you are aware of this but some people reading may not, but dipping the oil doesnt always show that there is no water at the very bottom of the sump. Assuming you got the pipe to the bottom of the sump however then you're right, because the first suction would have brought out either water or glupy emulified oil. The only real way to know for sure is to undo the sump plug and pour fresh oil through to flush it out.
If on the other hand there was still some water left in the sump or around the oil ways, from the last time you did the work and it was not cleared by a number of oil changes, this might be why you have emulsified oil there now. Trust me emulsified oil gets everywhere and marine oil is very sticky when emulsified and hard to get rid of.

This is just one thought.

But in the last picture there are a few water droplets, where on Earth did they come from? Unless its the oil separating, except if its not the above, its more likely from the cause of the emulsifying oil, which might explain why there is no water in the sump.
Ianfs
 
Posts: 1427
Joined: 24 Nov 2014, 18:40
Location: Hampshire, by the Sea

by BruceK » 29 Nov 2016, 14:15

If you have water in the rocker covers you will have it in the sump. Period. Have you done a compression test on the engine to rule out blowby on failed rings? Are both rocker covers on the 5.7 showing this? If just one cover blown rings where I'd put my money. If your bores got to look anything like the rocker arms your rings are shot and I'd bet money that at least one of your cylinders is shot. If a compression test shows all is good then things start going downhill. I'd look for a cracked block externally. Then I'd look at any oil heat exchange cooler you may have. Check the exhaust manifold. If that's good check the head and head gasket. If that's good then you need to read the manual very carefully for things like when replacing head did you use sealant round bolt threads if required etc. Did you re torque the head after the prescribed period etc etc. The down side of all this is really that engine probably needs a rebuild. If so, have a look at a replacement "short block" i.e. the block, head and all internals, no carb, manifolds ignition etc. You'd be surprised how cheap they are. Often considerably cheaper than a basic rebuild kit.
Last edited by BruceK on 29 Nov 2016, 14:23, edited 1 time in total.
BruceK
 
Posts: 525
Joined: 02 Nov 2015, 17:47

by BruceK » 29 Nov 2016, 14:20

Had a look. You can replace the 5.7 for ~ 1.8k as a short block. Hunting around may get it cheaper.
BruceK
 
Posts: 525
Joined: 02 Nov 2015, 17:47

by shibbs » 29 Nov 2016, 18:21

Hi Bruce,
Thanks for your detailed reply.. much appreciated.
So last year I did have the head off to replace a couple of valve seats, that was on the port side, Which, had the worst amount of moisture but both did and still do have moisture, port is still worse though.
I did a compression test at the time which led me to the valves, after the fix the compression on all was good.
I did another compression test the other week when I discovered the water again, and all still read good compression.
Now you mention re-torque of the head after replacement. I didn't do this, whilst I know it should be done, I was a little confused at the time as to do it, you will need to remove pretty much everything that had gone back on, i.e., manifolds, elbows, carb, inlet manifold, throttle linkage etc etc..
Maybe this is the cause?
I think my plan is to leave it tucked up for winter as it is now, fogged, drained etc and strip back down to re torque when the risk of frost has gone ready to run up again in spring..
I thought it might be a manifold breaking down but I removed the elbow to take a look and they still look in good solid condition.
A question... can the engine be run with the rocker cover removed? How much mess will it make?
I'm wondering that with the amount of water in there if I might be able to narrow down from which direction it might be coming from..?
I will also plan to flush the engine through with some flushing oil after a run up prior to new oil again.
Thanks again for the input..
Stu

Draco 2500 Crystal - Mercruiser 5.7, Alpha one - Chin Chin
User avatar
shibbs
 
Posts: 616
Joined: 25 Nov 2014, 20:28
Location: Hampshire

by BruceK » 30 Nov 2016, 10:08

Running and engine without the rocker covers on will be like having a shower with oil. I've done it before on an italian boxer engine when trying to determine cam timing and wouldn't recommend it. If you haven't retorqued the head it will be too late now. You will need to replace the gasket and start over if the gasket has blown. Hopefully you haven't done anything terminal but I'd be wary.
I have lived in some very humid environments in the tropics and where as this does cause some emulsification of the oil in the rocker cover not to the same extent as yours which is milkshake.
I am not very familiar with the 5.7 V8. Do you have any oil heat exchangers? Are you raw water cooled? Check any oil heat exchangers for corrosion too
BruceK
 
Posts: 525
Joined: 02 Nov 2015, 17:47

by shibbs » 30 Nov 2016, 15:30

Bruce,
I get your points and agree about the moisture, there is simply far too much water in there for it to just be condensation unfortunately.
As for the gasket, it will probably be worth changing it and going through the process again but that still doesn't explain why there would be the same (to a lesser extent) in the other side. All very confusing.
And as for the oil in the sump, I understand your point about if there is water in the oil in the rocker it will be in the sump but if it was it was seriously minor as the colour of the oil was good. In hindsight, I should have had it checked.
Stu

Draco 2500 Crystal - Mercruiser 5.7, Alpha one - Chin Chin
User avatar
shibbs
 
Posts: 616
Joined: 25 Nov 2014, 20:28
Location: Hampshire

by BruceK » 30 Nov 2016, 17:28

This is why I went for blow by as a first stab rather than head gasket. If your head gasket is gone I'd suspect emulsion in the sump too. But with blowby the water is in a gas state and condenses in the coldest part of the engine first. This invariably is the rocker cover and particularly the filler cap. However the rings may not be completely shot. As with most marinised engines with a cast iron head and particularly with raw water cooled engines, the tendency is for engines to run colder than initial design. This will allow blowback which is why your typical wife's car if she is a traditional house wife, always seems to have mayonnaise under the filler cap. It's a symptom of running the engine cold and never really getting it to temp (if the school run and shops are just round the corner that is). Your's however is significant by it's quantity. Either you are perpetually running your engine cold or you have stuck / worn rings. And this can all be exacerbated by water in petrol tank / humid environments or wet bilges or poorly positioned air intake vents in the hull etc

That's my initial diagnosis anyway. Thereafter I would look at head gasket and head installation procedures to see if you missed anything. Finally I would look at any oil heat exchangers that use raw water, and by implication any o-rings etc that seal the engine internals from any coolant. Lastly I would look for block cracks and by extension manifolds etc.
BruceK
 
Posts: 525
Joined: 02 Nov 2015, 17:47

Next

Return to Boat Maintenance & Repair Forum

cron