Volvo AQ171 Performance Problem

[summerwind]

Now that you have had more time in the bilges I would be interested to hear how you are getting on and especially to hear that you have fixed your problem.

 

[matto]

Still no luck despite more time working this weekend. I must admit I got a bit side tracked as the weather was good and it was necessary to drink a beer and relax a bit on Sunday instead of getting oily for once!

I will be checking the exhaust this evening to make sure its not blocked and also swapping the rev counters over in case there is some deviation in one.

The gearbox seems fine but I still need to check its exactly the same ratio as the other engine. I will let you know what I find but for now I am still puzzled.

BTW still not sure how to get to the oil pressure relief valve - any suggestions

Thanks!

Matt

 

[summerwind]

Oil pressure relief valves are often included in the oil filter housing. Look for an hexagonal head, often of brass or bronze.

Be careful as you slacken it off as inside you will find a spring and a plunger. This is the valve. As pressure builds in the oilways, the plunger is pushed back against the spring and allows excess oil to flow back into sump. The strength of the spring determines the operating oil pressure.

In your case you may find that the plunger will not come out as it is blocked by the build up of carbon and goo. This might mean that you have to take the whole casting off the block to get the plunger out and clean it and the housing.

Alternatively, the relief valve might be in its own casting, bolted to the block. The principle is the same. Some engines have the valve housing cast into the block, but again, the principle is the same. Look for the valve fairly low down on the side of the engine.

Hope this helps.

 

[matto]

Yes its a great help - thanks! I was at the boat again last night and took the time to remove the rev counters. I have got them at home now and will build a circuit to allow me to calibrate them (at least electronics is something I am OK at!) I want to make sure they are reading correctly.

This weekend I will take a look at the oil pressure relief valve and get that sorted.

Thanks again for your advice - I will let you know how I get on after Sunday

Cheers - Matt