Turbo Filter Issues

[amarosa]

Hi everyone. I am new here and have had a look around but could not find an answer. I have a 1984 34 foot hartley powerboat powered by a 1984 165HP volvo penta and have had for a year. The issue I am having is since putting on a new prop since the old one had died the turbo is struggling for air. This has clearly been an issue before because the person that had it before had rigged up a drain pipe attached to a car air filter. Since getting the new prop which is now the right size the turbo is struggling with air. I removed the pipe and opened up the engine case and goes fine so is clearly an issue with the bends in the pipes. My question is can I hook up two air filters and attach them to the stern of the boat on the transom with a cover for when not in use. Also there is no ventilation in the engine compartment and the cover goes over the engine completely so thinking of putting in a fan but not quite sure how to go about it. With the new prop at 2700 rpm the boat goes 13 knots whereas at 3400rpm with the old prop that was the top speed so the prop was definitely the wrong size.

[twinboat]

I have the same engine TAMD40B. This engine runs up to 3600rpms and if you cant get it up to that. You have too big a prop. As far as the turbo issue, my engine came with a aprox. 12X8 inch rectangle flat filter, right on the engine. Goggle the engine to see what it looks like. There should be engine room vents, allready in the boat. If not fix that, dont run pipes out the back

Sent from my VS840 4G using Cruisers Sailing Forum mobile app

[delmarrey]

How many hours on the motor? You could be having a turbo boost/drive pressure problem either in the turbo or the exhaust system.

[amarosa]

Thanks guys. So there are no vents anywhere. For some reason the old flat filter was removed and changed instead with the plumbing pipes. My guess is that was because there was no ventilation so can put those in. I have no idea about the hours. It had a full rebuild when I brought it and has done 150 hours on that. The guy that owned the boat before me only used it once a year whereas I am using it every week or so even in winter and a lot of distance as well. Is my first boat so slowly learning all the bits and pieces. Really enjoy getting to know about it more and working out issues as they go, is heaps of fun being out.

Twinboat yes that is the same motor, it has never gone to 3600. Used to hit 3400 and then got the new prop and did some hull cleaning and now hits 3200 but goes much faster. The prop is smaller so I am sending it back for a change in pitch which should make a difference.

[sparrowhawk1]

First, no vents that's bizarre. second, the prop should be sized and pitched to allow your engine to get to whatever its maximum rps are. 3rd, a common problem with turbos are the fan on the exhaust side getting covered with carbon basically disabling it

[amarosa]

Originally Posted by sparrowhawk1

First, no vents that's bizarre. second, the prop should be sized and pitched to allow your engine to get to whatever its maximum rps are. 3rd, a common problem with turbos are the fan on the exhaust side getting covered with carbon basically disabling it

Yes I agree with you re vents. My only logical thought was that it is such an old boat that it was never done and the people that have owned it since have had no idea. It is not an engine room but an engine bay cover in the stern but this has insulation all through it so is not helping! I can easily add them in however.

Second yes thanks for that. The prop guy has been great here in New Zealand in terms of changing it free of charge.

3rd thanks for that I will have a look. The impellor turns fine

[sparrowhawk1]

The impeller would still rotate freely. The carbon buildup prevents exhaust from spinning it efficiently

[goboatingnow]

Turbos need air filters generally. You need to provide air supply to the engine room. Not necessarily directly to the engine

Check around the engine hatch. If you see a lot of dirt buildup at the seals etc generally its a sign the engine room is under ventilated.

[amarosa]

Awesome thanks everyone. There is definitely a build up. I have worked out the size the ventilation needs to be so will head down today and start getting the holes ready and everything sized up. I should then be able to add the standard air filter in instead of the one that is there now