Kad32 twins - one down on boost - please help

[Bavnavkad]

I’d say it probably is. I have not long replaced a turbo and elbow on a kad32 single engine boat. Was lacking a little power and supercharger having to help more than it should. Your issue might be getting disguised a little more, having the other engine to help it along. Sent the turbo away to AET. Great job. Back on and the boat is running tremendously now. I’d take the turbo off and send it away before it completely goes and damages the casing too. Much cheaper to refurb just the turbine cartridge instead of the whole thing further down the line.

Yes, your right. The second engine does pick the reduced power engine up to about 3450 or so, but if I leave good engine at 2900 or 3000 it means the affected engine will drop back to around 3100, so it's not capable of going any further.

If I was to reverse that and have them both at 3000, and advance to WOT with the good engine, that one will go to 3600 leaving the other at 3000ish.

Lots of people pointing at turbo area, and the fact the good engine had one not long ago may be the answer.

If you don't mind me asking, what was the cost of refurb for you with AET

Thanks

 

[BruceK]

Thanks for your reply, I feel lots of people are pointing at turbo, so I think that's the route I have to go down, however at first inspection today. I notices the smallest amount of oil mist around the seal between turbo compressor housing and the pipe to aftercooler, so I am wondering if that could cause a notable drop in performance, the oil mist was extremely small, but tells air can escape there. But equally there is a drain hole in the intercooler, would this have any effect do you think?

oil mist reinforces my belief turbo bearings gone. Check intercooler hasnt gunged up with oil restricting airflow too.

 

[Bavnavkad]

oil mist reinforces my belief turbo bearings gone. Check intercooler hasnt gunged up with oil restricting airflow too.

As far as I'm aware, the turbos have a piston ring as the oil seal, and at low revs it seems it is normal for it to bypass a small amount of oil because of the nature of the seal, it does say this in the workshop Manual too.

Intercoolers have been done and both have hardly any oil inside, but at the base of the intercooler they have an oil drain hole, both of those are equal with the tiniest amount of oil misting.

I guess I could be wrong, but that's as I understand it. To be fair to you. I was hoping to see a more obvious sign such as the affected engine throwing more oil.

 

[QBhoy]

Yes, your right. The second engine does pick the reduced power engine up to about 3450 or so, but if I leave good engine at 2900 or 3000 it means the affected engine will drop back to around 3100, so it's not capable of going any further.

If I was to reverse that and have them both at 3000, and advance to WOT with the good engine, that one will go to 3600 leaving the other at 3000ish.

Lots of people pointing at turbo area, and the fact the good engine had one not long ago may be the answer.

If you don't mind me asking, what was the cost of refurb for you with AET

Thanks

I’ll ask the owner of the boat. Can’t quite remember. Might have been about £500/600 or so. Amazing service.
Apologies if you’ve said before. But have you had a look at the turbo and checked for play or wear ? The tolerance on these things is tiny. Easily affected by the smallest amount.
The other issue that had to be seen to on this engine was a blown cylinder head. Made obvious by the contents and actions of the coolant header tank.

 

[Bavnavkad]

I’ll ask the owner of the boat. Can’t quite remember. Might have been about £500/600 or so. Amazing service.
Apologies if you’ve said before. But have you had a look at the turbo and checked for play or wear ? The tolerance on these things is tiny. Easily affected by the smallest amount.
The other issue that had to be seen to on this engine was a blown cylinder head. Made obvious by the contents and actions of the coolant header tank.

Thanks, that does sound about right to be fair, so thanks.

In regards to turbo inspection, I attempted to have a look on the compressor side, however the Inlet elbow has two screws and one had broke so I have not removed it at this stage, I was going to pursue removing the exhaust elbow but this weekend I needed to use the boat. So as yet have not done that. Instead I did boost pressure check.

In regards to cylinder head, I think that's OK, she runs at 80degrees Celsius at WOT equal to the other engine, no smoke or steam, no over heat.

The coolant tank clean and only once it pushed coolant out, not much, it was when it was serviced and refreshed. It obviously had a little more than it wanted

 

[QBhoy]

Thanks, that does sound about right to be fair, so thanks.

In regards to turbo inspection, I attempted to have a look on the compressor side, however the Inlet elbow has two screws and one had broke so I have not removed it at this stage, I was going to pursue removing the exhaust elbow but this weekend I needed to use the boat. So as yet have not done that. Instead I did boost pressure check.

In regards to cylinder head, I think that's OK, she runs at 80degrees Celsius at WOT equal to the other engine, no smoke or steam, no over heat.

The coolant tank clean and only once it pushed coolant out, not much, it was when it was serviced and refreshed. It obviously had a little more than it wanted

Ok. Was there any movement or backlash in the bearings ? If you pulled on the compressor wheel nut ?

 

[Bavnavkad]

Ok. Was there any movement or backlash in the bearings ? If you pulled on the compressor wheel nut ?

No, I've not yet been able to get to it. The screw that holds the air intake cast elbow on snapped and would not come off, bur as I needed to use the boat this weekend, I just put it all back on.

You think next route to remove exhaust elbow ans inspect thay side and the elbow?