Variable geometry turbo-chargers

P

PCUK

Well-Known Member
Joined
29 Jun 2005
Messages
8,522
Location
Westleigh, Nr Tiverton, Devon.
Visit site
These are the items that have given diesel cars near petrol engine performance. The idea is very simple, relatively cheap and works well. BUT, Latestarter says they are a pain on boats due to their dislike of the damp (I presume). So what is the ideal service routine to keep them operating perfectly at all times. Over to you please LS.
 
I would have thought ( if I can be permitted to answer before LS) that using the correct oil is paramount for longevity .
And --- allowing a " cool down " period before switch off , to enable this correct oil to lubricate the hot bearings and movable vanes .
It's fashionable ,or it seem to me on here that there is a culture of buying the cheapest parts/ lubricants .
I know the manufactures rec oil is always more along with the filters ,but I think it's a false ecoconomy skimping on the oil
quality .
 
The early d3 was a real pain, it partially seized throwing up fault codes Turing the engine into limp home mode.

This mainly happened on boats located on the rivers where there just off idle speed, to be fair to Volvo they were never designed to goin a 30 knot sc29 to potter on the Thames or Trent, but they do.
A simple removal, clean the vv with carb cleaner and refit is the answer. The boost rod actuator also seizes up, again a simple fix.

The real answer is to use the engine in the correct application,ie at a sea at near on full load.

I remember when the kad 44 came out with its 4 valve per cylinder head, the Thames and Trent boats wore out the ball studs on the rocker gear, the push rods, even the rocker shafts, all because they were used at idle and just above, some even dropped valves when run hard.
 
Automotive engines run much cleaner than marine engines (Maybe up to a factor of 20 times cleaner, not at all sure, know sod all about marine bits bolted on the side). Dirty exhaust gas is not conducive to long term VV turbo reliability.
 
Last edited:
Automotive diesel engines tend to run cleaner than marine because of the duty cycle.

In my book there is no place for VG turbo on a marine engine you only have to understand cyclic automotive load and also look at propeller law curve to understand that. Some more enlightened marine applications of LDA (Light Duty Automotive) engines have switched to simple waste-gate turbo machinery.

Engines make maximum soot levels around peak torque, VW Marine as well as VP D3 have seen most of their problems when used on duty cycles reflecting periods at part load, i.e around peak torque. The Garrett swing vane VG design is sensitive to build up of soot on the back plate causing vanes to stick, design has been improved over the years, but truth is the more expensive sliding nozzle VG is a more robust but more expensive solution.

#1 It is not small changes of throttle but a decent dollop WOT running which keeps the wiggly bits happy.

#2 Suggestion that lubricants are issue is simply nuts, a healthy turbocharger should not be passing lube oil. As to hot shut down the last vehicle I came across with hot shutdown warning was a 1965 Ford D Series truck. I agree that a piece of construction equipment working in high load, high ambient conditions which is liable to be shut down moments after pulling full load are at risk. I cannot envisage any well ventilated marine application where engine is running at WOT pulling full load one moment and shut down the next, leaves me with vision of some pretty wild and exciting docking maneuvers.
 
Last edited:
PCUK said:
Thanks LS, How about service? Do you agree that regular cleaning is the answer. Makes sense to me.
Click to expand...

Only problem is that cleaning a VG is a filthy job, is there no way that you can give the motors some real tight wire and stretch their legs a bit from time to time. Far more enjoyable than swimming in brake cleaner.
 
You must log in or register to reply here.

Share this page

Top