Sealong
Active member
Hello,
I have a Volvo Penta MD2030B, new to me six years ago, and then with about 2000 hours running. The injectors are made from stainless steel and fit into the cast iron cylinder head using a screw thread and not a flange.
Four years and about 400 engine-hours ago, I went to remove the injectors to send them off to be cleaned and noticed that they were loose, which surprised me. Last year, I needed to remove the cylinder head to have some new valve seats etc, and again noticed that the injectors were loose. Yesterday, having done 60 hours or so since last year's top-end rebuild, I thought I would check the fit of the injectors and again they were loose.
Some additional information:
So I would be very interested in hearing from anyone who has encountered a similar problem and also from anyone who may have an opinion on what could be the underlying cause and how to deal with it.
Many thanks in advance
Chris
I have a Volvo Penta MD2030B, new to me six years ago, and then with about 2000 hours running. The injectors are made from stainless steel and fit into the cast iron cylinder head using a screw thread and not a flange.
Four years and about 400 engine-hours ago, I went to remove the injectors to send them off to be cleaned and noticed that they were loose, which surprised me. Last year, I needed to remove the cylinder head to have some new valve seats etc, and again noticed that the injectors were loose. Yesterday, having done 60 hours or so since last year's top-end rebuild, I thought I would check the fit of the injectors and again they were loose.
Some additional information:
- In each case when I have removed the injectors I have always replaced (with new Volvo Penta items) the copper washers that seats the nozzle end.
- I did not anneal these washers as I assumed that had already been done.
- In each case I have tightened the injectors to the correct torque (85NM).
- Loose in the above sense means finger tight and wobbling around in the threads.
- When I carried out the top-end rebuild last year, I meticulously cleaned the injector threads and seats in the cylinder head.
- It is very unlikely that the injectors are able to unwind in the cylinder head because they would tighten up on the high-pressure fuel line that feeds each injector, and this would provide too much resistance.
- There is no evidence of injector blow-by or leakage. I assume that although the injectors are loose in the threads, they are held firmly in position by the high-pressure fuel line.
- Similarly there is no evidence of a lack of compression - the engine starts (after the rebuild) in less than a second.
So I would be very interested in hearing from anyone who has encountered a similar problem and also from anyone who may have an opinion on what could be the underlying cause and how to deal with it.
Many thanks in advance
Chris
