Another Noise, Another Worry

I noticed a new engine noise on the way home from work the other day, so spent today investigating.  There was an intermittent plastic knocking noise, which emanates from the snorkel top.  I inspected the turbo with the ducting removed, removed the snorkel to check for contamination or damage and checked the filter, but found nothing.  As an experiment, I removed the breather pipe from the intake union, and the noise stopped immediately.  It transpires that the cyclonic breather on the side of the rocker cover also has a spring-loaded valve so that the intake isn’t continually sucking on the crank case.  It’s this valve closing that is making the noise, which then resonates up the snorkel, so it’s not a problem.  I think the reason that I’ve only just noticed it is that with the rings bedding in and now using regular oil, the pistons are getting less blow-by and so the crank case pressure is now lower, allowing the breather valve to shut.

I also replaced the rear prop shaft  with an excellent one from a very low mileage ex-MoD 109, so hopefully the slight vibration at 60mph+ that the old prop produced will be gone.
I also spoke to a few companies to source a solenoid valve for the fuel heat exchanger, but speaking to the veg oil specialists that provided the heat exchanger (Dieselveg.com), they were convinced that the small amount of injection pump noise I had suffered was due to air in the system rather than having hot diesel.  I had bled the system carefully the other day when I replaced the fuel filter as part of the service, so I ran the engine for a while with the heat exchanger operating, and didn’t find the noise reoccurring.  It looks like that advice may have saved me a fair bit of time and money, but I’ll keep monitoring the pump when on hot diesel for the noise just in case it does come back.  They also advised fitting a section of clear fuel pipe between the filter and injection pump to make any bubbles visible.  I may do this at some point if I find that air ingress becomes a problem.

I had a letter and a phone call today from the Heritage Centre to confirm that I have been chosen to participate on the Land Rover 60th Anniversary Solihull to Gaydon run on the 3rd of May.  There is a little confusion over which of my vehicles, the Range Rover or 109, has been chosen.  I think it’s the 109, but I did remind them that it’s not at all standard and is not very representative of the model year.  I’d love for it to take part, and they’re going to get back to me with confirmation of which vehicle is meant to be going.  Now I just need to arrange a swap with a colleague as I’m due to be at work that Saturday.