Engine Problems

TonyG
Posts: 266
Joined: Mon Sep 07, 2015 4:38 pm

Re: Engine Problems

Post by TonyG » Sun Jan 03, 2021 1:35 pm

Mark,

Good to hear you are working on the car again and encouraging for me to get back to doing mine!

I've written about this before, but I cannot stress how important it is to drain the old fuel from a car that hasn't been used for a while and put in some fresh petrol. This will have a huge impact on starting and subsequent smooth running.

Shelf life of modern unleaded fuel is just a few months in a sealed can but much less in an open vented tank like Rover used on our cars. If you compare old and new petrol you will see that it becomes very yellow as it ages. It's ok for longer in lower compression engines so I use the old stuff in my mower. However, it gets to the point that even that won't run on it!

My Tourer is a nightmare to start on petrol that's been in the tank more than 2 months, but that is higher compression than standard. I get around it by extracting the petrol from the float bowls using an old turkey baster and replacing with new stuff. Then, assuming the tank is almost empty, putting in a couple gallons of super unleaded and letting it mix. Once started it runs fine.

Oh for the days of 4 star without all the additives and ethanol we get now. Petrol lasted years back then....

Tony.
Tony Gilbert

P1 12 Tourer
P2 12 6 Light Saloon
Discovery 3
Discovery Sport

Manxman
Posts: 6
Joined: Tue Apr 28, 2020 9:44 pm

Re: Engine Problems

Post by Manxman » Tue Dec 28, 2021 9:20 pm

Thought I'd better post an update, although it's been a while due to a very strange year last year.

I traced the problem back to the fuel tank, the pick up pipe had split and so it was pulling air in from the tank and not fuel. We took the tank off to clean and paint it, repaired the problem and ran a new fuel line from front to back as well. The fuel line now runs on the opposite side, away from the exhaust, as much as possible to keep it cool.

We went to take the car out for a run today as it was dry and although it ticks over nicely and revs fine stood still, it has no power on the hills. There's no misfiring, popping or banging. It's like there's a rev limiter on it, but it revs higher when stationary.

What would cause this issue on an engine that otherwise seems fine?

I'm leaning towards the fuel side and am going to have the carb re-built. I know the needle is from a 14 but even so would expect the performance to be better than it is. I'm also wondering if the fuel pump is failing and not providing enough at full throttle.

All the best,
Mark

David2021
Posts: 128
Joined: Sun Jan 31, 2021 5:29 pm
Location: Stratford upon Avon

Re: Engine Problems

Post by David2021 » Thu Dec 30, 2021 12:43 pm

Hi Manxman
For what it is worth (& I may be teaching granny to suck eggs--daft phrase really!--) your problem will again have to be looked at logically starting with the basics.! Even if this does seem like "Deja-vu all over again"!!
1. Is the timing right (possibly over retarded?) Are the points closing up? Is the condenser ok?
2. Are the compressions all similar and high enough? Someone may know what is an "acceptable" pressure. Stuck or burnt valves show up on this test.
3. Is the fuel pump working properly...i.e. fuel starvation at high engine speeds, or load is possible, but in my experience unlikely unless there is dirt in the system.
I can see you have been down this route before, but.....
Happy New Year
David

Frost015
Posts: 21
Joined: Wed Oct 10, 2018 3:48 pm
Location: Stamford (Lincs)

Re: Engine Problems

Post by Frost015 » Tue Jan 04, 2022 12:34 pm

Just a thought (based on my own poorly diagnosed breakdown at the side of the road last year), if you are using new cheap points and condenser which (inevitably) come from China, these are of notoriously poor quality and short lifespan. Mine lasted for less than 25 miles.

Once diagnosed, I fitted an industrial capacity externally, and have had no problems since.

Ian
1936 Rover 12 Saloon

rgburlend
Posts: 5
Joined: Tue Jan 04, 2022 5:27 pm

Re: Engine Problems

Post by rgburlend » Thu Jan 06, 2022 7:23 pm

I would be suspicious of the distributor as well, it is true that capacitors available currently are often of poor quality but do have a look at the automatic advance and make sure it is free to move and that there is no excessive play in the shaft bushes. Check that the distributor has a good earth and that there are no cracks or signs of tracking on the distributor cap or rotor arm.

If these are all good, check the coil as these can break down and act as a Rev limiter.

The SU is such a simple device, it is less likely to be the problem and the 14 needle should be adequate but the 16 one might be better. These are very easy to change and are readily available.

Richard

GOY189
Posts: 520
Joined: Sun Oct 19, 2008 5:08 pm

Re: Engine Problems

Post by GOY189 » Tue Jan 18, 2022 2:34 am

The SU D3 carb on your 16hp should have an EC needle. Bear in mind that the change over on the 14hp from the 1577cc 6cyl (R6 needle), to the 1901cc 6cyl (EA needle) was in 1938.
Mike

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