Rover Sports Register Forum

While grovelling underneath and replacing some radiator hoses (In passing I managed to free off the drain tap in the metal link tube! Success!).....
I noticed that the forward face of the king pin assembly has two apparently untapped holes (3/8" (?) in it that are exposed to the elements (pins look nice and shiny and oily thank goodness - the Bijur seems to work ok!) HOWEVER are these holes supposed to have something plugged into them to keep the muck out? If not, Why not?

Now Thermostats...I have a bright shiny new one, but the car has a bit of an overheating history and no thermostat...what is the advice. I note that there is no gasket between the cover and the pump housing, only top & bottom of the 'stat, why? Aluminium to aluminium ids hardly a great seal!
I have flushed the system and will give i bit of a stress test run! Of course the temp gauge doesn't work, but I have an electric one that I am plumbing in so I can keep an eye on the temperature.

Next! Leaded or unleaded fuel. I had this conversation when an Austin Seven owner!...As the OHV engine is essentially a pre war design it will have been designed to run on unleaded (didn't come in until war time to boost the rating of aero engines and in 1947/8 we were still on awful low octane "Pool" petrol) so I am pretty sure that unleaded will be fine. (Preferably E5 % Max ethanol)The only benefit I can think of to use 99 octane with our low compression engines will be 0% Ethanol
I look forward to your comments!

Regarding lead in fuel,I read an article by an expert some years ago,and he said that metal absorbs lead 10 times more than it loses it .So if you have a car thats covered 10 000 miles it should be OK for the next 10000 miles on unleaded,providing it isnt worked hard by fast driving,or towing a caravan Len

Regarding the kingpins - can you upload a picture? also see here: https://wp.me/pXLKy-3AQ
Regarding the thermostat: No thermostat can cause overheating! see here why: https://wp.me/pXLKy-1so
Unleaded: https://wp.me/pXLKy-2lJ

David,

Re king pins; as Luli says, a picture would help. However, it sounds like the cotter pins are missing. Pretty much the same as bicycle crank cotter pins of old.

You need the correct type of thermostat. Meteor Spares can supply these I believe.

Unleaded fuel. Always a polarising subject, but I’m with you in thinking that my preWar cars were designed and built long before leaded fuel was the norm so why worry now. I try to use Esso super unleaded as this, quite likely, has no ethanol but may have up to 5%. This varies depending on which part of UK you are in. What I have found is that modern petrol has a limited life in the car fuel tank; maybe no more than two months before the car either won’t start or runs very poorly. This is because modern petrol has more than 100 additives, including butane for easy starting. With the open vented tanks in our cars this evaporates very quickly and the fuel deteriorates at an alarming rate becoming very yellow in colour Instead of clear. I’ve got cans of the stuff now from successive tank draining and even my old lawnmower doesn’t like it! Ok for parts washing but that’s all. I’ve found the solution is to have a temporary feed from a 5L can for Winter starting and moving about and, in the Summer, only fill the tank for long journeys. Keeping the tank almost empty means that fresh petrol can be mixed with the old and I don’t have to keep draining the tank. Even so the fuel in the carbs may need draining or fresh petrol squirted into the Venturi to get it to start before it’s flooded with duff fuel.

I did try lead and octane additive to see if it helped but this seemed to leave red deposits in the bowls of the carburettors, so I cleaned that out and didn’t bother again.

Lead in fuel provides upper cylinder lubrication but, more importantly, was developed by GM in the 30s to give a brighter, more progressive burn and, thus, smoother knock free running. As you say, this didn’t arrive in UK until the War for use in high octane aero engines like the Merlin.

Hope that helps a bit.

Tony

The prewar heads are different from the 1947 tourer head, post war. I wouldn't count on that unleaded fuel is harmless to it.

David,

Lulu, as always, makes a good point. Post War Rover may have continued with their preWar designs but, faced with steel shortages etc, will have specified the construction of their engines, with regards to cylinder heads, valves etc, to meet the needs of the time. This may have been the same as 10 years before or it may not!

I've read that engines designed for leaded and retro-fitted with hardened valve seats for unleaded fuel, still require lead additive. This is because use of unleaded requires the ignition to be slightly retarded causing it to run hotter.

Worth noting that unleaded fuel attacks many older rubber components like fuel hoses and filler neck pipes. These all need to be updated to avoid hazardous failures.

Tony

Thanks for the advice / information.
King pins....not cotters I am sure. They are for missing Bijur pipes, but a '47 12 I think only has top & bottom swivel pin valves.
However ….I see in the parts list L2 & 3 are " plug & washer for redundant oil feed tappings in axle beam!" Mystery solved...now what thread are the redundant holes? 3/8-24 UNF I imagine as the replacement modern lubricators require a 3/8 unf to 5/16 unf adaptor! Interesting as most threads on these cars seem to be BSF although in the Parts lists Rover mostly only define the diameter & length not the thread nor head pattern.Some BA and Whitworth threads are noted, so perhaps they are identified by exception. It is annoying that the diagram part numbers in the workshop manual do not tie in with the numbers in the parts manuals, but not a big problem.
Thermostat. Thanks Luli for your helpful explanation of the (pretty complex...thanks Rover!)workings of the water pump and thermostat. I have no idea if my car has the "restriction plug". There is also mentioned a "Plug for car heater tapping" which is not shown, but I think is in the angled hole on the side of the casting almost level with the top face of the casting. If this is the case I can probably use this for the sensor on my additional temperature gauge. I don't have a heater either, so could use the Heater tap hole instead for the gauge.
Fuel...each to his own opinion! I will do what I did on my ZA Magnette engine. Wait until I have to take the head off for something & then have it machined and fitted with hardened valve seats etc (possible tuning opportunity....!)

While the oiling method of the king pins had been changed in 1947 (including the king pins and hubs) the front axle remained unchanged. This is why the redundant hole are still there. If you have the correct king pin (two holes, not hollow) this can be left open. In any case the thread 3/8 BSF.
See also here: https://wp.me/pXLKy-4tS
In regard with modifying the head: I am fully with you.

Back to thermostats! It all came apart more easily than I expected! A lot of Hylomar down the vertical face of the alloy top housing...and gloopy bits inside! No sign of a thermostat nor part no 108! my new stat has a shroud that I think replaces the function of the restrictor (108), I have a 1950's KL aftermarket temperature gauge (I had a similar German one on my TR3A) and I have fitted the sender into the hose between the rad & the Stat top housing. I note that there is an access hexagon headed plug in the side of the water pump housing...what is its purpose? Anything to do with the (non existent) heater? If I can free it off it might take the thread of my gauge unit. Or not!
It will all got together tomorrow after I have bought some decent hose clips!

All back together now!
After reassembly and initial tightening there was a substantial leak from the thermostat housing so I retightened the nuts some more, leak was less.
I was nervous about tightening them too much (many bad experiences with Austin seven studs...) but I persevered using the 1/4BSW short tubular spanner and bar from the car toolkit as it is a relatively short bar, so not (in theory) possible to overtighten...well, nothing broke and the leak appeared to have stopped, so a test drive followed. I did about 10 miles including quite a long uphill pull. This was also an opportunity to check engine temperature as I have installed a 1950's KL temp gauge (which works well, tucked into the driver side cubby) With the thermostat fitted there is no sign of overheating so far (max about170-175). Next week I will take the car to a "gathering" at Gaydon and will have a 10 mile or so trip down the M40 so will see how the car responds to a relatively extended run at about 60mph.
As an afterthought, I called in with the car at Four Ashes Garage (just down the road at Pathlow) who are early Aston Martin specialists and they told me that they have remade and can supply the "bits" for the fuel reserve system (available on early DB's I think). Probably at old Aston Martin prices! They recognised the car as a Rover, but had never seen one before!