Many thanks to one and all for discussion and advice. The techical looking white silicone seal arrived from Jamie, and has so far given the most oil tight hour of running ever seen in South Wales. Will further slightly finger tighten the knurled fasteners when the exhaust manifold has cooled. Phew, let's hope that Jamie really has sorted the problem. Following certain Scottish suggestions, I did indeed check the crankcase/block fastenings, and many thanks to Steve Flake for using barrel nuts for easy acess. No looseness found, however.
Now the weekend calls, the roads will probably be almost empty as some sit inside watching cricket, tennis, and a form of motor sport that will be quieter, less exciting, and the paddock far less acessible than Chateau Impney. Pah, there will be no pre 1914 cars at Silverstone, spitting flames from exhausts and smelling of Castrol R.
17-07-2019, 11:06 AM (This post was last modified: 17-07-2019, 11:09 AM by Charles P.)
The Dave Dye cover arrived today.
Drill some holes where they're spotted, silicon baking sheet gasket as per Dunford Jnr's recommendations, and it's a good-un.
Perfect
Oh bother, dash, and other splutterings. Jamie's silicone seal seal, check fastenings between block & crankcase as advised, after first twenty mile trial run everything clean and gleaming. Now after 100 miles the torrent, well trickle, of oil has resumed. Does this indicate that even Jamie's special seal can't cope with less than flat tin tappet cover, or should I fear a bigger job relating to the relationship between block and crankcase. Fortunately scrutes at forthcoming nav events will be able to inspect the engine after the application of increasingly oily rags, but is an engine out job indicated for the winter?
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The Bennie Railplanes were powered by electric motors, so no dripping oil on the honest folk of Milngavie. There were quite a few aeroplane engines at Chateau Impney, the Spollon family seemed free of noise check requirements so exhausts were cast aside allowing the 27 litre FIAT to spit flames in all directions and the Napier Bentley to be rather louder than Shelsley the week before.
17-07-2019, 06:41 PM (This post was last modified: 17-07-2019, 06:47 PM by nrzam.)
I had a very similar situation and following a prompt from Ruaridh I found that the wear around the fuel pump pivot shaft was a major factor. I replaced the fuel pump with a new one only to find that I had petrol gushing from the carb. I replaced the top part of the fuel pump with the old one and used the old spring. All is now well with that particular leak cured.
FG's engine leaks from the same place. I have replaced the tappet cover gasket (with a proper cork string one) and I have replaced the replacement "U" type fuel pump with with the original "T" type, now that it has been overhauled with new valves and diaphragm and the leak is still there! To be fair, I have long suspected that it is the block to crankcase gasket, as there is a similar, but lesser leak on the off side front of the engine adjacent to the dynamo.
However, as the engine makes no funny noises (well no funny noises considering it is an Austin Seven!), goes well and blows no blue smoke, I am inclined to leave well alone. The oil consumption is about 1500 mpg which is in line with what the factory said it should use (should leak?).
Given the problems experienced by Reckless Rat, I have refrained from trying to tighten the block to crankcase nuts!
My engine is of the type that is bolted firmly to the chassis and i suspect that a lot of the problem is that the crankcase flexes slightly as it tries to stiffen the front of the chassis, but I have known four Sevens well during my time on this earth, my first RP saloon, my special, a friend's 1935 ARQ Ruby( which he had bought new from Thomas Startins in Aston) and FG, all of which leaked oil at the nearside rear of the crankcase, I am inclined to think that it is a characteristic of the cars
Mind you, I am of the school of thought that says:- "If it ain't broke, don't fix it!" so I shall live with the oil leaks until the engine has to come apart for overhaul. Thus I shall continue to wipe the oil away at the end of each day the car goes out. Rag is cheap and I get my oil (a good quality semi-synthetic 10W/40) from work for nowt so perhaps I am biased.
You can see a track of oil under the cover. That would tend to say cover/block joint or block/crankcase joint. Given that you've treated the former in the modern way, regretfully, you have to consider the latter I fear.
Having already paid the price of trying to fix something that was just a slightly annoying ( and not unusual) leak from the block/ crankcase joint ( replaced using the silicone gasket) I have found that there was still a leak from the bottom right corner if the valve chest. Having taken the cover off to replace the cork strip with a silicone one, I decided to properly check the trueness of the cover and found it splayed slightly at both ends, probably due to overtightening.. this has been rectified by placing the ends in a soft jawed vice and applying some "encouragement". The cover has been stripped, polished and repainted ready for the arrival of the French postal service... but that's another story. I will update once things are back together.
