September 27, 2018 at 4:56 pm #1427
hi i have a 1954 devon van 1200cc the engine had parts missing when i got it which have been replaced together with head rebuild for unleaded / crank regrind / block rebore all surfaces ground flat on rebuilding it all together the new all copper head gasket leaks all the head studs and nuts were replaced for new the head was fitted with no sealant the first time and head gasket cement the second time although the leak is minimal should i take it apart again / do you have to anneal a solid copper gasket the second time ihad it running until hot then done up the head nuts to 40 lb it still leaks HELP cheers tomMarch 6, 2019 at 5:27 pm #1521
Hi Tom, I’m surprised no one has responded to this.
Most cases of blowing head gaskets are due to overheating. So before you proceed any further – Did you rebuild the radiator. If not then replace it with an uprated one from the club. Secondly check that you have the correct 74 degree thermostat in it. Also did you clear out the waterways in the block by removing the core plugs and scraping out the rust? Lastly you need to run on Champion N8 Plugs set at 18 thou. If you don’t, once again the engine will run hot. You might also need to check that the timing is not too far advanced.
Once you have checked all of this then try the following when you fit a new gasket.
Once the head is built with new valves and springs then build up the head. Some rebuilders say that no gasket sealant should be used others swear by Well Seal. (This is what I used) Make absolutely sure that there are no metal burrs on any of the nut or washer faces as the slightest burr will cause a stud to fail in my experience. Ray has new nuts and washers I think.
Head gaskets of the correct type are available through the club. Best to get a genuine BMC type if you can find one.
Torque the head down (COLD) in the correct sequence starting at 10 LBS on the wrench and building up in 10 LB increments until 40 LBS is reached on each nut. Run the engine statically up to temperature and check for leaks and let it cool down over night.
Remember to re torque the head bolts (COLD) the next day before you start the car up or drive it in any way. You can then drive the car until…… you get to 100 miles when you will need to re-torque the head….. Then …..500 miles and lastly1000 miles… you will find that the nuts will bed down on 40 lbs/torque each time especially on the tappet chest side… at 1000 miles it they should not move… the head should be fully bedded in then. (At each interval please check the tappet gaps as they will move as the head and valves bed in)
This advice was given to me a long time ago by none other than George Coates. (Whom you may recognise as the Austin senior mechanic on almost every major prototype trial and Hess record attempt).
Hope this helps – Dave W.March 14, 2019 at 9:21 pm #1523
Hi Dave thanks for the reply I did take the head off again and annealed the solid copper gasket and refitted it my problem is very strange you can see small bubbles at the head joint nearest the bulkhead on the spark plug side I have checked cylinder compression all four are good and very close to each other after 1000 miles the engine has lost no oil or water starts on the button and drives ok my only mistake seems to be that I torqued the nuts down when hot if I have to take the head off again I will follow your advice to the letter. Thanks tom
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