rear of engine oil leak in 100D2 Bristol

[rpv1]

Hello, I recently bought an AC Aceca LH drive Bristol here in Los Angeles.  The car was originally imported here, sold here and always remained in the area.  It has a large oil leak out the back.  When parked engine off a 4 inch round puddle can form in minutes until of course it stops.  I understand there is no lip seal but a dynamic application. 
Update, the shop that sealed up the engine said the leak was not the rear main but some where else.  Waiting for more info.  Planning on taking the trans out, fixturing the engine to run in place and look for the leak.

[James Eastwood]

This is a subject close to my heart as I was the Ford of Europe Lubrication Supervisor for 10+ years. In production we put a Ultra Violet dye in the oil, then inspect the engine periodically with a black light, in a darkened room, or on the engine assembly line we check in a blacked out walk-in cabinet after the engine has run a cold or hot test. The challenge with oil is that it's typically moved with the wind through the engine bay, or fans in a dyno. The black light will pick out the smallest halo of oil around a bolt head well before it's detectable with the naked eye. You need to be slightly calibrated to the process as some hardware finishes will also 'glow' under a black light (but they tend to be more modern coatings).

On my Bristol engine I fixed some oil leaks when I had the unit out to do the clutch. I used a very different method; I attached quite a powerful athletic mattress pump to the engine breather (but anywhere that pressurises the crank case will do). In fact there was too much resistance with the engine so I had to set up a bleed to stop the pump working too hard and over heating, because you are going to run the pump for 10 to 15 minutes at a time. You then a get a house hold spray bottle and fill it with a water soap mix and spray it onto all the joints. Wow did I find a lot of leaks! You can do it in your workshop without needing to have the engine running. Air will come bubbling out of the smallest leaks that you would never find visually inspecting for oil.

So there's a couple of methods to consider.

James

[James Eastwood]

Sorry and other things to check for would be;

Dipstick calibration - fill the engine with the recommended oil volume, run it to prime the system, then let it sit for 10 minutes and see where it registers on the dipstick (level ground please obviously!). If dipsticks have been switched up, you maybe overfilling it.

The other things of course is make sure that your crank case has a breather set up, and when you rev the engine look for excessive exhaust blow-by (from rings or valve stems), as even with the correct breather, high blow-by will increase crank case pressure to the point where scroll type crank seals can be over come and leak.

James E

[TTM]

Interesting James, thanks for sharing. So were you able to get your engine 100% leak free?
For what it's worth I heard a few times that a Bristol engine that did not at least sweat oil a little was probably because it had run out of oil.