small oil leak, lots of smoke? Using a UV light to find it

[florio]

I'm looking for some feedback on what do to here, maybe someone with more experience can help!

I finished completely rebuilding this engine, a 2.4S from 72, and went ahead to start it up on a bench to check that it all worked and to do some basic tuning.

full thread here: Need advice on re-build of a rebuild

The engine runs great, but after running for about 20 min white smoke started coming out from the left heat exchanger (out of the hot air exit). I had been checking the advance at higher rpm's and was bringing it up to 4000 rpm. However, there are no obvious oil leaks. A small drop was apparent under cylinder 1, and I had to use a UV light to find where it was coming from.

Here is the area, hard to spot any oil!


But it shows up really nicely with the UV light, I added some fluorescein to the oil (loctite and curil T also show up!)



I thought it was coming from either the cylinder base gasket, or from one of the case through bolts as I had had some grief from using the blue o-rings and ended up replacing a few with the green ones (yes, I should have read about it first).

I removed the shroud, but did not see any oil from any of the bolts leaking there:



Nothing on the other side, either:


*So, is it possible that such a small oil leak only on the bottom half of the block would generate a lot of smoke?

*could it be that there were some crud inside that started burning off, and it will eventually go away?

*Should I fix it now, or wait to see if other gremlins appear?

*If I go for the fix, can I remove all three cylinders as a block, or should I disassemble the head first?

*Am I missing something in the hot air socket? The one on the right seems so small, I'm wondering if I'm missing a plate on the inside:



Thanks for any help or advice, as always!!

[safe]

Look like its from the cylinder base gasket. Did you check the case for cracks between The head studs and cylinder spigot? Mag cases are notorious for cracking here, mostly 2.7 but also earlier.

The smoke is probably from existing oil in the heat exchanges, if you reused the old ones and didn't clean them out properly.

[florio]

Thanks for the suggestion, I did check by eye, but nothing so large as to be easily seen. I can add that I did not see any oil or smoke appear until I started revving the engine a little, which certainly brought up the temperature.

Do you think I should go ahead and repair it now, or wait and see what happens?

[safe]

Go ahead and run and se if it burns off. Have the heater hose from the HE disconnected so you don't get smoke into the car.

[florio]

Actually, the engine is out of the car on a stand, with the MFI pump off, as well as the pipes down to the shroud (for taking the pictures above). I did this just before leaving for the airport on a week long trip for work I can either button it back up, or go forward!
I'm kind of surprised that the smoke comes only from one side, is it normal that the left-side air socket is completely open?