Ol’ Smokey: the MGB engine with the carbs off and ready to remove 1) the exhaust manifold, 2) the intake manifold, 3) & 4) the malfunctioning tappet side cover/vent plate with its PCV breather connecting pipe
For those that may remember, when I redid the transmission on my 1965 MGB and re-installed it, along with the engine, I decided I’d also freshen the cylinder head as the head gasket had been weeping very slightly. Anyway, I had a big and not so good surprise upon start-up. The engine smoked like an out-of-control tire-fire! Not that acrid, black smoke, but bluish oil-smoke…definitely, oil smoke. Great cumulous clouds of it! Now I must explain before I took things apart, it didn’t do this, it was running quite nicely thank-you. So, I was wracking my brains trying to figure out where I’d screwed things up. I checked the compression and the sparkplugs for blowby and oil fouling, nothing, they seemed to be pretty good, then I remembered, where previously I had been dumping into a racing-style catch tank, I had re-installed a proper-period style PCV valve and routing/piping assembly in an effort to bring the thing back to a stock, street spec and lo, that was the culprit! The problem was not the actual PCV, or the piping, mind you, but I traced the issue to a clogged side-cover/oil separator. In doing a bit of research, I found this is not an unusual thing and it happens quite often. I figured the simple solution would be to get another side cover and simply replace the thing. Not so fast, Buckie! The danged things are no longer available and the chances of finding a used one that isn’t equally bunged up is pretty slim. What to do? Well, with a bit more sleuthing, I found out how to clean and refurb the unit I had.
Step One:
Removal
Take off the carbs and unless you’re a contortionist, remove the intake and exhaust manifolds. Now you can get at that front tappet side-cover/breather unit. There’s one bolt in the centre of the thing holding it to the side of the block. Undo it and fiddle-diddle to pull the thing off. You will no doubt damage the gasket, but not to worry, you’ll want to replace it anyway. Just be sure you don’t drop any gasket crumbs and bits into the tappet chamber! Carefully clean them out if you do!
Step Two:
Cutting and cleaning the unit
For this step, we must first get inside the breather part of the side cover. The way these side covers are set up, they have an inner and outer stamping that’s welded together to form a chamber within the side-cover. This chamber is packed with a shredded metal substance much like a metal scouring pad. Sort of like very, very coarse steel wool. You’ll also note the inner stamping has holes drilled in it to allow oil to drain back into the engine. The purpose of this side cover construction is to vent the crankcase and allow oil vapour to escape, but the filling is there to provide a surface for the vapours to condense on and ultimately become liquid and drain back into the engine. When all is clean and new, it works quite well. When old and clogged up, it doesn’t!
I used a rotary tool with a fine, narrow cut-off wheel to cut a u-shaped flap in the backside of the cover and bent it back to expose the innards. Sure, enough, everything was clogged brick-hard with black, grungy coal-like residue. Now the fun part… dig all the clag out of the inside of the unit. Using a long pick, a screwdriver and lots of cleaner/degreaser and mineral spirits, I got the inside emptied and nice and clean.
Step Three:
Repack, and reseal
Now that the unit was all cleaned out, I did some checking and found the best stuff folks recommended for repacking was some simple, very coarse stainless steel scouring pads bought from the local store. I got them and proceeded to shove as many as I could into the unit. Once I’d got the thing jammed full, I carefully bent the flap back down into place making sure there were no deformations or things that could stick out inside and possibly foul the tappets and lifters. It seems you don’t need to worry about re-welding the cut on the flap if you made it slender enough as the inner stamping is full of drain holes anyway. Just be sure none of the stuffing can come out! My final operation on the side cover was running it through several passes on the wire wheel to clean everything up, then paint some engine enamel on the outside of it.
Step Four:
Re-install and hook up the PCV system
With a nice, clean and shiny new side cover/breather in hand, I placed a new gasket on the inside flange area and put the thing back in its place on the front side tappet chamber, re-installing the central bolt that holds it in place. Be careful not to super-over-tighten the retaining bolt, you’ll deform the cover and mash the gasket, it should be just tight enough to seal things and not come loose.
Now, you can re-install the exhaust and intake manifolds (remember to use a new gasket and make sure the mating surfaces are clean!) and then the PCV valve and feed pipe that routes back to the side-cover. After this, install the carburetors and set up the linkage. Once the assembly is back together, you can fire it up and test things. I found with my refurb, the smoking had immediately stopped, and the engine once again ran beautifully.
All in all, it wasn’t very difficult a task and also didn’t cost diddly. I hope this exercise will help anyone else facing a similar situation!
Cheers!
Doug Switzer