Oil leak or blow by?

Hi again. I love this site.

I test drove my 78 Midget a week and half ago and when I got back, among other problems it was dripping oil from somewhere on the right front of the engine. There was so much oil from this short ride and the past (before I owned it) that I couldn't tell what was leaking. I assumed that it was from a gasket or the front crank seal. So I torn the front of the engine down to the block, sealed the little block seal on the lower front of the engine, replaced the oil sump gasket, replaced the front plate gasket, and replaced the timing cover gasket and the crankshaft seal. After all that I got it running again and took it for another test drive. When I got back it was dripping oil from the right front of the engine... But the gaskets and seals didn't seem to be leaking. I have started thinking that the oil is coming from the dip stick. So I checked the compression, all cylinders were between 145 and 160 psi.
Is the compression what it should be? Am I getting that much blow by that it might be blowing oil out the dipstick tube? Is this a common problem? and what might it indicate? What should I do about it?
I'm calling in all the MG gurus, lol. Your help will be greatly appreciated!

Hi Jere,

I have the same exact problem - after taking my 1979 MG for a ride I started leaking oil. I couldn't figure out where it was coming from at first, and after some more trouble shooting I determined it was indeed blowing out of the dipstick.

Further investigation revealed that the amount of oil vapor being vented from the valve cover pan is very excessive. And if I pull the hose off and let it vent to atmosphere (you have to plug the hose going to the carb or the vacuum leak will cause it to stall) it quite blowing oil out of the dipstick - but then I have a lot of vapor blowing out of the engine.

I am in the process of tearing the engine down to replace the wiper rings - I don't know if this will help, but I wanted to do a rebuild anyway. Also, my temperature runs pretty hot - not in the red, but close enough. I am going to do a complete flush on the cooling system as well. It is my under standing the climate here in the states causes the motors to run a little warmer.

I am also rebuilding the carb since this is where the valve cover pan vents. In addition, I need to verify the hoses are correctly going to the right locations. The car use to have a polution control system, but it has been just about completely removed, minue the air pump.

If you come up with a solution please let me know. I'll do the same.


Thanks,

Manny

i had the same problem 2yrs ago. if you look at the dip stick, its friction fit and has a gasket on top. there must of been a reason for this design. i bent the dip stick alittle more and installed a o-ring for a gasket. haven't had a trouble since

TY both, Manny and RR, I checked and there is no seal on my dipstick, plus it is loose fit. I will do as you did, RR, and see if it helps.
Manny, I have zero emission system left. It was all disconnected when I bought the car and the car ran like crap. I couldn't get the carb to adjust and the idle was all over the place. So I replaced the Zenith with a downdraft Weber. I am not sure I have the Weber adjusted correctly yet but the idle problem is gone and there is more power on the test drive. I connected the valve cover vent to the air cleaner on the Weber. I think I will do as you suggested and vent it overboard, though it doesn't seem to be putting out much flow or pressure, but then again it might once I seal the dipstick.
Any other suggests would be appreciated, we are listening!

I just replaced my ZS with a Weber 34 DGEC on my '79. I am still a little worried that I've got a blow-by problem now. Prior to this, I didn't have nearly as much white smoke coming out the tailpipe. If I run my finger around the tailpipe, I'll pick up a fair amount of oil and when the car is turned off a wisp of smoke comes out -- sorta like Helen is blowing smoke rings at me.

Originally, I routed the valve cover hose directly to the emissions cannister -- this caused a bunch of white smoke. So I hit the books (and the forums) and discovered the problem of oil blow by. This is my first MG and my first attempt at working on cars myself so I'm a little lacking in the logic behind all of this. My question is: if vacuum is needed to pull the fumes out from the valve cover, otherwise oil gets blown into the exhaust, hy do some cars I see route the valve cover hose into the wheel well (overboard?). I re-routed my hoses back to how they were with my ZS - valve cover to the air cleaner intake, to the emissions cannister.

Had the same problem with my 79 with weber (apparently this is a common problem with 1500/weber set-up) - I'm in the process of changing to dual HS4's. Some suggestions after hours of research:
1. Better venting, either to atmosphere or separate canister with filter and drain. You can also vent direct into exhaust manifold by drilling and tapping a hole to make connection.
2. Washer on dipstick (as previously suggested).
3. Make sure the cap on the valve cover is non-venting type (VERY IMPORTANT). If not this may be the cause and may also cause ring damage.
4. Oil pressure relief valve may need adjustment or replacing.

Like I said - these are only suggestions - good luck!