MG Midget Forum

Had a bad day last fall, after a perfect 50 mile run the fan belt tore 10 miles from home. I have to admit I didn't realize what was happening at first, but when I did we were not in a position to pull over immediately but did so in a minute or two. She was hot as all hell, spewing antifreeze all over from the overflow tank, smelled hot oil, ended up getting a tow home. The real bad thing is this engine was totally rebuilt last spring and only had 900 miles on it, and I don't believe the failure was any fault of the builder.

So here is what I have, replaced the over flow tank and its not over heating. But the water pump is leaking and the bad part is when it's fully warmed up its blowing white smoke "antifreeze" out the exhaust, has a sweet smell. So I guess I have a head problem, going to pull head this weekend.

The fan belt pulley tore the belt. It was a stamped two piece pulley that separated, it also has been replaced. Lesson learned, a failed $10.00 part can cost a lot!

It appears to have a blown head gasket. Not difficult to replace. I use to perform this work in 3 hours. Make sure head is not warped. About every new MGB had leaking head gaskets back around 1974. I used to be a MG mechanic at a dealership.



Edited 1 time(s). Last edit at 2017-03-24 10:12 PM by jimbenedict.

What about the valve springs, could they also have been damaged? Do you suggest sending the head out to a machine shop?

It would take way more high temperature than overheating due to lack of coolant to damage the valve springs. Take head to auto machine shop and check for cracks & warping issues. The block and internal components are likely ok.

Will do,

Thank you!

Once the engine is in good shape change the oil and filter. Valvoline VR1 20w-50 is fine oil with proper zinc levels for flat tappet camshafts. If you want synthetic oil use Mobil 1 10W-40 Racing 4T oil. If in a southern climate with temps over 100F use Mobil 1 20W-50 V Twin motorcycle oil.

I use Valvoline VR1 oil due to the engine has 60K miles from previous owner and do not want any sludge broken loose with Mobil 1 synthetic oil.



Edited 1 time(s). Last edit at 2017-03-25 04:45 PM by jimbenedict.

I wont have the head off until tomorrow, started it today. The antifreeze looks fine, but not so good for the oil.

Definitely head gasket. You may want to put a cheap oil in it to start, get it hot and then drain and fill with whatever oil you use, just to get the gunk out. Some say that as soon as you get it hot (above 212F) that the water boils out, but in my opinion, its not worth having the muck running through the engine any longer than necessary.
Just my $.02

---

'58 Bugeye
'05 Mini Cooper S

The head is defiantly going to the Machine shop! Does anyone have any tips how I should clean up the block? I did look closely and don't see any cracks and it still moves smoothly. remember this block was just rebuilt 900 miles ago.

Nice work, it will be running again in no time.

Ordering the parts now, anyone try a Lucas head gasket? or should I stay with Payen?

Well it Lived! Got the head back Friday and reinstalled it this weekend and to be honest it seems to run better than ever. At the same time I replaced all the hoses, water pump and plugs. Let her run for about a half hour with new oil, going to change the oil again tomorrow. The oil that was in it was nasty, but really only 5 quarts came out. Thanks for all the help.

Congrats. I assume head was not warped. Use Valvoline VR-1 20w-50 oil. It has over 100000 PSI compressive strength. Some oils are rated 60000. It also has proper zinc for flat tappet engines. New engines are roller type tappets and the zinc amount is not near enough for older MGs. If you want synthetic, Mobile 1 for V-twin Harley engines also works. In other words do not play with just any oil.

Actually I was told the head needed to be taken down, it got real hot! Considering it was rebuilt less than 1000 miles ago, I wasn't happy. But its running great!

Now that you've warmed it up, be sure to retorque the head and check the valve adjustment, and then do it again in about 500 miles.

---

'58 Bugeye
'05 Mini Cooper S