The reality of classic car maintenance

We bought the MG nearly 2 years ago to actually drive, as opposed to spend time restoring it. This was particularly relevant with both Jennie and I being in our mid-70's.  The excessive but enjoyable time spent building drag bike engines a lifetime ago is best not revisited to maintain matrimonial harmony.  Buying a car with most of the restoration done has really paid off.  The upside of most classics is that that they're not all that complicated to work on, don't need too many special tools or computer-based diagnostic equipment.  The downside is that they need a bit more maintenance than modern vehicles.  Much of that work will be D-I-Y as most main line auto shops won't want to touch them as they all have their quirks or special requirements.  Even our village garage owner who is "old school" and a near neighbour makes a sign of the cross when I drop in, even for a social chat. 

Ever since we took ownership, the engine has had a slight oil weep from one of two tappet/pushrod covers. Slight enough for just an occasional drip onto the strip of vinyl sheet I have under the car in the garage to protect the carpet.  Yes, our basement garage has carpet, albeit the proper heavy duty industrial grade.  I can see the shaking of heads now but the garage was a once handy place to stick the multiple mates of our kids and similar when they were looking for a place to lay their bodies overnight. Even grandkids when they all descended at the same time.  Invasions of that magnitude are largely a thing of the past now.

Right, getting back on track with the oil weep......

It wasn't a big deal but being an anal retired professional engineer, it was like a slight itch that you couldn't scratch.  It would have been fixed earlier but for the fact that the carbs, heat shield, inlet manifold and exhaust manifold all have to be removed, then replaced for what is an hour's work at most to replace the leaking gasket.  Having never done the job previously and not wanting to cock it up big time, I reckoned that would take up to a couple of days being ultra-cautious.  A poor return on my time when I could be out driving it.  

The leak is buried under all this plumbing - bloody typical!

The North Island has suffered an extremely wet autumn and winter thanks to the La Nina weather system so it was an opportune time to bite the bullet and prepare to do the job in the face of an indifferent weather forecast.  Both of my repair manuals gloss over the job, but the MG Experience website forum had multiple posts on how to avoid further leaks so clearly, a bit of care was needed.  All relevant parts were purchased online, including some contingency materials just in case.  The good thing about owning an MG is that parts are relatively inexpensive and available.

First job was to remove the air cleaners and carbs.  I'd done this before to get the carbs rebuilt, including making a simple jig to stop carb linkages and springs from flying off and disappearing into dark recesses.  Removal of the heat shield and inlet manifold was also straightforward, even though it was uncharted territory.  Nuts, bolts, spacers and washers all went into labelled ex-catfood plastic containers to stop the Garage Elves from making them disappear without trace.

Carbs and inlet manifold off, just the exhaust manifold to pull clear

I wasn't looking forward to disconnecting the manifold from the rest of the exhaust system as access to the retaining nuts was a hassle, best accomplished from under the car.  Fortunately, the whole assembly could be pulled clear by a few centimetres and supported with a jack under the car.

The weeping tappet cover ready for removal

The front tappet cover was weeping from both the retaining bolt and from the joint surface with the engine block.  It virtually fell off once the bolt was removed, indicating poor adhesion between the mating surfaces.  The red sealant (see photo below) looked suspiciously like a previous owner had used Red Hermetite.  I remember using this on Triumph motorcycles back in the 1960's.  Triumphs of that era were notorious for oil leaks and the use of Hermetite did little to improve the situation.  To use a succinct and somewhat unambiguous description, the properties of snot as a sealant would have been an improvement.

Not much adhesion or sealing on display.........

The mating face on the engine block

Fortunately, members of the website forum previously mentioned had extolled the virtues of Hylomar Universal Blue jointing compound.  Developed by Rolls Royce for aircraft and turbine applications, it has a serious pedigree.  Not cheap, but a tube was purchased in advance.

It can be seen in the photo above that what remains of the cork gasket is narrower than the flange of the cover and the mating face on the engine block.  Several forum members recommended not using the official gasket and making a wider one from rubberised cork sheet.  Which is exactly what I did......

A pristine gasket cut from rubberised cork sheet

All mating surfaces were wiped with methylated spirits to remove any oil contamination and Hylomar was applied to all surfaces.  The torque setting for the retaining bolt was a miniscule 5 lb ft - well below the minimum setting of most torque wrenches.  However, an approximation given by one of the forum members was to gently tighten the bolt whilst grasping and gently pulling the vent pipe on the cover.  When the cover no longer moved about, that was pretty much spot on.  Easy peasy - worked a treat.

Front tappet cover in place with new gasket

The rear tappet cover showed no sign of weeping.  I spent a moment or two wondering whether to replace that as well but decided to leave well alone in case Murphy's Law decided to put in an appearance.  Reassembly of the plumbing and fuel system was simply a reversal of disassembly, with the proper torque settings and use of Hylomar on critical mating faces.  

All assembled and ready for a test drive

A 40 km test drive revealed no weeping at all and interestingly, there was little or no smell of hot oil.  Even though it was a weep rather than a leak, the proximity relative to the exhaust manifold must have previously carried the odour back into the cabin.  The real test will be over the next few hundred km but there's no reason to think that the weep hasn't been fixed.  There's also a slight weep from the overdrive unit but as that involves grovelling under the car, the inclination to fix that hasn't reached the "scratching the itch" stage yet.

Although the 1 hour basic task took most of the weekend to accomplish because of all the disassembly and reassembly involved, not to mention an abundance of caution; it was nonetheless an enjoyable experience gaining more knowledge.  Every day is a school day!

There's actually another reason I wanted to get the MG in pristine condition for the warmer months ahead. In a few weeks, I'll be having a replacement knee joint which will keep me out of action for a while.  Not looking forward to it one bit but it should address something which has become increasingly problematic over several decades.  New horizons beckon!

Test drive - Oamaru Bay, Coromandel Peninsula.  Someone has to do it!