Mayonnaise

[michael4]

At this time of the year the car is only doing short local runs, barely getting hot, and as a result it is turning into something of a mayonnaise factory.

(Oil and water are where they should be)

I wonder, if I drove around without the oil filler cap removed, would the moisture tend to escape rather than building up in the rocker cover?

If necessary I could always fabricate a filler neck extension out of a bit of rubber tubing to reduce the chance of oil splashing out. Mind you, rocker lubrication is present and everything is oily but I wouldn't describe it as 'splashing'!

Opinions please.

Obviously, taking the rocker cover off and cleaning it out is only a five minute job.

[Myrtles Man]

You could always experiment with a bit of radiator blanking to get things hotter quicker.

[Mr Spigot]

I would check that the crankcase breathing is set up correctly, not blocked, venting into the air filter or carburettor and also checking that you have the winter thermostat in place (88degC), rather than the summer one (82degC). Also check that the rocker box cap is the correct one for the breathing system. If that does not work, a radiator muff may work, but short journeys are likely to be the problem. Perhaps take it for a longer run every now and then. The Minor engine is overcooled which does not help.

[michael4]

On mine the breather comes up from the side cover to the air filter, it looks like the cap can also breathe. I will check to see if they are clear. I have no idea about the thermostat type.

For a starter I'll take your advice and raid the kitchen for baco foil. I remember it making an effective radiator muff in the past.

Please ignore the under bonnet unpleasantness!

[MikeNash]

Michael4,

This topic (like everything else) has been covered before so I'll point you to this viewtopic.php?t=42135&hilit=radiator+muff If you scroll down you'll see some hardboard blanks with circles cut out aligned with the fan that I'm still using. Like you, a good deal of my running is local, and being on country lanes, is necessarily relatively slow, and I suspect that with the heater switched on full, the radiator is radiating very little, indeed the thermostat is probably not opening.
These blanks help everything to warm up (and so prevent the mayonnaise) and they slip in front of my radiator quite easily. Thin painted plywood, would be better but the hardboard (now over 10 years old) is still standing up to the rain etc. And I'm sure simple square holes would work just as well!
Regards from MikeN.

[michael4]

MikeN, thanks for that, I have some ply somewhere lkeft over from another project. Will try and copy your blanks.

Regarding breathing, what is the little vertical tank in the breather tube. Is it some sort of expansion tank or filter?

[Mr Spigot]

Regarding breathing, what is the little vertical tank in the breather tube. Is it some sort of expansion tank or filter?

That little cannister is filled with wire wool to stop oil being drawn out of the crankcase into the carb/filter.

[philthehill]

Mayonnaise - a subject that has been covered for some considerable - since well before 1987 and was covered with suggestions to overcome it in the then Minor Matters Technical tips (my copy is dated 1987).
The recommendation back then was to fit at least a 82 degree thermostat or even better a 88 degree thermostat but that must be used in conjunction with a 14psi radiator cap so as to raise the boiling point of the coolant. Those recommendations still stand.
Some time ago you used to be able to buy a kit (Mr Grumpys if I remember correctly) that placed a cold air flow deflector/shroud plate in front of the rocker cover so allowing the rocker cover to warm up and displace any moisture inside the rocker cover. I have seen some posts recently regarding locally made kits. Both the after market and locally made kits used the thermostat mounting studs/nuts to hold the deflector/shroud plate in place. A locally made deflector/shroud plate should be easy to fabricate.

[svenedin]

I would second the already posted suggestion to check that the engine breathing system is not blocked and that the correct oil filler cap is in place (vented or non-vented) and if vented the gauze isn't clogged up). I think that engine breathing that is just about marginal in Summer suddenly shows itself in Winter.

I had a 1965 1098 many years ago that suffered badly from mayonnaise. That car had the rocker cover to air filter housing pipe. My current 1969 1098 uses the later tappet chest oil separator with pipe to a PCV valve. I have never seen mayonnaise in this engine in the 35 years I have owned it. So I am pretty convinced it is a breathing issue.

I also find that my engine does not take that long to warm up in Winter. I start the car in the garage, back out slightly (so that the exhaust doesn't gas me) and run the engine at a fast tickover. It's important that the heater control is closed when trying to warm the engine up or it takes too long. I only open the heater valve when the engine is hot. This is only possible on later cars with the cable operated valve unless you go to the trouble of opening the bonnet to turn the earlier tap-type valve.

It seems likely that the OP's oil separator is blocked which is very common. There are posts about how to remedy this on this forum. Basically there is gauze inside the oil separator can. This can corrode and get completely blocked. To fix this the gauze has to be removed by pulling it out and replacing it with a suitable replacement (stainless steel pot scourer). A new tappet chest gasket may be needed and a new cup washer under the machine screw that holds on the tappet chest cover (the old ones may not survive removal). The vented oil filler cap may also be blocked. They are a service item and are usually replaced with a new one but can be washed in petrol to clear the gauze inside.

Stephen

[mowogg]

I think it would be wise to revert through air breathing to standard. The oil cannister on the tappet cover should be coupled to the carb

[michael4]

As can be seen from the picture I have no PCV valve or provision for one. The breather hose from the oil canister/separator on the tappet cover goes directly to the air filter. I don't know if this is standard or not.

[geoberni]

There's a good chance the breather 'trap' is totally blocked. They were not intended for decades of use.
See this topic; there are several images on it showing the condition they get into and how they can be repaired.
Or even just do away with it...viewtopic.php?p=663439#p663439

[mowogg]

The oil canister should either go direct into the side of the carb or via a pcv valve to the inlet. Most go to the carb but its possible you have an earlier carb fitted without the connection.

I would either look to couple it to the carb or revert to the earlier type down tube

[michael4]

I think the fact that the head is a 1275 is not helping this.

I wonder if the manifolds and carb came with the head because there is no fitting for a valve on the inlet manifold, nor is there a fitting on the carb.

So as things stand I will need to attach the breather pipe to the air filter.

Oil filler cap is clear but my attempts to blow down the breather pipe and through the separator/cannister met with significant, almost total, resistance.

Don't want to jam anything down there while it is attached to the engine fo fear of getting bits of rusty metal into the engine.

Looks like I need to clear it out and invest in a s/s scouring pad.

The car and engine is 1970, registered '71. Engine numbers suggest original. I assume I need a neoprene tappet chest gasket for my concave cover?

[philthehill]

In my honest opinion I would check that the thermostat is the correct one (at least 82 degrees) and is working. The mayonnaise is caused by the lack of heat in and around the rocker cover. Until the engine heat level is determined nothing will change and mayonnaise will continue to be produced.
I consider that the breather canister is secondary to the thermostat but should be cleaned out as a matter of course.
If the head is as you say a 1275cc item it may not have the facility to house a thermostat. Does the head have a bypass hose?
What pressure is the radiator cap?

[michael4]

Phil,

Thanks for reminding me that I should be concentrating on getting the engine up to temp as quick as poss, I can deal with the breather as and when.

The cap is 4lbs.
Yes it has a thermostat, I will open it up and see what rating it is.
If the bypass hose is the little vertical hose from under head to lower radiator hose then yes.

The car has a temp gauge attached. I have no idea as to its accuracy. The sender is near the front of the head. It rises quite quickly to half way between 90 and 140 degrees, ie 115 degrees and then sits there. Seems the same summer or winter. Heater is quite good. I am going to borrow our son's hand held thermometer and see how the results compare. I also intend to do a little radiator blanking and see what effect that has.

The car came to me with no history so it is something of a voyage of discovery!

[oliver90owner]

115 degrees Fahrenheit? Either stupidly incorrect or indicates the engine is simply not warm enough. It should be up to around 190!

[StillGotMy1stCar]

Purely a guess, but I thought Centigrade and falsely reading high.
Assuming matched Gauge and Sender, then it is being supplied with 12V, when it should be supplied by the stabiliser with a voltage of proximately 10V.

Regards John

[michael4]

Sorry, should have said centigrade.

The gauge gives little confidence, I do not know if it is accurate or matched to its sender. The needle sits at approx 3/4 of the gauge. I had assumed over reading.

I will be testing using a hand held thermometer. What temp read close to the sender should I be looking for? 90 something degrees?

[svenedin]

An 82 centigrade is a standard thermostat so it should not open until 82 C. If you start the car from cold, the top radiator hose should remain cold until the thermostat opens. All of a sudden the top hose is rather hot. Simple as that but do be careful if touching the top hose as the fan blade is rather close. If when starting the engine from cold, the top hose becomes tepid as the car warms up you know the thermostat must either be missing or stuck open.

Stephen