Rebuilt 1275-running a bit "out of sorts"

[ndevans]

A short run today has shown up no water leaks, and no sign of boiling over and lifting the cap.
I've also managed to sort out the oil leak that was causing a small puddle to form after a run, and when idling. I thought it was the oil pressure relief bolt or the oil pressure switch that weren't tight, judging from where the oil was coming from.
Turns out it helps if the oil filter is screwed on properly!
The leak has now gone back to the usual couple of drops of oil after a run.

[ndevans]

Schoolboy error this weekend. After a good run, 110 miles to Bedfordshire, I checked the oil, and topped up. Went to the tip yesterday, then before the long run home, checked the oil and water again after the short tip run. Found the oil filler cap missing! I obviously hadn't put it back on properly on Saturday.
I did the 110 mile run home ok, after buying a spare fuel cap from a local garage. The ones with the 6 vanes that compress seem to be a good temporary fix. Little oil loss, and water loss seems better after enriching the mixture slightly.
So, what is the correct oil filler cap for a 1275, with breather "chimney" on the timing chain cover, feeding into the carb (HIF44) breather inlet, and with no vent pipe on the ticket cover? Do I need a vented or non-vented cap? The one I lost was vented, but the engine was 2nd hand, and for all I know, didn't have the original cap.

Cheers N

[philthehill]

This is the correct rocker cover cap for the 1275cc engine with timing chain cover breather.

https://www.moss-europe.co.uk/cap-oil-f ... soc=143371

Note that the cap in the link has a retaining strap/band which fits around the filler cap stub - so even if you leave the cap loose you will not loose the cap altogether.

[ndevans]

Thanks Phil. Yes, mine had the retaining strap, but it was broken. One of those things that I kept meaning to fix. Even a bit of insulation tape would have retained it.

Cheers N

[pgp001]

The filler neck on the rocker cover seems to vary in height a bit depending on which one you have, I found that my new vented cap from ESM would not seal down properly, but another one from my spares box fits perfectly.

Phil

[Declan_Burns]

Phil,
I had the same problem with the ESM cap. The seal is too hard and too thick so I made my own seal from 2mm silicone impregnated cork.
Then it fits.
Regards
Declan

[ndevans]

Thanks for the advice, I've ordered a cap from ESM as there were a couple of other things that I wanted from them. I'll make a seal if I need to.

[Matt]

The 23D4 does not have a vacuum advance but the mechanical advance compensates for the lack of vacuum advance. The 23D4 distributer was fitted to the 1275cc Cooper S. I ran a 23D4 distributor for many years with a similar engine spec to the OPs and never had a problem.

It was also fitted to the VERY early 1275 Spridgets - as in the first 2 or 3 months.

[philthehill]

The very early 1275cc Midgets/Sprites had several 1275cc Cooper S parts fitted. The crankshaft was nitrated EN40 as was the Cooper S, The 1275cc Midget/Sprite also had the EN24V conrods as per the Cooper S.
All got rather expensive so the quality of the items was reduced to cut costs.

[Matt]

Yes, I have one of the very early 1275 sprites...

But, annoyingly, it had a gold seal engine fitted, so most of those goodies are missing

[ndevans]

New oil filler cap from ESM just dropped off by postie seconds ago, fits well.

Cheers Neil

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[ndevans]

Ok, following on from the missing oil filler cap saga,I took it out for it's first long run with the new cap. I found, after a 110 mile run (roughly 40% motorway/dual carriageway, rest largely A road), this mayonnaise mixture under the oil filler cap, and inside the rocker cover. There is no sign of contamination of the oil on the dipstick, and no sign of contamination of the water in the radiator.
The car ran really well on the run, and on the return home, pulling well, cruising smoothly, purring along nicely at 60 on the motorway stretches.
So, have I got problems? Would/could a blocked oil filter cause this?
Cheers
N

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[philthehill]

Some engines generate mayonnaise whilst others do not.
Is the engine running at around 82 degrees? If the engine is not up to temp any cold areas will generate mayonnaise.
There used to be shields available to keep cold air off the rocker cover.
If you are not loosing water and/or oil I would not worry too much. Just enjoy.
A blocked oil filter would not cause mayonnaise.
Way back Duckhams Q20/50 oil used to create mayonnaise with the engine in great condition.

[ndevans]

I don't have a temperature gauge fitted, so I don't know what temperature it runs at, but I had the thermostat out recently (an 88°), and it seemed to open and close within a degree or so of the correct temperature. it's also the first time I've had a long run with the heater on since last year, and judging from the output from the heater, it's certainly producing heat!
I have a dual oil pressure/water temp gauge to fit, so I'll crack on and get it fitted.

Cheers N

[ndevans]

Could the mayonnaise be an early sign of a head gasket on its way out?

[oliver90owner]

It could, but just as (or more) likely not.

It could be excessive blow-by, running too cool, poor engine ventilation or simply the rocker cover too cool - just like PTH says.

I once fitted an alloy rocker cover to an engine (it looked smarter than the thin pressed steel cover). I soon removed it and reverted to the standard item as it caused condensation simply due to being too cool

[les]

Yes, I friend of mine fitted an alloy rocker covers to his Mini, a long time ago. Soon as I saw it I said it looked cool.

[ndevans]

Well it finally happened this evening. Started running rough on the way back from son's Kung Fu class, like it's on 3 cylinders. I nursed it the 3 miles home, and when I got back, sure enough, no water in the radiator. No sign of oil contamination, though I'm only saying that because the dipstick looks clean.
Head off tomorrow, I'll take a look at the gasket, and take it from there.

[ndevans]

Gasket failure again, as the photos show. Also the head & block didn't drain properly when I took off the drain plug on the block, and some water has got into two cylinders, and possibly the sump.
What's the consensus on 1275 head gaskets? As can be seen, this is a copper one, though it was unbranded. Do I go for a Payen, composite gasket? Or do I stick with copper gaskets?

Cheers N

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[philthehill]

Bad luck.
I would stick with the copper head gasket.
http://www.minispares.com/product/Class ... o%20search
I would change the oil & filter and clean up the top of the block.
There is no requirement to use any sealant on the head gasket. If you want to put anything on the head gasket a light smear of LM grease would not go amiss.
Re-torque after the first heat cycle.
Fit a set of later 'A' Plus head studs and flanged nuts which will allow the head torque to be increased to 50lbft.
http://www.minispares.com/product/Class ... o%20search
As they are out of stock here is a used set which is acceptable to reuse.
https://www.ebay.co.uk/itm/MINI-1275-EN ... SwLeFcROuw