Morris Minor Owners Club

Has anyone ever used one of these I know there are 2 types one has an angled top, I have been told that they quieten down the top end of the engine, is it true, does it only make a difference when driving or is it all a bit of folklore

I used one on my 1293 Mini engine because it looked more like a performance item (sad I know!). I can't say I noticed a reduction in the tappet noise though. Mine was the angled type with the alloy vanes.

A lot of these ar not suitable for the Minor because they don't have a breather pipe.
As for quietening the top end of the engine, that all depends on whether the noise is coming from there or somewhere quite close like the timing chain - which is more likely.

I might have missled a little here what I meant was do they quieten down the normal engine noise when running, assuming valve clearances & timing chain are all OK

A lot of these ar not suitable for the Minor because they don't have a breather pipe.

Neither do some late Minors (my Traveller and Jane's 2-door - both 1970)

Kevin, they might well quieten the tappet noise down a bit due to the thick aluminium, but I never noticed so it may be VERY slight.

Hi Kevin,
Do you want one? (Aluminium with angled + finned top surface and without breather)
They should make a small difference to the tappet noise, but as mentioned already the timing chain may drown that out anyway.

The only problem with them is that they don't have the lip where the gasket sits in, so lining a new gasket up can be a headache. I always used to 'glue' the gasket to the cover with a bit of blue instant gasket before fitting.

I have one spare too!

So its sounds like they are a cosmetic item and just make the rocker cover look err as Cam put it go faster without any real benifits at all, thanks for the replys.

They may be able to help in another way though. If the conductivity of aluminium is less than steel they could help to reduce mayonnaise build up which aparently is due, in some part, to the front of the rocker cover remaining too cool.

Ive heard that if you want to use higher ratio rockers then you need an alloy rocker cover because they are bigger and then the rockers wont hit the top of the rocker cover. Is this true or was the guy selling one on ebay trying to con me?
Tim

PETEE... re the 'front of the rocker cover stays too cool' I followed
this theory by making up a deflector plate for my Minor. It made
absolutely no difference. (The A series engines in the Mini are
blasted by cold air along their whole length because they are mounted
sideways and I never had mayonnaise troubles). I owned two Minor
1098's at the same time, the saloon always produced mayonnaise,
the convertible has never produced any to date. They were used in exactly the same fashion with the same thermostats and neither has
any problems with head gasket failures. On a normal car the fact
that it produces mayonnaise will point to head gasket failure or too
many short runs when the engine never reaches its optimum temp-
erature. For some reason this does NOT seem to apply to the Minor.

The one with the angled top is off a Metro - MG turbo I believe. It can have a breather bolted on top as is done with some of the MG ones . As it is a standard rocker cover it should give no more problems with the gasket than normal , unless you tighten it too much.
High lift rockers will fit under any rocker cover as the only difference is that they have the rocker shaft in a slightly different position giving more leverage.

A small benefit coms from using the alloy cover - it is a lot more robust to overtightening.
The thin steel cover has a tendency to distort (permanent), therefore a lifetime of leaks will occur for the next owners. The alloy one is a lot more forgiving to those people who overtorque the rocker cover fixings.

Well I've read in David Vizard's 'Tuning the A series Engine' that some of the big 1.5 roller rockers with a high lift cam will go up high enough at the adjuster end to hit the top of the standard rocker cover . Ive just bought an alloy flat top style rocker cover and the aluminium looks very thick, about 7mm, so I would not be suprised if it would block out tappet noise. I agree with ray - the threads on the bolts would probably strip before the rocker cover becomes distorted
Tim

I agree with ray - the threads on the bolts would probably strip before the rocker cover becomes distorted

Well, no. Ray's correct of course the alloy ones are far less prone to distortion BUT you CAN tighten them too much and they sink and crack. Well before the threads are tight!