Morris Minor Owners Club

Hi guys,

I've had a bit of an intermittent misfire which has changed into "now I can't drive my car" sort of misfire. When idle, it's fine. When revving stationary, it's also fine. But heaven forbid I should actually drive it and put some load on it. Generally speaking, 1st is ok, 2nd is mmmmm, 3rd is PPFT PSPT PTPTPTPT PARP, like a kangaroo learning to walk.

I don't have a compression tester, so I used the starting handle to feel. Cylinder 2 felt a little softer than the other 3 and that spark plug also seemed much wetter than the others.
I changed the dizzy cap, just because I had a new one handy anyway, as well as a general inspection of the pretty much brand new red rotor arm and points, Of course, nothing to report.
I would love to say the problem is the carb, because I'm fed up of having this b****y H2 carb and bodged adapter. But since I'm planning on changing either the manifold or carb to something better suiting, I though I'd take this time to check other parts instead.

Valve clearances were also adjusted a few months ago, so I know it's not that. So that's it, time has come for some learning. Cylinder head is coming off!

Now I've removed the rocker assembly, laid it out nicely with pushrods ordered as they were removed. I'm concerned that it wasn't until after removing it that I learned there is a sequence to undoing the nuts. I didn't follow this! Could I have caused any damage at the stage I need to be aware of?

I've hit a bit of an obstacle right now too with that being the head is near enough welded on! I left the studs to soak in WD40 (Strongest stuff I have, unfortunately) overnight and am hoping I can go back home after work and start him up to see if the compression will lift the head off. We will see.

EDIT: Backstory, I overheated my car late last year (The old cardboard in front of the radiator trick didn't work out for this idiot) so I thought it would be good practice to check the head gasket anyway.

I most definitely would not recommend trying to start the engine with no restraint! But without valve gear, it is unlikely to actually start? A soft faced mallet is usually a good tool to help loosen the seal.

Have you checked for a broken valve spring? Were all the valves lifting properly?

WD40 is a water dispersant - not a release oil . Try Plus Gas or any release agent . Appreciate its what you had to hand .

I would suggest that you remove those head studs (using the two locked nuts trick) that you can and soak those you cannot remove in Plus Gas.
WD 40 does advertise itself as suitable for freeing rusty items but I have never found it as effectives as Plus Gas.

Don't worry about the order you undid the bolts, just make sure they are done up according to procedure

And as Phil says, remove the studs and it should all then move

Don't worry about the order you undid the bolts, just make sure they are done up according to procedure

Too late to worry, obviously, but I do wonder why workshop manuals stipulate the order of head bolt removal? Please explain why you think engineers don’t know what they are writing - or does it really pay to follow the proper engineer’s instructions on these matters?

Having searched the BMC/BL workshop manuals all that I can find is the order of assembly/tightening the head nuts.
I agree that it is preferable to undo in the reverse order of tightening but as it is not quoted in the BMC/BL manuals I have to say that there cannot be much of an emphasis on doing the right thing. One thing I would say is tighten the head nuts in stages as per the tightening sequence so as to spread the torque forces through the head.

Thanks for the responses everyone!

Needless to say, cranking didn't work haha!

I've started removing the 4 big studs that also hold the rocker assembly in. Stuck on the fourth, two nut trick isn't working. Would it be too much to get vice grips involved on the smooth portion of the stud?

Should I also remove the studs on the left of the head too?

oliver90owner wrote: ↑Mon Mar 01, 2021 9:35 am I most definitely would not recommend trying to start the engine with no restraint! But without valve gear, it is unlikely to actually start? A soft faced mallet is usually a good tool to help loosen the seal.

Have you checked for a broken valve spring? Were all the valves lifting properly?

All valve springs are good, thankfully (Not quite ready to change one of them haha!). I've been using a rubber mallet to persuade the head, with little success so far. But I disconnected the entire intake system, it ain't starting

The more studs you can remove the easier the job will be. So yes remove those studs on the left of the engine.
It is more important to remove the studs than worry about damaging the stud so use what ever means necessary.
Head studs are readily available at small cost if you need to replace a damaged stud.

Having searched the BMC/BL workshop manuals all that I can find is the order of assembly/tightening the head nuts.

Hi Phil,

Try section AA.9. It clearly states the ‘how to’ for loosening the head bolts. Fig AA.5 has the order clearly shown. Not looked in other sections.

I must say that I have always followed the manuals (if available) or just loosened carefully in the opposite order to tightening.

Thank you for that.

Strangely enough the BL manual covering the 1098cc 'A' Series engine used in the Morris Marina does not specify slackening all of the cylinder head nuts in such a precision way when removing the rocker shaft assy. It specifies just slackening evenly the eight nuts (5/16" & 3/8") retaining the rocker shaft brackets to the cylinder head. Only when removing the cylinder head does it state remove the remaining cylinder head nuts.
It does state that the coolant should be drained before slackening any of the eight rocker assy nuts (and all remaining head nuts if fully removing the cylinder head).

The head is off! That was a battle, especially the final stud.
Naturally, I'd gotten water into every flaming crevice of the block though, so I'll have that to deal with.

But the head is off and I'm ready to start learning how to decoke, lap valves (of which I have knowledge of from my mopeds, just obviously with this being a grander scale) and just make sure the head is perfect for further use!

The head gasket seemed fine though, not blown through at any point. Replacing regardless as it doesn't feel like the proper copper ones.

Spring compressor arrived, so I've taken the liberty of removing the valves. Now my untrained eye has observed the following:

- Lots of carbon
- They're still very much circular, I don't see any burned/damaged valves
- There is minimal play when in the guides
- Some orange "rusty water" was present in some of the valve ports and on a couple of valves themselves

So other than lapping them, would you suggest any concerns or things to replace?

Also what's the best way to remove carbon from the valves AND the head itself without damaging anything? There is some on the surface of the head.

As it's an iron head I would go at it with scrapers and wire brushes in a drill, you can even use abrasive discs or drums in a dremmel etc. If you go carefull. (Wear a dust mask though)

For the valves I spin them up in a drill and use an fairly fine old file to clean them (not the seats !).

In the pics above the block looks a bit rough around the bores, I think you will need to clean that up to get a good seal as well.

kevin s wrote: ↑Mon Apr 05, 2021 9:29 pm As it's an iron head I would go at it with scrapers and wire brushes in a drill, you can even use abrasive discs or drums in a dremmel etc. If you go carefull. (Wear a dust mask though)

For the valves I spin them up in a drill and use an fairly fine old file to clean them (not the seats !).

In the pics above the block looks a bit rough around the bores, I think you will need to clean that up to get a good seal as well.

Hi Kevin,

Great pointers. I had forgotten about the block! I'll treat that once the head is ready.

I spoke to a gent from work who is involved in building cars for racing and he gave me some helpful tips and techniques that were definitely suitable back in the day, so here we go. Please don't burn me at the stake, but lend help if there are any mistakes! (See pictures and captions below, for some reason uploaded in reverse order?)

No real issues so far. Looks like you are doing a good job.

Personally, I would have used a scotchbrite disc or cup brush with an angle grinder for the head face - drills are OK but they are not designed for radial loading. It’s also why I prefer to clean up valves using a collet chuck in my lathe.

Making sure the head is as flat as possible is good. Again, I would whizz across on my surface grinder these days, if any doubt (my surface grinder will just accept a moggie engine block under the standard wheel, as well).

oliver90owner wrote: ↑Tue Apr 06, 2021 7:53 pm No real issues so far. Looks like you are doing a good job.

Personally, I would have used a scotchbrite disc or cup brush with an angle grinder for the head face - drills are OK but they are not designed for radial loading. It’s also why I prefer to clean up valves using a collet chuck in my lathe.

Making sure the head is as flat as possible is good. Again, I would whizz across on my surface grinder these days, if any doubt (my surface grinder will just accept a moggie engine block under the standard wheel, as well).

Thanks for the tips, Oliver!

So I finished the head. Got all the seats cleaned (brass brush on a Dremel) and valves lapped, finished with the surface too. New studs, new head gasket and the head is now in situ!

Since the refurb, I've done a good bit of pottering around in Eugene. However, after a rough total of 50 miles since his new head gasket etc, I've removed the oil cap to find some milkshake.

I'm hoping, looking at the below, you're going to say "oh yes that's totally fine" and not "oh dear, your head and/or block are ruined.

Pottering around, 50 miles , all in one go or lots of short trips?

John ;-)