'A' Series engine repair

[CHRIS1980]

Copper head gaskets are the best! Every time I put one of those Payen gaskets on it would be revisited very soon after.

[Squire_Dawson]

When the head came back I wanted to fit it without delay. First there were some other jobs to do - cleaning the push-rods for a start:

 

 

I just cleaned all the rust off and wiped them over with a cloth to remove all debris which would otherwise find its way into the sump. The tappet chests had a good coating of gunk aswell. The 1098cc engine has removable tappet chest covers which can be both a curse and a blessing.

The rocker shaft and valve rockers were in a right state, but all freely moving and in good condition where it matters.

 

 

This was not actually an oil-way but you get the idea of what rubbish builds up in these sort of places, like clogging the arteries of the engine.

 

 

So, after a petrol bath and brush it came out like so:

 

 

Nice, clean and ready to fit, you think? Not quite, as I decided to take the whole thing to pieces, which is easy because it just means removing a couple of split-pins.

 

 

And it was a good job I did. (Note that you should keep these parts in order so that they go back on in the same positions as they were).

This is what I found - shocking! No oil could possibly find its way through here:

 

 

And this engine had received regular oil and filter changes!

 

 

Into the petrol bath to begin with to try and dissolve the oil, then poking out the build up as best I could with a small nail. Then, I blasted it out with a hosepipe on its highest setting (I put the rocker shaft on some wood so as not to damage it). After this I wiped it down with a rag and left it atop a radiator for a day or so in order to thoroughly dry it out.

With all parts well cleaned, I re-assembled it in the same order and renewed the split-pins. Then, with the push-rods in place, the rocker shaft went back on, I torqued down the cylinder head and lastly torqued down the rocker shaft, making sure the ball and cup of the rockers and push-rods engaged properly. Spraying the lot with a liberal quantity of WD40, as it would be 'dry' for some time, I also fitted the top cover finger tight to keep any foreign matter and moisture out.

[Squire_Dawson]

I next turned my attention to the distributor. Fortunately Lucas distributors, as with the vast majority of the wares from the 'Prince of Darkness', are very well designed and robust. I don't think Americans understood British electrics very well, or even electricity in general, seeing as they used the same colour wiring for everything in their early cars. I did not even have to remove the distributor, though it is possible to do so without affecting the ignition timing - just remove the two bolts attaching it to the engine block.

After taking the cap off and removing the rotor arm, I pushed the condenser wire through its aperture in the distributor body. Then I could remove the entire base plate complete with points and condenser. It's only a matter of undoing the two Philips screws, seen below back in place to avoid them getting lost.

 

 

This is what I call good condition inside, reasonably clean and free from corrosion. Note the grease on the cam. Just a quick wipe clean was all that was needed here. The next photo shows the base plate assembly as removed, showing the long condenser wire with rubber grommet.

 

 

Here is a photo to show the then current state of play. The alternator had been removed for inspection and ease of engine block cleaning later on.

 

 

The rod I am pointing to in the photo below connects the vacuum advance to the base plate. The vacuum advance works off engine suction and is connected by a thin tube to the carburettor. Dependent on throttle position the base plate moves due to the suction so that, if I remember correctly, the ignition timing advances. These units contain a sort of diaphragm which can fail, so the way to test is by sucking on the tube and watching for movement and feeling resistance. There will only be a slight movement of the rod because we cannot create as much suction as an engine!

 

 

If the vacuum advance did fail, you can still get replacements and they are just screwed onto the distributor body.

 

Genuine 'Made in England' points have life in them yet. Just lightly filing away the pitting (not with sandpaper) is the way to do it.

 

 

This is the base plate, with my thumb on the bit which fits into the hole on the vacuum advance rod. The two parts of the base plate are meant to move freely. They were a bit stiff, but after a petrol bath to dissolve old grease and a drop of fresh oil, they were moving again without much resistance.

 

 

Before replacing the base plate I lightly oiled the bob-weights which can be seen in the first photo. Then, with it all back together again, I set the points gap using feeler gauges (should be a sliding fit) and smeared grease sparingly on the cam. There is sometimes a felt pad on the points assembly which you soak in oil, instead of greasing the cam.

 

All that was left to do was brighten up the edge of the rotor arm using a fine abrasive, and check the carbon brush in the distributor cap. I wiped the cap out too, keeping an eye out for the dreaded tracking. I'm not replacing these consumable parts for two reasons. The first, I want to see if they still work after all this time (especially the condenser). The second, it will be easier to fault-find than if I had replaced every part.

 

 

 

 

 

[DSdriver]

I would have the sump off and check the bottom end if I were you. Whilst its easy like.

I bought a supposedly OK DS engine but when it was stripped down one set of crank big end shells were found to be rotating on the crank rather than being held in place by the little bulges. If we had just put the engine in the car with fingers crossed it would have been sense of humour failure time quite soon after.

[Squire_Dawson]

Removed all loose rust from starter motor then dismantled starter motor for inspection.

 

 

The teeth are in reasonably good order, but the flywheel ring gear tends to suffer more. A slipping starter would be an indication of excessive wear. This is a basic, inertia type starter motor, nice and simple.

 

 

The magnets inside the motor attract the metal particles created every time the starter meshes with the ring gear, i.e. every time you start the engine.

 

 

Checking the motor brushes. According to the workshop manual, these were out of spec. as there should be more protruding (I forget the exact figure). However, though it is hard to see looking straight down at the brushes in this photograph, I decided to leave them as they were because 1) I judged there to be enough meat left on them, 2) the procedure to change the brushes is lengthy and ominous, 3) I have a NOS starter motor spare.

 

 

Wiped clean the commutator and the rest of the dust away using a non-fluffy rag dabbed in meths. If you turn the pinion down towards the motor body you can understand the action of the inertia type starter motor. It should return back on its own when released - the advice is not to oil this mechanism because the oil attracts clutch dust &c which clogs the mechanism, leading to a sticky starter. Incidentally, starter motors on cars this age have a square nut protruding from the end (visible here as the rusty tip) so that, should the starter motor stick, you can turn this nut with a spanner and free it off quite easily.

 

 

Re-assembly was straightforward and I gave it a lick of black Hammerite.

 

Moving on to the coil, which are essentially maintenance-free in that they should never be taken apart, but there are some checks to be done which will prolong its life and maintain top efficiency. Using a multimeter, I checked the primary winding for resistance, which the manual stated should be 3.0 - 3.40 Ohms for this non-ballast coil.

 

 

It is giving a good reading, showing the primary winding to be in order. Note that the resistance of the meter leads should be checked first and the figure subtracted from subsequent test readings.

 

 

The aluminium casing of this coil has had a hard life, being situated as it is at the front of the engine, susceptible to corrosion from salt air, natural decay and so on. Best to leave it alone and not try and remove the corrosion here. I suppose that eventually the casing will wear through and allow the oil to leak out. Though it's not clear in the photo, I am pointing to some serious pitting.

 

 

This data stamped on the end of the coil is important when seeking a replacement. Dated 1976, this is no doubt the original ignition coil. Be sure that, on chod of this age, you have the correct coil, as a ballasted coil will not work for long on a non-ballast igntion circuit!

 

 

Beware the dreaded tracking! The grease and grime on the black plastic should be thoroughly wiped off periodically, or a track can develop, rendering the coil kaput.

 

 

Terminals were in a bad state, not good at all for electrical conductivity. I cleaned them up using medium/fine emery cloth.

 

 

Not much left to do now, I hope to have this engine installed by February in time for the MoT, as the sticking valve plus what we suspect to be an air leak is causing erratic emissions readings. I will be giving the engine a coat of paint in satin black, which I believe is how BL painted them at this time. But first it needs a really good scrub up!

 

 

This is properly caked on!

 

 

Next I will be dealing with the SU carburettor.

 

 

 

 

[mercrocker]

good progress there, Squire...Loving that Avometer!   Worth looking after those old starters - modern ones are dog poo.

[Squire_Dawson]

Good old Skinner's Union carburettors. Simple, robust and reliable. It's what I like to have, even though it's obsolete technology, and arguably was in the 1970s, but it works well. Probably every shiter is familiar with them. The one I am dealing with here is a HS4 with Waxstat jet, which I understand incorporates a simple thermostat which adjusts the mixture according to temperature. Other cars I have owned used the HS4 with a plain red jet, so this is new to me. Another development is the fitment of a throttle damper, which should make for smoother throttle closure. When I removed this engine, parts of the Waxstat had come off and were lying on the throttle spring bracket, fortunately they were all there!

 

First up, after some dismantling, was the usual petrol bath.

 

 

I won't go into too much detail on this refurbishment. It was simply a clean and inspect job, with new gaskets and any other parts fitted when necessary. An important point is not to use any form of abrasive when cleaning these carburettors. Parts cleaner/petrol and a clean rag is all that's needed. The only difficulty I had was making sure the jet assembly returned fully when dispensing with the 'choke'.

 

 

When you pull the choke knob out, the jet moves down to give a rich mixture. When pushing the choke in fully, the jet assembly should move up to abut the jet adjusting nut. With the set up here, a steel rod controls this movement and the jet assembly was not fully returning, as seen above. Some judicious re-working of the steel rod soon sorted this out. By checking the action several times by simulating pulling the choke knob (a remnant of the original cable remained attached), it was proven.

 

 

This photo shows the mating surface of the carb to manifold, which must be spotlessly clean and smooth for the gasket to do its job, thus ensuring an air-tight seal.

 

 

The jet tube, being made of brass, wears out over time as the needle rubs on it, throwing the carburettor out of adjustment. If this be the case, it is futile trying to adjust the mixture: the only solution is a new jet, and likely a new needle. No such wear is apparent here, the hole still being perfectly circular to the naked eye. Microscopic degrees of wear are of no consequence on such an item.

 

 

The jet is sprung and 'floats'. To remove it, the screw needs to be undone and it should all pull out. Unfortunately this had rusted solid, but if the needle can be moved things can be left as they are. Note that when replacing, the needle holder should fit flush.

 

That's all I had to do to the carburettor, really. The float was checked for any pinholes, the float chamber needle valve checked &c &c. The only job left to do, after connecting it up, will be to fill the dashpot with clean engine oil.

 

The day soon came around to swap the engines over. I hired a crane from HSS for £50 to use over the weekend, and it was a really good one, very nice to use. I will leave these pictures for now, as there is much to be said on the engine removal procedure in a later post.

 

 

One other thing. I knew I was losing a drop of clutch fluid, but nothing drastic. There were no obvious leaks, yet the hose could sometimes be damp; it might have been condensation but I wondered nontheless.

 

 

Looks fine from the part visible when in-situ, yet...

 

 

lo and behold! Perished!

[Danblez]

Quality pipe action. Engine repairs not bad either! 😄

[MarvinsMom]

so much, MUCH quality....

 

first, the a-series engine which is one of the very finest english engines ever,

 

and then its an 1100 which is going back into an allegro, in limeflower?

 

so much win it might* break the internet!

[Noel Tidybeard]

look at that engine bay crying out for a 1750 tc