I was a little indecisive about what part of the car to tackle next. The chassis and running gear is almost complete, so I decided to work on the engine alongside it as I’m waiting for some parts to complete the brakes and steering. The engine/gearbox is an enormous and extremely heavy unit, far too heavy to manhandle around the garage. So much so, in fact, that I needed to build a custom dolly to enable me to work on it without the risk of falling over and causing damage to itself or me! So, this is where I’m at currently.
When I bought the car, I did consider attempting to start the engine after performing some basic maintenance work. Given that it’s not run for probably 30 years, I decided maybe that wouldn’t be the wisest decision, as the oilways could be blocked or any number of other issues which could cause the engine to self-destruct. So, I intend to partially strip it down initially, and make an assessment based on what I find then. The crank rotates freely and it feels nice and snug, but it’s obviously impossible to really know what’s going on in there until it’s taken apart. I’ll be wheeling it outside to clean it up first. Then it will be off with the carbs and ancillaries before taking off the heads and revealing the bits that will decide whether it’s a simple rebuild or if it will require a re-bore and new oversized pistons, along with the cost that’s associated with it. Fingers crossed!
OK, the car is now a rolling shell at least, with the steering complete and just the brake calipers required to finish it off. I’m holding out on those as they need either new sleeves fitted, which I am unable to find anyone to do at the moment, or to replace with new units which is mighty expensive. There’s no rush for them, so I’ve put them on the back-burner for now. So, with a line drawn under the rolling shell, the next on the list is to tackle the engine.
off all of the ancillary items without too much trouble, ensuring I took plenty
of photos of each component and carefully labelling everything in readiness for
The rocker chamber looked in good shape, but the next step would dictate my workload (and expenditure!) for the next year, so it was with great apprehension I undid the head bolts and started to remove the first cylinder head. It came away surprising easy and didn’t require any ‘persuasion’ at all.
Firstly I inspected the bores. These four are perfect, even the piston ring threshold was barely visible, and I couldn’t feel it at all with the fingernail test. Great news indeed.
The next thing to look at was the cylinder head. These are made of aluminium and if the car hasn’t been well maintained, and has been topped up with straight water instead of the correct coolant, then the channels erode badly and this can creep into the combustion area. This is very bad news indeed, as can make them totally unusable.
Well, the last owner had obviously been conscientious with the servicing because the corrosion in the head was minimal. A BIG sigh of relief. I had to end my work there for the day, and will tackle the offside head tomorrow, but from what I saw with the nearside head today, I am hopeful that it will be of a similar condition. I drove home tonight with a big smile on my face. A good day, a very good day!
So tonight I removed the second head and was pleased to find that this too, along with the pistons/bores, was also in great condition.
I carried on and removed more of the engine components until I praised off the tappet chest cover to expose the camshaft and followers. Hmmm, not so good there. The camshaft has a few lobes that have suffered some corrosion. Not the end of the world, and far better than the bores/heads needing work, but not ideal. Fortunately the cam followers have not been damaged at all, so will be re-used. At least it’s just a case of buying a replacement/used item and fitting it, no engineering work required. Corrosion damage like this is caused by condensation in the engine, usually from short trips, but because it’s so severe in this case, I think it is more likely to have been because the engine has been laid up for so many years.
So, a new (or rather ‘different’) camshaft is on order and it’s time to check out the crankshaft and big end bearing shells.
The crank journals were perfect, both for the main bearings and the big ends. Very happy about that indeed. Next to check the actual bearing shells.
They were (almost) all perfect too. All of the big ends and most of the mains were good (above), but the centre main bearing shells (below) show a little bit of wear. So out of thirteen pairs, just one pair showed wear, and even that was only just a little bit of the copper breaking through at the edges. There were no scratches, groves or damage at all. All three pairs of centre main bearings have a reputation for being the first to suffer in a worn engine, but I appear to have escaped lightly which gives me some confidence that it hasn’t done too many miles. I’ll replace all of the shells now as a matter-of-course, but they certainly would have held out for quite a while yet. The effort involved to remove and strip the engine, it would be foolhardy not to use this opportunity to replace them with new.
Time to give
the engine block a clean-up. I had
already checked for damage and there is none.
The water jacket was however, very murky inside. The rust had built up on the internal
casting, and needed a good cleaning. It
wasn’t so bad to cause any blockages, but it will certainly help with cooling
now that the water can travel unimpeded around the cylinders. I used a length of 6mm steel wire to push
around the insides where a screwdriver wouldn’t reach. It’s ideal to use as it frays in use and acts
like a chimney sweeps brush. Eventually
it gets too frayed, but you just chop off a few inches and start again. I also
popped out all of the core plugs to give myself better access to the water
jacket, and it’s wise to change them while the access is good anyway.
The resultant gloop spilled out of the lower core plug hole. Nice…… I guess it will take a few water flushes to remove the remaining residue from the system, but I’ll wait until it’s back together and the system is sealed to do that, before filling with the correct coolant mixture to prevent any reoccurrence.
Before I can start on the reassembly, the final job is to clean the pistons. It’s a rewarding job to see the transformation as you remove the years of carbon build up and the bright alloy reappears. Well, it’s rewarding the first time, the downside of it being a V8 is that there are a further seven to go…
The piston rings were all pretty good, just one had gummed up and needed a little bit effort to remove. I checked each ring in the bore, and they were all just a smidge outside the tolerance of 0.009 to 0.014 inches. Most were about 2-3 thou over that, with the gummed up one a bit worse at 0.021 inches. I’ll measure the bores later but I’m hopeful that it’s the rings that have worn as there doesn’t appear to be any lip in the sleeve at all. Everything on the engine so far has been standard sizing, so it’s never had a cylinder rebore or a crankshaft regrind.
were going well with the strip-down. Too
well. I guess I was pushing my luck too
far to expect that the camshaft would be all that was damaged. I removed the heads and they looked ok upon
initial inspection. The main area that
these alloy heads suffer damage is around the water channels. They corrode due to lack of, insufficient or
incorrect antifreeze being used. This
becomes a problem when it extends past the perimeter of the head gasket seal,
and in severe cases can even breach the wall into the combustion chamber. This was obviously the first thing I
checked. Both heads are fine in this
regard, so I was at that point very pleased.
The top of
the first head also looked to be problem free with no slack in the valve guides
after removing the springs.
This is where I lucked out! The OS head also has intact water channels, but upon turning over to clean the rocker chamber I was faced with two cracks in the alloy. Arrrrrggghhhhh!
That’s put a massive spanner in the works. This damage is above the water jacket in the head and is caused by the water turning to ice and expanding in the cavity. With nowhere to go, something has to give, and in this case it was the alloy head. So now I am faced with one of two options. One, buy a replacement head or two, get this one repaired. I have seen repairs made to these heads, and it seems a reasonably common failure point. Here are two that have been done that I found online.
I’ve made some enquires and I can find a replacement head, but it’s not cheap. I’ve emailed a few places for a repair quote but no reply yet. I’m still waiting for the main bearing shells and piston rings to come back in stock, so I’ll crack on with cleaning and preparing the other engine components. First up is the sump. I was not looking forward to this, and it took two days. The outside was covered in rock hard, oil coated mud and the inside floor was full of congealed oil, which had the consistency of yoghurt. What a messy job. I don’t have any ‘before’ images, but it looks in reasonable shape now.
I had a reply from a local engineering firm to say that they would take a look at my head as they were quite confident that they could weld it for me. Within 24hrs the head was back with me and I was heading home having paid what I consider a reasonable fee for the privilege. They had to chase the crack a little as they welded, and this meant that there’s a little excess metal in the pushrod tube. These are oversized, but I may need to trim a little away to get the end of the pushrod through. I will have to wait and see.
In the meantime, the bearings and rings have arrived, so I can start on the rebuild soon. Before that though, everything needs cleaning. The crankshaft of the V8 is unusual because in each big-end cavity, there is a sludge trap where any particles in the oil are collected due to the centrifugal force when the engine is running. Sometimes there are spoonfuls of the stuff! To gain entry to these, there are four plugs which need to be removed. They are renowned to be a PITA to remove as the threads are peened over in the factory to prevent them coming loose. In an attempt to avoid taking them out, I instead flushed the oilways with copious amounts of WD40 and used a flexible cable to dislodge and dissolve any sludge. But in the end I decided that I wouldn’t be confident that a stray piece would block the oil feed to the bearings with disastrous consequences. So, I used a Dremmel drill to remove the burr from peening and they came out reasonably easily, with just one suffering a little bruising of the hex socket from the allen key. I had been wise to be so thorough as there were still a couple of little bits of clay remaining, hardly anything but at least I can rest easy knowing they are now absolutely clean.
I wanted to ensure that the threads were perfect and that the plugs did not create any swarf when they were reinserted, so I ran a plug tap down the thread to clean them up and clear any remaining debris.
Some more cleaning and polishing done on some of the remaining components. I actually did a better job than this on the valves, but this was a capture half way through. I’ll post some completed ones when they’re back in the head.
The valve train (rockers) all ready to go. Interestingly some are steel and some bronze, or at least that’s the colour of them. All have hardened tips for the valve contact areas though, which did need a little polishing to remove the wear marks.
I was looking forward to polishing the rocker covers, because polished alloy can look so good. My enthusiasm soon subsided though when I remembered just how hard it is. Here are a couple of before/after split shots. I think the effort was worthwhile, now that my arms have recovered.
I won’t be needing any of the above polished ancillaries for some time, but I think I turned to these frivolous items because I am quite nervous of starting the re-assembly of the engine. These engines are not easy to come by, and the costs involved in rectifying any serious mistakes could push back the restoration by years. So I am fully aware of the importance of getting things right, first time. We are not at home to Mr Cock-Up.
I forgot to
take photos of the shells and crank prior to assembly, due to the pressure I
think. Anyhow, it went in quite well and
I used some assembly lube along the way to ensure the bearings are not running
dry on the first start-up. The only
issue was when I fitted the rear cap which is incorporated into the oil
pump. Back in the day, instead of a
rubber oil seal on the crankshaft, most cars used a rope (yes, that’s right….a
rope!) that fitted in a groove in the block and cap to prevent oil loss. This
is supplied in its raw state, and needs to be fitted and compressed to the
correct size before fitting the crank.
Well, I didn’t have the correct part, and so instead used the crank
itself to act as a sizing tool. It was
initially very tight indeed, but after an overnight settling in period and
removal of the very thick lube (I used a thin oil instead) it became far easier
to rotate. I’m happy with it now but
would have been uncomfortable leaving it so tight that it could mask any other
issues. I have heard of people using two
batteries in parallel to start the engine for the first time due to a tight
So with the crank in and torqued down, time to insert the pistons.
The original pistons were re-used as the bores were not worn, but it would seem churlish not to go to all of this effort and not replace the rings.
Here piston number 1 is being fitted using a piston ring compressor to ease it into the freshly honed bores. The new compression rings do have some manufacturing tolerance and I had to try a couple before finding the best fit, no problem with the oil control rings, they are a loose fit anyway. The compression rings though, are tending to be a bit long (tight) but the instructions state that the ends should not be filed to fit. I’m unsure what I’ll do if the last couple don’t match the bores. I’ll cross that bridge when I get to it.
So here they are, all pistons in and all rings fitting within tolerance. With no option other than to file the ends to fit, I filed the ends to fit. I can’t see I had much option really. ‘Gapping the rings’ by filing the ends is how they’ve been done for decades, so not sure why my rings said not to on the pack. Anyhow, they’re in now.
With everything now torqued down and all tab washers bent over, it was time to put the sump on. There is no gasket on the flat areas, just a rubber tube at each ends for the semi-circular seal. These were a right pain as they appear to be too large in diameter and there seems to be too much rubber to squash down. I did it in the end, but was quite difficult.
Next I fitted a new worm gear for the oil pump and distributor (well, it wasn’t brand new, but almost!) Mine had worn a bit as the gear is made from brass against the cast of the camshaft. Here’s the difference.
There would have been a fair bit of play, but as the shaft is only ever driven, it doesn’t matter too much. More importantly though is that the ends of the teeth can get very thin and eventually break off. Compare the thickness of the two above.
I then fitted the shaft with the new gear into the block and down into the oil pump. Hmmm, something wasn’t right. It was free 90% of the way down, then the last bit tightened quite a bit. I didn’t know if this was normal and neither the manual nor the internet gave any clues. No option but to remove the sump, the one that I just had so much trouble getting on! When it was removed, I could see that the shaft of the drive was not quite central on the input tube of the oil pump. The pump sits on the block and is fastened by three bolts. There is no adjustment to be made, so I wasn’t sure how to go about centralising the two. Fortunately, the tolerances at Daimler back in the day were not as good as now, and after slackening the bolts I was able to tap the body of the oil pump gently around with a hammer which gave me the fine adjustment I needed. Everything is now smooth as silk and I’m much happier and glad I decided to investigate.
So with the sump back on, it was time to fit the camshaft. I bought a replacement as mine was too badly corroded to use. The one I bought was much better, but not like new. The lobes and journals both have a very slight amount of pitting, although for a 55 year old car, I think I’m just being fussy. So I phoned for a price for a new one, £850. Suddenly the pitting didn’t seem so bad after all.
I coated the journals with assembly lube and popped it in along with aligning the worm gear for the oil pump and reattaching the timing chain/sprockets. These were perfectly usable and showed no real signs of wear. I had taken photographs of the timing marks and sprocket positions before disassembly to ensure that they were reassembled correctly. The consequences of getting this wrong could be disastrous.