Engine decisions.

Finally, after a few weeks of life getting in the way of classic car fiddling I’ve found some time to get down and dirty with the beast – picking up where I left off last time with the engine removal.

I’d already removed some of the ancillary bits and pieces – air box, carbs, manifolds, coil etc and removed and labelled all of the wiring to the block. Next in line for attention were the power steering pump and air con compressor – the former would stay with the car whilst the latter was too big to be removed with the engine in-situ and would be lifted out with the block.

The power steering pump is secured to both a bracket on the side of the block and to the front engine plate. After freeing the pump from these fixings I tethered it to the suspension turret to prevent undue strain on the hydraulic pipes and hoses.

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The power steering pump enjoying its limited freedom.

Nestled in under a slightly modified (i.e. butchered) battery shelf, the AC compressor is too big to extract from the car with the engine in-situ and was therefore disconnected from the rest of the system by undoing two hoses (I guessed correctly that the refrigerant had escaped long ago) and a couple of electrical connections so it could be lifted out attached to the block. I was initially in two minds about whether to keep the AC system or not, given that it takes up room in the engine bay, doesn’t work and will most likely be expensive to fix. However it would be a great asset if working and the retro interior unit looks good so I have decided to reinstate it as is (i.e. not working) in the short term with a view to recommission it at some point in the future. I have temporarily sealed off all of the hoses and connection points as best as possible to keep the system clean and hopefully moisture-free whilst it is disconnected (not that moisture’s a massive issue in the South Australian summer).

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The AC compressor has seen better days

Learning from my previous experience of extracting a 2500 engine from above, I removed the clutch assembly, flywheel and bell-housing mounting studs from the rear of the block, as well as the cooling fan from the crank pulley. The radiator was also removed and stored safely (incidentally a sticker on this showed it had been re-cored fairly recently – probably only a year or two before the car was decommissioned – and looks to be in great shape). This reduces the length of the block as much as possible and means that the chances of fouling on the bulkhead or slam panel during removal are greatly reduced.

Thanks to this preparation work, lifting the block out was relatively pain-free – it was connected to my engine crane via two one-tonne lifting slings and after the engine mounts had been unbolted it was liberated from the car with only gentle maneuvering around the bulkhead and steering rack required.

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That’s the tricky bit done.

With the engine out I’m going to take the opportunity to address a few little issues in and around the engine bay. One urgent issue that will definitely be rectified before the car returns to the road is the replacement of the rubber steering column coupling which is well on its way to becoming a useless collection of smaller chunks of rubber and metal. As luck would have it a supplier erroneously included one of these in a parts order I made a year or two ago and it’s been sitting on the shelf in my garage ever since so that will be a quick and free solution to a potentially dangerous problem. There’s apparently a bit of an art to fitting these involving a large jubilee clip so I’ll brush up on that before I get stuck in.

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I value the ability to steer so this is fairly high up on the ‘to fix’ list.

The engine mounts don’t look too bad so in the interests of keeping costs down I’ll probably stick with these rather than take a gamble on some new ones which may or may not last more than a few hundred kms.

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Engine mounts seem to be in reasonable shape.

The offside chassis leg, whilst very solid, has suffered from paint blistering where brake fluid has spilled down onto it over the years. It’s currently protected by a nice film of oil and grease but I’ll try to tidy this up before the engine is reinstalled. I’m not aiming for concours, especially under the bonnet, so I’ll try to match the paint up as best as possible and do a quick tart up with a rattle can for now.

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Needs a quick touch-up but its all solid.

Having decided that I’d procrastinated long enough by digging around my newly capacious engine bay it was finally time to turn my attentions to the engine itself. As I’ve written before, I have a replacement block which I was planning to drop into the car with minimal work other than the replacement of the thrust washers. However, given the hassle of removing the engine in the first place and the fact I’d rather not have to go through the process again anytime soon I decided to stick it on an engine stand and have a little poke around in its innards to see what condition it was in.

First things first – to avoid making even more of a mess of my already saturated garage floor I lifted the block on my engine crane, using an engine leveller to tilt it down at the flywheel end. This allowed me to remove the sump plug and the coolant drain plug and make sure that the block was as fluid-free as possible before turning it upside down on the stand.

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Harvesting the various fluids.

I then removed the flywheel and attached the engine stand’s mount to the backplate of the engine using grade 8 high-tensile fittings…

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It’s easier to attach the mount to the engine first.

…before lifting the whole assembly and fitting it onto the engine stand…

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Thar she blows.

So far so good – it hasn’t fallen off yet despite me giving it a really good wobble before unhooking the crane. It’s just a cheap and cheerful stand from Super Cheap Auto but it’s rated at 450kg and seems to be doing its job well. It’s a little stiff to turn over single-handedly but it’s not impossible, even for a skinny-armed guy like me. Hopefully the back plate won’t get bent with the weight of the engine hanging from it but I’ll check it with a straight edge when it comes off and swap it over for a spare if there’s any doubt.

With the engine spun over on the stand whipping the sump off was easy – it looks fairly good in there on first inspection and isn’t too sludgy…

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Eat your dinner off it?

My first port of call was the thrust washers – there are two on the 2500 engine, either side of the fourth main journal of the crank. Whilst the end float was measured to be within spec at about 0.006″, the problem here was obvious – one (the front-most, which takes most of the load when the clutch is depressed) had started to break up. The crank bearing faces seem to be OK – there was some very light scoring to the front-most one where the bearing has broken up, but nothing that was able to be felt with a fingernail. Both of the existing thrusts are standard size so when rebuilding I’ll experiment with adding one oversized one to the mix to try to bring the end float down to the lower end of the tolerance range.

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Thrust washers are definitely due for replacement.

Taking off the main bearing caps for inspection produced some mixed results – the bearing shells themselves are aluminium-tin which do not show any copper as a wear guide but they looked generally OK, if not a little tired with some light scoring in places…

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Main bearing shells look OK.

The crank journals themselves also looked passable – again some light scoring but nothing that could be felt with a fingernail. At this point it looked as though a new set of standard size bearing shells might be all that was needed to inject a good few more years of life into the lump…

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Crank journals don’t look too sinister.

Sadly the big ends were a different story – both the bearing shells and the crank journals had deeper scoring than on the mains with undulations able to be felt with a fingernail on most of the journals…

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Big end journals not so pretty.

…whilst the bearing shells weren’t in much better shape either…

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Neither are the big end bearings.

So at this stage my simple refresh had grown in scale from chucking in some new bearing shells to including a crank regrind. Seeing as I was now edging into rebuild territory it got me wondering how far to go with the engine work. I saw my options as follows:

  1. Do the bare minimum – chuck in new bearing shells and thrusts and reassemble as-is. It’ll probably go on happily for years given the fairly light use it will get from me.
  2. Do a half-arsed job – get the crank ground and fit new bearing shells and thrusts. Leave the block as-is.
  3. Go full monty – strip it down completely, get the crank ground and the block re-honed/re-bored with new bearing shells, thrusts, rings and/or pistons as necessary.

In hindsight I’m kicking myself for not carrying out a compression test on the engine whilst it was up and running in the parts car – but the unexpected arrival of this car and the need to remove the other one from my driveway as quickly as possible unfortunately meant this wasn’t the best use of my time.

In order to get some sort of idea of the condition of the bores and rings, prior to removing the head for a visual inspection I decided to run a leak-down test on the engine. I acknowledge that the results of such a test might not be 100% accurate given that a) the engine hasn’t run for a while and b) the test is ideally carried out on a warm engine, but given the circumstances I decided it was better than nothing.

The test involves setting each piston in turn to TDC on the firing stroke (i.e. both inlet and exhaust valves are closed) and then feeding compressed air into a cylinder at a known psi with a second gauge showing the leakage in percentage terms from that cylinder.

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Leak-down testing apparatus.

Four out of the six cylinders showed a leakage at around the 50% mark (not so good), with cylinders five and six showing a lower figure of around 30%. Given the fact that the engine’s been upside down on the stand for a week now and only cylinders 5 and 6 show any oil dripping out of the spark plug holes I suspect this is more to do with oil passing through the rings from below and improving the results for these two cylinders as opposed to them being less worn than the other four (i.e. essentially the results show the difference between a wet test and a dry one).

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Slightly better results for cylinders 5 & 6.

Given the obvious hisses coming from both the dipstick and, more prominently, around the cam followers I came to the conclusion that the air was escaping past the piston rings – either due to worn/stuck rings and or worn bores. Ideally I’d put the engine in the car, run it for a while (including giving it a couple of good Italian tune-ups) and then carry out compression and leak-down tests to get a more accurate idea of its condition. However, the thought of putting it all back together again only to potentially have to take it all apart again in a few weeks fills me with dread. I’d quite like to drive the thing.

So this leaves me thinking that the best (albeit most expensive) course of action is to go full monty on this bad boy – strip the block down, get the crank ground and the cylinders honed or bored as needed. Fit new pistons and/or rings, new bearing shells and thrusts, a few new seals and gaskets etc. Given the fact that it will be mated to a rebuilt gearbox it should mean the drivetrain will be largely sorted for the foreseeable future.

I’ll have a look at the cam shaft when the block’s stripped and make a decision about that at the time, the same goes for the oil pump. I’ll also have a think about the head – worst case scenario I can clean it up, give the valves a quick lap and run it as-is for now with a view to getting it rebuilt with hardened valve seats when funds eventually allow. But then again my mission has had a habit of creeping slightly of late…