1997 3.9 V8 EFi Refresh

[Phill S]

Recently removed from a Disco 1 with only 61k miles on the clock, I'm hoping to be able to give this guy a fairly light level of treatment:

 

But first of all, what am I trying to do? It's going into a 1987 2.5 NA diesel 110 Ex-Army that I'm building up as an expedition vehicle for long distance travel. Less concerned about cooler climes, but plans are afoot to be travelling to hot places too - Eastern Turkey, Baku, Israel, Egypt, North Africa etc etc. So I'll want the engine oil cooler option. Can't see me wanting to exceed 70mph on motorways, but it'll be spending most of its time on country roads, with a certain amount of unpaved mountain tracks. All of this barring covid, war, bank account emptied by Land Rover ownership etc.

From a starting point of 61k miles, the aim is to renew all seals and gaskets to stop up/head off the leaks, and sufficient work to get it to 120k miles. Ish. After that I'll do a major overhaul with the aim of a further 80k miles taking it up to 200k total. You'll be ahead of me already, but the aim is to be replacing items like the water pump, core plugs etc before they fail, rather than searching the back streets of Cairo.

I'm pretty familiar with the engine in its 3.5 carb form, but EFi is new territory for me. There will be dumb questions.

I should also say the engine was running nicely before removal, but had a pronounced RPM related tick, which sounded to me like a stuck hydraulic tappet

 

Oh yeah - engine number:

 

Just around the exterior, the core plugs have more corrosion than I would like to see:

 

And jumping ahead slightly to the point after the flywheel came off, the cam core plug at the rear has been leaking:

 

They're cheap and easy to replace, so that'll be 8 x 602152 and 1 off 602146 to be replaced. I don't think there are any others on the main block that I need to worry about at this stage - or are there?

 

So - spark plugs out:

 

That lot look pretty sooty to me?

 

First look inside:

 

That looks a whole lot more ginger than I'd expected. The right side gingerer than the left. Odd. So, overheating, poor oil change schedule, sub-standard oil, normal?

 

In this state I could only do a compression test cold, but done dry all looked well within limits. A leakdown test and all pretty good, but suggested at least two exhaust valves hissing. All inlet valves ok. Cylinder heads off job then

 

But first, I thought I'd check out the timing chain and gear:

 

Engine tipped on its side to show the chain is pretty sloppy, so I'll be replacing the chain and the two gear wheels. Distributor drive gear will be good for another 60k miles. I think

 

Heads off and engine looking less pretty inside than I had hoped...

 

Heads no too bad:

Or am I just getting used to it? Both heads pretty much the same. 

Out with the valve springs, and on a first look I've got at least two exhaust valve guides shot. One with about 0.3 mm slop in it, so actually the tappety noise might have been coming from that? And do I recall correctly that valve guide replacement is a pain on these engines?

 

I've just started coming down with covid, so it'll be a few days before I can get into the workshop again, but would be interested in any thought and comments in the meantime.

Time for my lunchtime Lemsip....

[FridgeFreezer]

UNC-UNF Exhaust studs + brass nuts, ARP head studs, duplex timing chain, stump-puller cam if you're feeling flush.

[Mo Murphy]

Deep pockets for the long distance Fuel bills ! 😉

Mo

[FridgeFreezer]

1 hour ago, Mo Murphy said:

Deep pockets for the long distance Fuel bills ! 😉

In a 110 a 3.9 should be pretty good - 18+mpg if you can keep your toe off the loud pedal, very relaxed drive and will pull higher gearing (disco transfer case) especially if you're not towing.

[Phill S]

3 hours ago, FridgeFreezer said:

UNC-UNF Exhaust studs + brass nuts, ARP head studs, duplex timing chain, stump-puller cam if you're feeling flush

Well, I can afford the brass nuts, but I'm planning to save the camshaft replacement until the major overhaul at 120k miles. On a first look the existing stock shaft looks  pretty good, but I have a whole bunch of measurements to take when I can shake off the lurgy and get back down to my workshop.

In the meantime though, what do we make of the sooty spark plugs and gungy pistons?

[smallfry]

1 hour ago, Phill S said:

In the meantime though, what do we make of the sooty spark plugs and gungy pistons?

Probably been started and run for short periods. On and off transport and moved around the yard. Prior to that, given the low mileage, short journeys. Wouldnt worry about that.

Check the camshaft carefully and look at the shape of the lobes, especially the ones third and fourth from the rear. These are normally the ones to go first.

Provided it is actually OK, and TBH I would be surprised if it does NOT show any wear, and given where you want to go, I would change the bearing shells, piston rings, timing chain and gears, and rocker shafts also.

[Phill S]

Ok!. Got some measuring up to do once I'm back on my feet...

[Bowie69]

That colouration looks pretty normal, even for 60K, I wouldn't be worried about it at all.

As you have it apart, a cam, lifters and a decent timing set, check the bearings, get the heads serviced and slap it back together.

[Junglie]

Hiya. I have a 3.9 with fittings and pipes for an oil cooler that I don't think I'll need.

If you want to swap non-oil cooler bits for my oil cooler ones I'd be happy to oblige.

I'll put pictures up if you're interested, but either way please keep posting as you're doing the same as I am with the engine.

Cheers,

Simon

[Phill S]

Thanks guys - good stuff here. I'm in the thick of covid, but will endeavour to remain coherent...

13 hours ago, smallfry said:

Check the camshaft carefully and look at the shape of the lobes, especially the ones third and fourth from the rear. These are normally the ones to go first.

I'll pull the camshaft out and give that the once over. I've yet to properly check the hydraulic tappets, but they looked like what I would expect - minor wear pattern, although one had some slight pitting

 

13 hours ago, smallfry said:

I would change the bearing shells, piston rings, timing chain and gears, and rocker shafts also

Timing chain and gears a definite - see pic above. I assume you would include small ends under the heading bearing shells? Haven't checked over the rocker shafts yet, but will give them some attention

 

11 hours ago, Bowie69 said:

get the heads serviced

Assume you mean the valve guides here? I was surprised to find quite so much slop in one of the exhaust valves - need to check thoroughly on all of them rather than my previous quick look. With about 0.3mm slop, I reckon that's the prime suspect for the ticking noise I heard with the engine running in the donor vehicle. Is replacing valve guides on this engine really that specialised a job?

 

11 hours ago, Junglie said:

please keep posting as you're doing the same as I am with the engine

Feel free to weigh in with your own pics and questions on your engine. You may be dealing with things that I haven't thought of

 

11 hours ago, Junglie said:

I have a 3.9 with fittings and pipes for an oil cooler

Well the Disco engine comes with the takeoff and plumbing for the oil cooler - I just need to work out radiator/connections and plumbing for my 1987 110.

On that score, can anybody point me at a parts book for the Defender 3.9 EFi? I have time on my hands just now and will obviously need to work out 101 items of hoses, cooler connections etc etc when it comes to the final fit. 

[ThreePointFive]

19 hours ago, FridgeFreezer said:

In a 110 a 3.9 should be pretty good - 18+mpg if you can keep your toe off the loud pedal, very relaxed drive and will pull higher gearing (disco transfer case) especially if you're not towing.

Yeah but you've got to remember these diesel boys are operating at a dizzying 25ish mpg, next level hyper-miling... 

Having done two rebuilds very recently, I'll be following this with interest. I can't tell you what best practice is but I definitely made my share of mistakes.

[Phill S]

32 minutes ago, ThreePointFive said:

I definitely made my share of mistakes

Would you be prepared to share any of those? Don't want to make any mistakes....

[smallfry]

It does not have small end bearings. The gudgeon pin is a press fit in the conrod, so the piston housing, is the bearing. I do not recall ever having a V8 with that problem.

If you take them out, make sure you keep them in the right order AND the right way round. You will see on the conrod beam a dimple, and these must face each other on each big end journal.

[Phill S]

24 minutes ago, smallfry said:

It does not have small end bearings

Interesting, and I'd like to understand how the gudgeon pins work. They take the full load of the power developed by the combustion chamber, so being pressed into the conrod there must be some kind of bushing in the piston rather than rotating in the body of the piston? The overhaul manual describes lubrication "to the thrust side of the cylinders" in slightly vague terms, but it sounds like the conrods are drilled along their length in the conventional way to supply the oil? So that would mean the same oil supply is used to feed the gudgeon pins?

I guess I'll be able to answer my own questions when I get the pistons out to refit the rings and change bearings. As for getting the bits back together correctly, I wouldn't want to dismantle the pistons/conrods unless absolutely necessary - anyway, sounds like it's engineered as a long-life item

Sorry - covid gets pretty boring...

[ThreePointFive]

1 hour ago, Phill S said:

Would you be prepared to share any of those? Don't want to make any mistakes....

Just a few to begin with, all very stupid as I write them here but luckily most now rectified:

Not having the liners checked for slipping when the block was first stripped

Not checking piston ring gaps

Not checking the valve guides properly

Putting new lifters on an already-run-in cam for rear 4 cylinders

Thrusting an aftermarket oil pressure sensor

Not getting someone with experience to check my lifter preload and then continuously doubting my own work

Not using enough assembly lube on the first build 

Generally not asking for help when I really should have.

I'm sure most people wouldn't make these ridiculous errors, but I did.

[Phill S]

1 hour ago, ThreePointFive said:

I'm sure most people wouldn't make these ridiculous errors, but I did

I can put my hand up to 3 of these, not on the RV8 engine, but these things are easily done when you don't know. And that of course is the reason for having started this thread...

Thanks for being big enough to write those up, not everybody would do that

 

1 hour ago, ThreePointFive said:

Not checking the valve guides properly

So were you able to do the valve guides yourself? They shouldn't be all that difficult should they?

Edited March 12, 2022 by Phill S
More questions!

[Bowie69]

Guides are a machine shop job.

[FridgeFreezer]

Honestly I'd not start dismantling pistons, rings, valves etc. unless you really feel the need to do a full rebuild. At 60k it'll likely need nothing, maybe a cam if it's worn - and if you're doing a cam you want to do lifters, and then on the way in & out you may as well do the chain.

You could spend a lot of time & money on what's a basic & cheap engine. You're only ever another £500 Disco or Range Rover away from a cheap replacement lump or upgrade to 4.0 / 4.6.

[smallfry]

3 minutes ago, FridgeFreezer said:

Honestly I'd not start dismantling pistons, rings, valves etc. unless you really feel the need to do a full rebuild. At 60k it'll likely need nothing, maybe a cam if it's worn - and if you're doing a cam you want to do lifters, and then on the way in & out you may as well do the chain.

You could spend a lot of time & money on what's a basic & cheap engine. You're only ever another £500 Disco or Range Rover away from a cheap replacement lump or upgrade to 4.0 / 4.6.

There is a lot of truth in this. I thought the idea of buying a low mileage vehicle and filleting it, was to just transplant as is, and sort out any problems (if there are any) later. 

However, with my past experience of these engines, now you have it in bits, I would certainly check the camshaft very carefully. If you have already removed the oil pan, you may as well do the other stuff as its not that expensive compared to other vehicles.

BTW you are correct re the gudgeon pins. Direct in the piston, no bushes. 

[FridgeFreezer]

Yep - once it's in bits you may as well fit the nice parts on the way back out, they're not even expensive in the scheme of things. Most expensive thing would be a cam, but it's the easiest time to do the change so may as well.

[reb78]

I wish you'd taken my 3.9 if you are going to rebuild this one anyway... you could have had it for £300 complete!

Edited March 13, 2022 by reb78

[Phill S]

2 hours ago, reb78 said:

I wish you'd taken my 3.9 if you are going to rebuild this one anyway

Yeah, but this is meant to be a refresh not a rebuild. We'll see how it turns out. You might be right yet...

 

22 hours ago, FridgeFreezer said:

Honestly I'd not start dismantling pistons, rings, valves etc. unless you really feel the need to do a full rebuild

Yeah I've got my sensible boots on....

 

18 hours ago, smallfry said:

I thought the idea of buying a low mileage vehicle and filleting it, was to just transplant as is, and sort out any problems (if there are any) later

Nope. The idea was to buy a low mileage engine and do a refresh job to give me a good engine for reliable long distance travel with a life of a further 60k miles, after which I'll pull it out again and do a full rebuild. So for this round of work it means dealing with anything that's likely to be a problem, and leave those things that look good. Except for the ticking noise, which I put down to a stuck lifter, the engine was performing beautifully when I took it out for a test drive.

And just to summarise the logic in what I've done so far.

1. Compression test good and consistent all around. Done cold because it didn't have the wit to do it in the vehicle when the engine was runnable
2. Leak down test gave me hissing on at least 2 exhaust valves
3. Heads off and valves out to check the guides. One exhaust valve terrible, one poor - I need to take the time to measure them all accurately though
4. Front timing cover off. Chain sloppy, distributor gear fine, oil pump fine.

The covid seems to be backing off now, so I was able to get down to my workshop for a couple of hours this morning

I emptied out the lifters. Nothing stuck there, so my prime suspect for the ticking noise moves to that sloppy exhaust valve, I'd put up the vid I took before dismantling so you can hear it, but it's way over the 20MB limit. Anyhow, I've never heard a valve make that amount of racket before.

Back to the lifters. Take a look at this:

 

I have 14 gooduns, like the one on the left - normal wear, and unless you can tell me different good to put back in. The middle one shows what happens when a lifter gets stuck in the rotational sense - u/s. On the right some pretty significant pitting. Would you use that?

 

On 3/12/2022 at 3:08 PM, ThreePointFive said:

Putting new lifters on an already-run-in cam for rear 4 cylinders

Do tell. What happened? But no I'm not going to do that because...

 

18 hours ago, smallfry said:

I would certainly check the camshaft very carefully

Yessir! Easy job for where I'm at right now...

 

Now am I right in thinking inlet and exhaust lobes are supposed to be the same shape?

So I guess I'm looking at a new camshaft and full set of lifters. We're looking from the rear of the camshaft here, and guess what? The nearest lobe matches the pitted lifter.

 

The bores look fine

 

So I'm going to leave the rings and bearings alone. I reckon they're going to be fine to get this engine to 120k miles. But happy to be told I'm wrong...

Haven't yet checked the rocker gear, but my forward plan is to replace:

1. Camshaft and hydraulic tappets
2. Timing chain and gears
3. Valve guides

And put it all back together again - whaddayareckon?

 

Nearly forgot...

22 hours ago, Bowie69 said:

Guides are a machine shop job

How come? All you need is a press and a reamer aint it? And an ounce or two of cunning

Edited March 13, 2022 by Phill S

[Phill S]

P.S:

On 3/12/2022 at 10:07 AM, Phill S said:

...can anybody point me at a parts book for the Defender 3.9 EFi? I have time on my hands just now and will obviously need to work out 101 items of hoses, cooler connections etc etc when it comes to the final fit

 

[reb78]

17 minutes ago, Phill S said:

P.S:

 

Lrcat should have all you need?

[ThreePointFive]

https://www.lrworkshop.com/diagrams

This one's good, and less.....Putin-y