Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Plus 8 engine queries

I’m considering an 80s plus 8 which has a 3.9L V8 which was originally a 3.5l modified by John Eales in 1995. Has anyone any experience of these engines and do they have any weaknesses. I’ve been reading about cracking off the block but that may just be hearsay.
Alternatively I’m also tempted by a more recent V6 Roadster as I’ve found a few more pennies!

John Eales has an excellent reputation for building good V8 engines. The only downside of one of his build is that, depending on the specification he used, you might end up with something that is a bit too much for normal road use. Only a test drive will tell you.

I don't know if the 3.5 can be uprated to 3.9 but - do you know if John Eales used a 3.5 block or a 3.9?

I cannot comment on the block cracking. Someone who knows all about the V8 block will be along in a while to help you.

The receipt for the work says “fit engine 3.9 modified” so may well be the larger one. It does seem a bit odd to me that one could get another 400cc from the 3.5 but then I’m no v8 expert.

I've never heard of a Rover V8 cracking, but no doubt someone has managed it. As I recall, the capacity can be increased with a longer stroke crank. Plenty has been written about Rover V8 capacities over the years. Heads vary in efficiency.
The biggest weakness of the Rover V8 is the accumulation of black tar over the whole of the inside, so first job is to take the oil filler cap off and look inside. If the visible rockers are black and tarry, the whole inside of the engine is likely to be that way. It can only be controlled with regular oil changes, and minimising cool running.

The engine I took out of my MGBV8 after 100k miles was totally shot. The tar varied between thick sludge and bonfire toffee. It ran well, even though two cam lobes were gone completely. I only did the last 10k!!!!

Excessive camshaft wear is a common problem on the Rover V8 engine.

Regular oil changes with oil of the correct specification is essential for minimising this.

Sounds like "your" engine may be have been changed for a 3.9 unit. A John Eales engine may also have various upgrades, pity you can't find more about it.

I'm no expert but I assume it's possible to identify the original block size by the engine number.

I have a John Eales 3.9L in my 1980 +8 fitted in 1990s and has done 150,000 miles. Without tempting fate, it has never been touched.

Yes the Rover V8 does have a reputation for cracks in the block , BUT, I have never heard of this in a Morgan application.

It probably occurs in the much heavier 4x4s like Range Rovers and Discoveries when driven very hard with poor maintenance.

This engine is remarkably tough, it will withstand almost anything you can throw at it as long as it is properly maintained, and the fluid levels are regularly checked.

I would not worry about a modified engine , especially by John Eales, as above Stephen has done 150,000 miles and I have covered 75,000 with ( I assume) a similar set up

Regarding the choice between the +8 and the Roadster , this is a much more complex question.

The more modern design V6 is a much more efficient engine , so the fuel consumption will be much better , the emissions are better so you don't fall foul of the new ULEZ type regulations.

The big negative of the Roadster is the low ground clearance, which is partly helped by a modified sump.

The sound track of the V8 is definitely a cut above the V6 (someone described it as being "the full orchestra")

The only way is to try both and let the right car pick you.

Worth pointing out the 3.7 V6 Roadster doesn't suffer from grounding issues generally, the engine being designed for fore and aft mounting. Would have to go back a few years to when mine last touched although the most severe speed bumps will catch any Mog out. Having reduced length seat mount bolts and side exhausts helps. The lowest point now is the inverted U section gearbox cross brace were it dips for clearance.

well, the V8 is a bit agricultural and very American as that's where its from of course however, the Eales modified engine will be a whole lot better, his work on the V8 engine was excellent. On the whole the engines are bomb proof and if you get a wrong-un then it's likely to be because of poor servicing and too long between oil changes which these engines will just not tolerate. Oil is the cheapest repair you can make to this engine and look to change it annually or every 5000 miles whatever anyone tells you! Engines treated like this can achieve star-ship mileages. In the motor trade if a car fitted with a V8 of the Buick variety had dirty oil you wouldn't touch it because quite frankly these engines die when treated like that.
In the Morgan the V8 is quite a lump, not because the engine is particularly heavy, actually its surprisingly light for it's size but the gearbox is huge and of the land Rover fitment.

Those who love the V8's won't consider anything else and if it's the sound you love then it's the car for you but you need to drive a few different variants before you part with the folding first! As it all depends on what you want to do in your car. Try the plus 4, It's no slouch! and if you want to chase around A and B roads it might be a better bet. Then there's the 4/4, Your money will go further here and a good late model with the superb later Ford engines with VVT are just heaven in and around the countryside and feel very light to drive and you won't spend too much in the garage on fuel, service or repair. The plus 8 was superseded by the Roadster, V6 and smaller but far more power and fast too. Best way to describe it is as a fast GT which drives like a plus 4 but comfortably eats the miles even on motorways

. The V8's in my opinion feel heavy to drive and they really do have a lot of torque available from almost no revs at all and this can make them a bit of a handful in anything but dry conditions and an Eales modified 3.9lt with a probably lightened fly wheel might be even more twitchy!
so the advice to 'try it first' is good. See how it feels and think about wet roads if its in the dry! If its a track day car you're after, well that's another thing altogether!

Above all, don't be in a rush. The car as they say will find you. Take a trip out to one of the big main dealers and drive some, Find what you really want for your Morgan. You can then start your search for the car that'll be resting in your garage!

I had a P6 rover V8, for a while in the early eighties. IIRC I was told to keep the breathers in clean condition. Otherwise the engine would attract condensation in the crank case, that would cause “sludge” to build up. I used to change the oil every 3000 miles. Bit of an “overkill” methinks now.