[E38] - 728i vs 740i

[Lord E38]

Interested in finally picking up my dream car (see username). Which engine would be best? I've heard the 728i can be surprisingly economical, but it would be replacing an XJR and I know I'd miss the power. The 740i on the other hand sounds like a real monster, but it seems far more expensive to keep on the road.

[g3org3y]

These are often discussed in the Smoker Barge Thread

728i = M52 6 cylinder engine. Considered very reliable.
740i = M62 8 cylinder engine. I understand this engine can have issues with timing chain guides.

All E38s are old cars now so can be expensive to maintain. Fuel tanks are a known issue. They are relatively heavy so consider that wrt suspension and brakes. Also look out for rust.

I think if you're coming from an XJR, I think you'd be disappointed by the lack of performance with the 728i

[alpinab3]

Keep the XJR. The 740 will be pedestrian compared to that plus they are all very needy and rusty now.

[rassi]

alpinab3 said:

Keep the XJR. The 740 will be pedestrian compared to that plus they are all very needy and rusty now.

I would tend to agree with that. The XJR is a rocket ship in comparison to even the 740, let alone the 728. The 740 is on par with the non-supercharged 4 litre XJ. If you do want to go for an E38 why not a late 5.4 litre V12 750i?

[alpinab3]

rassi said:

I would tend to agree with that. The XJR is a rocket ship in comparison to even the 740, let alone the 728. The 740 is on par with the non-supercharged 4 litre XJ. If you do want to go for an E38 why not a late 5.4 litre V12 750i?

The 750 is barely any quicker than a 740. You are not going to get anywhere near XJR performance unless you start going to Alpina £££

[naturalaspiration]

728i has extremely reliable M52TUB28 engine, detuned by BMW so as not to jeopardise 735i sales. In order to wake it up it is necessary to replace vanos seals (unless done) , fit intake manifold (and ideally also) off a M54B30 - straight swap, followed by ECU tune. The engine also likes LM Ceratec additive as it really revs freely with it. You will gain around 25-30 BHP with it.

Mine is currently at 270k Miles, haven't touched the engine so far - need to get that M54 inlet camshaft...

The main issue to be aware of on any pre-Bangle BMW is rust.

Edited by naturalaspiration on Friday 3rd September 15:07

[Lord E38]

naturalaspiration said:

728i has extremely reliable M52TUB28 engine, detuned by BMW so as not to jeopardise 735i sales. In order to wake it up it is necessary to replace vanos seals (unless done) , fit intake manifold (and ideally also) off a M54B30 - straight swap, followed by ECU tune. The engine also likes LM Ceratec additive as it really revs freely with it. You will gain around 25-30 BHP with it.

Mine is currently at 270k Miles, haven't touched the engine so far - need to get that M54 inlet camshaft...

The main issue to be aware of on any pre-Bangle BMW is rust.

Edited by naturalaspiration on Friday 3rd September 15:07

I think I read one of your old posts about cheering up a 728 a while ago. Is yours an Individual Sport in Biarritz Blue?

[Penguinracer]

I can only compare my E32 750iL to an E38 740i - but once into triple figures the V12 will run away from the V8. Delimited the E32 750iL was tested at 170 whereas the 740i would have no chance of threatening that figure.

My '88 which I've owned since 2000, sits at a steady 4k rpm at 130.
The build quality of my E32 is superb (even compared to my C140 Merc 600 coupes), better than the E38 740i my brother owned.
Nothing compares to a 12 - primary, secondary & tertiary balance - a V8 is okay in a pick-up or a grocery-getter - but certainly has no aristocratic pedigree.

[d_a_n1979]

naturalaspiration said:

728i has extremely reliable M52TUB28 engine, detuned by BMW so as not to jeopardise 735i sales. In order to wake it up it is necessary to replace vanos seals (unless done) , fit intake manifold (and ideally also) off a M54B30 - straight swap, followed by ECU tune. The engine also likes LM Ceratec additive as it really revs freely with it. You will gain around 25-30 BHP with it.

Mine is currently at 270k Miles, haven't touched the engine so far - need to get that M54 inlet camshaft...

The main issue to be aware of on any pre-Bangle BMW is rust.

Edited by naturalaspiration on Friday 3rd September 15:07

In agreement with this

I loved my 728i and it never felt underpowered nor did it ever struggle to get to license losing speeds.

Yes it's not a V8, so it doesn't have the low down grunt or the sound, but the M52 is a bulletproof engine and much cheaper to fix & maintain in comparison to the M62 V8 etc...

As said, the issue for any E38 now is rust, so any car has to be thoroughly inspected, everywhere and the fuel tank needs to have a proper look-over too as they're known for leaking etc...

Suspension & cooling systems are prone to issues with age, but easy to sort & not silly expensive either.

Very much like the E39s, parts are easy to source etc...

[Touring442]

The E38 is like an old E39 but even worse. Rust, cooling system, rust, ABS modules, broken springs, oil leaks, rusty tank, chain guides - a never ending litany of drama unless you pay £££ for a proper low mileage car. If you must, the 750i is the one to have. It IS faster than a 740i and the V12 is magic.

[g3org3y]

Touring442 said:

The E38 is like an old E39 but even worse. Rust, cooling system, rust, ABS modules, broken springs, oil leaks, rusty tank, chain guides - a never ending litany of drama unless you pay £££ for a proper low mileage car. If you must, the 750i is the one to have. It IS faster than a 740i and the V12 is magic.

M539 Restorations would agree.

[Touring442]

Unlike the 4.4, the M73 is near enough unbreakable. Simple engineering, one cam per bank, no Vanos and proper chain guides. It's over 100 that they really get going.

[naturalaspiration]

Lord E38 said:

naturalaspiration said:

728i has extremely reliable M52TUB28 engine, detuned by BMW so as not to jeopardise 735i sales. In order to wake it up it is necessary to replace vanos seals (unless done) , fit intake manifold (and ideally also) off a M54B30 - straight swap, followed by ECU tune. The engine also likes LM Ceratec additive as it really revs freely with it. You will gain around 25-30 BHP with it.

Mine is currently at 270k Miles, haven't touched the engine so far - need to get that M54 inlet camshaft...

The main issue to be aware of on any pre-Bangle BMW is rust.

Edited by naturalaspiration on Friday 3rd September 15:07

I think I read one of your old posts about cheering up a 728 a while ago. Is yours an Individual Sport in Biarritz Blue?

Yes.

[naturalaspiration]

I actually quite like the turbine sound of the BMW signature I6 engine, naturally aspirated amd with port injection. Gentleman's express vs chesty V8 brute.:-). V12 is of course double I6 so sublime in every way, my only gripe is that I like that confident turn in into corner with the lightweight I6 in the front. I drove a V8 and in corners it felt like I was sailing with genoa on...I can imagine V12 only being worse in that regard. With I6 you keep the revs up and it is surprisingly nippy, plus you can actually hear it!

[Lord E38]

d_a_n1979 said:

In agreement with this

I loved my 728i and it never felt underpowered nor did it ever struggle to get to license losing speeds.

Yes it's not a V8, so it doesn't have the low down grunt or the sound, but the M52 is a bulletproof engine and much cheaper to fix & maintain in comparison to the M62 V8 etc...

As said, the issue for any E38 now is rust, so any car has to be thoroughly inspected, everywhere and the fuel tank needs to have a proper look-over too as they're known for leaking etc...

Suspension & cooling systems are prone to issues with age, but easy to sort & not silly expensive either.

Very much like the E39s, parts are easy to source etc...

I'm interested to hear about what it was like to own this car. What was fuel economy like? How did it compare to other cars you've owned in regard to performance and comfort?

[d_a_n1979]

Lord E38 said:

d_a_n1979 said:

In agreement with this

I loved my 728i and it never felt underpowered nor did it ever struggle to get to license losing speeds.

Yes it's not a V8, so it doesn't have the low down grunt or the sound, but the M52 is a bulletproof engine and much cheaper to fix & maintain in comparison to the M62 V8 etc...

As said, the issue for any E38 now is rust, so any car has to be thoroughly inspected, everywhere and the fuel tank needs to have a proper look-over too as they're known for leaking etc...

Suspension & cooling systems are prone to issues with age, but easy to sort & not silly expensive either.

Very much like the E39s, parts are easy to source etc...

I'm interested to hear about what it was like to own this car. What was fuel economy like? How did it compare to other cars you've owned in regard to performance and comfort?

This was mine, 2000 728i






Re economy; no specific memories; then again I work from home and do around 4-6k miles a year, max. So economy is never a worry

But from memory it was similar to my E39s, so around 18-22 around town and 32-36 on longer motorway runs etc

Re performance; it's not a performance car nor a B road hoonigan But it did very well for itself, got up to speed with zero issues and will pass licence losing speeds with no issues either. The M52s a solid lump and performs well. As above, with breathing mods, it'll do even better

I lowered mine on BC coilovers; it needed a full shock & spring overhaul & by the time parts were added up; inc all new top mounts all round, it came in more expensive than BC coilovers, so they made the most sense. It wasn't stupidly low, but lower than factory. Zero issues with speed humps and no catching underneath etc

I did have bodywork done to it through age and corrosion; OS sill was replaced, NS sill was tidied up; both resprayed as well as front bumper and wings/bonnet (pebble dashed etc).

Never had any electrical issues at all; OEM head unit (cassette) was removed and I fitted a Kenwood single DIN Bluetooth head unit and had the hands free mic situated next to the rear view mirror; so perfect for hands-free calls and A2DP music playback etc. I didn't fit the patch cable for the steering wheel controls, but it's all easy to do

Interior was solid, very clean & hard wearing leather. All solid inside and no squeaks/rattles

Brakes are decent (Brembo 4 pot calipers up front); just ensure you use decent discs & pads (OEM BMW, Textar, Jurid or the likes of Mtec / ATE). I replaced the brake lines with HEL and had the front brakes fully overhauled (Big Redd)

Handbrake mech can be an issue if it's not been used/looked after; so ensure that works as it should and look to have it overhauled

Autobox is ZF IIRC; so if no proof, it needs to be serviced properly (fluids & filter etc)

They ride superbly on 16" alloys and tyres (I had Style 60s with Michelin Alpin A4 winter tyres) and as the pics above, 18" Style 32s for summer alloys & tyres. The 18s look superb and the car rode fantastically, I personally wouldn't ruin the ride with 19s or 20s; the E38s a waft bus IMO

Hope this helps

[McGee_22]

A year ago I would have said that if you're going to get an E38, get the V12.

All the toys and way more power. A V12 in either E38 or E32 form will leave its V8 siblings in its wake with effortless ease - the sstraight sixes, sonourous as they are, would not get a look in.

But a year on, V12 prices are way up as people either listened to me or decided to get a V12 while they could. Now I would suggest buying on condition, colour and spec - and that includes the 'ginger stepchild' 735i.

Anyone of them, in good condition, would make a great driveway addition. If you're getting a V8, I would strongly factor in a timing chain and guides change as they are old now and it will give you peace of mind. Any E38 will also need a gearbox filter, flush and oil change unless there is cast iron proof it has been done with a bill to prove it.

And the achilles heel of all E38's, the petrol tank; they all rust and all need some tlc - if you're looking at a car - offer to brim the tank and see what the owners eyes do - it will be £100 risked but you'll know instantly if it's leaking and be able to either walk away or factor in a discount to get it replaced. If you end up looking at a V12 or lwb car, factor in a bit more money to change it as it a 95l tank and not available as an aftermarket like the 85l tank of lesser models.

[Penguinracer]

McGee - love your collection..I feel.the E24's are the most beautiful BMW's made...and your B12 - well it speaks for itself.

I think you're right about the V12's getting snapped-up in the last 2 years as collectors identify the final bargain classics which will standout when EV's dominate as daily drivers.

[Lord E38]

McGee_22 said:

A year ago I would have said that if you're going to get an E38, get the V12.

All the toys and way more power. A V12 in either E38 or E32 form will leave its V8 siblings in its wake with effortless ease - the sstraight sixes, sonourous as they are, would not get a look in.

But a year on, V12 prices are way up as people either listened to me or decided to get a V12 while they could. Now I would suggest buying on condition, colour and spec - and that includes the 'ginger stepchild' 735i.

Anyone of them, in good condition, would make a great driveway addition. If you're getting a V8, I would strongly factor in a timing chain and guides change as they are old now and it will give you peace of mind. Any E38 will also need a gearbox filter, flush and oil change unless there is cast iron proof it has been done with a bill to prove it.

And the achilles heel of all E38's, the petrol tank; they all rust and all need some tlc - if you're looking at a car - offer to brim the tank and see what the owners eyes do - it will be £100 risked but you'll know instantly if it's leaking and be able to either walk away or factor in a discount to get it replaced. If you end up looking at a V12 or lwb car, factor in a bit more money to change it as it a 95l tank and not available as an aftermarket like the 85l tank of lesser models.

Dealers are really taking the piss on 750iL's. Check this out:



Thanks for your advice r.e. buying on condition. Insurance is also a consideration for me because I'm 18. IIRC 728i's are about £1.2k a year, 740i's about £900 (same as my XJR)

[Lord E38]

d_a_n1979 said:

This was mine, 2000 728i






Re economy; no specific memories; then again I work from home and do around 4-6k miles a year, max. So economy is never a worry

But from memory it was similar to my E39s, so around 18-22 around town and 32-36 on longer motorway runs etc

Re performance; it's not a performance car nor a B road hoonigan But it did very well for itself, got up to speed with zero issues and will pass licence losing speeds with no issues either. The M52s a solid lump and performs well. As above, with breathing mods, it'll do even better

I lowered mine on BC coilovers; it needed a full shock & spring overhaul & by the time parts were added up; inc all new top mounts all round, it came in more expensive than BC coilovers, so they made the most sense. It wasn't stupidly low, but lower than factory. Zero issues with speed humps and no catching underneath etc

I did have bodywork done to it through age and corrosion; OS sill was replaced, NS sill was tidied up; both resprayed as well as front bumper and wings/bonnet (pebble dashed etc).

Never had any electrical issues at all; OEM head unit (cassette) was removed and I fitted a Kenwood single DIN Bluetooth head unit and had the hands free mic situated next to the rear view mirror; so perfect for hands-free calls and A2DP music playback etc. I didn't fit the patch cable for the steering wheel controls, but it's all easy to do

Interior was solid, very clean & hard wearing leather. All solid inside and no squeaks/rattles

Brakes are decent (Brembo 4 pot calipers up front); just ensure you use decent discs & pads (OEM BMW, Textar, Jurid or the likes of Mtec / ATE). I replaced the brake lines with HEL and had the front brakes fully overhauled (Big Redd)

Handbrake mech can be an issue if it's not been used/looked after; so ensure that works as it should and look to have it overhauled

Autobox is ZF IIRC; so if no proof, it needs to be serviced properly (fluids & filter etc)

They ride superbly on 16" alloys and tyres (I had Style 60s with Michelin Alpin A4 winter tyres) and as the pics above, 18" Style 32s for summer alloys & tyres. The 18s look superb and the car rode fantastically, I personally wouldn't ruin the ride with 19s or 20s; the E38s a waft bus IMO

Hope this helps

Thanks, I'll keep all of that in mind. Your car was F-ING beautiful!!

Edited by Lord E38 on Monday 6th September 12:46