42 replies to this topic

[Fast Ivan]

Sort of related.  Would anyone recommend adding fuel injection cleaner to the gas for the SPI?

 

yes

[Spider]

Off hand, the Injected Minis make much better low RPM Power than the Carbed models and this allowed them to fit taller Final Drives while loosing little in terms of drivability.

 

It also leads to the Camshafts wearing prematurely too.

[pete l]

Why does it wear the camshafts ? it's only pushing on tappets isn't it ?

[rich_959]

Going back to when MPI's were brand new, I went from a 1990 998cc Racing Green to a 1997 Cooper. While I loved the 998 and it was well serviced and looked after, it did have constant lumpy running niggles in the wet, despite replacing just about everything ignition-wise. Main issue was sourced to a faulty brand new replacement coil (which had made me replace everything else). But even after sorting that, it still used to splutter in really wet weather, with the weather shield in place. No matter how many new distributor caps I tried, or spraying with water dispersant etc. 

 

Not a fair comparison as the MPI I replaced it with was brand new but for me it retained all the charm of driving the 1990 carb car, with smooth all-weather running, broad power band (ok, not going to set the world on fire) and reasonable dual-carriageway/motorway comfort and noise levels. What's not to like? I've not had anywhere near the amount of mini's or general mini experience as most folk on here but for me, all the pleasure of driving a mini comes from the chassis, and as long as it's some form of A series up front with that familiar noise, I'm not too fussed how the fuel gets in!

 

When getting back into Minis 20 years later I've opted for another MPI, mainly for nostalgia (because it's a car I wish I had kept) but also because I know it will probably go for weeks or even months in winter without being ran, and I think (or hope) that the later cars will deal with this treatment better. I may be wrong - wouldn't be the first time!

[JXC Mini GT]

I have never owned or driven an injection Mini, I have only owned GT,s , so when I returned to mini ownership after 30 years it had to be a GT, I prefer the more basic mechanics of a carbed car without any electronics.

[Spider]

Why does it wear the camshafts ? it's only pushing on tappets isn't it ?

 

Because the engines are reving slower at the same speeds.

 

The Camshaft Lobes and the Tappets are only lubricated by what's thrown off the Con Rod Big Ends and that's about all.

 

At lower engine speeds, from what I've observed, there's not enough Oil Flow to properly lubricate the Cam. Keep in mind, the fundamental design of the Engine goes back to the 40's (first in production in 51) and they were designed to turn at higher revs than they generally do when Injected.

 

While a few changes and up-grades have been done to the engine over the years, this is one area that has remained the same.

[pete l]

I didn't know that, but I would of thought that a crankshaft spinning around at 2000 rpms would throw up more than enough oil to the camshaft. 

 

Does that mean a car standing at traffic lights is a no no with the engine ticking over ?

[Alice Dooper]

Our MPI starts first time every time no matter how long it’s been sitting. It idles lovely, if slightly rich and apart from a pain in the hole replacement fuel pump that I put in as from preventative maintainable before a session of long runs it has let us down.

The coolant and oil temperatures always sit nicely no matter if we are sitting in traffic, hard driving over country roads or long motorway runs. The longest drive we’ve done was just over 5 hours on a mix of motorways and B roads and not a problem.

We have been fussy about oil changes, tappets, plugs and added an extra engine earth. All easy stuff.

True, the engine bay is seriously over rammed and a pain to work in, made worse by the addition of a fuel pressure regulator, but it’s worth it.

If it wasn’t for the heavy steering and keeping he body shell off crappy salted winter roads, I’d use her as a daily driver. The higher final drive takes a bit of acceleration out but she pulls well low down in the Rev range and cruises lovely on big roads.

[riktanius]

Becuase of my experience with 90s injection Japanese cars, I just feel more comfortable with the SPI/MPI cars. I know that carbs can be a little cleaner and may lead to more power with proper tuning, but I enjoy the right amount of computer in my drivetrain.

[Pete - W.Sussex]

I didn't know that, but I would of thought that a crankshaft spinning around at 2000 rpms would throw up more than enough oil to the camshaft. 
 
Does that mean a car standing at traffic lights is a no no with the engine ticking over ?

Sounds like a logical conclusion and the at idle issue would apply to carb models in exactly the same way. However, whilst I am no expert at all, with bedded in cam and followers there should be sufficient oil film to prevent damage and I’m sure we would have heard more about it before now if it is a big issue. Nonetheless, I hate my engine ticking over and I like to give it a blip of the throttle every now and then if I’m stuck in a tickover position. I’ve always thought that at 2k rpm you are getting sufficient oil on the cam - that’s an oft quoted minimum for running in a cam and followers.

[Dusky]

Unfortunately when it comes to the Mini the SPi injection was an early attempt and many injection systems of that era can appear over complex and tricky to set up, the MPi is a much simpler system and fundamentally the same as most modern systems. If I wasn't so unsure as to whether my JDM has some dependence on the ecu for the air-con, I'd convert the SPi setup to the twin injector MPi setup.

If you want to see clutter ... try working on a late model JDM Mini!!!

It amazes me how rudimentary most European injection systems were in that era. While Chevy had developed their tuned port injection we were still fiddling around with 1 Injevtor just replacing a carb jet.

[cp2708]

Constant idle speed. Not influenced by oil temperature, electrical load.

Edited by Moke Spider, 24 June 2019 - 02:15 AM.
Keep it clean please

[Ade-Cooper]

cheaper then most carb (older models).............................