So, I've been following the ACE Engineering Discovery 2 LS Conversion thread for some time now- it's at 107 pages as of this post. I believe I've read through all of them- it's tough to tell at this point- but I'm wondering about those of you that have completed the conversion and are driving your rigs now- was it worth it and how are they running? From the main thread it honestly seems like a serious trade off of Rover problems for what I'll call- "Conversion problems". Here's a list of what I've seen so far off the top of my head:

• I've read a ton of posts where the LS motors just seem to cut out and shut off while driving down the road- Most seem to happen while at higher RPM's - and everyone seems to think it's ECU related (?) but I'm wondering if it's been sorted yet, officially. I mean for some of us we already have oil pump problems and crank position sensor problems- how did this solve that?
• More problems with M&S lights and weird transmission issues- with the programming or something where it sends error codes to the dash and lights the alerts
• Poor mileage still- around 14MPG is what I'm seeing on average- now- that is probably better then the 4.0 or 4.6 by one or two MPG- but... not really impressive by any stretch. I do understand these are aerodynamic bricks- but come on... a diesel can get over 20 easy- maybe even 26-30.
• A long list of hose fitment issues causing leaks of vital fluids- from transmission fluids to oil to coolant... Don't we already have that problem with Discos?
• The motor doesn't sit straight in the chassis... what?!?!! Seriously- that's a thing?!?! I understand the newer version of the kit should help eliminate this- with adjustable mounts that can help- but that's just plain strange- how can an engine with a flat mount to a bell-housing not sit straight in the chassis? I know ACE has said the tolerances on our Disco's is crazy bad from one frame to another (Don't doubt that- it's BMW "engineering")
• Coolant leaks (again- don't we already have those?)
• Crank Position sensor problems (see above)

This is just a short list from working my way back from page 107 this morning... certainly not all-inclusive. So- my very serious question to those that have done the conversion- has it been worth it? I mean I totally understand the draw of more power from a V8 that actually is engineered well and in normal circumstances is extremely reliable- but I've been watching the builds and it seems, so far, like the swap is anything but reliable. In fact it may has as many or more problems than the original Rover V8's at this point in the "knowledge base". But I could be completely wrong- maybe some of you that did the swap are not posting any longer and just out enjoying mile after mile of trouble free driving and wheeling and just not posting about it. Maybe I need to dedicate a week to reading every post from page one through to the end to make sure I haven't missed any success stories or awesome reviews-

Please understand- I REALLY, REALLY want to like this swap and do it- even though I have a new (sub 25k miles) top-hat sleeved 4.6 from Atlantic British that should be "reliable"- but has already proven it just won't slip a sleeve- all the other problems are still there ;-( There is still a lack of power in it- it still hunts for gears on every mountain pass with my 33 inch tires- it sucks gas like crazy- it STILL F'*#ing overheats (215) even thought I've done every coolant tip in this forum except a new- all-aluminum radiator, and I still don't have a locking diff (2003 ;-( ).

So that's what this post is about- a REVIEW from the installed base of users- what's great about it so far- and what's sucked... and still sucks? Would you do it again- sell your truck- go diesel- go all-electric? Let's have the review without having to hunt through 107 pages of the normal thread. Flame away users... maybe I'm way off base.

 

I think the swap is great for people who know what they are getting into or for shops that are interested in that sort of thing. No engine swap for an engine that wasn’t supposed to be in there is easy. Plain and simple: If you don’t have a solid background working on cars, you should not attempt the swap on your own.

Generally, I think your impression from the thread is a bit misguided. Most of the comments were from either beta testers or people installing early kits. A lot of the bugs have been worked out and the latest kits are much better than the earliest ones. Like most threads (and forums in general), most people only comment when they have issues or questions. It would be great also if people would just post their own problem threads so the solution could be easily found and didn’t have to be rehashed multiple times in the future, but unfortunately that is what that main LS thread has turned into.

I would be careful not to conflate your term “conversion problems” referring to actual issues with the design of the swap kit with general issues that come with any major engine repair (like tightening up hoses after 50 miles, etc). I’d say a lot of the things mentioned are general issues. Those general issues do not imply problems with reliability. While the swap does introduce its own challenges, in my experience once these are solved they tend to be solved for good and not reoccur.

Dialing the swap in can take some time and mileage (and patience too). CKP can be troublesome and a bit of trial and error, but it is doable. I’d say 90% of M&S lights are from that. 5% from low battery. 5% from wiring problem with ECB box or elsewhere. Once all that’s sorted the M&S lights stay off and trans shifts normally.

I haven’t had any major leaks since I got everything dialed in. No coolant leaks of note. Did have a minor transmission fluid leak because the AN fittings I used did have some seepage issues, but tightening those helped. I switched to a dual transmission cooler setup. I have a very minor leak from the oil filter o-ring, but that should be fixed at next oil change.

I have seen as high as 15 mpg with my Disco with the roof racks and weighted down with bumpers, big tires etc. Stock 4.0, I would be lucky to get 12 mpg. I have heard of stock-ish Discos seeing as high as 17-18 mpg with LS. Mpg depends heavily on your tune in the LS computer. An un-optimized, start-up tune is not going to get the best gas mileage. If you want the best mileage, a custom tune needs to be done by a professional tuner that can watch engine parameters while driving.

Can’t really comment on the high RPM shut-off. I would imagine issues with the tune are to blame in part. Intake can cause issues here too if it’s not free-flowing enough (my thread has comments on this). The kit doesn’t provide an intake, just directions on how to build your own. My engine is pretty straight on the mounts (maybe a tad off). There’s not a lot of room for the driver’s exhaust manifold and the frame rail. I had to loosen the transfer case mounts to pull it straight. Strangely enough, some engines come a bit off from the factory (like the Mercedes G-Wagen).

The biggest advantage of the LS swap is once you get it dialed in, it just goes. The engine has not skipped a beat in the close to 3 years its been there now. I never trusted the Rover engine, but I trust the LS. Basically all its needed since being dialed in has been oil changes. I keep fiddling with things, but that’s just me. Next up will be a custom Griffin radiator and electric fans (because I really don’t like the plastic tanks on the factory radiator). I've towed with it, and I've done some fairly substantial offroading with it. I'm starting another Disco build soon, and that will probably get an LS at some point (sooner rather than later if the Rover V8 in it is cooked, which I'm starting to think it is).

ACE has sold a lot of these kits at this point. A chunk of them went to shops. You might find more recent discussion of the kit on Facebook. If you end up doing the swap, read the manual as many times as necessary to understand it before touching a bolt - it will make things a lot easier later.

 

CaptainAaron
Excellent points all around (I did read your separate thread) and I'm very glad to hear now that it's dialed in- you just drive it and don't worry about it. Part of my concern with doing the swap (yes- i've turned a bolt or two) was just exchanging Rover problems (that never seem to really go away) with what I did term "conversion problems". It's good to hear that maybe the "conversion problems" I'm referring to actually do go away once they've had the correct attention.

I'd love to hear more reviews from anyone that actually has finished their project like CaptainAaron and is now driving and enjoying their conversion!

 

Any engine swap is only as good as the installer.

That being said, is there even a debate about which motor is more reliable with the LSx vs the rover 4.0 family?

 

Very true about installers. It's not unheard of for LS truck motors going 300k+ miles with regular maintenance. I think it is lucky if you get over 100k with a Rover V8 without doing at least head gaskets, if not more.

 

Agree with both- LS engines are famously reliable- easy to work on, and parts are really inexpensive. Definitely no debate about it being a better choice then what Rover put in! There's a reason why there are so many LS swaps into non-GM vehicles all over the world. LS Swap the World is a IG account for a reason.

 

I currently have over 10,000 miles on my ace swap. I daily drive and off-road fairly frequent with it. I have the hi rpm cutout issue, I cleaned the map and maf sensors with the proper cleaner and it took care of it for about a month... it only cuts out at a heavier step on the throttle, so I have to be careful not to get into a situation where I need 100% power. Been battling M+S lights and transmission problems since I bought from ace. Also anyone planning on doing serious off roading needs to find a super low profile oil pan, the GM low profile I found hits the Diff and has no cracked the oil pan. I have a 3" TF lift currently. Waiting on 4.5" lift from RTE and researching low profile oil pans. Overall happy with the swap but the trans issue and rpm cutout are always in the back of my mind.

 

I'd suggest getting a new standalone GM ECM from PSI and see if that helps with the throttle cutout issue. It sounds like a tuning problem. For oil pan, maybe look at notching it at the little bit that hits? M+S probably is either your CKP or maybe bump up your idle in the GM tune. In the beginning, mine would have the M+S lights on if the idle got too low, bumping it up in the ECM tune helped. Also consider going to 150A alternator.

 

Thanks for the response. Excuse my lack of knowledge on the stand alone ecm, but would this be as simple as removing the old one and putting into place the new? And what is the difference from the one ACE uses? Also would they have to tune it to ACE specs to make it work? ECU's are beyond my capabilities and I bought this rig directly from ACE

I did notice when I originally didn't drive it often I would get the m+s flashing lights but when I daily drive I don't. I do understand the voltage issues with those warning lights. However the last 2 trips off roading about 3 hours trails in low range when I get back to pavement it is not wanting to shift into 4th. So I use my scan gage and clear codes (4th gear ratio) or something to that regard. This happened again yesterday then after the 3 hour highway drive back home car sat for 20 minutes and I drove to wash and lights started flashing again... I really appreciate your knowledge and opinions!

 

Yes, you would order an unlocked GM ECM from PSI. It's a standard GM ECU that they unlock and tune to be plug-and-play. They run about $200. They have a base tune and you can request adding specs that ACE requires for it to work that are in the manual. I think it sounds like either the ECM, its tune, or the sensors are an issue when it comes to that cut out thing. Factory airbox can be a problem with that too, but changing to K&N air filter fixed that for me. I know the PSI base tune works pretty well. Make sure they set the idle base at all times for at least 750.

M+S lights very well could be a voltage issue. The M+S lights after sitting for a while is a bit of a sign of a voltage problem, and the 4th gear ratio could just be erroneous because of wacky voltage. A while back, my alternator was dying (but not dead) and it gave me all sorts of strange issues. Trans computer is really sensitive.

Here is the replacement P38 Bosch 150A alternator I got, only $100 at Rock Auto. I think the 20 extra amps helps a lot with the added GM electronics and for the winch etc:

https://www.rockauto.com/en/moreinfo...W6ul8v88znn4Mn