New Engine for my Elise S2

[jpeliseS2]

Hi all - just joined, just got an Elise s2 that has a warped 120 K series and I want to replace it with either a 160 Vvc or the Toyota engine…or maybe just the same as it had. Not sure…what are the costs and pitfalls ?! Is there a best place to source engines ? Any help much appreciated 👍

[stevensr34]

First - you won't get a Toyota engine to fit into the space that a K series was in. So just forget that option.

Next - maybe getting your engine fixed is a quicker/safer option than looking for another second hand engine (of questionable quality)?

(remember, the newest K-series engines out there are now approaching 20 years old)... 

Edited June 16, 2022 by stevensr34

[exeterjeep]

There are a few new heads around, the K series has been improved in recent years - even after MG/Rover stopped. If you have a look at https://en.wikipedia.org/wiki/Rover_K-series_engine can see that the head gasket issue seems to have been resolved.

Rimmerbros are MG Rover specialists and they have full engines listed with exchange. https://rimmerbros.com/Item--i-GRID001207 

I have done 6 head gasket changes on the various MG's I have had. Although on one car the problems remained as the bottom end had problems with the pistons. The engine had suffered hydrolocking. In this case though the head had not warped.  

 

 

[deanb]

If it's just a warped head then why not just get a good second hand head? There are plenty about.

I swapped my Elise s2 Rover engine when it started blowing out big clouds of oil smoke at 107,000 miles. I suspect the rings had gone.

I rang Dave Andrews, the Rover K series guru (see DVA Power website) and he said to fully rebuild it as a standard engine would be £3000 ish (iirc), more obviously if I wanted the head ported, bigger valves etc.  He said I would be better off finding a good second hand engine, so that's what I did.

I put a wanted ad on the seloc website and two days later a guy offered me a Lotus Sport 135 engine with Piper 633 cams and verniers for £850.  It had done between 25000 and 30000 miles. I bought it and had it fitted and it has been brilliant.

I realise I got lucky, but if I were you I would put some wanted ads on the various Lotus forums and perhaps MG forums (and facebook pages) for a good low mileage engine. Also talk to people who do Honda and Duratec swaps as they may have some Rover engines that they removed from customer's cars.

MGF breakers might have something too.

If you find one, fit a new head gasket, cam belt and water pump when it is on the bench. 

In my opinion the Rover K is a good engine if you fit the later multi-layer steel gasket and don't let it overheat (turn it off in traffic, sometimes bring the revs up to 2000 from idle to push more coolant round and so on). It really suits the Elise because it is so light.

The 120 bhp engine is a bit weedy though. You could fit a ported and flowed head with big valves, better cams and verniers and an emerald ecu if you have money to spend. Or just second hand MG 135 cams for £150 will get you to 135 bhp on existing ecu and make it rev better at the top end.

Be careful if you are going to 160 bhp and above because the pistons fail - you need the MGF Trophy 160 pistons instead (or forged pistons if it's 190+ bhp).

A vvc engine is a great thing - 156 bhp out of the box and still with low-down torque, but I am not sure what you have to do to wiring looms and so on. Someone that knows more thsn me will help you with advice I'm sure!

Good luck with it.

Dean

[exeterjeep]

4 minutes ago, deanb said:

if you fit the later multi-layer steel gasket

Some considerations about the MLS, there is a new elastomer gasket. May be worth a read....

https://www.dmgrs.co.uk/pages/why-the-mls-gasket-isnt-quite-all-its-cracked-up-to-be

MG Rover mobile mechanics know a lot about K series, and do a few odd jobs on K series fitted to the Elise.

I fitted an MLS gasket to a ZR in 2016 and it is still going. Head was not warped though. Car now got to 100k.

Wheeler Dealers did a K series performance upgrade to an Elise when Edd was on the program.

[SonicBob]

The k series can be a solid engine. We've built many for rallying. We always fit a cometic gasket and use arp bolts. the K uses very long head bolts ( reaches right down to the crank web) and these can stretch. Given the engines propensity to overheat, it does not take much for the head to lift and blow that silly little pink rubber seal. then your engine cooks and the head warps. The head can be fixed. you mill it flat again, re-cc your combustion chambers, re-cut your valve seats and since it's in bits, open out the ports a little. Yea, just get a fresh head. Even then, you might want to gas flow it while it's in bits, bigger vales, etc... You can alter the alter the water flow by fitting an interference fit plug in the water way and drilling it out, which can force water in a different direction, but one problem is the thermostat, fit an 82 degree instead of an 88, or lower. 

They do respond well to wider duration and bigger lift, especially if you go down the bigger valve route. Not difficult to achieve 100 hp per litre. I don't know how "Programmable" the OEM ecu is, on K series I've built for rally cars, like Mk II escorts, we obviously have to go to aftermarket ECU.

For big revs from a standard K you're gonna wanna replace your rods and pistons for forged, not nasty cast, but the lotus variant must have some decent internals already, so probably cams and a minor remap could yield good performance improvements...

There is more. If you have the thing on the bench, then you can deck the block to suit your head gasket and desired compression ratio, though to increase compression, you will really need to CC the combustion chambers and check the piston heights. Then you need to check your valve heights, which means a dry assemble with some plasticine ( don't use blu tak) on the pistons, so you can measure the piston to valve clearance. It's important that you don't go for a a cam with more lift than your valve diameter will support ( roughly 1/4 dia in lift, though often you might want to exceed that slightly to allow for the inviscid layer) also, a must is three angle valve seats and don't over lap in your valves. Just a thin pencil line touch is all that is required or you defeat the object. We prefer a gentle recut, with a minimal final lap, to get the seal.

Now, to increase your compression ration, you're gonna have to change the timing, and this is best done on a dyno, but a rule of thumb I go by, is start at 32 degrees and if it det's, retard it. Also, you're cams will need a refuelling, and again, that level of change is a dyno job. Start with more fuel than you need, weak will burn holes in your pistons when you pull on it. We use DTA (ecu) quite a lot and have some standard maps for the engines we build.

Oh, and if you've decked the block, CC'd the head and fit cams ( or any combination) your timing marks will be for shit, so get a crank degree wheel ( Kent cams provide them) and some verniers and dial in your timing on lift. If you're lifting the rev range, valve springs will come in to play and TBH anything above 7.5k I like to use solid lifters, though some hydraulic will work into 8K, I don't like to risk it. when you're smashing up and down the revs in and out of corners you don't want fluctuations in oil pressure messing with your valve train. You need a consistent supply to the crank and big ends.

Finally, dry sumps do wonders for reducing internal engine component drag and ensuring a consistent oil pressure... 

Edited August 5, 2023 by SonicBob