bmwe21.net forums

M30 is a right boat anchor.

just found the perfect engine on paper, bmw n42b20s from a e46 320si, trouble is i only think 200 where produced for the uk, they come with a lovely carbon fiber cam cover
finding one may be a problem.

Nice engine but not the strongest, think I'd go for S14 instead...

nas80 wrote:M30 is a right boat anchor.

Yeah - so they say. Weight is hardly any different to an M52 though. 8kg at most.

I'll throw out the challenge - show me an M20 that makes more power & torque than a stock M30B35 at 210hp and 305nm? Then show me the cost of building the motor - no a 2.7 with a 731 head swap won't get close. Yes you can turbo the M20, but you can also do the same thing to the M30 (even using factory parts if you like from the M106). The timing chain on the M30 removes the timing belt weak point too.

A chip / MAF conversion will put the M30 at roughly the same power as an M52 2.8 with the M50 inlet (approx. 230hp) and the M30 will still eat the M52 for torque. Of course the stock M52 has both less power and torque than the M30.

Still - yes - it's a tractor motor I know.

Since doing my e30 M30B35 swap I have to admit to being a complete convert after making the same kinds of comments myself, and dreaming of 2.7L stroker M20s in my e21. As a daily driver they are great.

The S14 would obviously be the ultimate as Jeroen has suggested. Injection is still Motronic & thus simple to wire up, and weight distribution would be awesome. You could still use the M10 gearbox too if you didn't want to lash out on a Getrag 265.

nas80 wrote:M30 is a right boat anchor.

Oi!!!! Don't you start!

This is what i'm building atm, from my "Boat Anchor"



New shells, bearings, chain guides, piston rings, and maybe "O" ringing the block too as i'm going Supercharged on the old girl.

.
Once this build is finished, i'll be looking to do the same in the E21.
Atm, the head has had 3 angled valves and seats, and is now having some mild porting done so the ITB's match the head inlet ports.

Nice! ITBs and supercharging should be a challenge, but awesome in the end

Nice plans indeed!

luke wrote:

nas80 wrote:M30 is a right boat anchor.

Yeah - so they say. Weight is hardly any different to an M52 though. 8kg at most.

There's been some inaccuraceies in this thread concerning the M30 so let's put the record straight.

Firstly, the M30 weighs in at 143kg which is a whole 25kg more than an alloy blocked M52.

Secondly, the pre-87 M30's had 218 hp while the post '87 changed to a smaller bore & longer throw giving 3430cc. This gave another 2 hp but bumped torque up to 232 lb/ft. They had larger valves & inlet ports all designed to counter the effects of a catalytic convertor. This engine was fitted to the E32 7-series & E24 Highline 6-series. The E34 5-series was detuned to 211 hp, alledgedly so that it wouldn't be faster than the 7-series.

Boat anchor? The M30 came with a forged crank & build quality that enabled it to cover big miles. The highest mileage on the BMWCC E24 register had 366,000 miles on the clock before it was written off in an accident. I've heard of of one that clocked over 600k miles on the same bottom end.

Alpina versions put out 245 or 260 hp depending on spec. This was still docile enough to pull a heavy 7-series around. Sacrifice some low end torque for some high end power & 280hp is easily achievable.

Torque is directly related to capacity - more capacity, more torque. Horsepower is basically torque x revs. This is why motorbikes have high hp but little torque & conversely an 11 litre artic tractor has less than 250hp but enough torque to pull a 44 ton load. So, with an extra 700cc capacity the M30 will always have more torque than an M52.

However, BMW considered the M30 to be too heavy for the E21 so designed the small block M60 (later renamed M20). I think they probably knew what they were doing.

Whether you go for a small capacity screamer or a large capacity lugger depends on what you want to do with the car & how you want to do it.

143kg is that just the block or everything attached? it sounds about right.. I hear the M30 is about the same weight as the m50

on that basis I've driven an e21 with that weight and although its ok you certainly feel that extra weight especially when your on some sharp s bends. it might not seem like much weight difference between engines but it makes a difference in an e21!

the m52 all alloy is really light. I can lift for a couple of seconds without anything attached to the engine using my bare hands.

that m50 I took out - no way could I lift that its much heavier.

I think the inaccuracy happens because the m52 in the usa isn't alloy. they got a cast block over there. (lol unlucky!)

btw the m5x engines also have forged cranks too.

as Andy says different horses for different courses.

Rav320uk wrote:

nas80 wrote:M30 is a right boat anchor.

Oi!!!! Don't you start!

This is what i'm building atm, from my "Boat Anchor"

haha i knew id get a rise for that comment. your new engine looks awesome man - your going to need to brace your e21 pretty good to handle all that torque.

Rav320uk wrote:

nas80 wrote:M30 is a right boat anchor.

Oi!!!! Don't you start!

haha knew id get a rise from that comment!

your new engine looks awesome man - your going to have to brace your e21 for all that torque.

i know this is a bit off topic but whos going to be making the conversion plate to mount your throttle bodies?

nas80 wrote:143kg is that just the block or everything attached? it sounds about right.. I hear the M30 is about the same weight as the m50

the m52 all alloy is really light. I can lift for a couple of seconds without anything attached to the engine using my bare hands.

I think the inaccuracy happens because the m52 in the usa isn't alloy. they got a cast block over there. (lol unlucky!)

as Andy says different horses for different courses.

Sorry - yes I was thinking of the iron block engine. The M30 weighs around 8kg (give or take depending on ancillaries / flywheel etc) more than the iron block M50/52.

I do also agree with Andy about horses for courses (hence my S14 comment). I just find the comments that float round the internet quite funny where people will brand the M30 a tractor motor, then in the next breath praise their mates "i" headed 2.7L stroker and how grunty it is, when in reality the time, effort & $$ it takes to build up an M20 to even get close to the stock M30 outputs is actually a lot! + the M30B35 is actually more under square than the 2.7L and has most of the improvements that were also lavished on the M20B25 so it revs fine.

I'm not bagging the M20, I've owned several and had a blast driving them, but many BMW engines have now dropped into the swap price range - even the M54 would be possible these days and not too prohibitively expensive. There are many options for swaps around, including the varied 4s we've discussed in this thread, which would make an e21 nice to drive.

We did get ripped off slightly down here in Australia on our M30 specs vs. the UK... M30B35 was 208hp / 305nm for the e32 / e34 engine, the M30B34 in our e28 was only 182hp / 290nm (I don't think we got the M90 engine with the M88s bore and stroke).

nas80 wrote:

Rav320uk wrote:

nas80 wrote:M30 is a right boat anchor.

Oi!!!! Don't you start!

haha knew id get a rise from that comment!

your new engine looks awesome man - your going to have to brace your e21 for all that torque.

i know this is a bit off topic but whos going to be making the conversion plate to mount your throttle bodies?

Hi Nas

I've already bought them from a link Jason provided me, from Germany.

I'm on the verge of buying another set for the E21.

This engine build is for the E30 Chromie I have, with Supercharger

I drove a really well sorted m30 powered e30 race car at Brands earlier in the year and it was nowhere near as nose heavy as you might imagine. They'd spent a while sorting corner weights and getting spring/shock & ARB combination sorted and it was actually pretty neutral. It pulled like a train out of the slow stuff too.

As Alpina proved, it is possible to sort the handling.

The M30 was an incredibly tight fit in the nose of my 635 but there must be more room in an E30 because you can buy engine mounts with 3 installaton positions. The rearmost position requires some quality time with a lump hammer in the gearbox tunnel.

Australia has bagged quite a few of the UK's best M635's in recent years.