Most bulletproof BMW engine?

Thu Jul 17, 2008 11:33 am

M20's are shit!!! I dont have much faith in them, simply because my mates are never done boiling them.

A good serviced e36 m3 engine (s50 i think) is what i have confidence in, young dallat done a wee test and the engine came out on tops while screaming its wee heart out

Fri Jul 18, 2008 1:19 am

I had an E36 316i with the m43 engine and ran it from 74k to 159k with no problems. It used virtually no oil or water. Very economical on longer journeys as well.

Fri Jul 18, 2008 4:20 pm

m10

i recon the m21 will be a very strong engine

Sat Sep 06, 2008 10:11 am

If you go on mye28.com and look for the "mileage" threads etc, you'll think the m30 is indestructible, people routinely have 200-300k miles on the clock no issues. Personally I blew the bottom ends on 2x m30 engines but I beleive that was due to a mickey mouse oil cooler and filter housing setup that screwed me over at high rpm. Since that I've had an m30 engine in my drift car and after about 10 hard days of abuse it still sounds/feels/drives/looks exactly the same despite being 20 years old, having like 150k on the clock, and not even having an oil change all year (despite me keep meaning to), it loves the limiter.

I also had an m10 for a month or so, and apart from distributor issues it also loved the limiter, even after being stood for 6 months and having 115k on the clock.

My m40 engine lasted about a month before the big ends blew, but that was on track with 2 litres less oil than it should have had

So it didn't do too badly, it also drove 130miles home on the motorway at 60mph no problems even though it was knocking badly lol. The replacement engine (a snip, at £30) lasted a month before I sold it but the later owner thrashed it more and it was still ok, just got noticeably noisier in general after a couple of weeks of abuse.

Sat Sep 06, 2008 10:22 am

deffo the m30 IF ITS LOOKED AFTER!!!the m30 is so unstressed,its only about 65-70 ish bhp per litre,wich is pretty low really.as long as you watch the banjo bolt,and change the oil and anti freeze regularly,it'll just keep going

Sun Sep 07, 2008 10:25 am

I don't think any of them are bad. The new all alloy engines are amazing engineering, I was shocked at the weights and economy BMW are getting nowadays. Of course, there's always a price for living on the edge.

Sun Sep 07, 2008 11:17 am

stonesie wrote:Based on the M10 isn't it?
The M10 has the title of being the base of the most powerful 1.5 i can think of too

They still use the base design now. So this has to be the one.

btw m20 is an m10 with two more cylinder's too.

Sun Sep 07, 2008 1:29 pm

Andy, out of ignorance and curiosity what did a N42 Valvetronic engine come in?

Sun Sep 07, 2008 2:02 pm

m20 ftw!!! iv never had a problem with heat issues, cracked heads, engines randomly shitting themselfs... my only demon is the electrical side of things... the earth strap did help btw! i just turn the key and she springs to life... cant ask for anything else.
saying that iv never owned a non m20 bmw.. but if you service and replacing parts that are needed and you shouldnt have any problems... look after them damn it!

Sun Sep 07, 2008 3:13 pm

zaust wrote:btw m20 is an m10 with two more cylinder's too.

An M30 is an M10 with 2 more cylinders.

Fri Sep 12, 2008 10:32 pm

i heard the m10 bottom end was so touch that bmw used the basic design structure for a base for its 80's turbo f1 engines

Sat Sep 13, 2008 5:56 pm

dimebag_from_hell wrote:M20's are shit!!! I dont have much faith in them, simply because my mates are never done boiling them.

A good serviced e36 m3 engine (s50 i think) is what i have confidence in, young dallat done a wee test and the engine came out on tops while screaming its wee heart out

Try telling them that when they're diffin them to keep an eye on the temp gauge and taking it for a run after, instead of just parking up and changing tyres. I used to give my 325 dogs abuse and I just needed to replace rotten hoses and a head that went porous

Sat Sep 13, 2008 7:25 pm

Simon13 wrote:M30's aren't as tough as the folk lore says imo. A good M20 is tougher and an M50 is pretty heroic also

My generalisation would be that the M40 engine is the worst and the rest are tough!

Gotta disagree there si mate. M40 is a strong little engine. Pretty slow and belted rather than chains but a tough little bugger in my experience (2 of)

Sat Sep 13, 2008 10:28 pm

I have had two m10 engines die on me - one crack it head and its bottom end - only had 115K on it.

I have find M42's pretty reliable - I had one 318is with 220K on it - ran fine. I currently have a e36 with 177K on it - it would be very easy to reduce the mileage on it, if it wasn't for the slightly crappy trim. The engine is solid!

I think most BMW engines are reliable if they are looked after -

Sun Sep 14, 2008 10:20 am

s14 and m50 get my vote.. m20's are just too old now and like above suffer from many a cracked head..

Sun Sep 14, 2008 11:45 am

Totally disagree with the S14, so many are garage queens and those that are not usually one of the best looked after and serviced engines due to its racing pedigree and badge snobism. Most of the heavily used ones have regular mods and tweeks throughout its life meaning the heads been off and all sorts which totally removes any sense of reliability its not same as an M30 thats been raped along 300k with just oil and filter changes therefore impossible comparisons.