M51 diesel conversion

[gareth]

i have been thinking for a while that i would like to do this for a laugh!

as my wife is getting bored of her 1.8 16v corrado doing 21mpg (when the E34 525i sport did 24mpg!!!!) and missing having a RWD car SHE suggested that it might be a giggle to buy a very nice local 316i tourer, drop in a big TD pot and have his&hers heart transplanted tourers! (got to love her ey?!)

i know there was the E30 324td but that was the M21. i expect the basis of any conversion i do will be a 525 tds or maybe a donor E36 or E39. i can see the E34 being cheapest though.

the initial questions:
has anyone done it?
is is essentially a M20 diesel? (physically, eg mounts etc)
is the M51 tunable? if so, power figures?
are there any differences between the TD and TDS other than just the intercooler?
would i be better off getting a continental M21 donor?
will the M51 handle running on vegetable oil (one of my favorite cheapo moves!!!)

some specs at the bottom of the page: (green bit)
http://www.unixnerd.demon.co.uk/enumber.html
141bhp 206lb.ft not at all bad as standard, bet it would rape a 325i, just!!!

[Jon_Bmw]

Gareth the best bit about that is that you could buy a cheap cheap omega diesel as they use that bmw engine. I can't think what differences there are between the engines bar the intercooler, but can almost garentee the turbo will smack the engine mount as it sits underneath the manifold. Well thats what happens if you could bolt a m51 manifold and turbo to an m20. Perhaps the block is taller or the engine mount is lower in the 5 series?

Still seriously thinking of getting a turd of a diesel and using vegtable oil in it and then cranking up the boost

[gareth]

ooh, that's an idea!

is it a brainy diesel or a basic old one? if it's brainy, i might be better off having a bmw donor for the wiring compatability side of things. if it's a basic diesel, the omega route could be a good one!

how would i get around the engine mount clearance problem? custom engine mount maybe (a bit like the M30 one that sweeps under the exhaust downpipes

re running on veg il, my 406 DT loved it! it ran smoother, quieter and rather than smelling like a train, it smelled like a scrummy BBQ!!!

[12345kevin]

will the M51 handle running on vegetable oil (one of my favorite cheapo moves!!!)

From what i've read, it's the pump that is normally the problem with using veg oil, so as long as you use a pump that can handle it should all be well. A peugeot one should be OK, as al lthe Taxis seems to be using it

[jaistanley]

Another concern about veg oil is that it's a very good solvent. So much so it strips all the waxy crap from the inside of your diesel components and clogs things with it.. To get around this, slowly introduce the veg oil mixing it with less and less diesel each fill up till you're finally sticking two fingers up at the man'.

Jai

[gareth]

will the M51 handle running on vegetable oil (one of my favorite cheapo moves!!!)

From what i've read, it's the pump that is normally the problem with using veg oil, so as long as you use a pump that can handle it should all be well. A peugeot one should be OK, as al lthe Taxis seems to be using it

depends on the pump fitted... the lucas / cav one will die at anything over 50% veg oil (sieze pump, stop cambelt, stop cam, valves-pistons-bang)but the bosche (german!!!!) one will handle neat veg oil. hopefully bmw stuck to bosche like they usually do!!!? mine was a bosche one and we did 20k on nothing but veg oil and didn't have any problems. if the weather gets cold, diluting it with unleaded works a treat. i never put diesel in it!!!

[agent006]

Range Rover also uses the M51 engine.

[gareth]

Another concern about veg oil is that it's a very good solvent. So much so it strips all the waxy crap from the inside of your diesel components and clogs things with it.. To get around this, slowly introduce the veg oil mixing it with less and less diesel each fill up till you're finally sticking two fingers up at the man'.

Jai

as in the above post, we did 20k in the 406 on veg oil sometimes mixed with other stuff (diesel or unleaded) and had no problems. in that time i did a fuel filter swap (should do them regularly on diesels anyway as the suck up so much shite!!!) so that may have cought some of the goo. i've read that a lot of people when converting keep all the tools needed for a fuel filter swap and a spare filter in the car just in case. usually after a few thousand miles the bulk of it has gone and you may have spent £30 on fuel filters but your first tankful will have saved that!!!

[gareth]

Range Rover also uses the M51 engine.

cool! must be a good engine then!!!

maybe i should keep the range rover running gear for a bit more fun!!! 325tdsx?

[Jon_Bmw]

Range Rover also uses the M51 engine.

Yeah they certainly did, a common transplant i think was the 2.4 bmw diesel into them too. I don't think they came from the factory with the 2.4 anyway. Awaits to be corrected.

[gareth]

one thing to point out to anyone reading... obviously i pay all of my taxes as the government make it so easy for me to do so!!!!!!!!!!!!!!!! as / when they do without me having to register as a fuel supplier (along with shell, bp etc) i'd happily pay them. bearing in mind that we are the only eu state who want tax for biofuels!!!

the reason it is mad not to run on veg oil... you produce 1/5 of the pollution when burning it! it's also got a lot less nasties in it than 'normal' diesel emissions.
throughout europe this is welcomed by tax excemption
in the UK, the government still wants our money for this regardless and atually makes it hard to 'do the right thing' legally.
in the UK, to keep up with the eu, you can't buy a pint of milk in a supermarket...

madness...........

[agent006]

Awaits to be corrected.

Available with the 525tds engine from the factory between 1994 and '02. Even still has BMW written on it.

[Chris-W]

Yep - Range Rover engine is 100% BMW. Lovely engine, very revvy for a Diesel. Only complaint is that it's a bugger to start hot.

[320Touring]

Yep - Range Rover engine is 100% BMW. Lovely engine, very revvy for a Diesel. Only complaint is that it's a bugger to start hot.

I can second this!

the shed of the iS fired up straight away, whilst the flashy rr took an eternity to churn

[fuzzy]

SHE suggested that it might be a giggle to buy a very nice local 316i tourer, drop in a big TD pot and have his&hers heart transplanted tourers! (got to love her ey?!)

i assume that as your wife has hatched this amusing plan that SHE will be getting stuck in and getting oil under her fingernails?

[Chris-W]

the shed of the iS fired up straight away, whilst the flashy rr took an eternity to churn

And all 37 of his Scotch mates stood laughing....

There's a mod to the ECU for the plugs which forces them into action regardless of engine temp, desirable on M51's to say the least!

One other thing - they fracture and eventually snap their aux belt tensioner arms.

[320Touring]

the shed of the iS fired up straight away, whilst the flashy rr took an eternity to churn

And all 37 of his Scotch mates stood laughing....

There's a mod to the ECU for the plugs which forces them into action regardless of engine temp, desirable on M51's to say the least!

One other thing - they fracture and eventually snap their aux belt tensioner arms.

2 Scotch ( like the egg) 1x Norwegian and 1x Northern Irish.

as for mods, is it not the 525tds (intercooler beastie) that responds awfully well to a tuning box?

[Chris-W]

as for mods, is it not the 525tds (intercooler beastie) that responds awfully well to a tuning box?

I believe so - have had talks with a supplier of such gadgetry promising +10-15% torque/bhp/mpg for small(ish) money.

[Toby_Unna]

good good well that sounds like plenty of decent reasons to get on with it, when are you starting Gareth

cracking idea if you ask me.

should i be running my 205 on veg oil then? haven't so far due to the legality side of things, is it really that much of a pain to pay tax on it?

[Jon_Bmw]

Yeah, you mix it with 1 part veg oil and 9 parts diesel don't you toby, but be careful you don't slip and put 9 parts veg oil in and 1 part diesel

[johnna]

Would it fit up to the box? Would the mounts fit the e30???


I really fancy this conversion...

[gareth]

SHE suggested that it might be a giggle to buy a very nice local 316i tourer, drop in a big TD pot and have his&hers heart transplanted tourers! (got to love her ey?!)

i assume that as your wife has hatched this amusing plan that SHE will be getting stuck in and getting oil under her fingernails?

damn bloody right she will! she hsould be ok though, she's got an OND in mechanical engineering and started a degree in engineering. probably quicker if she keeps me well fed with the and cakes though!

[gareth]

good good well that sounds like plenty of decent reasons to get on with it, when are you starting Gareth

cracking idea if you ask me.

should i be running my 205 on veg oil then? haven't so far due to the legality side of things, is it really that much of a pain to pay tax on it?

if we go ahead, i reckon we'd buy a decent tourer and then look for a good engine or donor over the next few months. summer would be a nicer time to do it than with the current weather!

regarding your 205, have a look at what fuel pump you have. if it's a lucas / CAV one then afaik it's risky as they tend to die and often take the cambelt with them with obvious results if it's bosche then you're in luck! starting at 10% veg oil / 90% diesel give it a go. i worked up until i was running 90% veg oil and 10% unleaded (thinner than diesel) then thought 'sod it' and chucked 100% sunflower oil in and it was fine. i had a bosche fuel pump...

the low temperatures at the moment are the stumbling block and keeping the fuel thin (veg oil get very gloopy when cold) is the biggest problem but to do it properly you just need to heat it up. i was going to rig up a 405mi16 oil cooler. this sits on the oil filter and uses water to cool the oil. my thinking was to connect the fuel supply though the water pipes on the cooler thus using the hot engine oil to heat the fuel. either that or a proper heat exchanger from a mr2 in the heater hose or soemthing. either that or a bought / homemade electric one.

it may be tricky for some to do but i reckon you should be able to manage

google things to look for are SVO (straight vegetable oil), WVO (wast vegetable oil), biodiesel (processed WVO brewed into sort of 'proper' diesel)

there is a lot out there about legality too. it's as illegal to use it without paying tax as it is to use red diesel. the gorvernment are not making it eeasy to do it but if you're set up then you can say you're using 5 litres a month and pay your £3 or whatever... there is no way of them checking. after all, you've already paid VAT on it but the rest of the EU don't pay a penny of tax on eco-friendly biofuels.

things may have changed recently though as it's been a while since i looked.....

if anyone wants a email full of links to useful sites i found, pm me and i'll lob them over.

[gareth]

Would it fit up to the box? Would the mounts fit the e30???


I really fancy this conversion...

i hope so. afaik it's basically the evolution of the M21 which is in turn basically a M20 diesel.

the gear ratios are likely to be all wrong though, as is the diff ratio.

more research needed methinks! found this though:
http://www.bmwworld.com/engines/m21.htm
http://www.bmwworld.com/engines/m51.htm

[johnna]

That is giving me the horn!!!

I fancy junking the m20b20 in my cabby for an M51...


...especially as I may be commuting 60 miles a day again very soon.

[Jon_Bmw]

Johnna i can just imagine you know, roof down. black smoke out the arse end and smelling like a chippy. Quality.

[johnna]

Thats me!!! I resemble that accusation. Then I'll install a derv lump in the cabby...

[320Touring]

gareth- dunno if this is any use to you?

Cars For Sale
OFFERED
BMW 325 TDS M registration. No TAX or MOT. New engine rebuild. Bodykit. Spoiler. Big alloys. Big exhaust system. New £400 lowered suspension. Bump on wing (wing supplied). Offers or swap for why. Renfrew - (sadt-02-2970) Tel: (07005) 921031
Price: £400.00
Town: Renfrew
Postcode: PA49

[Jon_Bmw]

Its a fairly "Big" car that one Neil.

[johnna]

Small price, so big mileage too?

[gareth]

gareth- dunno if this is any use to you?

Cars For Sale
OFFERED
BMW 325 TDS M registration. No TAX or MOT. New engine rebuild. Bodykit. Spoiler. Big alloys. Big exhaust system. New £400 lowered suspension. Bump on wing (wing supplied). Offers or swap for why. Renfrew - (sadt-02-2970) Tel: (07005) 921031
Price: £400.00
Town: Renfrew
Postcode: PA49

sounds ideal! fraggable ebay goodies too by the sounds of it. shame the AA rout planner gives me either 612 miles or 470 miles (depending on what location i put in, renfrew or PA49)... dammit!

[Toby_Unna]

sorry to continue off topic (esp as it's such a good topic!) Gareth.

assuming you don't use old chip oil where's best to buy the stuff - the big drums in tesco? not thought about this before as 50+ mpg is quite nice even at 90p/litre, but i guess i ought to really!

as to what fuel pump's on it... well the car cost 75 quid think it's bosch, if not i'll take the risk

[johnna]

pm sent you rotten thug you.

[320Touring]

Its a fairly "Big" car that one Neil.

banging choons!

just thought a "rebuilt engine" would be useful...

[gareth]

sorry to continue off topic (esp as it's such a good topic!) Gareth.

assuming you don't use old chip oil where's best to buy the stuff - the big drums in tesco? not thought about this before as 50+ mpg is quite nice even at 90p/litre, but i guess i ought to really!

as to what fuel pump's on it... well the car cost 75 quid think it's bosch, if not i'll take the risk

i used to buy 3 litre bottle of 'vegetable' oil (rapeseed usually) from tesco at 54p/litre. the fun bit was walking about the shop with the whole bottom of the trolley totally full of them! 22 at a time!!!

i would then go out to the recycling bank with a funnel, pour them in (2 man job to make things easier) and drop the bottle into the plastic recycling bank how eco friendly is that! i did get funny looks throughout though!

it's cheap (about 45p/litre) to but it in 20 litre drums from a cash&carry if you know someone with an account.

if this all works ok with your car then it might be worth getting a couple of old oil drums, a oil pump and some cheap engine oil filters and clean up old stuff for free