M20b20 to m52b28

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linke30
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Thu Jan 17, 2019 12:31 am

Hello all,
So it’s been confirmed that my head from my m20b20 is cracked.
I’m not to sure about trying my luck with another (I might have to).
Been looking at swapping in a m52b28.
It’s looking like a lot of work and money.
I don’t know if this is because I’m pretty new to my e30 still. I’m used to vw/Audi. I have put a TT engine in my golf so I’ve done a swap before but this is looking like quite a bit more work.

Is it the right thing to do, or should I be looking at other options?
Any opions or advice would be great as I’m feeling bit lost after the news that my head is no good :(
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aimlessrock
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Thu Jan 17, 2019 8:48 am

Any engine swop will involve some element of cost and time dependent on your skill set and budget. If the B20 was sufficient for your needs why not just put up a post looking for a good used head?

If your in the NW i have a couple of bare b20 heads in my shed.
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linke30
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Thu Jan 17, 2019 5:46 pm

This is definitely an option. I was just tempted by the opportunity to upgrade.
I don’t mind spending the time and money on it (to a degree) as it will be worth it.
Maybe I just need to read in to a bit more and make a complete list of what I would need and weigh it up.
How likely is that other heads are also cracked?
How much are you looking for yours?
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Brianmoooore
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Thu Jan 17, 2019 6:53 pm

It's very unlikely that a B20 head will be cracked. They are far less likely to crack than the B25.
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linke30
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Thu Jan 17, 2019 8:15 pm

Hi,
I’ve only spoken to the machine place over the phone.
They said it’s cracked and scrap.
I heard it was a common problem?
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Brianmoooore
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Thu Jan 17, 2019 8:37 pm

linke30 wrote:
Thu Jan 17, 2019 8:15 pm
I heard it was a common problem?
B25, yes, B20, no. Any cylinder head can crack if overheated, but the B25 will crack on the top surface of the head, through the rear cam bearing, at the slightest provocation.
Where is your head cracked?
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linke30
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Thu Jan 17, 2019 8:53 pm

I’m sure to be honest, pretty sure he said along the top.
I will pick it up tommrow after work and see what they say.
I don’t know how much they are worth. Could they be hoping I don’t come to pick it up if I think it’s no good?
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aimlessrock
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Fri Jan 18, 2019 8:53 am

B20 heads are relatively inexpensive as its not a particularly desireable engine. If the machine shop have determined your head is goosed then source a good replacement one. A number of engine swops are all documents in the wiki but think carefully about it. A well executed conversion undertaken by known zoner (Danthe for example) will likely be an investment and enhance the driving pleasure, a home brew budget transplant will likely devalue the car and you will spend your days chasing faults .
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190 Mercedes (1988)

"there is nothing more expensive than a cheap E30"
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aimlessrock
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Fri Jan 18, 2019 8:55 am

...before you consider any engine swop check the position re insurance.
E30 320i Convertible (1989)
190 Mercedes (1988)

"there is nothing more expensive than a cheap E30"
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linke30
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Fri Jan 18, 2019 9:47 pm

Okay thanks guys,
Done some adding up and it’s looking like abit too much at the moment. Would ideally want to complete it before my current cars mot, tax and insurance runs out which would add unwanted pressure.
I will try a source a new head, hopefully some near me can help.
Thanks for the help guys
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HRH-squidlips_III
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Fri Jan 18, 2019 11:49 pm

i was in the same position a few years ago m20b20 that overheated on a decent run but was fine around town
i went down the m52b28 route and i don,t regret it though i underestimated how long and how much money it would take but not buy to much if you don,t mind the wait
id say put the time and money into a m52 transforms the car in my opinion the m52 has enough tech to make it a modern,ish engine but not to much that it lacks character
and the m20,s had been out for a while before ending up in the e30
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linke30
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Sat Jan 19, 2019 8:02 pm

Squidlips, what did you find the most challenging bits? How much did it cost if you don’t mindsaying?
What gearbox did you use??
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Brianmoooore
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Sat Jan 19, 2019 9:14 pm

Most challenging bit, if doing it all DIY, must be modifying the exhaust manifold and mating it up to an E30 exhaust system. Most of the rest is just collecting and fitting the right bits, sometimes with minor mods.
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HRH-squidlips_III
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Sun Jan 20, 2019 3:36 pm

the most changeling bit buy far was not fitting the zf 328 gearbox to the engine prior to installing the engine lying on my back all day trying to lift it up and get it lined up right what a nightmare
the exhaust i found easy as all i did was cut two v,s were the manifold turns down about 2" out from the head and bent by hand, trial fitted bent again etc until both manifolds cleared rack ,block and the rear wishbone bush
i used e38 manifolds as my donar engine was from a e38 728 i bought for 400 quid i also used the front calipers, brake booster and master cylinder, wiring loom is no good also engine arms they need to be from e36
to me the sump was the hardest part that's why i went e38 as the sump is the right way round
other than the gbox moving the brake booster over an inch to clear m50 manifold and getting that all working again and that wasn,t really that hard i,m not a mechanic but i,ve moddied 3 other cars throughout the years and this was no harder
i thought the wiring would be the hardest part as i hate car electrics but was surprising easy done in a few hours
did plenty of research and theres loads of well documented write ups on the net
cost i hate to think so many different roads you can go down which gbox etc determines if you need to change diff ratio etc biggest expense was the car 400 and complete custom exhaust another 430
all up id say 1500 more if you do rack conversions brake upgrade etc
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linke30
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Sun Jan 20, 2019 7:19 pm

All worth it in the end!
So you used the box from a e36?
If so did you have to mod the gearbox mount/bracket?
Did you remove the ews?
The wiring I’ve seen you can buy adaptors to make it real simple. But I’ve not read any reviews or anything o them.
Mines a auto cab so I would need to get rear discs and abs etc from a 325 I guess.
Looking like I will replace the head for now and maybe slowly start collecting the pArts and do it next winter or somthing
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HRH-squidlips_III
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Sun Jan 20, 2019 8:52 pm

yes worth it in the end as i intend to keep the car for a very long time (give it to my kids when i'm gone long)
if you don,t see yourself keeping the car i wouldn't do it though better off putting a m20b25 in or 2.7 if you don,t mind spending a bit of money and want the torque a m52b28 offers
as the car will proberley worth more with a b25 if you intend to sell in the next 5 years or so
and yes i used the e36 328 box no mods necessary other than a solid and lightened flywheel off a my m20b20 if you want to save money you could use m52 dual mass and clutch
use the m20 gbox mount and shifter assembly
ews was deleted from the 728 ecu
i wouldn,t buy a wiring adaptor as im hopeless at wiring but managed to do the wiring in a few hours and was way easier than i thought only about ten wires to match up and with the right info is a piece of cake even for a beginner
as i used the e38 brembos on the front i needed bigger calipers on the rear so i brought adaptor plates for drum arms and put e46 rear calipers on
replacing the head for now and spending the time reading up and collecting the parts as cheap as you can is definitely what i would do
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Brianmoooore
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Sun Jan 20, 2019 9:20 pm

linke30 wrote:
Sun Jan 20, 2019 7:19 pm

Did you remove the ews?
As long as you have the EWS receiver, its ring antenna, and a matching chip from the key, it's best retained. It's the only remotely effective way of immobilising an E30 from being driven away. System just needs power to the receiver and a single wire to the engine ECU.
The wiring I’ve seen you can buy adaptors to make it real simple. But I’ve not read any reviews or anything o them.
A totally unnecessary expense and introducing a point of potential unreliability. As HRH-squidlips_III says, the mods. to the loom aren't difficult once you get stuck into it.
Mines a auto cab so I would need to get rear discs and abs etc from a 325 I guess.
If you have a cab, your brakes, front and rear, are identical to a 325 already. There is a difference between hub carriers for ABS and non ABS cars, but this will only be of concern if you wish to add ABS.
All ABS equipped E30s have the same brakes, except for a minor difference on the rear of tourings.
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linke30
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Mon Jan 21, 2019 6:20 am

Yes I intend to keep the car. I don’t plan on ever selling it.
I was looking at the adaptors as I got someone to make a new loom out of my golf harness and the Audi TTS harness which they Ballsed up on massivly. I spent. Very long time correcting the work and hanging upside down under the dash sorting it out. I didn’t want to have to touch wiring again haha
But if it’s a easy as you say then it should be very simple compared to what I had to do.

I would buy a complete donor car so I would have all the ews parts...

I only have drums on the back. It’s a 1990. This isn’t standard then?
If I’m going though the effort I would rather get all the brakes up to best standard I could while it’s all in bits
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aimlessrock
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Mon Jan 21, 2019 8:47 am

the way that E30 prices are going (especially chromies) i took the view some time ago that my cab will in years to come likely be more desirable and possible worth more as original car with its original engine and box etc in full oem spec. If i want a more modern power plant i have my daily (leased).
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190 Mercedes (1988)

"there is nothing more expensive than a cheap E30"
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Brianmoooore
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Mon Jan 21, 2019 10:07 am

linke30 wrote:
Mon Jan 21, 2019 6:20 am


I only have drums on the back. It’s a 1990. This isn’t standard then?
Most definitely not! All cabs., from the first one made, had disc brakes at the rear.
To be more exact, they have both a drum brake and a disc brake at the rear, but the drum brake is of a fairly small diameter, is solely for the handbrake, and the disc brake is fairly obvious behind it.
Post up a pic.
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linke30
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Mon Jan 21, 2019 7:31 pm

Im sure it doesn’t! Maybe it does. I never noticed a calliper but I’ve also never gone out of my way to look.
I’m doubting my self now!
Still new to the car really. I shall see the car on Saturday so will try and get one then.
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linke30
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Sun Jan 27, 2019 5:17 pm

So I got confused :| it has got discs on the back...
moving swiftly away from that, here is the cracked head. If you zoom in you will see the circles area.
You can hardly see any it in real.
You can feel it with your nail in the cam bearing.
Got new head sorted now so just need to order gaskets now!
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linke30
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Sun Feb 10, 2019 5:05 pm

So I got a 2nd head that was also cracked..
Not having much luck

There is a e36 not to far from me. 1995 2.8 auto. Full bmw history. Passed recent mot with no advisory’s.
Looks like good car for potential donor.
My question is, does the auto box that would be on this car need any modification to get in the e30 with the 2.8?
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