E12 vs E21 2.0 heads

[Markwemple]

My 76 has an E12 head but came with a E21 2.0 as a spare. It's currently running a Weber 32/36, otherwise stock,  as far as I know. Which head is better or what benefits do they each have? TIA!

[AceAndrew]

Hi Mark,  there are hours of comments/information you can go through that cover this very topic.

 

For example, here's one that should get you covered.

https://www.bmw2002faq.com/forums/topic/140561-difference-between-e12-and-e21-heads/

 

Best of luck on the rabbit hole!

 

Edited May 12 by AceAndrew

[tech71]

1 hour ago, Markwemple said:

Which head is better or what benefits do they each have? TIA!

It’s not really about that, both are good heads.

It’s about which head is compatible with your installed pistons, there are several different configurations of pistons. See above😉

[Markwemple]

Thanks guys. I couldn't remember. So I need to put this up for sale as it's not compatible with my engine. Now to figure out value.  

Edited May 12 by Markwemple

[TobyB]

'Pends on your 'Pistons.

 

Everything goes great with flattops.

 

t

 

[ray_]

[Buckeye]

year 76 BMW used E21 cylinder head. You suppose to have flat top piston in your block if is original and it is 1976 car.

e10_1975_us-1.pdf

Reading Conserv post I stand corrected. CA version uses E12 head

 

Edited May 13 by Buckeye
CA vesion used E12 cylinder head

[Markwemple]

15 minutes ago, Buckeye said:

year 76 BMW used E21 cylinder head. You suppose to have flat top piston in your block if is original and it is 1976 car.

e10_1975_us-1.pdf 9.97 MB · 0 downloads

So maybe someone swapped heads on my 76

[Markwemple]

I'll have to.use a borescope to look

[tech71]

36 minutes ago, Markwemple said:

So maybe someone swapped heads on my 76

Possibly the entire engine, do body and engine VINs match?

37 minutes ago, Markwemple said:

year 76 BMW used E21 cylinder head.

Except for CA smog equipped, they had an E12 head, right?

[Markwemple]

27 minutes ago, tech71 said:

Possibly the entire engine, do body and engine VINs match?

Except for CA smog equipped, they had an E12 head, right?

Where's the database that matches vin to engine?

[Conserv]

4 hours ago, tech71 said:

Possibly the entire engine, do body and engine VINs match?

Except for CA smog equipped, they had an E12 head, right?

Exactly: CA-spec 76’ ‘02’s used the E12 head and 8.1 (very low) piano-top pistons — versus 49-State versions, which used E21 2,0 heads and flat-top 8.1(?) pistons. This was solely a 1976 distinction.

 

The original block’s engine number was the car’s VIN — without exception. More details concerning engine identification are here:

 

 

Below is a set of 8.1 pistons for an E12 head.

 

Regards,

 

Steve

 

[Conserv]

The value of an ‘02 head is dependent on (a.) whether its overall thickness is still within acceptable spec, (b.) the presence or absence of cracks, (c.) the straightness of the head, (d.) the amount of corrosion or damage therefrom in the water jackets, (e.) the presence of past repairs or modifications, and, at minimum, (f.) the condition of items such as valve seats, valve guides, camshaft bearing surfaces, etc.

 

In short, a typical 50-year-old ‘02 head is probably worth something between nothing and $2,000.

 

Fairly recently, BMW still had a few brand new E21 2,0 heads: $1,800-$2,000 for a bare head. No other models of heads have been available from BMW for a few years.

 

Regards,

 

Steve

 

[tech71]

1 hour ago, Markwemple said:

Where's the database that matches vin to engine?

We dont need no stinking data base! Cars VIN is on the data plate, engine VIN is located on flat spot above and just aft of the starter. If they match, engine is original to the car, if they dont then engine has been replaced.

[resra]

2 hours ago, Conserv said:

The value of an ‘02 head is dependent on (a.) whether its overall thickness is still within acceptable spec, (b.) the presence or absence of cracks, (c.) the straightness of the head, (d.) the amount of corrosion or damage therefrom in the water jackets, (e.) the presence of past repairs or modifications, and, at minimum, (f.) the condition of items such as valve seats, valve guides, camshaft bearing surfaces, etc.

 

In short, a typical 50-year-old ‘02 head is probably worth something between nothing and $2,000.

 

Fairly recently, BMW still had a few brand new E21 2,0 heads: $1,800-$2,000 for a bare head. No other models of heads have been available from BMW for years.

 

Regards,

 

Steve

 

Steve, I bought a 121 new bare head from BMW back in 2019 but since its been NLA already.