E21/ 2.0 Single row timing gear to E12 head.

[Mikesmalaga72]

(76 2002)...

Since the late 2002 engines w/E21 2.0 heads /w/ flat top pistons use single row timing chains can one simply transfer the timing gear to an E12 head and use that? I`m used to the double row chains on earlier cars. Would there be any performance differences if any between E21/2.0 and E12? Thanks!

[Preyupy]

There is no problem just moving the single row timing chain.  With a stock cam and valve springs it will work just fine.  There is a slight reduction in the life expectancy of the single row timing chains (they do stretch a bit quicker than the dual row chains) but you are looking at 100k miles or so before that is noticable. 

[Mike Self]

1 hour ago, Mikesmalaga72 said:

Since the late 2002 engines w/E21 2.0 heads /w/ flat top pistons use single row timing chains

Per the factory parts book, it appears that all M10 engines in 2002s used a duplex timing chain, as there's only one part number showing for a timing chain.   

 

I thought the single row chains began with the 1.8 liter M10 engines used in the later E21s; the 2 liter M10s in the 77-79 E21s also used a duplex chain.  

 

mike

[bergie33]

Straight swap over.  My Tii had a factory replacement E12 head with a single row chain/sprocket.  When I rebuilt the engine, I took that off and went back to the original two row chain/sprocket for durability and originality.

[tech71]

4 hours ago, Mike Self said:

I thought the single row chains began with the 1.8 liter M10 engines used in the later E21s; the 2 liter M10s in the 77-79 E21s also used a duplex chain. 

From my experience that is correct

[tech71]

6 hours ago, Mikesmalaga72 said:

Would there be any performance differences if any between E21/2.0 and E12? Thanks!

With flat top pistons? yes, some.

E21 2.0 head combustion chamber is 60cc

E12 head combustion chamber is 61cc

Compression will drop from 8.1:1 to something a bit lower

Edited June 28, 2023 by tech71

[Conserv]

7 hours ago, tech71 said:

From my experience that is correct

+1

 

My ‘76 49-state version has always had a double-row chain. I suspect the single-row chains we find on ‘02’s are post-factory replacements.

 

Regards,

 

Steve

 

[Tommy]

5 hours ago, tech71 said:

With flat top pistons? yes, some.

E21 2.0 head combustion chamber is 60cc

E12 head combustion chamber is 61cc

Compression will drop from 8.1:1 to something a bit lower

Change would be around 8,1 to 8,0:1 which in practise is nothing. Bit over 1 percent difference.

If the question is - "any" difference, then "yes some" is correct answer in theory. But noticeable or measurable difference - No.  

[AceAndrew]

No reasonable durability issue inside functional lifecycle window, and less reciprocating mass.  Pretty common upgrade on performance/racing builds.  To each their own.

[tech71]

I assembled an engine last year utilizing NOS TRW single row timing chain and sprockets, why, you ask ? 
Purely cost motivated, stuff  cost a fraction of what  OE double row stuff was running cost wise.

[SydneyTii]

I could be way off, but I believe the upgrade is the same chain as an S14, which I think is single I believe… unless my memory is failing me… highly likely 🙄

[tzei]

S14 t/chain is double row.

[SydneyTii]

😂 told yer! Hopeless memory 🙄

[TobyB]

Yeah, the single row showed up with the 1.8i head.

 

However, BMW remans got the single row after that, so

it's quite possible to have a 2002 reman engine with the single.

 

Me?  I run whatever's cheapest, too.  I've never seen either fail.

It's quite possible the single stretches- but by that point

in the engine's history, I'm replacing at least the chain, anyway....

 

t