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1.9/2.1 Cylinder head differences
Posted: 22 Oct 2015, 20:15
by sherlylock
Evening folks,
I'm in the process of rebuilding my 2.1DJ engine and I've got a few spare engines for spares if I need them.
Both my 2.1DJ heads are cracked between the valves (as they do!)
Both my 2.1MV heads are also cracked.
I took the heads off the 1.9DG engine that I have spare and they both uncracked and look in quite good nick (despite the engine being an unknown and obviously stood for ages)
The heads are slightly different to the 2.1 heads though.
Valves are the same size, inlet ports look the same shape but there are differences.
Main ones I can see with a cursory look are:
Inlet ports look slightly smaller (but the same shape)
The inlet valves look more shrouded than the 2,1 heads - slightly different chamber shaping.
Question is - can I use these on my 2.1 rebuild and am I likely to experience much performance loss
Casting number on the 1.9 head 025101375
Casting number on the 2.1 head 025101375C
I realise photos would help this thread - will add some tomorrow to clarify
Cheers all!

Re: 1.9/2.1 Cylinder head differences
Posted: 22 Oct 2015, 20:33
by Jawin89
Re: 1.9/2.1 Cylinder head differences
Posted: 22 Oct 2015, 20:48
by itchyfeet
dg and dj heads are the same
my dg heads are marked 025101375
not sure about suffix somebody will know.
later heads were polish made not german maybe that.
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 07:18
by bigherb
As Itchy said, DG DJ MV heads are the same. 025101375 are early heads, superseded by 025101375C
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 07:34
by ajsimmo
If you have power steering, make sure the drillings are there (on the replacement head from the DG) to mount the pump carrier on the O/S head. Just a thought...guess how I know! Can easily be drilled and tapped if needed.
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 07:42
by silverbullet
I naiively thought I was the only person to have seen one of those undrillled heads

Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 08:01
by ajsimmo
Ha! Not just me then. Daft thing is I realised after I'd built the engine that the left hand one was drilled and could have just fitted em t'other way round. Never gave it a thought til I stood there with pump bracket in hand and said "b0!!0x".
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 10:35
by itchyfeet
anybody know what number is cast into a df head?
vagcat just gives assembled part numbers not the casting part number
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 11:06
by bigherb
DF are suffix B
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 12:04
by itchyfeet
bigherb wrote:DF are suffix B
thanks so
025101375B for DF
025101375 or 025101375C for DG or DJ
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 12:58
by sherlylock
Few pics of the differences:
LH (clean) is the DG, RH is the MV (C suffix on the casting). Note the chamber shape around the valves. Looks more shrouded on the DG
Inlet ports look enlarged on the MV head.
Presumably then this is just a progression in the design of the head to improve it from earlier models to later models?
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 13:40
by silverbullet
DF has smaller ports, valves and a feeble cam, hence only 60PS (when new...)
Best avoided altogether imho, woefully underpowered.
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 14:10
by itchyfeet
itchyfeet wrote:dg and dj heads are the same
my dg heads are marked 025101375
not sure about suffix somebody will know.
later heads were polish made not german maybe that.
Actually my late DG heads are C suffix (just checked) so all late DG/DJ engines had them.
Re: 1.9/2.1 Cylinder head differences
Posted: 23 Oct 2015, 20:16
by 123-jn
I have an AMC head on once side of mine and a head like your MV head on the other side, They are slightly different I would say the AMC has slightly more volume in the head cut out around the valves but in reality there appears to be no real difference. Both sides manage about 170psi of compression. So I would use the uncracked ones. However Both of mine have cracks between the valves less than 1mm and on removing one to change the valve guides after 10,000 miles there was no change to the cracks so I gather that isn't too much of an issue either. I have known people use a punch and gently close up the cracks as well as getting them welded but so far I would say its not worth it. The valve guides however I have discovered are very important to the sound given off by the valve gear. Do not take any notice of Haynes allowing 1.2mm of side play. I allowed 0.8 on one head and have had to take it off to do the guides to shut it up. With New guides I now have about 0.15 which is so much less noisy. It is worth recutting the seats if they are too wide also back to about 2mm in width ish. (Ps hope to drop in on you in a week or so and see how the build is coming on!!!!)
Re: 1.9/2.1 Cylinder head differences
Posted: 16 Feb 2019, 22:38
by lucas
Hopefully is acceptable to revive and old post but this is exactly the issue that I'm having. I did post something in the chat forum but it's probably more appropriate in here.
My existing engine is fitted with 025101375 heads, I have found a set of 025101375C's and fitted one so far, the issue is that even with the tappet screws wound right out the rocker is pushing the valves down?
Are they not compatible or have I got something wrong?