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Discussion Starter · #1 ·
Here's a question for the Opel sages...
I recently was offered the chance to buy a 1.5 or a 1.6 CIH Head. I would prefer to get the 1.6, since it has the fourth cam bearing unlike the 1.5; but I need to establish which 1.6 Head I am looking at. I want the version that has the same CC as the 1.5. How many ribs are on the front of the head? What other identifying marks I would look for in a photo? I could sure use some direction here... anyone? Bob?

Thanks a bunch in advance,

Darrin
 

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The simplest method to determine if the chamber design is the same is the plug reach. Does the 1.6 head use .460" or .750" length plugs? Stock 1.5's use the longer plug. A short-plug 1.6 head has the same chamber volume, it just will end up having slightly lower compression if you decide to unshroud the head after installing larger valves.
 

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Discussion Starter · #6 ·
I haven't had good success with using the plugs as a guide. Probably a combination of my poor german and the fact that we never received the 1.6. The information I am being told is that both the 1.5 and the 1.6 head use the same plug, and they are both short(.460")!?! Was there ever a short plug 1.5? If there was that might explain some of the communication problems that I am having. Are there any other ways to confirm a head? As I understand it the number of ribs on the front can be used to determine the type of head. No ribs - 1.5 or a 1.6N; Two ribs - 1.9H, 1.9S, or 1.9US; Three ribs - 1.6S. Can this be used, or was the change in plugs a casting change that had nothing to do with the type of motor?

Perhaps Opel used the old 1.5 tooling for the 1.6, with a few minor modifications. So early 1.6 heads have longer plugs. Then later, they did a major revision that allowed the 1.6 to share the same plugs as the rest of the CIH line. I have no evidence or proof, just a random thought I had.

I would like to put the head on a 2.0, so I think I would be better off installing larger valves. But I know from what I have been told that they wont flow without unshrouding them. SO I guess that locks me in. How much compression will I loose? and how much will it hurt the performance? Thanks a bunch!!!

Darrin
 

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All the 1.5 heads I've seen had long plugs (.750"). All the 1.6 heads I've seen that were removed from passenger cars had the long plugs too, but they were from the early '70's, and other than the 4th cam bearing the looked exactly like the 1.5 heads.

The most recent 1.6 head I saw was a later casting ('78) and it had the short plug. It makes sense that they standardized the plug length, they did this even with the 1.7 heads (.460" plug). It seems that the heads you have shown us are new heads, not from actual running vehicles, but rather NOS stuff. So they would have the latest 'updates'.

Opel did this also with their exhaust manifolds....early 1.9 Sprint manifolds had one bolt pattern, then the 2.0 Sprints had another larger pattern. But, when you ordered a 1.9 and 2.0 manifold later on from the Opel dealer (as I did in the '90's), they were the exact same casting (as the 2.0), the flange was just drilled differently for each application. More cost effective this way.
 

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RE: Compression and airflow.

Don't worry about the loss of compression. With a 2.0 shortblock and big valves in a 1.5 OR 1.6 head, you can still easily get 10.5:1. You probably don't want more than this unless you have a real healthy camshaft, or it will detonate horribly on pump gas.
Even with a ton of unshrouding, if you mill the head enough you can get over 11:1 no sweat.
 

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Discussion Starter · #10 ·
Another Option?

Bob,
Do you know if the 1.6 CIH engine offered in the Vauxhall Cavalier is identical to the Opel 1.6 CIH? Did they have the same engine options (1.6S & 1.6N) as the Opel line? My thought is that the engines were probably the same, but I don't know for sure.

Thank you,
Darrin
 

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rallye73 said:
Bob,
Do you know if the 1.6 CIH engine offered in the Vauxhall Cavalier is identical to the Opel 1.6 CIH? Did they have the same engine options (1.6S & 1.6N) as the Opel line? My thought is that the engines were probably the same, but I don't know for sure.

Thank you,
Darrin
Well, if in fact it's a CIH engine in the Vauxhaul, it'll be the same. Otherwise all bets are off. I can't say that I know if Opel/Vauxhaul were crossing over drivelines at that point.

Bob
 

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Vauxhall/Opel

Vauxhall Cavaliers used the CIH Opel engine till 1981 and Vauxhall Carltons right up till 1988. These were Opel produced Cam-In-Head motors in varrious sizes. 1.3 (I think) and 1.5 ; 1.6 ; 1.8 ; 1.9 ; 2.0 ; 2.2 and 2.4 litres (I know).

The advantage of Vauxhall is that the owners usually speak fair to middling English.
 

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Discussion Starter · #13 ·
@#%$&!

Great News! I received the NOS 1.6 head today :D
Bad News! UPS had dropped it :eek:

Does anybody have any idea of the value of an NOS 1.6S head? I need to file a claim with UPS. When it was dropped, one of the front bolt holes that seals the head to the timing cover partially collapsed. I intend to drop it off at the machine shop tomorrow and see if they redrill the hole and how much the head will need to be milled to make it flat.

Bob, how much would you "estimate" would need to be removed from a short plug head (it has a 1980 casting date). to reach a CR of 10.5 after the valves are unshrouded on a 2.0 shortblock. I know there are a multitude of variables here. Just looking for a rough estimate to let me know if I have a fancy boat anchor after I hear from the machine shop.

Darrin
 

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rallye73 said:
Bob, how much would you "estimate" would need to be removed from a short plug head (it has a 1980 casting date). to reach a CR of 10.5 after the valves are unshrouded on a 2.0 shortblock. I know there are a multitude of variables here. Darrin
You should be at about 10.3:1 'as is'. Depending on the amount of material removed for unshrouding, you might have to remove .020" or so. Of course the only way to truly know is to measure the chamber volume and calculate the compression.

Bob
 
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