1972 GT Factory High Compression engine?

[Gumby]

I finally got around to checking the engine numbers on the block today while I was doing some minor work on my GT.

Here is the picture of the numbers.


As I understand it the asterix at the beginning and ending of the numbers indicates that it is a high compression engine.

What baffles me is that I thought only 68-71 GTs had a high compression engine in them. I'm sure some of you may be thinking that well the previous owner must have replaced the engine with that one. I got this car from the original owner, who stated he had never had the engine replaced or rebuilt. This car has an interesting story, which might account for the engine being what it is.

The car was originally ordered in Portland, Oregon. The buyer cancelled the order and so the dealer was left with this car already built sitting over in Germany. Fred who eventually purchased this car shortly afterwards, flew to Germany to get it. He and his wife drove it around Europe while they were there and eventually had to shipped back to the US. Fred remembered that it was around Valentines Day that they were in Europe, so it would have been an early 72 GT. Fred stated the car was originally intended as a US spec GT, so I would think it should have been like any other 72 GT. I haven't checked to see if it has the sway bars on it (I'd be in heaven if it did) like all the Europe spec GTs did.

I have complete service records of this vehicle since it was purchased back in 72, I'll have to double check though them but I doubt I will find anything about replacing the engine. The engine has 168,XXX miles on it and is still running strong. The original owner took excellent care of the car.

Have anyone here seen a 72 GT with a factory high compression engine?

[Anonymous D]

European-manufactured Opels,
did have the higher-compression
engines installed in them after 1971.

As far as current performance expectations,
whether an engine originally came with
the 9.0 compression ratio pistons,
is a part of what it will do. Some heavily worn
9.0 ratio engines, will be outperformed
by low-mileage 7.6 ratio engines.

Therefore, it's more important, to do
a compression test (correctly) and determine
what the engine output actually is.

A guide to doing a compression test,
is available in the "Tune Up" tip pages
at Opel Motorsports Club

[2 Fast 4 U]

Originally Posted by Gumby ...As I understand it the asterix at the beginning and ending of the numbers indicates that it is a high compression engine.

Nope, that is only for not adding anything more to the engine number.
The "S" behind the 19 indicates that the engine has a high compression, for the European market there were 2 types of engines the "N" engines and the "S" engines. The "N" engines had a low compression and used low octane gas and the "S" engines had a high compression and used high octane gas

[hallgeir]

Had a look in the 68-73 Opel and GT parts book, and it says:

PISTONS
69-70 All GT (1.9 Engine)................623441.......PISTON, w/rings & pin (std.)

71 All GT (1.9 Engine)
from eng. No
19S-556000 to 19S-767444....623464.......PISTON, w/rings & pin (std.)

71-73 All GT (1.9 Engine)
from eng. No
19S-767445.........................623507......PISTON, w/rings & pin (std.)

As I understands it, the low comp engine has different pistons, so I would think they started at engine No. 19S-767445.

[GTJIM]

In a rather large sample of engine numbers some time ago it became apparent that an engine number with * # * was originally a hi-compression motor and with just one * was originally lo-compression.

My GT was assembled 24.04.1972 and originally had engine number *19S 0940070 and was lo-compression till the original owner had the dealer replace the pistons with flat top ones and a Weber 32/36 DGEV install to increase power soon after purchase (it is an automatic - so really needed them)

Your motor is considerably prior to this - around 35,000 motors so may just have been one of the last factory hi-compression motors.

What is the VIN Number of your car? Could you check to see if your motor has flat top pistons - by looking in through the spark plug holes with a bore light for a rifle? We are looking for the transition point engine number from high to low compression.

[Gumby]

If I get some fair weather later on this week I will take a look to see if it has high compression pistons or not.

I'm a little confused, there seems to be conflicting information regarding what numbers actually indicate a high compression engine.

[GTJIM]

Originally Posted by Gumby I'm a little confused, there seems to be conflicting information regarding what numbers actually indicate a high compression engine.

Some of us think Opel does it on purpose - to keep us guessing!

[George]

I'd think the only way to tell for sure if its high or low compression is to look at the piston top as the high or low compression will both fit in the same block.

[Gumby]

Or run a compression test...I'll have to take the spark plug out either way.

[Gumby]

Sorry this took so long! Between work and bad weather the Opel didn't get the attention she needed. BUT I have managed to get the head off as of last night.

I'll get pictures of it later before I put it back together but it had flat pistons!!!!! A factory high compression 72 Opel GT, something that I think is an awesome peice of history.

So yes this is one more engine that has the two stars at the beginning and end of the serial number on the engine block and is a high compression model. I think you guys might be on to something!

[Gumby]

I doubled checked the stack of papers the original owner gave me, he said it was the complete maintenance records for the car. The pistons and head were never replaced; at least nothing was detailed in the receipts. It has 168,xxx original miles on the engine. It has a 10 bolt style head but it has hydraulic lifters in it, which I find to be curious.

Has anyone else ever encountered an engine like this?

GTJIM: did you still want to know the vin number for the vehicle?

[nobody]

The double asterick motors ended in 70 and even if the distributor did the flat top upgrade they never changed the motor numbers. ONLY and only if you are the original owner can you verify motor numbers......my 74 wagon has flat tops and a 3 bearing head, but I know by looking at it that it isn't original. Even little old ladies that only drove it on the sunday will tell you stories.

[GTJIM]

Originally Posted by Gumby GTJIM: did you still want to know the vin number for the vehicle?

I am still collecting numbers as there is continuing uncertainty about the Hi-Lo compression transition date.

It is always quite possible that Opel installed numerous Hi-comp motors in GTs bound for the U.S.A. after the cut-off date due simply to logistics.

Scenario:
There is a ship to be loaded in Hamburg with GTs US bound and a week before hand Opel is making Euro Hi-comp motors ... there are dozens of these left over at the end of the Euro production run and the fresh supply of Lo-comp motors has not reached the assembly line. Further,it is nightshift on Friday and the Production Manager has been told he must have twenty GTs ready for transfer to Hamburg to meet the ship .....
wink, nuddge & say no more!

[Dan-MI]

I've seen in a couple threads that engine blocks with an * on either end of the block number indicate a high compression engine. I've got a 72 that I bought from the original owner. He did not do an engine swap. My engine has the two asterisks on it. How can this be unless the double asterisk doesn't really mean high compression. I thought 71 ushered in the era of low compression engines. I've not had the head off so I don't know what the pistons look like. Since it has the oringinal sickly Solex on it still (and it is sick - no choke for instance), it runs fine, but it's not real fast. I also checked the Opel Club site. They have a list of difference between model years. My 72 has only some of the differences that they say the 72s had. So I'm guessing it must be an early one, using up some old parts. But I'm curious about the double asterisks.

[nobody]

I just pulled the head off of a 74 motor that was supposed to be original. I'm pretty sure those 40 over flat tops and the finned pan weren't stock in 74. Was the original owner a little old lady that only drove it to church? Did you get the original title that the car was sold with? Basicly don't believe it until you see proof.

[jvandyke]

Originally Posted by Dan-MI But I'm curious about the double asterisks.

Pull a plug and have a peek.

[MICAH1]

I have a 1973 engine and will need to check the compression, but are we sure about these marking that indicate high and lower compression engines??? Check out the photo.