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Discussion Starter · #1 ·
Now, I know it's really hard to get an opinion out of a car enthusiast, but I figured I'd try.:lmao:
I want to get my 73 GT running as is, but I also want to build a nice but low budget extra engine to drop in next winter. I'd like to get the car running with the stock engine for this spring, so the wife can drive it and we can maybe show it around a little.

What's a good way to go about finding a reasonable quality and priced 1.9 liter engine? Are any of the larger displacement engines a direct drop in replacement for the 1.9? Are any of those a better performance option in the 'bang fer the buck' category?

I'm just itching to tweak a set of manifolds and a head ala RallyBob's suggestions, and I want to experiment with quad mikuni carbs, too.

To hijack my own thread, how easy is it to tune a Weber for high altitude use? I live just below 6000 feet and frequently drive over 11,000 foot passes here in Colorado.

Now, if anyone out there actually *has* an opinion about any of this, let er rip. :)
 

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I vote build the second motor. There are usually one or two engines available on the Ad Board on this forum. Also Opel GT Sourse has many options to start with.
 

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Discussion Starter · #4 ·
Lindsay- I actually cut and pasted the suggestions in that thread and made a text document that I saved. RallyBob's expertise is just amazing. I guess I'll just keep an eye on the ad board here- and start haunting local junk and salvage yards.
 

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There a already rebuilt 1.9 that's the last reminant of the Opel Stash in Atlanta thread. Dr. Collins wants $1000 for it. It's not a short block assembly, it's a long block. Just add your alt, water pump, starter, intake/carb/exhaust and drop in....
 

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What's a good way to go about finding a reasonable quality and priced 1.9 liter engine?
Step one is researching and defining practical goals. Certain model types and years of Opel heads and blocks are better suited for either "drop in" use or performance rebuilds. Once you have identified what you want and what are the critical procedures to evaluate each of the various designs of Opel 1.9L engines, then your browsing through the local yards or local ads will be more productive.

Are any of the larger displacement engines a direct drop in replacement for the 1.9? Are any of those a better performance option in the 'bang fer the buck' category?
All of the larger Opel engines require modifications for installation, although in the case of most 2.0L's it's not as involved (only an electric fuel pump if you retain the carburetor). Consideration of non-Opel parts or engines widens the field of prospects, but can introduce additional complications.

I'm just itching to tweak a set of manifolds and a head ala RallyBob's suggestions, and I want to experiment with quad mikuni carbs, too.
Definitely start with research, then go from there.
 

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It depends on what your looking for HP

I would personally rather build an engine myself than buy an already rebuilt one. You just never know what went into it....the threads on this site will give you many ideas on how to gain a few ponies here an there at a very low do it yourself price. If your talking sidedrafts or minuki's be prepared to dump serious cash into a motor to make those add ons worth the effort. HP just aint cheap....and it doesnt come from one specific area...its a multitude of different things. Good luck...
Joe
 

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"What's a good way to go about finding a reasonable quality and priced 1.9 liter engine?"


If it hasn't already been sold, there is a rebuilt 1.9 engine, complete with clutch and T-5 5 speed for sale on the ad board here. $700.
 

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Discussion Starter · #10 ·
Well, as yellaopelgt points out, I want to rebuild it myself. What I really want is either a stock 1.9 engine from a 73 gt (or whatever), or to find a heap of parts; 73 smog intake, rally exhaust, good used block, etc. I want to eventually build a 9 or 9.5:1 compression, torque cam, very streetable engine with some good pep.

Actually, since I *have*a '73 smog intake, I would like to start with an intake that will fit my existing engine. That way, I can do some mild porting and polishing, install it, and then have the 73 manifold to really work over carefully.

I'm not in a hurry, (my budget won't let me hurry), but I wanted to sort of get a community consensus on a good way to go about doing this.

I ♥ this forum. :yup:
 

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The 1973 model-year cylinder head is noted for being more vulnerable to warping and developing cracks when overheated. Later-year Opel 1.9L blocks (after serial number #1103265) also were originally outfitted with weaker rods which are not suitable for high-performance use.

These are just a couple examples to illustrate why researching model-year differences in engine components is advocated (prior to making any purchase decisions).
 

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If you are ever in eastern PA, I have a complete engine you can have. It does not spin so I don't know the condition. It even has the clutch assembly and bellhousing. It would need a complete rebuild, including degreasing.

One day I might break it open to see if I can get it to spin.

I have a high compression engine which does spin. I'm going to refresh(new gaskets) and place in my '72 GT with a low compression engine. It was going to be completed this year, but $$ got in the way. I want an electric hoist to lift/lower the engine since I'm usually out there by myself.
 

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Discussion Starter · #13 ·
Thanks, jlthunder. They'll probably be ice skating in hell before I ever get to PA. :no: I really appreciate it, though, (and if 'global warming' keeps going like it has, they'll be ice skating in hell for the 2012 olympics...) :haha:
 

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'D' makes some valid points. The scariest potential issues are with the later heads. We're talking about late 1972 through 1975 heads with 10 large head attachment bolts and 2 smaller attachment bolts at the front of the head.

These later heads were designed for use with unleaded gasoline, and have a slightly different metallurgy compared to the older heads. The exhaust seats were then flame-hardened to resist valve seat erosion due to the lack of lead as a lubricant. As a direct result, the greater hardness/brittleness of the seats was also responsible for a tendency for the heads to crack. Most prone would be #2 and #3 exhaust seats. If I had to make an educated guess, I'd say that 80% of the later model heads I've removed from core engines were cracked...they really are that bad! They do not tolerate being overheated at all. In general, Opels like to be kept below 195° F, with 210°-215° being the upper limit. As you near 220°-230°, the head's life is seriously at peril! Above that failure is virtually guaranteed.

For me, the best cylinder heads to choose from are the late 1970 through late 1972 heads. To clarify further, these are the heads with four camshaft bearings that are secured with 10 head bolts only. The four cam bearings allow for less camshaft deflection in a performance application, and the exhaust seats of the head were NOT flame hardened therefore the castings are more ductile (less prone to crack). For some reason, 1971 heads appear to be the best to modify for racing use. They are physically easier to port (cast iron material not as hard), and the port walls are usually somewhat thicker too (.220" to .240" usually).

Only slightly less desireable are the 1968-late 1970 heads with three camshaft bearings. They are perfectly adequate for almost any street performance buildup. They also have 10 head bolts, and have non-hardened exhaust seats. They just have three cam bearings. So they are best not used in an all-out racing application.

As a side note, the year of the timing cover being used *should* match the year of the cylinder head. The heights of the covers were different as were the head gasket designs.

For any of the heads without factory flame-hardened seats, I will usually have press-in hardened exhaust seats fitted to allow the use of unleaded fuels without accelerated wear. Try to keep the OD of the seat the same diameter as the valves being used, and do not make the seats deeper than 7/32" (.21875"). This is to preserve the overall integrity of the head casting.

As far as the blocks are concerned, there are some differences over the years. 1975 blocks are a different casting, and have the heater core feed line at the passenger rear side of the block (5/8" hose barb). Normally on the earlier blocks there is a drain plug at this location.

Early blocks (pre 1971) will not have all the bosses cast in for the various oil dipsticks Opel used over the years in various chassis. So you will be relegated to using an aluminum oil pan if you use an early block, since the steel oil pan versions have the dipstick hole cast directly into the block (or at least the bosses are present which can be drilled out). Early blocks also have *slightly* thinner webs at the main cap areas, and smaller main caps as well. I suspect if you were building a 400 hp turbo engine this could be of some concern, but again in normal applications it's nothing to worry yourself with.

If you decide on a 1971-1974 block, then you get the optional dipstick bosses cast into the block itself, the larger main webs, and the larger main caps. Any of the aforementioned blocks can readily accept a .040" overbore, and as long as there is no appreciable core shift....080" to .090" overbores are acceptable too. This would bring the displacement from 1897 cc's (93 mm x 69.8 mm) out to 1979 cc's (95 mm x 69.8 mm which is the factory Opel 2.0 litre displacement) or to 1989 cc's (3.75"/95.25 mm x 69.8 mm) which is a common size used when aftermarket forged pistons are fitted.

HTH,
Bob
 

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Discussion Starter · #16 ·
RallyBob- thanks for the detailed and extremely informative post. As soon as I get the time and weather, I will fix the electrical enough to use the starter to pull compression readings. That should tell me what shape the rings and heads are in, anyway.

I'll pull the valve cover to see what the head bolt pattern might be. I'm crossing my fingers- the carb has been swapped for an aftermarket (Holley 5200, the local experts think) and so maybe I'm going to luck out and find that a previous owner changed the head to a more desirable one.

One can only hope.:yup:

Thanks again, everyone.
 

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If you can see the edges of 2 bolts under the front edge of the valve cover it is a 12 bolt head. IIRC. Someone please correct me, if I am wrong.
 

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At the front corners of this later head, you can see the extra bolt holes (countersunk, for 8 mm allen-head type bolts). As previously mentioned, you can just see the edges poking out from under the valve cover.



A 10-bolt 1971 head. Note the more rounded front corners of the head, and lack of bolt holes there.

 

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Discussion Starter · #20 ·
Thanks for the photos, Bob. And the comments, Wrench and Rm.

Among my photos on this computer, I found a picture of the corner of the head that looks like it's pretty round. I'll have a closer look on my lunch break today, but this looks pretty promising...

I still plan to pull the cover so I can see how many cam bearings there are.

Now my wife says I have to build a garage to keep the car in. Did I ever tell you all how much I love this lady? :D
 

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