Stupid questions thread.

[MonkeyNutZ]

What was changed throughout the years on the 1.9L engines? I have a 73 1.9L and was hoping to change to flat top pistons, but would I need a new cam shaft? Does anyone have info on the cams and heads?

Depending on the condition of my engine it would be cheaper to just buy a new running engine, what year would be best?

Sorry for the morass of questions, but I'm a bit irritated with the prospect of spending $3k on an engine rebuild only to realize I could've bought a running engine from a good year.

[GTJIM]

The '73 motor has a hydraulic cam and the earlier hi-compression ('flat top piston') motors from Kadetts and GTs 1969-70 use a solid lifter cam - but either cam could be used with flat-top pistons.

Finding a good running 1969-70 hi-compression motor is the trick! Unless it is out of a running car you simply do not know how good it is - that is why most people rebuild motors ... to know what they have.

The 1972 and later 12-bolt heads like you have on your '73 motor a generally regarded as most likely to crack if over-heated where-as the earlier 10-bolt heads seem to last better ... but still crack if badly over-heated.

Plenty of info on the heads and cams scattered through the site - more searching!

[markandson]

Originally Posted by MonkeyNutZ What was changed throughout the years on the 1.9L engines? I have a 73 1.9L and was hoping to change to flat top pistons, but would I need a new cam shaft? Does anyone have info on the cams and heads? Depending on the condition of my engine it would be cheaper to just buy a new running engine, what year would be best? Sorry for the morass of questions, but I'm a bit irritated with the prospect of spending $3k on an engine rebuild only to realize I could've bought a running engine from a good year.

Here is an interesting thread for you to check out

[MonkeyNutZ]

I'm looking to buy a 71-72 head, I'm going to use a better cam, valves and flat top 1.9L pistons. Any foreseeable problems with that? I've got a local shop that's going to be doing the rebuild.

Anyone got a spare 71 or 72 head? OGTS has a used 72 head but they haven't really looked it over for cracks, they want $125.

Thanks a bunch.

[MonkeyNutZ]

Moderate thread resurrection

I plan on painting my GT jade mist green, but I'm worried that doing a tan (buckskin?) interior would be next to impossible and that black would be a better choice.

Were all of the interior colors offered with off of the paint colors? As in, would a jade mist green car have a buckskin or black interior?


What interior color is this?

[First opel 1981]

What are the ramifications for connecting rods being installed backwards on the pistons?

I just put the pistons in the engine I am rebuilding and with the pistons oriented correctly, the notch on the bearing cap points toward the front of the engine, not the rear. The pistons don't have notches on them but the recesses for the valves are in the correct position.

Yes I am sure I am putting the bearing caps on properly and yes, I am sure the pistons are correctly aligned.

Will it cause any problems with the rod reversed?

[RallyBob]

Originally Posted by First opel 1981 What are the ramifications for connecting rods being installed backwards on the pistons? I just put the pistons in the engine I am rebuilding and with the pistons oriented correctly, the notch on the bearing cap points toward the front of the engine, not the rear. The pistons don't have notches on them but the recesses for the valves are in the correct position. Yes I am sure I am putting the bearing caps on properly and yes, I am sure the pistons are correctly aligned. Will it cause any problems with the rod reversed?

The oil holes in the rod beams are facing the wrong way. You will not get pressurized oil squirting under the piston, so the pins and skirts get reduced lubrication.

[First opel 1981]

Originally Posted by RallyBob The oil holes in the rod beams are facing the wrong way. You will not get pressurized oil squirting under the piston, so the pins and skirts get reduced lubrication.

How much reduced? I'm just getting frustrated with everything going wron on this rebuild.
Just finished torquing the bearing caps when I realized the issue. I was sooooo hoping to have this engine finished tonight.

[opelwasp]

Reduced enough that you will be rebuilding the engine much sooner than you'd like and you'll likely be 100 miles from nowhere.

Why risk it? It will be much more costly to replace later, so why not to it right?

[First opel 1981]

Originally Posted by opelwasp Reduced enough that you will be rebuilding the engine much sooner than you'd like and you'll likely be 100 miles from nowhere. Why risk it? It will be much more costly to replace later, so why not to it right?

I won't be risking it. I just needed to whine a little. It really seems like this engine is a Murphy original. I just have to remind myself that it is a 37 year old engine and its pretty lucky to have survived till now.

I guess this gives me a good reason to go buy a shop press too...

[RallyBob]

I think you run a higher risk of damaging the pistons trying to press off the pins and re-press them again.

FWIW, racing engines generally run NO oil holes in the rods, they rely on splash lubrication only. Opel added the oil spray to ensure 200,000+ mileage from these engines at autobahn speeds (remember the German origins!). You can probably drive at US-legal speed limits for 20 years without the oil spray. Maybe more.

Or if it really bothers you, you could drill the other side of the rods for the oil holes. The angle and location need to be the same, as well the rod bearings need a feed hole drilled. But it's another option.

[First opel 1981]

Hmmmmm, that redrilling sounds like fun as long as I have a bit small enough and strong enough. I don't think I do though.
The wrist pin is pretty tight. I already tried. I didn't have the right support for the piston though and think I need a shop to get the wrist pin done.

Luckily the piston wasn't damaged in the first attempt.

Decisions, decisions....

[RallyBob]

Originally Posted by First opel 1981 The wrist pin is pretty tight. I already tried. I didn't have the right support for the piston though and think I need a shop to get the wrist pin done. Luckily the piston wasn't damaged in the first attempt.

Usually a machine shop will install new pistons/pins onto the rods by heating the small end of the rod and freezing the pins. Then the difference in thermal expansion/contraction makes the pin install easy...you can fit them in by hand, no press required!

Removal of an existing pin from an assembly means you need a piston fixture as you've stated, because it's REAL easy to f**k up a piston otherwise!

[First opel 1981]

Well, after much consideration, examination of the connecting rods, the squirt holes, the wrist pins, a bungled attempt at pressing a pin out (luckily not damaging the piston, cost of machine shop....etc... I have decided to drill a new squirter and block off the old one. Blocking off the old one is now the only concern. Its a tapered hole so probably won't be an issue.
I will just drill the hole in 2 stages. The first stage will be with a larger bit than the squirter and stopping right before it goes through the rod. Then I will drill the last little bit with a 1/32 drill bit.

bottom line is this will be the best result with the smallest risk and least damage to the wallet.

Thanks all.

[jeff denton]

I suggest you take them to an engine shop and ask them to simply flip the rods for you.
We racers prefer not to re-use a piston that has been pressed on for pin removal, but for street use it happens all the time.
Alternatively I'd not be terribly afraid to run it backwards, for street use.

[First opel 1981]

Originally Posted by jeff denton I suggest you take them to an engine shop and ask them to simply flip the rods for you. We racers prefer not to re-use a piston that has been pressed on for pin removal, but for street use it happens all the time. Alternatively I'd not be terribly afraid to run it backwards, for street use.

"We racers"?
~L~
I'm assuming you mean those of us who like to head to a track as opposed to those of us who just like to teach a rice burner a lesson at a stoplight, right?

Anyhow, this is what I did.

I decided that since it was Saturday I would just redrill the squirters on the opposite side of the rods. I matched the angle of the hole and drilled a 1/8 hole 3/4 of the depth of the final hole. I then switched to a 1/16 bit and drilled it the rest of the way. I did it with a Dremel and managed to hit the angles within a degree or two.
Then I took some brass finish nails that were a little over 1/16" and drove them into the original holes. The heads were a tad larger than the 1/8 pilot hole as well so it was a tight fit. Then, for good measure I bent the tip of the brass nail over so it can't possibly wiggle loose and fall back into the bearing.

Finally I drilled the new hole in the bearings themselves. I used the 1/8" bit with the Dremel and then used a 1/4" bit as a deburring tool. I just spun the 1/4" bit with my fingers.

I'm confident that, though this wasn't the "proper" solution, it is one that will work for the normal life of an engine.....100K miles or so. I call it a custom modification now. ~LOL~

I probably won't ever think about it after the engine is fired.

[First opel 1981]

After looking through the GT wiring diagrams it looks like if the amp gauge is fried, it will wipe out all of the electric supplied to the entire car. Basically, nothing will work.

Is this correct?

[Redskinsjbs]

On the '73 Diagram it doesn't seem to be so. I think that it is a parrallel circuit to another supply circuit in the fuse box

[Redskinsjbs]

Here is a snapshot of the wiring diagram with only the wires in question in it.

http://farm4.static.flickr.com/3653/...de06fd.jpg?v=0

[First opel 1981]

Originally Posted by Redskinsjbs Here is a snapshot of the wiring diagram with only the wires in question in it. http://farm4.static.flickr.com/3653/...de06fd.jpg?v=0

That would work great but do you have it in a larger readable format?

I have a FSM but it's in the oven getting the moisture out. The wiring diag is in color but, as you know, there are lots of wire runs in the diag that cross and it gets a little confusing.

[Redskinsjbs]

Hows this?

[First opel 1981]

Originally Posted by Redskinsjbs Hows this?

ACK!! I'M BLIND!!!



Thanks. I think it answered the question.

I totally forgot about the stupid fusible link. I hope thats the problem. It would make life so much easier.

[opelwasp]

Originally Posted by First opel 1981 After looking through the GT wiring diagrams it looks like if the amp gauge is fried, it will wipe out all of the electric supplied to the entire car. Basically, nothing will work. Is this correct?

Yes if the AMP gauge is dead there will be no power from the alternator. Just had this problem. Modern cars no longer use AMP meters so why should we? I eliminated mine after the thing shorted out and caught the fuse box on fire as I was driving. Gonna get a volt meter instead.

[First opel 1981]

I checked today and it the problem is the fusible link.
Bypassed it with a test lead and everything works as designed.

Thanks for posting the HUGE wiring diagram. I would have missed it without a large one.

[First opel 1981]

Who created the one in the PDF above.

I would like to know if he would like input as to possible incorrect runs and other possible errors.

Just trying to help.

Thanks.