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Opel Rallier since 1977
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All good questions. I'll take a stab at answering.
  1. The Euro cam duration specs are taken seat-to-seat; i.e., at the crank angles where the valve leaves and then returns to the valve seat. This is a hard parameter to measure, as what constitutes 'on the seat'? Is it .001" lift from the seat or .0001" from the seat or what? Many of the cam profiles have such super sloooow lift rates off the seat that the measurements become highly variable and very vague. And, since it is a value that is hard to make any use of when 'designing' in a cam, it is of limited use.
  2. The standard duration measurements in the US are advertised duration and duration at .050" lift at the lifter. The advertised duration is measured at a specified lifter lift, and is typically .005" or .006" lift for most US manufacturers.
  3. The duration numbers for the OGTS cams (some of which are based on the old Isky grinds) are advertised durations.. or at least something close to that; they are definitely not the durations at .050" lift. 2 of these numbers these numbers (for the 256 and 268 durations) are the same identical duration numbers that are in the 1974 Isky catalog for their solid grinds for the Opel 1.9L. But, as has been explained in the other thread I made, these durations may or may not apply exactly when Isky changes the grind to that for the same cam in a hydraulic grind. This gets further complicated by the fact that at the time when these were designed ( in the late 1960's), Isky was not using the .006" lift method when measuring advertised duration. Isky was using lifts like .010" or .012" (these numbers are vague to me) at that time for measuring advertised duration on hydraulic cams, which gives shorter advertised durations than for the .006" lift method.
  4. As for the cam card that you received, the .050" lift duration is pretty clear. But the other larger duration is not. There is too small a degree difference between the .050" lift and the 'other' duration number for even the most aggressive hydraulic lifter cam. So this duration is probably being checked at something like .010" lift at the lifter... or maybe .015" or .018" lift? Who knows? I really do NOT trust that cam card at all. The only way to know what you really have for 'advertised' duration is to actually measure this cam and get the true numbers; that duration has a direct bearing on your situation, as advertised duration is the best number to use to predict low RPM torque.
Yeah, I know... not a definite answer. But that is what we are dealing with in this Opel CIH cam world at this time in history. IMHO, we are really going to have to get a better library of cam profiles to know what we have. The .050" numbers are all we have that is pretty consistent but the advertised duration numbers are 'squishy' to none.

Now as a guess as to what your actual advertised duration was for the original 2.2L cam.... we can work off the relative difference of the Euro duration (seat-to-seat) to measured advertised duration for a stock 1.9L cam and apply that to the Euro duration of 285. But that ends up with an estimated advertised duration of somewhere around 235 degrees; that is possible for a stock American V8 but I have my doubts that it is accurate for an Opel cam. So again, we are just purely guessing without measuring, and I don't think that does you much good.

So do you have that old 2.2L cam? If so, ship it here and I'll measure it. That is the only way I can see to get useful comparative data.
 

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Opeler
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Discussion Starter #222 (Edited)
Yeah, I know... not a definite answer. But that is what we are dealing with in this Opel CIH cam world at this time in history. IMHO, we are really going to have to get a better library of cam profiles to know what we

Now as a guess as to what your actual advertised duration was for the original 2.2L cam.... we can work off the relative difference of the Euro duration (seat-to-seat) to measured advertised duration for a stock 1.9L cam and apply that to the Euro duration of 285. But that ends up with an estimated advertised duration of somewhere around 235 degrees; that is possible for a stock American V8 but I have my doubts that it is accurate for an Opel cam. So again, we are just purely guessing without measuring, and I don't think that does you much good.

So do you have that old 2.2L cam? If so, ship it here and I'll measure it. That is the only way I can see to get useful comparative data.
Unfortunately, I do not have the original 2.2 stock cam. It had a cracked lobe (or maybe 2) and I didn’t see any value in it. I am hopeful that someone on here or somewhere may have a stock 2.2 cam that can be measured, because I am very curious what it is. It’s a true torque producer, that much I know.
 

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Opel Rallier since 1977
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Unfortunately, I do not have the original 2.2 stock cam. It had a cracked lobe (or maybe 2) and I didn’t see any value in it. I am hopeful that someone on here or somewhere may have a stock 2.2 cam that can be measured, because I am very curious what it is. It’s a true torque producer, that much I know.
With the smaller duration number, even if it is seat-to-seat, it points in that direction. But it is always a case of the 'devil is in the details'. Example: I recently checked out an old Norris cam here, and if one was to guess on advertised duration based on the seat-to-seat from that Norris cam and the typical Isky or stock Opel cam ramps down at the low lifts, you would end up way off on the advertised duration number. If you get the advertised duration wrong, then any computation of dynamic compression ratios and cranking compression (both of which are good indicators of low RPM torque) are going to be significantly in error.
 

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Just Some Dude in Jersey
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Dude, grab the baton, call or message Charles or RallyBob, join Facebook, I can't be your info and parts fetcher. Facebook is where all the Opelers are. Period. My Group is the modifiers forum, YOUR forum, and it has 1000 members. If you want Opel parts and info, that's the place to go. No offense intended here. Look at how many people respond to your threads regularly. 5-10. If you had started your quest on Facebook you would have been done months ago. :)
 

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Opeler
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Discussion Starter #229
Dude, grab the baton, call or message Charles or RallyBob, join Facebook, I can't be your info and parts fetcher. Facebook is where all the Opelers are. Period. My Group is the modifiers forum, YOUR forum, and it has 1000 members. If you want Opel parts and info, that's the place to go. No offense intended here. Look at how many people respond to your threads regularly. 5-10. If you had started your quest on Facebook you would have been done months ago. :)
Thanks man. I sent a message. Appreciate it
 

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Opeler
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Discussion Starter #230
I pulled the tank out of my GT last night. The experience was less than fun, but not the worst. I can hear some things rattling around in there and some of the gas that came out was sticky....like on my garage floor and the towel stuck a bit when pulling it up. Weird.

Once I gave it a good overview today, it isn’t as bad as I thought it would have been. The inside looks pretty darn good, and the fuel sock is still in there. The outside has some surface rusting to it and the bottom fuel outlet fitting is pretty crusty & rusty. I’m going to take it to a shop to have it hot-tanked and repaired if necessary. I’m still debating what to do with some necessary changed when going to EFI...just fuel return fitting installed or an in-tank pump, which would include a return.

Here are pictures of the tank...

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Eric
 

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That looks mint!
 
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Dude, grab the baton, call or message Charles or RallyBob, join Facebook, I can't be your info and parts fetcher. Facebook is where all the Opelers are. Period. My Group is the modifiers forum, YOUR forum, and it has 1000 members. If you want Opel parts and info, that's the place to go. No offense intended here. Look at how many people respond to your threads regularly. 5-10. If you had started your quest on Facebook you would have been done months ago. :)
When you get a minute, I have some questions about my Manta.
 

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The tank looks very nice 🤙🏼
One thing I would do if I ever remove my tank for restoration (and I like the idea of the in tank fuel pump also), is to drill out the upper passenger vent completely for the charcoal canister for a return line in case I convert over to FI. I don’t see why you wouldn’t, I suppose they made the hole small so fuel wouldn’t come out from the tank? I can’t think of any other reason for the restriction
 

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Opeler
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Discussion Starter #235
Well, I just finished up a freshening up of my gas tank. I took it to a shop and had them hot tank it, look for leaks, and make any repairs needed. Inside looked good, no leaks were found, but I had to have a threaded bung put in it because the old outlet was rusted really bad. They also added another one on the back passenger upper corner for clean out purposes.

Once I got it back, it looked like this:
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Then I took a wire brush to it to clean it up and finish taking off some of the surface rust on the backside flange. After that, it looked like this:

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Today, I wanted to finish it up with some new paint. First I applied a self etching primer:
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Opeler
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Discussion Starter #236
To finish it all up, I applied a couple of coats of finish paint. I personally have never cared for the deep black abyss of the back of the GT, so I decided to take the tank in another color direction other than black. I know many may not like this, but I think this looks clean and like a brand new modern tank.

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Looks beautiful!
 
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Tank looks good, I wanted to share this info. on a connector for your tank line.
 

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RunOpel
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That tank really cleaned up nice and the paint looks super :)
 

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Opel Rallier since 1977
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and some of the gas that came out was sticky....like on my garage floor and the towel stuck a bit when pulling it up. Weird.
Actually not weird. That 'sticky stuph' is ethanol that was in the fuel that naturally separated out and settled to the bottom, and then absorbed water. That ethanol/water mix will form a sticky gum that will mess up the whole system, especialy in a carb. Once it gets to this state, it will never 're-dissolve' and so that is why old fuel should be pulled and dumped; mixing in new fuel does no good to fix this gum once it forms. Using a fuel stablizer will help some. but the real cure is to stop using ethanol fuel for a car that sits for more than few months. It only takes a few months for the ethanol to start to separate out if the fuel is untreated; treatment will extend that time some.

And even if ethanol fuel is not used, then there will still be oxidation of the fuel... it will turn more and more yellow and start to smell more and more acrid and 'varnish-y'. Fuel stablizer is supposed to prevent this for a year minimum but even that will not stop fuel from oxidizing forever.

All that time of your car sitting allowed all of this to happen. I have a couple of cars that rarely get run, and they get the fuel sucked out of the tank and system every year or so. And our snowmobiles get most of the fuel sucked out at the end of each winter, and fresh fuel with stablizer put in for the spring/summer/fall.

Tank looks nice!
 
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