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Resident Curmudgeon
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Discussion Starter · #41 ·
As cool and potentially fun, there would be a whole bunch of fuss and bother needed to make it reasonably streetable. The guys here who are suggesting that yes you can tune it to drivability are heavily into engine stuff and think it would actually be fun to make that dragon roar. But are YOU willing, at your point in life, to go dragon riding? It appears that the guy had enough knowledge to go pretty far with the project, with a custom dizzy, but then said he couldn't tune it for low speed driving. Are you willing to school yourself up enough to out do him?

How much money for this whole car and engine is a factor. Are you really just wanting to buy a nice 1900, but don't really want a fussy engine car, no matter how fast it is? If you're more comfortable with street designed Opel engines and just want an engine that works, take Kyler up on his offer. If the dollars work out.
The guy didn't do it himself. The engine was rebuilt by Foreign Affairs of Minneapolis using the parts that he brought to them. From the paperwork, they spent hours trying to make it run correctly after the rebuild was done, but came to the conclusion that the carbs were just too much for the motor. I know that the odds of me "out-schooling" them are zero.

I want a smooth running cruiser. As long as it can keep up on the highway, I'm good with it. I'm way too old and brittle to be racing!
 

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Pedal Smasher
1973 Opel GT
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If you want a good cruiser, drop a Getrag 240 5 speed in a GT. Charles Goin might still have one for sale.

I have a 2.0 in my GT that I know I won’t end up using but I can’t say much about how it runs. It definitely needs the carb either tuned or replaced so it will idle.
 

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Resident Curmudgeon
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Discussion Starter · #43 ·
If you want a good cruiser, drop a Getrag 240 5 speed in a GT. Charles Goin might still have one for sale.

I have a 2.0 in my GT that I know I won’t end up using but I can’t say much about how it runs. It definitely needs the carb either tuned or replaced so it will idle.
I had a GT with the 5 speed. It was nice, but it's easier for me to get in and out (especially out!) of a 1900 style. This Ascona has the 5 speed, although there's a pin that holds the linkage together that needs to get put back in place. Seems to be a bear to get to.
 

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Pedal Smasher
1973 Opel GT
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Oh, I forgot you're looking at an Ascona.

I'd say Kyler's engine could likely meet your wishes. I'd consider selling the engine currently in my GT, since I'll be building a 2.4. But I'm sure Kyler's engine is already dialed in, so there would be fewer headaches to deal with. You rarely see a dialed in engine for sale or trade.
 

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Discussion Starter · #45 ·
Now that I have the car and some paperwork, a few items of information that I got from the PO need to be corrected. The cylinders were bored to 3.6912, and the pistons measured at 3.6862. Also, the carburetors are the Italian Weber 40DCOE, not 45s. I know it has a hard time idling, but I have no idea how it runs out, since a pin is missing from the shifter linkage. PO did a temporary fix with some sort of bolt, and I have the pin, but getting the pin into place and putting an e-clip on it to hold it there is proving to be rather difficult since I am neither a contortionist or double jointed.
 

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Opeler
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Now that I have the car and some paperwork, a few items of information that I got from the PO need to be corrected. The cylinders were bored to 3.6912, and the pistons measured at 3.6862. Also, the carburetors are the Italian Weber 40DCOE, not 45s. I know it has a hard time idling, but I have no idea how it runs out, since a pin is missing from the shifter linkage. PO did a temporary fix with some sort of bolt, and I have the pin, but getting the pin into place and putting an e-clip on it to hold it there is proving to be rather difficult since I am neither a contortionist or double jointed.
So, you bought it?? Pictures please!
 

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Detritus Maximus
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That looks like a nice car. I really like the color, but I'm not sure that the engine color works with it.

Unless there is a problem with the carbs/motor causing your issue, I suspect most solutions will be engine out. If that is the case, milling the existing pistons (depending on the bottom side of the piston heads) may be the most reasonable cost-wise. This would avoid re-honing/reboring to fit a new set of pistons and a lot of labor tearing it all down. As long as the rods/pistons/rings/bearings do not get mixed up before reassembly.
 
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Yes, unless they are hollow domes (machined underside), you can mill off what you want to get to the desired compression ratio.
Bob, how much piston thickness is needed after milling? The following seems very similar to what the OP is asking.

One of the Calgary Opel Co-op guys (Jason Selby) has a similar "problem" with excessive compression ratio created by domed pistons. They are ostensibly 11.5:1. When I measured compression pressures, I saw between 190 and 200 psi. Yikes. The guage might be reading a bit high, so I am going to re-do with a new digital gauge. But it is not out by more then 15 psi based on a recent comparison on my engine. Atmospheric pressure here at 3000' ASL is at most 14 psi. I think the domed piston CR is more like 13.5:1. This is the engine I mentioned in a previous post that has suffered cam lobe and lifter failure. So it is coming out and apart for some kind of rebuild in any event.

The engine was built by a known Previous Owner, but much of the details are unknown to Jason. Gil Wesson is compiling a list of what the PO purchased through OGTS, but I suspect the pistons did not come from them. We have been told that the cam is an Isky OR66H (aka OGTS "Combo" Hydraulic) with 0.420" valve lift and 268 degree duration.

At present, the engine has a Weber 32/36DGEV, an OGTS header, and 2" exhaust. I believe it has 2.0 valves (waiting on Gil to confirm) but no significant intake modifications. I have suggested Jason install a surplus 38DGES that the Co-op has, and I have acquired a fair bit of experience in jetting one of those in my car.

Jason wants a "streetable" engine, but with decent power, say a bit over 100 HP. But of course he is restricted by a budget. I have suggested the following:

1) Mill the piston tops to reduce compression ratio. We can do that "in-house" as one of the co-op members has done that while building his RallyBob-stroker 2.4. Aiming for ~10:1 CR. De-glaze and install new rings (assuming the bores look OK, and they should be, as this engine has less than 5000 miles on it)

2) If piston milling isn't sufficient, install a thicker head gasket (or double head gasket?)

3) New hydraulic Combo cam and lifters

4) Modify the cam gear for a Comp Cams offset bushing. Several of us here are running the Combo Cam with the cam timing advanced 4 degrees, with quite good results.

So the questions I need answered, if you would be so kind:

1) What is the minimum piston top thickness to leave?

2) is a double head gasket viable if required?

3) if we can't get the CR down to under 11:1, what cam spec might you suggest? OGTS has some longer duration cams (such as their Max Comp, 0.430 lift and 284 degrees duration, but solid lifter only). Getting a cam custom ground is a bit problematic here, and likely won't fit Jason's budget.

4) Can cam timing be used to offset some of the dynamic CR? I am uncertain, but I think advancing the cam can do that. The Comp Cams bushing kit comes with 0, 2, 4, 6, and 8 degree bushings. We would "degree" the cam to confirm. Any suggestion as to what to start with, assuming the Combo Cam, and 11:1 static CR?

5) Any other suggestions or comments?

Thanks in advance.
 
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Resident Curmudgeon
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Discussion Starter · #51 ·
No if I rebuild one I’ll build it closer to your engine’s specs. Something about the 1.9L makes it have much more low end torque than my 2.0L despite having identical upgrades and carb tuning.
1.9L to 2.0 isn’t really worth it IMO. The OGTS pistons are really only 1.98L anyway

A 1.9E and 2.0E make 105HP and 110HP respectively. It pains me that I paid $2k plus for 5 extra horses in my other car. The single SSD gained me nearly 20HP for less money.
Kyler - Did you get my PMs?
 

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Just Some Dude in Jersey
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Bob, how much piston thickness is needed after milling? The following seems very similar to what the OP is asking.

One of the Calgary Opel Co-op guys (Jason Selby) has a similar "problem" with excessive compression ratio created by domed pistons. They are ostensibly 11.5:1. When I measured compression pressures, I saw between 190 and 200 psi. Yikes. The guage might be reading a bit high, so I am going to re-do with a new digital gauge. But it is not out by more then 15 psi based on a recent comparison on my engine. Atmospheric pressure here at 3000" ASL is at most 14 psi. I think the domed piston CR is more like 13.5:1. This is the engine I mentioned in a previous post that has suffered cam lobe and lifter failure. So it is coming out and apart for some kind of rebuild in any event.

The engine was built by a known Previous Owner, but much of the details are unknown to Jason. Gil Wesson is compiling a list of what the PO purchased through OGTS, but I suspect the pistons did not come from them. We have been told that the cam is an Isky OR66H (aka OGTS "Combo" Hydraulic) with 0.420" valve lift and 268 degree duration.

At present, the engine has a Weber 32/36DGEV, an OGTS header, and 2" exhaust. I believe it has 2.0 valves (waiting on Gil to confirm) but no significant intake modifications. I have suggested Jason install a surplus 38DGES that the Co-op has, and I have acquired a fair bit of experience in jetting one of those in my car.

Jason wants a "streetable" engine, but with decent power, say a bit over 100 HP. But of course he is restricted by a budget. I have suggested the following:

1) Mill the piston tops to reduce compression ratio. We can do that "in-house" as one of the co-op members has done that while building his RallyBob-stroker 2.4. Aiming for ~10:1 CR. De-glaze and install new rings (assuming the bores look OK, and they should be, as this engine has less than 5000 miles on it)

2) If piston milling isn't sufficient, install a thicker head gasket (or double head gasket?)

3) New hydraulic Combo cam and lifters

4) Modify the cam gear for a Comp Cams offset bushing. Several of us here are running the Combo Cam with the cam timing advanced 4 degrees, with quite good results.

So the questions I need answered, if you would be so kind:

1) What is the minimum piston top thickness to leave?

2) is a double head gasket viable if required?

3) if we can't get the CR down to under 11:1, what cam spec might you suggest? OGTS has some longer duration cams (such as their Max Comp, 0.430 lift and 284 degrees duration, but solid lifter only). Getting a cam custom ground is a bit problematic here, and likely won't fit Jason's budget.

4) Can cam timing be used to offset some of the dynamic CR? I am uncertain, but I think advancing the cam can do that. The Comp Cams bushing kit comes with 0, 2, 4, 6, and 8 degree bushings. We would "degree" the cam to confirm. Any suggestion as to what to start with, assuming the Combo Cam, and 11:1 static CR?

5) Any other suggestions or comments?

Thanks in advance.

Opelmel seems to be leaning towards the wise choice of handing the engine off to someone more hungry for HP and who is into taking apart and modding engines(Kyler). Kyler's offer seems to be the best path for him. Remove the radical engine with issues and install Kyler's known-good 2.0, which Mel is more comfortable with, and he'll be up and driving in no time.
 

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1) What is the minimum piston top thickness to leave?
.090” is considered the ‘ragged edge’ safe minimum thickness for a forged piston. I prefer .125” or so (about 3 mm)

2) is a double head gasket viable if required?

I wouldn’t! That’s just a good way to push out two gaskets at once.

3) if we can't get the CR down to under 11:1, what cam spec might you suggest? OGTS has some longer duration cams (such as their Max Comp, 0.430 lift and 284 degrees duration, but solid lifter only). Getting a cam custom ground is a bit problematic here, and likely won't fit Jason's budget.
A Max Comp cam is close to a perfect match to that kind of compression ratio.

4) Can cam timing be used to offset some of the dynamic CR? I am uncertain, but I think advancing the cam can do that. The Comp Cams bushing kit comes with 0, 2, 4, 6, and 8 degree bushings. We would "degree" the cam to confirm. Any suggestion as to what to start with, assuming the Combo Cam, and 11:1 static CR?
Retarding the camshaft will lower cylinder pressures (advancing it increases the cylinder pressures). But it will also hurt low end power and throttle response. It will however smooth the idle a bit.

5) Any other suggestions or comments?
Yet another thread showcasing it’s not all about the parts you throw at an engine, but rather choosing parts that compliment each other!
 
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Could you not just have Cometic make a thicker head gasket to drop .5-1 point of compression? May require an adjustable cam sprocket to retime the cam , but you wouldn't have to disassemble the bottom end. You could also swap to a less aggressive cam on the process.
 

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Op, if you do decide to sell or trade engines and there's one near each person, I've heard Fastenal offers relatively affordable location to location shipping if you secure it to a pallet. It's a way for them to make use of all space on their trucks.
 

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Can Opeler
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Hey guys I got back to Mel on this.

I’ve decided I just don’t have the time and money right now to take on this bad boy. My car just isn’t ready to use this much engine reliably on the street AND the track. And frankly don’t have the time or money to do it this year after researching what I’d want to do to it.

My little 67 Kadett is nickel and diming me a bit too much lately along with my new (to me) 1959 house lol.

This is engine darn near exactly what I’ve always wanted to build, it just has about 20% more compression.

One thing I was looking at but can’t afford was a custom head gasket. Has anyone tried that? If Mel could get one made that drops is compression to 9.5:1 or so he could put in a stock cam. Thoughts?
 

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Über Genius
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9,532 Posts
Hey guys I got back to Mel on this.

I’ve decided I just don’t have the time and money right now to take on this bad boy. My car just isn’t ready to use this much engine reliably on the street AND the track. And frankly don’t have the time or money to do it this year after researching what I’d want to do to it.

My little 67 Kadett is nickel and diming me a bit too much lately along with my new (to me) 1959 house lol.

This is engine darn near exactly what I’ve always wanted to build, it just has about 20% more compression.

One thing I was looking at but can’t afford was a custom head gasket. Has anyone tried that? If Mel could get one made that drops is compression to 9.5:1 or so he could put in a stock cam. Thoughts?
Your head gasket would have to be a quarter inch thick to get to 9.5 from 11.5
 
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Pedal Smasher
1973 Opel GT
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A change to the head gasket won't drop the CR enough. The gasket volume in calculating static CR only accounts for roughly 10% of the total chamber volume. It's not enough to make a 11.5:1 domed piston streetable.
 

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What about this as an option?
Book Font Publication Motor vehicle Newsprint

or this?
Photograph Publication Font Book Parallel


I had a mechanic over 25 years ago, granted on a GT, remove the crank & pistons underneath with the engine in the car, reworked (knurled two of pistons) and re honed #2 & 3 cylinder with the block in the car, he had to have #1 & #4 de glazed etc. Reworked the head and replaced the clutch.

I kept wondering why he didn’t just pull the engine?
I just retired that engine & clutch a few years ago.

I guess it might be too expensive to have it sent to a mechanic and wouldn’t be worth it unless you could do it yourself. It seems easier than removing everything in this case.

Just food for thought, since the rest of the engine seems to have very redeeming qualities.
 
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