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RunOpel
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929 Posts
That's what I thought. This is a job that is on my to do list. This will be uncharted territory for me. Is it hard to remove the calipers? My goal is to completely restore the brake components.
 

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Can Opeler
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3,207 Posts
Didn’t work on any of my Opels today, but I did dig out my ZF 5-speed from long time storage. It will finally be going home to NH for good!

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If You ever decide to not use that 5 speed in the future I’d happily buy it and install it the second I get it.
I’d have to improve my sound deadening a bit, but close ratio strait cut gears would be so fun.
 

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Super Moderator
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13,225 Posts
If You ever decide to not use that 5 speed in the future I’d happily buy it and install it the second I get it.
I’d have to improve my sound deadening a bit, but close ratio strait cut gears would be so fun.
No extra sound deadening needed. The ZF’s do not have straight cut gears. They were an OEM option if you recall. They are the only ‘aftermarket’ 5-speeds that are direct fit. Shifter comes out in the stock location, and they use the OEM automatic driveshaft from the model vehicle they are fitted to. No custom parts needed.

Too bad they are $3500-$7500 these days.
 

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Opel Rallier since 1977
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1,217 Posts
If You ever decide to not use that 5 speed in the future I’d happily buy it and install it the second I get it.
I’d have to improve my sound deadening a bit, but close ratio strait cut gears would be so fun.
Well if it does not have the deafening sounds of a racing/rally trannie with the straight cut gears, what the heck good is it? LOL
 

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Opel Rallier since 1977
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1,217 Posts
Doing the last steps on the present new engine:
  • Checking piston-valve clearance.... juuuust enough. The edge of the 2.0L intake valve came very close to the eyebrow edge. but plenty of room to the bottom of the eyebrow.
  • Confirming piston-head clearance..... running reeeely tight on this one.... right at .028" over on the quench side! Never have run it that tight; some of the local circle-trackers will push down to .025" from time to time. So we'll see....
  • Timing cam.... came right in at 107.5-108 ICL on a simple OR-4H cam. Good enough.
  • Piston clearance where milled over on the spark plug side clears.
Just about time for a head gasket and button this puppy up!
 

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Super Moderator
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Confirming piston-head clearance..... running reeeely tight on this one.... right at .028" over on the quench side! Never have run it that tight; some of the local circle-trackers will push down to .025" from time to time. So we'll see....
If it makes you feel any better, one of the best running Opel engines I've ever built and raced had the forged pistons .015” above deck with a .032” thick (compressed) head gasket.

The pistons never touched the head, but you could clearly see the combustion chamber carbon pattern on the piston top!
 

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Opeler
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3,594 Posts
If it makes you feel any better, one of the best running Opel engines I've ever built and raced had the forged pistons .015” above deck with a .032” thick (compressed) head gasket.
The pistons never touched the head, but you could clearly see the combustion chamber carbon pattern on the piston top!
That supports the theory that when the piston is below the block deck, the combustion force is wasted because it is pushing the sides of cylinder. When the piston is sticking above the deck, almost all combustion force is pushing the piston rather than being wasted pushing the cylinder.
Following the same logic, flat pistons contribute to the engine power, rather than dished pistons.
 

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Opel Rallier since 1977
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1,217 Posts
The gas pressure exerts equal pressure all around. For a given cylinder pressure, the force on the piston is the piston area times the pressure.... regardless of whether the walls see any of that same pressure or not. None of the pressure is 'wasted'. Edit to add: And the only mechnical energy that goes anywhere is via the piston because 'work' (energy consumption) is force moving something; since the cylinder walls never move, no mechanical work/energy is consumed in the walls.

Pistons being above deck just contributes to higher static and dynamic compression ratios... which raises overall cylinder pressures and temperatures... which raises force on the piston, which raises torque/HP.

Thanks Bob... .017" is tightest piston-to-head gap I have ever heard of.. wow! I like quench/squish effect and my experience is that it is a real help in fighting detonation.. but no objective numbers to back that up, just general observations with higher CR's and the end results. The good part is that it occurs to some extent in all these closed CIH chambers and the commonly available pistons.

BTW, this engine is going to have a true static CR of 9.3-9.4 with a .040" Felpro head gaskets, as opposed to the true SCR of around 8.7 for the typical flat-tops. I'd sorta like to be nearer to 10:1 but these pistons needed a good home, and are what they are. The head and deck were shaved a combination of around .020-.025" to get to a fine surface RA (surface finish) in case I wanted to used the Cometic MLS head gasket.
 

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Opel Rallier since 1977
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1,217 Posts
Engine getting painted today. Rather than going to the auto parts store for black engine paint, it is gonna be Chrysler Red, since I have some of that around! I have enough black for the valve cover. I've done Chevy Orange and Ford Blue in the past with silver valve covers, so I don't seem to be able to get this right anyway LOL. This Chrysler Red won't look so great in a yellow car but what the hey!
 

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Registered
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1,666 Posts
Engine getting painted today. Rather than going to the auto parts store for black engine paint, it is gonna be Chrysler Red, since I have some of that around! I have enough black for the valve cover. I've done Chevy Orange and Ford Blue in the past with silver valve covers, so I don't seem to be able to get this right anyway LOL. This Chrysler Red won't look so great in a yellow car but what the hey!
I'm voting for an all black engine in yellow car !
 

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Opel Rallier since 1977
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1,217 Posts
I am with you man! That is a righteous color combination. But I thought I'd maintain my self-isolation discipline and use what I had.

If I post pix, I'll precede it with a warning for viewers to put on their eye protection LOL
 

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RunOpel
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929 Posts
That's beautiful Vincent and Manta Rallier your color combo will look awesome :)
 

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Opel Rallier since 1977
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1,217 Posts
Either that or hideous....LOL

Primed the engine today.... got pressure..... but no oil was going into the head. Stopped the drill 30-40 seconds later and heard the old 'oil pissing on the floor' sound. The pump is good... it very efficiently pumped all the oil out the back of the main oil gallery! Those stinkin' machine shop guys... they cleaned the oil gallery and did not put the plug back in. It's not my job to check on that, is it? :p LOL
 

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37 Posts
Had leisurely weekend of putting my car back together. New rear end installed (Thanks, Keith!), front end completely rebuilt and the car back on the floor.

Driveshaft is supposed to be done tomorrow. Then all I need is my flywheel back from the machine shop and we'll be jamming gears.



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Found that #17 magnet in a box of parts. Couldn't resist. Haha
 

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RunOpel
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929 Posts
Very nice looking NC-K9 :) And Manta Rallier, as funny as it sounds, its NOT. But at least you know what the problem is :)
 

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Super Moderator
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13,225 Posts
Mark,
There's is a poly bushing on the front. I was gonna run heim joints in the front too, but I figured it would be a harsher ride.
That’s my preferred methodology for a street car too. The urethane isolates well, but the heim joint at the rear improves articulation over bumps.
 

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Can Opeler
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3,207 Posts
My rear trailing arms are helm joints on both sides. It is a bit harsher (not enough to write about), but more than anything it transfers more axle noise to the cabin.
 

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Opel Rallier since 1977
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1,217 Posts
Good deal NC; IMHO that is a wise things to do. Yeah as a rallier, I am super concsious of what damage shocks can do.

There have been any number of ralliers who have tried running things lke solid top strut bushings... most of them fail from the shocks. It only takes one good hit. I owned/ran a big US rally in WV for a few years. On one stage, there was a washout straight across the narrow road on a downhill section; it was cautioned in the routebook and in the stage notes. One of the early Subie's did not slow down... busted out both solid strut tops right there. Their rally was over.
 
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