I hear ya. Yes, the spun rod does seem to point to lack of oil, yes, I plastigauged and measured oil clearance.

Maybe installing oil restrictors, still not sure. I do know that there have been a slew of camshafts getting ruined, pitted, grooved etc.

Unthreaded
 

Ran into an issue installing the clutch on the flywheel. The clutch mounting bolt holes on the flywheel are only partially threaded. I will probably just tap them the rest of the way. I think I will ask for a partial refund.

http://forums.pelicanparts.com/uploa...1751651160.jpg

The twin plug distributor cap adaptor is looking good. I’m still waiting for the cap and rotor to be delivered.

http://forums.pelicanparts.com/uploa...1751651402.jpg
http://forums.pelicanparts.com/uploa...1751651402.jpg

Update
 

Finally got the parts in I was waiting for to finish up the twin plug.

http://forums.pelicanparts.com/uploa...1753723486.jpg
http://forums.pelicanparts.com/uploa...1753723486.jpg
http://forums.pelicanparts.com/uploa...1753723486.jpg
http://forums.pelicanparts.com/uploa...1753723486.jpg
http://forums.pelicanparts.com/uploa...1753723486.jpg

While turning the engine over by hand I noticed some vibration, sticky rubbing when turning very slowly. The light lube I had given during assembly didn’t hang around for six weeks, so I planned to take the motor apart to lube everything again.

Then I decided that perhaps I could just fill the sump with fresh oil and turn the motor by hand, generate enough power to get the pump working. Well, it worked. I used three quarts of oil and it smoothed out immediately, and after three turns the spay bars started oozing oil.

http://forums.pelicanparts.com/uploa...1753724151.jpg
http://forums.pelicanparts.com/uploa...1753724151.jpg
http://forums.pelicanparts.com/uploa...1753724151.jpg

Moving forward with the installation.

Having built and run dozens of these types of twin plug conversion, we always come up with the same conclusion. The rotors are out of balance and present way too much load on the top shaft bushing. Porsche's resolution to this situation is a support bearing.
Below you have my solution.

http://forums.pelicanparts.com/uploa...1753725189.jpg

I should have expected that you would design something so strikingly similar to the Cloud City catwalk.

I was thinking I may be ok because of two things, my shaft is shorter because the adaptor adds only about 3/4” and that the top rotor track is such that it rides in the groove in the cap which keeps the rotor aligned.

I do see how I could fit a bearing and support though so I’ll probably do that. It looks like yours is a bolt on piece. Is it available as a separate piece?

When I posted that picture I misspoke. The distributor I posted was a development between Aaron Burnham and Supertec. Gen I.
Aaron may have some of those bearing plates.
Our Gen II distributor uses a slightly different design. Mounting and bearing plate incorporated in a single piece.

http://forums.pelicanparts.com/uploa...1753803032.jpg
http://forums.pelicanparts.com/uploa...1753803032.jpg

Thanks Henry. I will take your advice and figure out a similar solution.

Replacement electrical panel looks good. Are the switches to isolate and run just one ignition or the other?

Yes, they are for one or the other, for tuning and diagnosing. I don’t plan on running on one ignition. Initially I planned to use a single three position switch for upper, lower, or both but that got too complicated, so went with simple on/off switch for each.

It’s running very smooth. I’m pleased. I have a little more work to do before a road test and tuning.

http://forums.pelicanparts.com/uploa...1754275815.jpg
http://forums.pelicanparts.com/uploa...1754275815.jpg
http://forums.pelicanparts.com/uploa...1754275815.jpg

Took a quick shakedown drive. Running very rich but smooth. I left the jetting the same but changed the chokes to 40’s.

The timing is set at a basic curve no map set up yet.

PMO 46 on normal height manifolds/40 chokes/ F11 tubes/ 187 Fuel/ 187 Air/ 57 Idles.

12.3 at idle 950
11.4 through 2800
11.8 through 4500
12.2 - 12.6 through 6000

I think 40 chokes are right. I will go up to a 190 or a bit higher air.http://forums.pelicanparts.com/uploa...1754414730.jpg

Well, how does it feel?

My guess is that you can add 5 degrees more timing, all in by 3500.

I did add exactly 5 degrees. I have a vacuum curve too but turned it off for now. I dropped the fuel jets down to 175, still rich but getting closer.

Feels really good. Spins up effortlessly, really smooth all the way through. Good oil pressure and coolers are working great keeping the temps down, so I don’t have to worry about rpm temperature control. I think that the 40 chokes are going to be perfect, plenty of torque down low and it certainly isn’t lacking anything up top. I’m really hesitant about pushing it too hard, after the last build and the rod bearing incident, every little rattle, ping and tick has become amplified.

The twin plug is a game changer, the idle is as steady as I have ever heard, even dialed it down to 700 rpms and it doesn’t miss. I did switch between running both or top and bottom and there is a drop in rpm’s when switching from both to one, but no difference running the top or the bottom.

Much more tuning to do. I’m still working my day job full time and I can only afford about an hour on afternoon tuning drives in a 110 degree air fryer.

Took an evening tuning run and did three jet changes, I’m creeping up on the right blend.

I’m tuning from slightly rich and every change gained a few points towards perfection as evidenced by smoothness, torque and horsepower.

I’m sticking with the F11 Etubes, they have shown a repeatable steady progression from cruise to redline.

The AFR goal is 12.8 idle to redline. Thats never going to happen with carburetors. Rules are to finish at redline no leaner than 13.2.

Here’s where I’m at;

Fuel. Air. Light Cruise. Redline Finish.
175 190. 11.3 12.2
175. 200. 11.5 12.4
175. 205. 11.7 12.5
175. 210. 12.3. 12.7

So the next jet change is a 220 air. Stay tuned….

http://forums.pelicanparts.com/uploa...1754536385.jpg

That is golden information..

The engine bay looks soo good, very tidy.

Kudos

I didn't know they made a 12 plug 123 distributor. Neat.

This twin plug 123, is my adaptation of the 123 single plug into a twin plug distributor. AFAIK this is the first. There is a company in Germany that makes a twin plug distributor and uses two boards from 123 in a single housing.

Back to tuning……


F11’s ain’t going to work out. I went down the rabbit hole to the end and in I can’t get a decent light cruise AFR# without going way too lean at top end. I went all the way up to 260 airs and light cruise never leaned out above 11.8- 12.2 ish and would lean out to 14 at 5000 rpms, not good.

So now I have F7 and F2 tubes. And I am going to order some F3’s.

Congratulations! Glad to see that she's up and running. As someone who has yet to do the first start on a full rebuild / "while you're in there... / upgraded components - I cannot imagine your sense of relief and smile on your face when all is well at start up. Beautiful engine bay, wiring, and Targa. Please share more pics of car and engine bay. Love it. Patrick

Shane, I ran F3 then to a F7 and now I am running F24's.
Keep the up dates coming..

F24’s, that’s what they used in the 906.

I’m making progress, went down to a 55 idle jet, part throttle light cruise is at 13.4, which is nice. But now I have a couple of lean bumps during normal acceleration that I have to fill in. The lean gaps are between the idle to progression and progression as the mains are kicking in.

All of the sudden I remembered that the idle circuit gets tuned first, and that part throttle light cruise is 95% Idle circuit, 5% progression, and 0% main.

Going down this path myself albeit with far less success. Idle can influence AFRs up to 4500-5000RPM in light cruise. Did you move to F7? Think that brings main in sooner if leaning out bc of RPM alone (so gradual acceleration keeping out of fuel enrichment pump). Otherwise maybe fuel enrichment pump?

Half a turn on the accelerator pump shaft made the low end happy, the F7 made the transfer to the main happy but the WOT was off at 7k so now I am trying out the f24 which is made for mashing it out of corners.
I disagree on the steps now. On first set up start at idle and work up the RPM. For WOT tune with emulsion tubes and the clean up the bad RPM spots.
I am dealing with battery, dead fuel pump, dead starter right now so Friday I might have some more numbers for you..

Yes, F7. The lean spots are only with slow acceleration. The pump jets are doing well with rapid acceleration.

Yes, start up was nice. The twin plug is magical! I’m not sure if anyone else has ever used a 123 distributor with a CCW rotation to fire a twin plug but it’s working great for me.

I’m in the process of building a twin plug distributor using a Marelli body … will post some progress updates in another thread

That’s great! I look forward to following along.

PMO Circuit Contribution Chart with AFR plot.
 

I’m working on a chart showing a basic generalization of the circuits and the contribution throughout a slow acceleration without pump jet enrichment. I think that it’s close. The progression circuit is probably a bit too steep in the beginning, probably close.

http://forums.pelicanparts.com/uploa...1755052686.png

I'm having to come up the curve quicker than I'd like on carbs but I think of the idle and progression circuit as functionally the same circuit. Idle/progression blends into main ... where and how it blends, depends on:
- position of throttle valve vis-a-vis progression holes ... too exposed at idle and it brings in main circuit sooner (not your condition)
- size of idle air corrector (or maybe even idle jet) ... this could be it but I'd h have expected it deeper into RPMs. If it's too small, it may lean our idle/progression circuit at higher RPMs within the idle/progression circuit
- idle mixture screw ... if too far in to get idle AFRs acceptable, it leans out the air/fuel mix flowing through the progression holes which will bite right before mains takeover
- emulsion tube ... when it brings in mains as you described above.

I could have that all wrong but it is my best attempt at unpacking the theory.

I think the only way to clean up a lower rpm lean spot as progression is coming on is to use smaller chokes to increase the signal strength, or to richen the idle using bigger idle jets or adjusting the mix richer. I don’t think the main circuit contribution is significant at the lower rpm. Sacrifice a bit of fuel mileage to run smoothly. It’s about finding the balanced sweet spot.

It really is all about signal strength, I’m sure the 38’s you sent me would be an easy fix. I’m still trying the 40’s. Ian really believes the 42’s would be perfect.

Use what you have.. I am running 38's with a smaller cam and I pull to 7k now easily and have the 123 dizzy set for a 7200 cut out.
I ordered some F66 emulsion tubes to see what those run like?

Success.
 

Success. —— 46 PMO with 40 Chokes

57 idle jets, F11 Tubes, 185 Mains, 205 Airs.

Tuned to 13.4 AFR at 950 rpm idle, light part throttle cruise is 12.6 at 2900-3100 rpm, to 6800 rpm is 12.6.

This is a plug that’s been through all the tuning, it’s cleaning up nicely with the right tune.

http://forums.pelicanparts.com/uploa...1755462141.jpg

Congratulations! Got to be happy with that.

Curious what plug and heat range you’re running?

That's a good-looking spark plug.

Top plugs are NGK BPR8ES 14mm hole
Bottom plugs are NGK D8EA 12mm hole

Thanks Pete! That means a lot. I sent the picture to Ian and he said the same.

If it looked any better I could lick it! :p

I did, it was an unsweet, dry, light, charred mocha with a strong mineral finish. Not an hint of unburned fuel or a trace of oil. Exactly as expected.