DDK - Die Deutschen Klassiker

Thanks for the great comments

Went for a short blast today in the sunshine, great fun.

Really at the start of the shake down process

Adjusted the clutch arms screws so it needs less pressure to operate. Also have a new 993 master cylinder to fit.

We changed the ignition switch wiring. Previously when you moved the key from ignition to activate the starter motor it turned the fuel pump off. Now it starts on first turn.

Managed to hopefully pin the slight hesitation when accelerating to one of the manifolds. The face is being skimmed so will sit flat on the gaskets and prevent air ingress, throttle hesitation and popping. Fingers crossed

Also hit a problem where the 964 oil thermostat to the remote oil cooler did not open. Given how hot it is even on a short run I would have though it should have opened up the secondary circuit. Still trying to workout what the issue is.

Re fitted the manifold with skimmed head, didn't make any difference, still slight hesitation as throttles are slightly opened to accelerate from steady speed. I have read as much info on the various sites but no firm conclusions, just lots of maybes. I have some more ideas to try next week. The suspect manifold has a repair where it was cracked, maybe there is microscopic holes which allow air to be sucked in, making it run lean around the No2 cylinder also compression is lower at 150. The crack is closest to No1 so does really make much sense. I need to look if I can swap the manifolds left to right as a temporary measure just to see if the problem changes. Also not sure why when you remove No2 ht lead the hydrocarbons don't increase. Small steps. Anyone had any similar experience?

Another step of discovery
I swapped the manifold over side to side, thinking that if the repaired manifold was an issue this would transfer the problem. So warmed the car up, popped the oxygen analyser on and the hydrocarbons were the same.

We then squirted easy start over the manifold to carb joint over No 2 cylinder. Hydrocarbons came down, must be a clue. I took the carb off, to check further, looking at the butterfly shaft to bush joint there is a little play, potentially enough to allow enough air ingress to make a difference. So carb is on route to a local engineer to re-bush. At least this would explain the symptoms.

Slight change of plans, I have ordered over sized shafts at 8.2 mm and a suitable reamer. Hopefully they will arrive soon.

What a night mare!
The 8.2 mm reamer and over sized shafts arrived very quickly which was a great start. Dissembled the Zenith carb's butterfly's and shafts, taking plenty of pics for future reference. Oddly the reamer did not have the usual square shaft on the end for a tap wrench. The reamer started cutting fine then completely stopped. At this point called in the artillery. At least I was not doing anything wrong. Much head scratching and the whole lot was taken away to the machine shop. I believe it ended up being a combination of grinding a square shaft, grinding a more defined lead in and plenty of grinding paste and way too much time. The Zenith was returned and ready for assembly. So despite taking plenty of pics always want, just one more from a different angle! I manged to get everything back together and working probably. Fitted the Zenith carb back on the engine and fired up. Once the engine was warm squirted easy start and no engine note change, quick look on the analyser and no hydrocarbon change, ie no air being sucked in from the wrong place.
Yes a result!

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You're being tested! Good to hear you're getting there though

I fought the carb and I won!

So the new oversized shaft at 8.2 mm did not solve the problem on its own. I wondered if the worn shaft had caused the throttle valves to also wear. I ordered up a set of three from Italy. They arrived yesterday. I spent around 4 hours installing the new ones. Very easy to install but to get each one to fit the same took some time. I measured everything as I was dissembling the old ones and the throttle valve on #1 was smaller by 0.015 mm, not much but enough? All the carb chambers came out at 39.85 mm and the new valves at 39.95 mm. Also measured the distance from the bottom of the carb to the depth of the valve when closed and adjusted all to be identical at 15.6 mm when fully closed, thinking they should open at the same time.

The difference between old and new components seemed very marginal. I refitted the carb this morning, not overly confident, I fired up the engine and let it warm up, popping and pinking.

With help, the idle and air fuel mixtures where adjusted and suddenly the HC and CO2 where within reasonable limits. Not enough time today to balance each carb chamber the same but its already better than it ever was. Very confident that we have cracked the problem.

On to the next issue

Nice one, it's pretty rewarding when you solve a problem like this

Despite the weather, I had a really great time driving the car back home. Such a great feeling to have built my own car and get it on the road. Wow its going to be fast. Too many cars, buses and tractors on the road to try it anywhere.

Already started on a new snagging list, but just looking forward to the next smiles per miles

Top stuff

Not sure if Walter Rohrl has been following this build, but his Roadster definitely has a resemblance...



https://www.hotcars.com/rally-legend-ro ... 6-history/

Nice 356, its like the car Porsche would have built had they not produced the 911

Still working on the carbs, I think I am close to the limit of my patience. I changed the fuel pump jet O rings, size found on the Pelican. The engine just wont start I suspect the new O rings are not sealing in the chamber and fuel is not being pumped via the jets but around the O ring. The rings looked wet and some evidence around the gasket of fuel.

These are 3mm ID x 2mm CS Vitron 75 sha
DFIB5332
Changinging to 3mm ID x 3mm CS Vitron 75 sha, which should arrive today

One of the pump jets was blocked again
IMG_4760

Everything laid out, cleaned and ready for the new O rings
IMG_4761

If this does not work then pushing the button on new 46mm PMO's

So I have been struggling with getting the engine running smoothly and reliably. I believe there is more than one issue at play so made the plunge and ordered some parts to get the project from the garage to the road.

New flame thrower 1.5 ohm coil and 1.6 ohm ballast resistor. Should match the 123/tune distributor better and prevent voltage drops
1 5/8 RSR style headers in stainless steel, apparently this or SSi equivalent is needed to run smoothly with the PMO's.
New oil lines to prevent clashing
Oil catch can with filter, still trying to source one
GT3 style silencer, and stainless straps. Not sure if there will be a clash with the lower rear valance. But will deal with it as needed
PMO 46mm carbs kit with correct chokes and main jets.

As parts arrive will update with pictures

Pat left some parcels today;

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IMG_4798

IMG_4800

IMG_4802

Nice!