17/11/2012 Distributors,Valve Timing and Backfiring.

Its a cold day here in Harrogate and I am taking the opportunity to do some housekeeping on new parts, and logging on my spreadsheet what I have bought and need to buy. Also feeling guilty that I havent written more…………..

I will catch up on my log as I have a huge amount of photos and information to post. Over the past couple of weeks I have been looking at giving the engine a good clean and a tune up and service while its out of the car. I built an engine stand, and the the whole engine and transmission sits nicely on that.  It has the dual purpose of allowing me to roll the Bike Lift I bought underneath to hold the engine if needed. and I should be able to use the engine stand to roll the engine under the car with a good clearance. The parts were also chosen so they can be dissassembled and be used as a car rolling stand for the body. I would like to be able to roll the whole body out of the garage when the weathers good enough to work outside.

The engine runs quite rough to me, admittedly all the engine tin apart from the fan shroud is off so pre warm for the carbs is not in place, but even so I think it could be better. I started off with the cold engine and set the valve gaps as per my vast collection of Porsche 356 and 912 books. With the Knecht  air filters off I could see that there was some blowback, not much but a little.  So did the gaps again, and checked them but still got a little popping, also when I increase the revs manually I get over run, where the engine will stay at about 2500 revs for a while and will only come back down if I reset the idle screws. This needs a lot of thought. I dont want to sart re setting various things to find I have screwed up the whole feel and running for the engines carb and timing.
I replaced the spark plugs which were heavily sootoed with Bosch WR6BC whcih was what was already in there. After a lot of digging around on 912 BBS and Registry and 356 Registry I have come up with an alternative which I will try at a later date which are the NGK B7HS.  I replaced the air filters with the Knecht/Mahle LX213. I then tried to undo the oil filler plug which was slightly rounded. With the correct 5 sided 19mm socket it wouldnt move and indeed rounded more, so at the moment its still in and I am pontificating various methods to remove it. Meanwhile I dropped the bottom filter housing and drained the oil that way. It gives me a chance to have a look at the mesh and magnet and also then remove the top oil filter casing for rework and the oil filler for rework and the Fan housing.

I have been toying with the idea of putting in electronic ignition , the type that mounts in the distributor cap. There seems top be a couple of types out there. Petronix are popular in the states, but expensive and I havent yet found someone who stocks them over here in the UK. My dizzy is Bosch part number is 0 231 129 031 this is the centrifugal advance, aluminium body type which I believe was a European addition as the original distributor was a 009 – unreliable, could be wrong on that but need further research. It seems to have a VW cap on it (1 235 522 069 with a 200 stamp). I dont know if this is having any effect on the running. So In  hunting for a correct cap and distributor I have found:

Distributor: Bosch 0 231 129 031
Points  Bosch 1,237.013.081
Condenser Bosch  1.237.330.292
Rotor Bosch  1.234.332.215
Cap Bosch  1.235.522.059

This distributor was a stock item on the 356 and as an upgrade item on the 912, or available 1968 onwards.

So I will get an order off for these and replace them to rule out this as a problem area.
The coil looks like the original Black from Bosch as well , as a dress up item I have been looking at the Bosch Blue Coils  ( Coil, ignition BOSCH 0 221 119 027)  have managed to find a local source for these  for £25 excluding shipping from MisterAuto.co.uk  which seems like a good deal to me so have ordered one of these. Although I am not sure what will arrive as there seems to have been a change over the years in colouring ranging from pale to dark blue:


Heres a 66 with the Knecht filter housings and Blue coil

I will keep the existing cap, rotor, and coil as backups held on board for any “far away from home” incidents. Ha.

Note: I did a little research and found that the Solex 40 PII are prone to a little blowback when cold, so its not unusual, also the left exhaust header to the Bursch exhaust is not fitted too well. This may have some effect on what I am hearing.

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