Sonntag, 29. März 2020

re-routing the air flow

When the original type 3 oil cooler is removed, the engine tin needs to be modified. There is a gaping hole left when the external adapter is installed instead of the cooler. The viably important flow of air for the engine would be lost, resulting in even hotter engine temps and possible fatal engine failure.

To avoid that, the cooling tin needs a block-off plate in the former oil cooler area. So, in order to "fabricoble" such a plate, the exact set-up needs to be assembled to measure all dimensions needed.

The first obstacle was the M8/M6 threaded bolt for the oil cooler fixation. I vividly remember the problems I had on the 1776 Streaker engine I assembled some years ago:
Here is the hole story:

This time I was more clever, soaked the thread bolt over night in penetration oil and used grip pliers on the bottom of the pin, to minimze the risk of stripping the bolt. (less flex, less chance of breaking):
Luckily, this time it worked just fine and I was left with a perfect M8 threaded hole.

It is always a good idea to use brand new seals whenever you assemble things, these silicone oil cooler seals are confirmed to be bullet prove in my last builts, so a new pair was installed:

The adapter was the next part to be installed and fixed properly:

Paper or card board is usually the first step for every template I make:

transfer to a piece of sheet metal is the next step:

Here is the block-off plate in its initial shape:

After fine tuning the fitment, the sheet metal shall be crimped onto the cooling tin

Here you can also notice the other block off plate in the ignition lead clip area:

he small plate in detail, maybe total overkill to use 4 captive nuts, but where else can you ever use M3 captive nuts?!

Almost finished, card board template vs. finished article

and finally, everything installed with a small rubber seal on the bottom to avoid rattle and air flow:

Let the work begin!

As with every modification / repair / improvement, dismantling is always the first step, so I removed the generator, Weber carbs with the (selfmade) linkage, the 123 Distributor and countless wires and lines and  also test fitted the breather box and engine case breather / mechanical fuel pump delete:

Always check new parts carefully!

After I received all the new stuff, I started to check them in detail. There were quite some things to improve:
the oil cooler adapter had some burrs in the flow passage of the oil:

with a little action of the Dremel, I removed those burrs in no time (sorry for the blurry pic):

As mentioned in my previous post, the fittings of the adaptor looked strange somehow - but only after I tried to assemble a hose fitting. It just didn't work. I measured inner and outer thread diameter as well as thread pitch, all seemed fine

Upon closer look, it dawned on me that the thread is LH (left handed), so it was no wonder the hose fitting didn't fit!

New year - new project!

Hi to all my Blog visitors - I have to admit, my attempt to blog more in 2019 failed miserably!

This year I try my best to improve! With the ongoing Corona virus I guess there will be plenty of time to do updates and new stories.
The biggest modification for the Volksback is an improved oil cooling system. Especially on those hot summer days, the oil temperature raised - and in parallel - the oil pressure dropped to levels which are not healthy. 130°C oil temp @ 0,2 bar oil pressure even triggered the oil pressure indicator light, which makes me nervous every time!

The plan for this season is a vast improvement in the oil cooling. After countless hours of reading forums like (for me, still the source of great info!), checking Google for pictures and talking to friends and "experts", I made my own plan. It involves better cooling, but without the hassle a full flow system brings along, like a special oil pump, routing the oil line between engine block and the fan - which is tricky on the type 3 engine - and so on.

Here are some parts involved:

A huge oil cooler with electric fan, numerous AN8 fittings, an external oil filter, hose clamps, an adapter for the external cooler and another adapter block, to connect all this stuff to the original oil cooler passages on the engine block.

After I knew what I wanted, I started ordering parts (mostly on ebay and from Hoffmann Speedster). Which sounds easy, but actually wasn't. The external cooler adapter came with the wrong fittings (LH threaded) and after the seller sent new ones, which was actually no big deal, he admitted to have sent wrong parts and send "correct" ones free of charge. Unfortunatelly, the new fittings were really rough in the threads and not usable. So, I had to order some more black anodized fittings from another supplier. Also, the package with fittings and braided line got lost by DPD and it took almost 2 weeks before I finally had those parts on my work bench! There is also a new breather box, especially for the type 3 "pancake" engine, just for looks.

Talking about looks, the engine is running great, but currently, the looks of it leave a lot to be desired. It is a bloody mess of wires and lines - more like a snake pit:

During the oil cooler modification, I will also upgrade to an electric fuel pump, for even cleaner looks in the engine compartment.

... more to come, soon