Justin's Raven

[justin.schoeman]

Made some good progress at last. Bottom end is buttoned up for the last and final time (either that, or next time I open it is with a sledge hammer...).

Measured the deck height:

Final compression ratio with existing shims is precisely 8.0:1 (I used a thicker head gasket than before - the previous compression ratio was 8.3:1 - and they were running mogas. Probably explains the detonation damage.)

I will go with 8.0:1 and run it on Avgas for now.

Measured and set ring end gaps - needed to be opened up 0.002".

Cleaned up the cylinder heads (a full day's work there):

head.jpg (41.13 KiB) Viewed 2142 times

If you ever get a chance to look at an original, genuine VW head - they look like swiss cheese, with lots of BIG holes for air to flow through. The new 044 castings are much beefier, but the casting quality is poor, with flashing restricting, or completely obstructing most of the cooling passages. The fins on the side were restricted to <30% of the size, and most of the cooling holes around the exhaust valve and outlet were heavily restricted, or blocked entirely. I recon I have got at least 70% more air flow though these holes now.

What many people don't seem to realise is that fins do not cool an engine (well - they do, but not very much at all) - what cools the engine is air flowing past the fins. So with all these holes blocked, or restricted, the cooling efficiency of the head is seriously comprimised.

I just needed to clean the top end bits and pieces, and bolt them on - but was running short of time before my vacation. Instead of rushing things, I decided to rather spend the time pickling everything. Which left the slight problem of a closed crank case, without any oil... Being the adventurous type, I decided to simply put the pickup of a venturi spray attachment into a bottle of engine oil, and spray some oil into the engine. Worked like a charm, but I think the backspatter has effectively pickled my entire workshop... Gonna be a hell of a mess to clean. (Oops.) Never mind that I now look like an oil wrestler (from a horror movie). Oh well, live and learn.

Will hopefully have this baby purring away within a week of returning from holiday, but until then - MERRY CHRISTMAS!

:D

[Tortoise man]

Justin hello
Vlieg jou Raven of is jy nog besig om te bou eerste keur dat ek hoor en toevallig lees ek op mirco nou van die projek van jou
groete Tortoise man

[justin.schoeman]

Not flying yet, but soon. I hope.

[justin.schoeman]

Top end fitted and busy with the valve geometry:

With the existing push rods I can get it very close, but not perfect. Need to decide if I should leave it as-is, or buy new push rods, and make them 1.5mm longer...

[Tortoise man]

Hello Justin
Hoeveel tyd nog voor jy vlieg

[justin.schoeman]

3 weeks of work (barring further problems), and then some paperwork

[Jean Crous]

TTTTTttttttwwwwooooo weeks and counting

[justin.schoeman]

The schedule slips a little further, but progress is being made. Engine is hung, and most ancillaries are connected.

Still need to finish the valve geometry (just can't get it perfect...). The inlet manifold has a little interference on one of the magnetos - so I need to have it bent out a little. Aside from that, just a little wiring and plumbing to go, and she should run!

Still need to decide on the oil cooler location. Aeroconversions recommended a cooler under the engine, but have now started using one on top of the engine. I prefer the top mount option, and just want to confirm some details with them.

[Oupa-G]

Nice looking exhaust some very nice bending. Good Luck

Cheers Oupa-G

[justin.schoeman]

Nice looking exhaust some very nice bending. Good Luck

Cheers Oupa-G

I wanted something simpler, but Bert de Graaf refused point blank to make T joints - waaay too inefficient for him. Top notch work (except for the minor glitch on the inlet manifold, which warped slightly at a weld). Two exhausts + inlet manifold (all in stainless) + some good advice for R2500. I would highly recommend them!

[Go Vert]

Jissliekit Justin did is nou die kiefste looking prop wat ek nog gesien het, Outsteekend wa kry ek so prop.

Trevor

[justin.schoeman]

Jissliekit Justin did is nou die kiefste looking prop wat ek nog gesien het, Outsteekend wa kry ek so prop.

Trevor

Could be quite interesting to fire it up with that on the front. It is just a 'handle' for securing the crank while I set the valve geometry and static timing...

[justin.schoeman]

Will be hearing back from Aeroconversions today about the valve geometry and oil cooler layout. Until then I have been working on the baffles:

The cardboard piece is a mock-up of what will be an aluminium sheet. the masking tape in the middle is the mould for the inter-cylinder baffles. I have decided on a mixed aluminium/composite construction. Aluminium for the large flat sections, and very high temperature sections (around exhaust ports, etc.). Composites for the compound curves around the cylinders. Using LR211F resin with a glass temperature of 170C - which should be fine, as I see a lot of sonerai builders have done composite baffles with West expoxy (only 90C).

Still hoping for first start this weekend!

[t-bird]

Did you start it ?

[justin.schoeman]

Don't ask. Decided to go with the bigger oil cooler. Work interfered with fun (again), so I didn't finish the bracket in time to get the oil lines made up. Finished the bracket over the weekend, but didn't get time today. Hopefully drop off the templates tomorrow, and get the pipes on Wednesday, or so. This _should_ be the last thing before I can actually start the beast...