What 102 mm Pistons can one get?

[Typ 4]

I can only imagine the difficulties you have encountered so far, that's quite a special project

[wreck]

those heads look interesting . a bit of welding should be able to fix any issues . were they done in NZ ? When I do another engine I'll chose a crank with a chev rod journal size for the bigger selection of rods and better pricing .
I'm doing a minor rebuild , just new rings and cylinders honed (deutz) I've got 103mm JE pistons , the ring lands are still in spec . If the pistons had been worn I was looking at using LS3 pistons from DSS . Then making caps for the 22mm pins to fit the 23.5mm pistons .

[Typ 4]

Yes, these heads were done in NZ, at first we were playing with the idea of machining a 1.8 head down at the left and right hand sides and welding ported aluminium blocks on for type one exhausts Ronal Jüttings Sonax beetle had some extremely welded heads that were converted to type 1 exhaust ports at some stage. They would have developed so many issues that the idea was flagged.. Many prototypes were made, time and money lost and the project died, hence it would be nice to get at least one set running.
I jumped the gun a little bit with the crank, not researching if there could be problems with rod availabilities, a chevy jounal crank does make more sense. It was just too tempting when CIP had a sale and I have a few sets of genuine VW crank and rod bearings so here we are
Your idea with the LS3 pistons sounds interesting, it could well be that this engine will get some other pistons in the end if the Yamaha type pistons are not what I hoped for. They are quite short, 55 mm and the 22mm gudgeon pins are 70mm wide, they will be very light but may cause issues with rocking so will need at least a 5.500" rod.

[Typ 4]

The "famous" SONAX bug

[wreck]

pin caps .jpg

I was just trialing ideas , One cap is made from a gudgeon pin , bored out to fit the 22mm pins to suit my rods . The other was made from a piece of brass rod . The advantage of using an old Chev pin is you only have to bore it and the OD is alright spot on for the pistons .

I made the same mistake when ordering my crank and went for the 2LT journal instead of the chev/buick one . The advantage is better clearance to the cam .

The next set of heads I do I'd like to weld up the combustion chamber and add a fin and move the seats out 6mm to 10mm , mainly to be able to work the exhaust port short turn better as well as being able to continue the profile of the seat top cut into the combustion chamber .

[Typ 4]

Good idea on the piston! There are some pistons, especially on diesel engines that have bronze bushes pressed in which allows the use of smaller gudgeon pins. The VW/Audi 3.0 TDI has that and it works very well.

Clearance was the main reason why I wanted an 80mm crank plus the 50mm journals, here is hoping rods will be available again.

These heads have a smaller exhaust port angle, in fact we were thinking of casting them like the angle flow ones but gave up on it. There are a few exhausts around that should work well when shortened. I like the idea of a nice header and collector.

[Typ 4]

TDI Piston

[patto]

Hey Typ4,

Whats the back story to those heads? could be cool to revisit the project if more affordable then straight up CNC heads

[Typ 4]

Hey Patto, the idea came up when a mate raced a quick bus with engine plus heads on the 2.9 liter. A friend of mine here liked the idea and we were talking things up and many casts later here we are. The initial plan was to cast them in NZ and have them machined and sold in Germany. The first halfway usable ones were transported in my suitcase during a trip there but we soon realised the cost for casting, machining and shipping were astronomical. Unless there are a few parties involved that have a labour of love, it's just not worth doing. I reckon the Remmelle, Orratech and Thorsten Pieper heads are the way to go!

[patto]

Cheers for the reply Typ4,

I too experimented with some type 4 heads but i canted the valves also. one day ill get around to finishing them

[Typ 4]

Have finally received the pistons and the first impressions are not bad. Did a rough measure with the verniers and looks good, machining is nice and no major damages occured during transport. Just need some rods and the build can start.

[Wally]

Nice flat tops! The valve notch is 'nothing' fortunately.
Cast piston it seems, 6/100 clearence, hope its enough. Would seem a benefit to hone the old cylinders properly as a few /100 extra I would see as extra insurance

[Typ 4]

Yes, the cylinders will get a hone and here's hoping these pistons don't expand too much. Thinking of getting another one and metallurgy tested for comparison what's in there. They are very nicely finished though and may receive a HPC anti friction coating.