Gti6 2070cc Engine Build And Questions

[leitoo 0]

My engine gave in a few weeks ago and after disassembly I found out the crankshaft needed changing.

While I was at it I decided to go for it and up the cc's a bit by putting in a crank from a XUD9 (88mm stroke)

I will be using 86,5mm forged pistons with modified pin height and deeper valve cutouts to avoid the valve to piston issues this engine suffers from since I will also be putting in a PeterT Stage 1 inlet cam.

 

Yesterday morning I went to the machine shop and dummy built the engine in order to determine what the piston speck should be. With the std crank the pistons came 1mm below deck at TDC. Is this correct for the std XU10J4RS? Do pistons sit below deck with the std crank? I was under the impression that pistons came up to deck.

 

Then when putting the diesel crank in the pistons came up to deck which is quite confussing.

Could anyone shed some light on this matter?

 

Many thanks!

[welshpug 1,662]

sounds like RFY not RFS, do you have any pictures?

[decoc182 0]

Or perhaps from the s16 (XU10J4D/Z)

[welshpug 1,662]

Or perhaps from the s16 (XU10J4D/Z)

 

that's what I said RFY is the S16/2.0 Mi16.

[leitoo 0]

No pics here, will post some when I get home but they are deffinitely RFS pistons, small valve pockets and pistons with a dish. They're exactly as the ones on Welshpug's avatar.

 

I fear the engine might have been repaired before and been assembled with other rods than standard. Are there any rods that might be slightly smaller in lenght thus making te pistons sit lower?

[welshpug 1,662]

they can't be exactly the same s Mine, as Mine are modified

 

I have no idea what rods could be used to do anything like this.

[leitoo 0]

I was thinking that they weren't exactly the same after I wrote it

It's quite strange, I've measured the rods now and they are 158mm, so Std length.

I will have a play with the head over the weekend and measure everything again to know for sure where I stand

 

Does anyone know what the volume for the dish on the pistons is? I will have to go over my compression ratio calculations once again...

[petert 590]

When you add an 88mm crank to an S16 rods/pistons you get zero deck height. Not sure about GTi6 though. I'd be buying some S16 pistons and rods.