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XUD to XU conversion?

Blufires

Member
I've got an XUD9TE in my 405 SRDT wagon. I've started to get the itch for a revvy petrol engine with cams and individual throttles, and I'm tossing up between:
*getting an XU10J4R/RS engine to clean up and eventually install.
*getting just the head and putting it on the XUD9 block that's already in the car.

Both are iron blocks, though the XUD9 has the same bore and stroke as the aluminium XU9J4. Are there any other differences I'm missing?

Also, if I wanted to increase the compression, would I want to mill down the head or the block?
Would I be able to avoid a modification plate, as the XU10J4 (non-R or RS) was a stock engine for the series 2 405?
 

PeterT

1000+ Posts
You could certainly use the block and crankshaft. You'd need to bore out the block to suit an XU10J4 piston and use an XU10J4 rod. There will be heaps of compression, ie approx. 11:1.
 

Blufires

Member
You could certainly use the block and crankshaft. You'd need to bore out the block to suit an XU10J4 piston and use an XU10J4 rod. There will be heaps of compression, ie approx. 11:1.
Do the diesel ones sit further up in the cylinders to make the ~22:1 compression? I thought it was just a smaller cavity in the head. Could you avoid boring the block by using the pistons and rods from an XU9?
 

Dave

1000+ Posts
I can only guess that an XUD head basically has no combustion chamber and the valves are vertical therefore the xud9 pistons would not have valve cutouts - only a pocket to help with combustion.
 

PeterT

1000+ Posts
XUDTE blocks are sought after in the UK. They're used for race engines to make 85x88, ie 1997cc, for under 2L class. The diesel oil squirters are replaced with petrol versions, as their excessive orifice wastes a bit of oil pressure.
 

Dapco Auto France

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