16V on a 8v Block "I think not"

[jeremy]

You could probably use an iron block for a petrol engine - later petrols use iron blocks - but I don't know if they are the same as the diesel block.

1.7's have smaller bores - so there may be block/valve collisions with a 16 valve head.

If you hope it'll work as a diesel - think about the lack of compression and pre-chamber for an indirect engine. Direct injection modern engines do drop the compression from 22 or 23:1 to about 16 but probably need the very high injection pressures used on the HDi cars.

Seems that the iron blocks were not needed for strength when the 16 valve was current - and their block is a special casting as I understand it with cross bolted main bearings.

The thing about all the XU range is that they were all very good at the job they did, and looked after properly all seem capable of en extremely long life without problems.

[Vanny]

the XUD7t has 83mm bores and the D6C inlet valves are 34.7mm, so bags of room to play with, a whopping 13.6mm!

It would run as a diesel, pre combustion chambers are not vital but important if you want any sort of reliability or longevity from the engine, and there are ways round not having one cast into the head.

Something would likely need to be done about the compression ratio (D6C has a ratio of just 10.4:1), but there are always turbos, additives and NOS.

it would be possible to to have a diesel block with a 16v head, might even be able to make it run, but it would be like trying to mount a brick through the middle of the windscreen, deffinately possible but completely useless (and you'll spend ages cleaning up the bits!)

[docchevron]

Or you could just fit a HDi 16V engine, which will pretty much bolt straight in.

their block is a special casting as I understand it with cross bolted main bearings.

<anal mode>
Not quite, only main bearing cap number three is cross bolted, on three row ECU cars the front bolt is replaced with a stud that the knock sensor is attached to.
</anal mode>

[simonbx17]

i was only have'n a laugh just thought the extra valves would make the old girl faster!

didn't vauxhall make a 1.9 16v diesel vectra? that worked o.k.

i thought the difference between the 1.7 and 1.9' was the strokes rather than the bores?

[jeremy]

I think a number of the newer more powerful Citroen/Peugeot/Ford HDi engines are 16 valve, the 2.1 XUD was 3 valve.

The difference is that while on a petrol engine a pentroof combustion chamber with angled valves is used, a diesel one still has a flat combustion chamber (or virtually flat.) This is necessary to get the compression.

[docchevron]

i thought the difference between the 1.7 and 1.9' was the strokes rather than the bores?

3mm difference in the bores, thats all it is.

I think a number of the newer more powerful Citroen/Peugeot/Ford HDi engines are 16 valve, the 2.1 XUD was 3 valve.

you are quite correct sir!