Compression / Pin Heights Of 83mm Bore Xu Pistons

[welshpug 1,628]

I'm looking to find information about the aforementioned pistons, want to know if they have a 37.5mm compression/pin height and if they have any dish at all, and whether they have enough meat for 4 valve cutouts...

 

I know D6C mi16 have 37.10 mm compression height and are flat topped with 4 cutouts, DFW are similar but a lower height at 36.2mm.

 

I am aiming to put together a fairly cheap engine that needs to have 8 valve rods under a 16v head with a piston to suit (due to the length of the rods, and the cost of custom rods) an Mi16 piston could fit but only if the rod was machined narrower at the small end, and the compression height of said Mi16 piston is not ideal, a flat top SRI XU9 piston would be, and would fit the rod ( I think...) though would need 4 valve cutouts adding, though that would be cheaper than decking the block and liners to suit and Mi16 piston.

 

A swap to Mi16 rods isn't possible due to the stroke I want to use.

 

Any ideas?

 

another question I forgot to ask, is it the XU9J2 D6D engine that has these? 9.3-1 compression ratio and a much larger cylinder head chamber by the sounds of things.

Edited September 29, 2009 by welshpug

[James_R 3]

You'd machine the Mi pistons to suit the rods not the other way round, Nick did that successfully on his Mi using 8v rods and crank.

[welshpug 1,628]

any particular reason to do the pistons and not the rods? setting up time would be quite a bit longer and more difficult, whereas doing the rods would be a doddle, they'd only need taking down to normal Mi16 width.

 

any idea on the XU9J2 piston?

[Galifrey 1]

any particular reason to do the pistons and not the rods? setting up time would be quite a bit longer and more difficult, whereas doing the rods would be a doddle, they'd only need taking down to normal Mi16 width.

 

any idea on the XU9J2 piston?

 

Main reasons I can think of are impact on strength, and impact on balance.

 

Machining some alloy away will have less impact then machining some steel away on the overall balance?

[welshpug 1,628]

I'd understand that reasoning if they were already narrow, but they are wider than an Mi16 rod and would only need to be taken down to the same width as an Mi16 rod.

[Galifrey 1]

I'd understand that reasoning if they were already narrow, but they are wider than an Mi16 rod and would only need to be taken down to the same width as an Mi16 rod.

 

Wasn't aware of that

[James_R 3]

I guess because that's how the 8v piston rod combo goes and the pin/rod is designed so. Latterly heat generated from narrowing the road is worse than the head from removing the material from the piston??

[DrSarty 90 1 Cars]

Slightly OT Mei, but is there any mileage in exploring the use of BMW components, as it seems some are interchangable? Just an idea.

[welshpug 1,628]

not a clue actually Rich, I've only done general maintenance on them so only know the basics, I'll see what I can find though.

 

seems that the XU9J2 flat top pistons with some cutouts in them is a way to go though (I don't want the expense of custom rods or/and pistons and block+liner decking) they'll fit the rods I have and have a higher deck height.

 

 

 

 

 

 

 

Dieciséis válvulas para el triunfo! ? most definitely, unless you go for veinticuatro válvulas a ganar! ZX 16v?.....

[welshpug 1,628]

re-BMW component compatibility, nothing applicable to an alloy block so far, conrods look to be suitable for an iron block or a 1.9 engine, the bores in a BMW engine are typically 86mm+ on the sixes, and 93 or 95mm on the big 2.3/2.5 S14 engines, not sure of the smaller 1.8 and 1.9's as yet.

[DamirGTI 329]

Take a look if you can find something useful here :

 

http://rapidshare.com/files/286608328/Peug...onSpec.pdf.html

 

Damir

[welshpug 1,628]

Damir, thanks very much, took a while to figure out what all the numbers meant, but the flat top XU9J2 look perfect.

[Issam 0]

You'd machine the Mi pistons to suit the rods not the other way round, Nick did that successfully on his Mi using 8v rods and crank.

You mean machine the pistons to have lateral clearance for the small end of the rod?

or machine the piston for the wrist pin?

 

If it is lateral clearance sure but if it is for the wrist pin then we usually just rebush the rod

 

The XU motors have a 150mm length connecting rod correct?

[petert 556]

The XU motors have a 150mm length connecting rod correct?

 

Depends on which version.

 

eg.

 

XU5 - ?

XU9 - 143mm

XU10J4 - 150mm

XU10J4R - ?

[B1ack_Mi16 67]

Depends on which version.

 

eg.

 

XU5 - ?

XU9 - 143mm

XU10J4 - 150mm

XU10J4R - ?

 

Pretty sure the XU10J4 have 152mm rods, just same as T16.

This also goes for XU10J2 and XU10J2TE.

 

And XU10J4R/RS do use 158mm rods.

[Mandic 0]

Isn't it just R with 158mm, and all other XU10 have 152mm?

 

Cheers

 

Ziga

[welshpug 1,628]

You mean machine the pistons to have lateral clearance for the small end of the rod?

or machine the piston for the wrist pin?

 

If it is lateral clearance sure but if it is for the wrist pin then we usually just rebush the rod

 

The XU motors have a 150mm length connecting rod correct?

 

 

It is lateral, the pin is the same size though the 150.5mm rod is not bushed, nor does it have enough material for a bush to be fitted I have been told.

 

As you can see here the rod I have in the appropriate length doesn't fit into the XU9J4 piston.

 

 

XU5 rod - 150.5mm

 

XU7 rod - 150.5mm (same part as XU5, longer stroke, shorter piston)

 

XU9 143mm.

 

XU10J2+J2TE+J4 + T16 152mm

 

XU10J4R/RS 158mm.

 

also, XU5+7 have 45mm big end pins as opposed to the 50mm of the XU9+10.

[B1ack_Mi16 67]

Isn't it just R with 158mm, and all other XU10 have 152mm?

 

Cheers

 

Ziga

 

True, R/RS is 158 all others are 152 for XU10.

[Issam 0]

It is lateral, the pin is the same size though the 150.5mm rod is not bushed, nor does it have enough material for a bush to be fitted I have been told.

 

As you can see here the rod I have in the appropriate length doesn't fit into the XU9J4 piston.

 

 

XU5 rod - 150.5mm

 

XU7 rod - 150.5mm (same part as XU5, longer stroke, shorter piston)

 

XU9 143mm.

 

XU10J2+J2TE+J4 + T16 152mm

 

XU10J4R/RS 158mm.

 

also, XU5+7 have 45mm big end pins as opposed to the 50mm of the XU9+10.

Interesting.Thanks for the information!

Thanks for the information.I have access to the following FORGED connecting rods:

* 159/21mm

* 150/20mm

* 144/20mm

 

And these come with an EDM hole for forced pin oiling.

Only issue is the big end is 50mm in diameter except on the 150 with a 46mm diameter.

 

http://i226.photobucket.com/albums/dd25/is...pg?t=1254406001