Xu10j2 Block And Xud9te Crank

[sub205 5]

Hello,

 

i'm currently thinking about building a block from this 2 components.

 

the diesel-crank mentioned above is a forged crank as i think.

the 2mm more hub will result in pistons comming 1mm more out on top of the block.

 

how will the compression ratio be with that combination?

 

anyone tried this already?

 

do i need a refurbish-headgasket (1.4mm instead of 1.2mm) to have a drivable cr ?

[welshpug 1,622]

Are the 10J2 pistons dished and come flush to deck?

 

 

or are they flat top and sit 1mm below like the RFY XU10J4?

Edited July 3, 2009 by welshpug

[sub205 5]

Are the 10J2 pistons dished and come flush to deck?

 

 

or are they flat top and sit 1mm below like the RFY XU10J4?

they are dished and come flush to deck, yes.

 

[carbers205 1]

Ive done this!

I had to take 1mm off the top of each piston which were the same as yours to avoid them hitting the head at TDC.

The CR was certainly higher but I never got the opportunity to measure exactly how much. The extra torque that the added capacity (2045 instead of 1998) and the increased CR was very good. Driveability was definitely improved as you could pick up smoothly in lower gears than you normally would.

The diesel crank is a straight swap and is a bit lighter due to having 4 webs rather than the 8 in the XU10.

 

Andy

[sub205 5]

Ive done this!

I had to take 1mm off the top of each piston which were the same as yours to avoid them hitting the head at TDC.

The CR was certainly higher but I never got the opportunity to measure exactly how much. The extra torque that the added capacity (2045 instead of 1998) and the increased CR was very good. Driveability was definitely improved as you could pick up smoothly in lower gears than you normally would.

The diesel crank is a straight swap and is a bit lighter due to having 4 webs rather than the 8 in the XU10.

 

Andy

have you used a normal diesel (xud9) or a turbodiesel crank?

i think the turbodiesel has 8 webs and is forged.

 

personally i like the webs, the xu10 is running much smoother and the car is more silent, especially in idle.

 

how did you took off 1mm from the pistons?

Edited July 6, 2009 by sub205

[carbers205 1]

My crank only had 4 webs but I was sure it had come from a TD. I certainly didnt find much difference in smoothness between my original 8 webs and the 4 I replaced them with.

The pistons were skimmed in the same way you would skim a head I believe.

[sub205 5]

My crank only had 4 webs but I was sure it had come from a TD. I certainly didnt find much difference in smoothness between my original 8 webs and the 4 I replaced them with.

The pistons were skimmed in the same way you would skim a head I believe.

a skimmed head has a rough surface with the skinning-lines.

this would be bad for a piston, because the carbon will have better chance to settle down there and the piston will get dirty really soon.

polishing it afterwards seems to be recomended.

 

maybe the 306 is better damped, so you cant hear the engine noise / vibrations that much as in a 205, the difference is really noticable.

or maybe this is because my old engine hat a rougher idle because of the afm and the sharp camshaft? dunno ...

[carbers205 1]

Youre right, the pistons will need to be polished up once most of the metal has been removed.

I may be wrong but I thought the extra webs were there to keep things smooth at higher revs rather than at idle? Either way I doubt the AFM and cam will have been helping matters!

[sub205 5]

Youre right, the pistons will need to be polished up once most of the metal has been removed.

I may be wrong but I thought the extra webs were there to keep things smooth at higher revs rather than at idle? Either way I doubt the AFM and cam will have been helping matters!

afm? i dont use this rustical technology anymore ;-)

maybe the webs do have impact on higher revs, but to my knowledge (practical) they help at lower revs, the smoother idle is notable, my car does not vibrate as much as with the xu9 engine. at mid revs the extra weight of the webs help a bit for more torque.

at higher revs AND most notably on turbo engines they help to reduce torsion forces at the crank. especially for supercharged engines the webs are absolutely necessary, the 2.0 16v turbo has also a forged crank.

[carbers205 1]

I guess the other thing to consider is what use the engine will be put to, if it is for racing and track days or just as an every day car.

I can only really comment on what I found from my build experience and that is that I didnt find any difference in smoothness between 4 webs and 8 on an every day basis. The other thing to note is that with so many factors in the engine being changed at once, would you know if the engine was not as smooth whether its the fault of the increased capacity, higher compression ratio, less webs on the crank, different camshaft etc?

Its all really interesting stuff!

[B1ack_Mi16 67]

I really can't see the 8 webs doing much of a difference on idle revs. not much at high revs either really.

 

All the Forged XU cranks have 4 webs, including the 2.0 16v Turbo (405 T16) engine.

 

The cast ones have always 8 webs in 16v versions, but at least 1.9 8v ones are 4 web cast ones.

 

The 1.9 TD engine have a forged crank with 4 webs as you say, I have one myself.

(Although Hilgert have found a 8 web Mi16 crank in a 1.9 TD engine once, so they might have been using some different crankshafts from engine to engine )

[megavolt0 0]

HI! I have XUD7(161A) crank. It has 8 webs. (From PUG205 GRD)

Edited October 21, 2009 by megavolt0

[B1ack_Mi16 67]

HI! I have XUD7(161A) crank. It has 8 webs. (From PUG205 GRD)

 

This certainly looks like a cast one.

[Jamal 2]

I really can't see the 8 webs doing much of a difference on idle revs. not much at high revs either really.

 

All the Forged XU cranks have 4 webs, including the 2.0 16v Turbo (405 T16) engine.

 

The cast ones have always 8 webs in 16v versions, but at least 1.9 8v ones are 4 web cast ones.

 

The 1.9 TD engine have a forged crank with 4 webs as you say, I have one myself.

(Although Hilgert have found a 8 web Mi16 crank in a 1.9 TD engine once, so they might have been using some different crankshafts from engine to engine )

 

 

My 2.0 8v Turbo has got 8 webs too.

Is the T16 crank really has got 4 webs?

[B1ack_Mi16 67]

My 2.0 8v Turbo has got 8 webs too.

Is the T16 crank really has got 4 webs?

 

Yes T16 crank has 4 webs and is forged.

[Vili 17]

The 1.9 TD engine have a forged crank with 4 webs as you say, I have one myself.

(Although Hilgert have found a 8 web Mi16 crank in a 1.9 TD engine once, so they might have been using some different crankshafts from engine to engine )

 

I've tried to search information on this matter and what I've found is that fully counterbalanced crank is used in some of the early 306 diesels. Most of the 1.9 Diesels with or without turbos are 4 web, regardless what model they are from.