Tips to fit an XU9 (88 mm stroke) crankshaft into an XU10J4RS block

[BrenoKuster 0]

Hello, greetings from Brazil.

 

I’m preparing to fit the XU10J4RS block in my car (I’m currently running an XU7JP4 block with the XU10J4RS head and manifolds). Along the way I had the opportunity to acquire an 88 mm stroke crankshaft, probably from a ZX Volcane 1.9 8V (XU9J2).

 

The crank I bought has only 4 counterweights, and their external radius is 8 mm larger than that of the XURS crank. Because of that, the counterweights on this XU9 crank collide with the jet-oils in the XU10J4RS block.

 

I’m not keen on removing the jet-oils, so at first I considered machining the counterweights of the XU9 crank so it would rotate freely in the XU10J4RS block with the jet-oils installed. However, to do that I would need to machine about 8 mm off the counterweights, which would reduce mass and, most importantly, shift the counterweights centre of gravity, completely changing the compensation of the reciprocating motion of the pistons. I’m afraid this could be catastrophic for the engine.

 

Therefore: I’m dropping the idea of machining the counterweights. My remaining options are:

 

1. Find an 88 mm stroke crankshaft with eight counterweights, which theoretically has a smaller external radius and would not collide with the oil-jets. Such crankshafts are hard to find in Brazil and are very expensive. I know that these crankshafts came in XUD series engines. Here in Brazil, diesel is only permitted in utility vehicles, so the XUD engine was only available in models like the Chevrolet Tracker and Suzuki Vitara around 2000–2004. They are difficult to locate and costly, since diesel versions of those cars are valued by the off-road community.
2. Remove the oil-jets and replace the original connecting rods with rods that have internal oil passages for cylinder lubrication. However, I’d prefer not to remove the oil-jets, I imagine they are more efficient for lubrication and piston cooling in a more “sporting” usage.
3. And that brings me to the reason I’m posting here: Relocate the jet-oils for cylinders 1 and 3 (which are the only jet-oils that currently hit the counterweights) to the opposite side of the counterweight path. This will require some machining of the block, but I imagine this is the most correct path for my application. Has anyone here dealt with this issue? Has anyone needed to do similar machining for jet-oil placement?

 

 

 

 

Some measurements I took:

 

XU10J4RS crank weight: 17,5Kg

XU9 crank weight: 14,2Kg

 

XU9 crankshaft:

• One counterweight per crank throw.
• Mass of the counterweight: approximately 695 g.
• Distance from the center of gravity of the XU9 counterweight to the crankshaft’s longitudinal axis: 49.5 mm.

XU10J4RS crankshaft:

• Two counterweights per crank throw.
• Mass of the thicker counterweight: approximately 611 g.
• Mass of the thinner counterweight: approximately 418 g.
• Combined mass of the two counterweights: 1,029 g.
• Average distance of the centers of gravity of the counterweights to the crankshaft’s longitudinal axis: 45.0 mm.

XU9 crankshaft after proposed machining:

• Mass of the machined counterweight: approximately 547 g.
• Distance from center of gravity of the machined counterweight to longitudinal axis: 45.25 mm.

[petert 630]

I've never fitted an XU9J2 crank to that block, but I have fitted XU9J4 and XUD9TE cranks many times, without having to alter anything. The XUD9TE crank is forged and only four conterweights. It fits perfectly. That would be my choice.

 

Last choice would be to machine the XU9J2 crank and get it rebalanced.

 

I don't think the XUD9 crank is forged. We never got them here.

Edited November 25, 2025 by petert

[welshpug 1,712]

do you get the DW10 in brazil?

[petert 630]

DW10 crank is a great idea. It was used in heaps of vehicles:

 

Initially available in the midsized models, such as the Citroën Xsara and Xantia and Peugeot 306, 406 and Peugeot 206 it was soon spread across the PSA range, such as the LCVs, while a 16-valve version(RHW), with 109 PS (80 kW; 108 hp), was used in the large MPVs built in association with Fiat. Suzuki was a customer for these powerplants, using them in the European Vitara, Grand Vitara, and XL-7. Eurovan-based commercial vans, the Citroën Jumpy, Peugeot Expert and Fiat Scudo were available with a 94 PS (69 kW; 93 hp) DW10 BTED engine, which is essentially an intercooled version of the original 90 PS (66 kW; 89 hp) design.

The DW10 was used as the basis for the new family of Duratorq Diesel engines co-developed with Ford and Volvo it is used in the Focus, Kuga, Mondeo Mk3, Mondeo Mk4, C-Max and C30/S40/V50/C70, besides various Citroën and Peugeot passenger models. The DOHC 16-valve powerplants were mated to a second generation common rail injection system and a variable-geometry turbocharger, pushing power to 136 PS (100 kW; 134 hp) (RHR). It is fitted with a six-speed manual transmission or six-speed Aisin-automatic transmission (in Citroën C5 from summer 2004 onwards).

[BrenoKuster 0]

Thank you, petert and welshpug, for your replies.
 

@petert, the builds you did using XUD9TE crankshafts, were they in an XURS block with the jet-oils still installed? I find that very interesting. I always assumed that cranks with only four counterweights usually had a larger outer diameter on the weights.
 

I’m giving up on the idea of machining the counterweights on the XU9 crank because the opposing mass to the rod–piston assembly would end up much smaller than in the original setup. I’m concerned that this would significantly affect second-order vibration cancellation. From what I understand, dynamic balancing can’t replace the inertia needed to counteract the piston’s reciprocating motion. I’m gathering the numbers to model the final balance factor of this modification, but I’m already looking into other solutions.
 

Regarding crankshafts derived from Diesel engines: here in Brazil, the law only allows Diesel engines in heavy vehicles (pickups and trucks), public-transport vehicles (vans and buses), and light utility vehicles only if they’re 4x4. Passenger cars are not allowed to use Diesel engines.
We did have the DW10 here, but as far as I know only in the Chevrolet Tracker/Suzuki Vitara from the early 2000s. It’s very hard to find these engines being sold in parts, and when you do, they’re usually expensive and with little remaining oversize for machining. I looked around a lot and found nothing available.

That’s why I’m considering machining the block and repositioning the jet-oils for cylinders 1 and 3 to the opposite side of the counterweight. In the builds you’ve done using other crankshafts in XURS blocks, did you not need to modify anything on the jet-oils? You kept them installed in the same locations?

[petert 630]

To be exact, they have been XU10J4 blocks, but they're the same. ie they share the same two fixing point oil squirters, rather than the single point squiter. Maybe the later type would be an easier solution?

[SRDT 228]

What do you plan to do with the pistons sitting 1mm higher?

The 88mm EW10 crank could also be a solution but you need Ø45mm rods. You may also need to regrind the main journals to a XU repair size like on the 96mm EW12 crank.

Speaking of the EW12j4 was this engine sold in Brazil?

[petert 630]

3 hours ago, SRDT said:

What do you plan to do with the pistons sitting 1mm higher?

The easy way to do this, is to use XU10J4 pistons and rods, with the 88mm crank. Then you get zero deck height. Normally the XU10J4 pistons sit 1mm down the bore. Block height is 235mm.

eg

stroke/2 + rod length + compression height

43 + 152 + 39 = 234mm

44 + 152 + 39 = 235mm

 

I'm not a fan of XU10J4RS pistons & rods at all. The pockets are too shallow for any decent camshaft and they're pressed pins. The XU10J4 in contrast are full floating and have deep valve pockets. Even with an 88mm crank, you can run 0.065" of inlet lift at TDC safely. The longer 158mm rod is great, but that's the only benefit.

Edited November 27, 2025 by petert

[BrenoKuster 0]

@petert Thanks for the reply! I looked into DW10 crankshafts over here, and the only one I found is priced at about 10× what it should be, with zero information about dimensions. Diesel engine parts in Brazil are really overpriced. It’s hard to find good options, it’s nearly the cost of a special-order billet crank, and unfortunately I’m not willing to invest that much for this.
 

@SRDT I’ll be ordering special-order pistons with 87 mm bore and with a dome to raise the compression ratio, that way I would compensate the compression height directly in the piston design. But I’ve heard from a friend in the UK that it’s common practice to simply fit a thicker head gasket and change neither piston nor rod.
Regarding the EW12: although I once saw an EW12J4S exhaust manifold for sale, there’s no record of PSA ever homologating a car with that engine here, only the EW10s and the V6s. If any EW12s exist here, they were privately imported, not brought in by the dealer. In other words, they would be extremely rare in Brazil.
 

Anyway, in my build I plan to assemble the RFS with domed pistons to reach around 14.5:1 cr and use deeper valve pockets specifically to ensure safety in future cam upgrades, with stock rods and that’s it. The crankshaft was an opportunity buy, but it’s giving me far more work than I was prepared to deal with: things like machining the block, changing rods and/or deleting the jet oils, I’m giving up on the idea. Would there even be any truly meaningful gains from using this crank? Does anyone have a power-and-torque curve comparison for an XU10 before and after fitting an 88 mm crank?
 

Thanks!

[petert 630]

If it's that hard, I would give up on the 88mm crank, stay with the 86mm crank and spend the money elsewhere. Buy full floating rods to suits your new 87mm pistons. Are you going to run E85? I have a set of 163mm rods here, brand new, to suit the Wossner Kit Car pistons. There's a story here of how I modified them to suit the XU10J4. I removed some of the crown to get them down to 12:1.

With that much compression and the very long rod, it will have plenty of torque. Add some decent camshafts and it will be a very strong engine.

 

[petert 630]

Another option is get some 162mm rods made and use a Honda 87mm K20 piston. I’ve built two of these this year. Whilst a bit more expensive, I think this is your best option.

Edited December 3, 2025 by petert