Diesel Internals In J4

[cammmy 1]

Hey Guys

 

I was wondering. Would it be possible to fit a XU9 diesel crank/rods/pistons to a J4?

 

Was thinking that if I turbo the car, it could be a good alternative to buying aftermarket forged parts. Given that diesels are built to put up with constant punishment.

 

I realise that diesel pistons have crap cold tolerances. I ALWAYS warm the car up before driving it, so I don't think this is a huge issue.

 

Alternatively, could the J4 head be fitted to a XU9 diesel motor? I think someone in aussie has done something similar with a 306.

 

Ta

[cammmy 1]

Right, I've pretty much been told this is a no go.

 

Does anyone know if the standard J4 pistons are hypereutectic?

[Ryan 99]

The diesel crank fits I believe, and some of them are steel as opposed to cast like the Mi16 cranks, although they're not as balanced. Not sure if the big ends are the same though, or whether you'd need different rods.

[cammmy 1]

Yeah, apparently it would take a lot of machining to make them rev like an Mi crank.

[welshpug 1,657]

not really, I know of a few 2.2/2.3 MI6's that rev quite nicely.

 

they typically use the 88mm crank for a 2.1 ish, or the 2.1 TD for 2.2+

[cammmy 1]

Sweet.

 

Are the cranks cast like the Mi ones? I'm mainly looking at this as a less expensive way to get tougher bits. Figure the diesels parts should be readily available and able to take a lot of punishment.

 

Does anyone know about the suitability of diesel rods and petrol pistons?

[B1ack_Mi16 67]

You can just forget to use the rods I would say, they are heavy and not very suitable for high revs, well it might work of course, but they are _heavy_

 

The piston pins in the diesels are way thicker, 25mm small end on the 1.9 TD and 30mm small end on the 2.1 TD.

So it really won't work without modifications to the small end of the rod...

 

The cranks are good though, I have a crank from the 1.9D, and that one is cast if I remember correct.

 

The 1.9TD crank however is 88mm stroke and is forged with 24mm wide rod journals, meaning a normal Mi16 setup should fit, well Mi16 would fit a 92mm crank with 26mm wide rod journal too as the mi16 is piston located anyway and have clearance on the big end.

 

The 2.1 TD 92mm crank is also forged. I have one of those balanced and offset-ground and revs to 8000rpm, that's with increased stroke to 94.5mm due to the grinding.

[cammmy 1]

Sweet!

 

I think I will just get the standard rods shot-peened.

 

Thanks for the info.

 

 

[cammmy 1]

What rods are you using? If the stroke is longer would it not mean piston to valve contact would be much more likely?

[welshpug 1,657]

custom rods, and no more likely than any other engine, less so if anything due to larger valve cutouts.