Looking for inspiration..Rebuild or replace

Hi lads I have a dilemma as to which way to go so would thought I would put it up here.

Story is I have had from new an 06 2.5 174 5 pot t5 panel van which is used as a works van but I started modifying in 2010 when the engine hydro locked on the diesel that leaked into the sump from the tandum pump.
In 2011 the core plug popped out the head and the engine dropped number 5 exhaust seating and stopped the valve from seating correctly so you can guess the rest. Cylinder bore was re- sleaved and rebuild with a bit of balancing here and there so a steady increase in power every time. It currently is over 280bhp without the LPG and just on 300bhp with it on the torque is a bit more than vw intended at over 600nm but it makes me want to go to work
Number 5 is suffering from lower compression due to the wrong piston rings being fitted at the time of the rebuild in 2010 and has worn the sleave to the point now where it needs a new lining. Now...
The purest in me is saying to keep what it came with and do a bit more but there appears not to be the tuning potential on the 5 pot pd as the rest of the engines in the vw range.
The engine itself was only produced from late 2003-2009 in the UK so a short production run and was only fitted in the t5 and the touareg. Probably down to emissions
My idea here is to strip out the engine and get rid of the plasma coating it came with in the other 4 cylinders and re- sleaved all 5. What I'm trying to find is another piston that is over sized to be a suitable donor and machine the sleaved to suit.
Possibly low the compression to get in more air for the bigger bang and port out the head to flow more air.
Fit larger nozzles to what I have at the moment or change out to the v10 touareg or phatton 560cc injectors with a larger nozzle.

The other option is to change from a transverse to an inline v6 diesel common rail and fit the manual gearbox with the Quattro running gear, a lot of work but could be fun
It's a works van and the load in the back does vary so having more power on the front wheels trying to find traction is possibly a problem, the same as rear wheel drive and being unloaded
I have a donor van that I can use as a mock up before it's transferred into the current vehicle I have so to reduce down time before the current engine expires
With the v6 I can see a few problems...ECU from the donar talking to the vehicle, gear selector cables and drive shaft lengths.
Also trying to reduce the nose weight by pushing the engine back as far as possible without interfering with the front drive shaft angles to reduce under steer.
I could be looking at another potential 150 bhp and another 200-300 NM of torque from the v6 but it's time and ££££
I need a bit of guidance and sensible answers

Interesting on the plasma coating, wiki says aluminum block. 81mm bore, so just get pistons from any 81mm PD motor. BHW would work IIRC
Or, if you're sleeving all five you could go smaller, get some 79.5mm ARLs to get more thickness in the sleeves. you'll need 3 of one of the pistons, and 2 of the other, look at the valve configuration to figure it out

I think the engine was done as a case study to see what could be achieved. An aluminium block with 12 radial arranged rods to hold it all together rather than the heavier caste iron, For its size it is a light engine.
The bore coating has been known to flake off like chrome off a steel wheel on some of the later bnz/bpc code engines but these are classed as a lean burn engine and are euro 4 compliant.
Just trying to work out my options even if I get a used block to carry out machine work.
The other option would be to use a roston stroker conrod and a spacer on the top, then I could use the standard 81mm piston as its a 5500 red line.
If I keep the 5 pot its going to be lighter than the v6 and less work.

[486] said:

to get more thickness in the sleeves.

Click to expand...

The number 5 has been sleaved already and the plasma coating was machined out with a couple of passes as that stuff is hard, but the problem is that soft rings were fitted to the piston instead of some harder rings when fitted in the soft bore. On a strip down in March it was found that the engine builder had also stripped the threads out the block for the oil pump and at the higher rpm's the pump was leaking out around the body. That in itself would reduce oil lubrication to that end of the engine through the bearigs and on the spray bar. Bearings were found to have heat damage on the big end top shell but the mains were ok.

What about possibly using a Crafter block? It's 18:1 compression and an iron block. The aluminium/sleeved block has it's limits, especially when it comes to over-sized pistons where the area between the cylinders gets quite thin. An example of this would be in the BMW E46 chassis where the regular M54 used an aluminium block, but the M3 used an iron block because of the larger bore.

DT_Tuning said:

What about possibly using a Crafter block? It's 18:1 compression and an iron block. The aluminium/sleeved block has it's limits, especially when it comes to over-sized pistons where the area between the cylinders gets quite thin. An example of this would be in the BMW E46 chassis where the regular M54 used an aluminium block, but the M3 used an iron block because of the larger bore.

Click to expand...

Hi guys
I was on your rollers in April with James in his yellow t4
I'll have a look at the mb 5 pots but I think they are going to be to long to use in a transverse position. With the pulleys and maybe an adaptor plate made to fit the mb to vw gearbox there and not enough room between the subframe.

Festa said:

Hi guys
I was on your rollers in April with James in his yellow t4
I'll have a look at the mb 5 pots but I think they are going to be to long to use in a transverse position. With the pulleys and maybe an adaptor plate made to fit the mb to vw gearbox there and not enough room between the subframe.

Click to expand...

Oh, hi

Yeah, our rollers do get around.

I think we might be talking about two different things. The Crafter was available with a 2.5L TDI which was just a common rail version of the VW R5 TDI. That said, I'm just suggesting it might be something worth researching as we've not attempted this ourselves.

DT_Tuning said:

Oh, hi
Yeah, our rollers do get around.
I think we might be talking about two different things. The Crafter was available with a 2.5L TDI which was just a common rail version of the VW R5 TDI. That said, I'm just suggesting it might be something worth researching as we've not attempted this ourselves.

Click to expand...

I think there was a redesign on that engine as it kept eating turbos due to bad oil flow also the CR wasn't the best
Both sprinter and crafter were rwd but the crafter did offer a 303 PS 295 bhp engine which are like hens teeth, but still only available in a 2.5 in cast iron block where the mb was available in a 2.7 or 2.9 which was fitted in the ssangyong or Chinese 4x4.
For reference vw did have a touareg that used the r5 engine that took part in the Dakar, the version from 2007 had a supercharger fitted with the turbo because of restrictions imposed on air intake size and it produced good power/torque. It also only had to last the coarse ..
Thanks for the heads up anyway

I though i would update the latest
After the other refresh of the top end and a bit of track action the engine finally had to be retired the rear engine support arm had pulled it's fixing threads from the block due to the twist of the engine torque, it had to come out.
Whilst out i discovered some other faults one being the head was cracked through the number 5 injector port, worn valve stems, a cracked oil return from the turbo and the bores had over heated.
The engine has been stripped to go to the machine shop where they informed me that one of the intermediate gears had broken from its shaft and was self consuming the block around the gear...Not a pretty sight.
New used replacement block sourced , stripped and sent up to the machine shop for machining but it has no piston spray nozzles
The new block is a bnz code to replace my axe code engine, the new replacement block is a 2007 but the machine shops bnz engine has the spray nozzles must be an earlier unit. Want to run with piston cooling as what i have planned.
Going to change out the captive threaded sleeves for the main crankshaft bolts and head bolts so i can use grade 12 bolts but will have to get these custom made.
Five new cylinder liners going in and a line bore.
Looking to get the moly 4340 forged rods rifle drilled but can't find anyone to do them, do i need to ?
I'm also getting the head altered to tidy things up a bit
Don't no wether to start a build thread or not as it's been a bit epic and the machine shops do take some time.