Hello guys

I hope that anyone could help me with my "little" problem. I own an XK R model year 2007 with 4.2 V8 Supercharger AND variable camshaft timing / variable valve timing.
This engine is broken (half of the cylinders have no compression) so i bought another engine. Basically it is the same one:
416 HP
4.2 litres
Supercharger

Now I wanted to swap the engine but it is somehow different. Well I found out that this engine is from 2005 (so one of the first engines) without VVT
Can I swap the parts for the VVT from the damaged engine to the MY05 engine?
What is different between those engines, do I need a new timing chain or any other parts?

I want to use the 05 engine because it has low milage and very good compression.

 

With enough money and time anything is possible. However, treat these engines are essentially different engines that share some hardware.

I think your options are: a) get matching engine to do a conventional engine swap b) (risky and costly) use short block from your donor engine and everything else (after through check) from your original engine c) (risky and costly) get ECU/electronics from 2005 and try to get that engine running in your 2007 after redoing wiring harness.

When you mentioned you have no compression, did you determine the root cause? If you have something like sticky/burn valves you won't be able to swap heads.

 

No I have not determined the root cause yet. I am still disassembling the engine. I have checked the donor engine yesterday again and it seems that the seller has sold me a completely wrong engine. The engine is from an X100 jag with 396 HP. He sold me the engine as 416 HP for X150 models.

After some discussion he agreed to refund the money and we will return that engine.

So the problem is solved. I will search for a 2007 engine with VVT in a new thread. Maybe someone has a good offer for me :-)

THanks for your help.

 

Since the VVT's are driven by oil pressure I assume you'd need to do some machine work to the heads to get them to work.

Hopefully your second engine will have the correct parts.

 

I have disassembled everything yesterday. I would say the root cause is clearly visibly

The piston rings are broken and the piston is deformed due to the heat inside.

 

Any idea why it overheated?

 

I think because of the broken piston rings.
Oil could flow into the cylinder and that oil is combusted in combination with gasoline.
This increases the combustion temperature and the piston starts to melt / deform.

 

I'd bet someone was running 87 octane in it...

 

Something doesn't sound right here. Why would rings just break. This is the result of the problem and not the cause . How many miles were on this engine. Is this the only piston affected or were there others. I would remove the piston and see what the bottom end looked. Also what is the side wall damage and if it's just this one cylinder can it be repaired/sleeved or bored/honed.

 

Maybe they broke because of the heat if the oil film was lost at higher velocity. We are allowed to drive as fast as we want at some highways in Germany

I do not know.

We only have 90 octane or better in Germany. We only refuel with 95 octane

I have found a new block with new pistons and crankshaft.
The cylinderhead and all valves will be revised.
New timing chains and seals too.

The car has about 170.000 km

 

I would also replace the knock sensors in the intake valley then. Still leaning towards detonation and I wonder if your octane rating is the same as the states?

 

US uses AKI, pretty much everyone else uses RON........

 

Have all your injectors cleaned and flow tested before you put them back in,

Knock sensors aren't all that effective at wide open throttle, too much noise when the motor is revving hard.

 

Yes I will do that. I have seen that you cannot repair anything on this engine without disassembling everything

Thats a bit sad.

 

I only suggest you have all the injectors checked because your picture of the piston looks very much like it was lean and burnt that hole through the piston.

A failed/clogged injector would cause that.

It would be a disaster to put the same injectors back in, and have the same problem on a new bottom end...

 

Bingo. Absolutely gotta run the good stuff on blower engines.

Take tons of pictures and post them here. There's a lot of experience and maybe we'll be able to determine what killed it. At the very least get all of the pistons out of the bores and post pictures of everything, including any damage.

That pic is pretty crazy. I wonder how long the gasses had been cutting at that bad spot for it to get that large? What things other than injectors do you think would kill an entire bank? VVT timing, after cooler coolant blockage? Weird stuff.

 

Maybe I will remove the pistons when I have the time to do so.

The big question for me is: if the piston overheated due to leakage of the injectors why is the cylinder head including all valves in realtive good condition compared to the piston?

 

The piston may have had some porocity/voids in the melted area that aided in bulding a hot spot.

 

Chibbi.

Back to your original question.
Yes you can swap parts from your newer engine to the older one you purchased.
It will be a lot of work. If time is money for you, then you are better off finding a 4.2 S/C with VVT.
1. You will have to swap the engine harness to the VVT one. In order to do this all the accessories and mounts will have to be removed from the long block, (Down to the long block with exhaust manifolds.)
The harness branches are routed below all the accessory mounts.
2. You will have to remove the supercharger, and intercoolers and use your old intercoolers and sensors mounted to them, as well as the SC inlet manifold and throttle body. May have to swap the EGR lines as well.
3. You have to swap the camshafts and VVT modules on the front of the engine. Involves removing the supercharger pulley and timing cover, and timing chains. (Might as well replace the timing chains and tensioners while you are at it.
4. You will have to drill out the oil feed hole in each head to be able to get VVT to work. (Or swap heads would be better if your old heads are good. (Will save lots of time overall.)
5. You will have to adjust all the tappet/lifter clearances for the VVT camshafts. (Lots of time and fun. - Or use your old head assemblies )
6. Swap valve covers that fit the VVT solenoids.
7 This is the list of the main items. I am sure there are other details that I am forgetting.

I would estimate $600 to $800 in parts and gaskets.when all is done, plus a lot of time.

 

If i'm not mistaken, it was not the entire bank damaged, only this one cylinder? In which case a poor injector not delivering enough fuel would cause a lean condition in that cylinder, and with the other three cylinders on that bank being fuelled correctly, the AFR reading from the O2 sensor on that bank may not have been far enough out for the ECM to see it as lean.

Not leakage, but blockage. Not enough fuel = lean.

I have seen similar damage to pistons on motors running nitrous oxide, too lean, too hot, hole burnt through at the skirt.
The pistons are aluminium, the rings are steel, as are the valves, you know the properties of Alu compared to steel...

I'm not saying this is what happened, i'm saying you should check the injector flow rates to rule it out as a possibility.