Mk2.5 engine in Mk2?
Discussion
My MK2 engine has died, it's been making horrible noises for a while and on investigation it appears it's beyond economic repair.
I am considering just getting a new engine, have looked into a straight replacement but remember someone saying the 2.5 engine is a fair bit better than the mk2, so wondering about fitting on of these.
Has anyone done this, is it a straight swap? Is it worth doing?
The other thing I'm considering just buying a cheap MK2 (or even a Mk1) but I would like to keep mine going if possible.
I am considering just getting a new engine, have looked into a straight replacement but remember someone saying the 2.5 engine is a fair bit better than the mk2, so wondering about fitting on of these.
Has anyone done this, is it a straight swap? Is it worth doing?
The other thing I'm considering just buying a cheap MK2 (or even a Mk1) but I would like to keep mine going if possible.
peak power is comparable between the Mk2 and MK2.5 engine.
Later engine is slightly higher compression so a bit peppier on paper, also with the VVT you gain a mild improvment in midrange torque.
The thing is unless you're willing to purchase a VVT controller, or fit an aftermarket ECU, or transplant an entire MK2.5 VVT loom (horrible job). You're not going to get the midrange benefits from the VVT. Leaving it unplugged leaves the VVT in full retard, which is where is sts at low and high rpm (moving to full advance during midrange.
Otherwise and assuming you get the MK2.5 coils it's a drop in replacement. Just ensure you keep all the temp sensors from your old engine. You'll also loose VICS, but I don't think your ECU will care one way or the other.
Thinking about it you might have to adapt the EGR crossover pipe, as the fitting is different on the MK2.5 engine at the exhaust end (plus the EGR solonoid is in a different location). You could retain the MK2.5 exhaust manifold, but you need both the mani and the downpipe. Note that the downpipe has the CAT rather than the midpipe section on a MK2, so you'll either have 2 cats or you can replace the midpipe with an aftermarket version (the route is identical MK2/MK2.5
Later engine is slightly higher compression so a bit peppier on paper, also with the VVT you gain a mild improvment in midrange torque.
The thing is unless you're willing to purchase a VVT controller, or fit an aftermarket ECU, or transplant an entire MK2.5 VVT loom (horrible job). You're not going to get the midrange benefits from the VVT. Leaving it unplugged leaves the VVT in full retard, which is where is sts at low and high rpm (moving to full advance during midrange.
Otherwise and assuming you get the MK2.5 coils it's a drop in replacement. Just ensure you keep all the temp sensors from your old engine. You'll also loose VICS, but I don't think your ECU will care one way or the other.
Thinking about it you might have to adapt the EGR crossover pipe, as the fitting is different on the MK2.5 engine at the exhaust end (plus the EGR solonoid is in a different location). You could retain the MK2.5 exhaust manifold, but you need both the mani and the downpipe. Note that the downpipe has the CAT rather than the midpipe section on a MK2, so you'll either have 2 cats or you can replace the midpipe with an aftermarket version (the route is identical MK2/MK2.5
Thanks, that's very useful.
I had a quick chat with my garage and it sounds like there's a huge amount more work in fitting a MK2.5, given it would cost a fair bit more for the fitting work, and also cost an extra £80 in insurance, and it isn't hugely superior than I may as well stick with a MK2 engine.
I had a quick chat with my garage and it sounds like there's a huge amount more work in fitting a MK2.5, given it would cost a fair bit more for the fitting work, and also cost an extra £80 in insurance, and it isn't hugely superior than I may as well stick with a MK2 engine.
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