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Today's little job - MGF VVC inlet manifold swap


FridgeFreezer
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As some may know, the 1.8K suffers from leaks of the inlet manifold o-rings (often mis-diagnosed as head gasket because of the coolant loss that can sometimes accompany it). Unfortunately, the inlet manifold is a big affair and made of plastic, so it waggles about and leaks. Mine seems to have developed an appetite for o-rings, things would be good for a week or so and then it would start to leak again. Not a big problem, except that the air leaks mean incorrect fuelling which means it drives badly - shudders on pulling away and doesn't accelerate smoothly, low-end torque suffers as does MPG.

So, looking for a solution I found that MGF inlet manifolds are available for about £50 on eBay - they're from the same 1.8 K-series lump, albeit with VVC, but they're made from aluminium. So, one was duly purchased and today's job was to make it fit. While I was at it, I took some very bad and out-of-focus pictures should anyone want to know what's involved. For those playing along at home, half the photos are from a previous O-ring change, but I stuck a few in to illustrate things I didn't snap this time round.

If you are replacing the O-rings then this may also be helpful, you can skip most of it.

We start with a normal Freelander engine bay, feel the power!

imor_Image114.jpg

In no particular order, pipes need to be disconnected from things. If you're just doing O-rings then only the two pipes from the rocker cover to the inlet need be disturbed, everything else can stay. This is the brake servo pipe, which is on a push-fit connector in the back of the plenum. You also need to remove the water pipe to the header tank (far left of the manifold where it meets the block) and PLUG IT WITH SOMETHING or coolant will pee everywhere when you pull the manifold off (guess how I know :P ). There are a couple of vacuum pipes to remove too.

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I chose to leave my throttle body where it was and unbolt the inlet manifold from it, there are four bolts holding it on, two of which are tricky to get to and one is a right pain the bum. You can leave this alone if you're just doing O-rings.

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Then you need to undo the 13mm bolts holding the inlet manifold on - there are more than you can see, so make sure you get them all!

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Then away it comes:

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If you're just doing O-rings, this is as far as you need to go - just pull the green bit out, replace, and put it all back together:

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Old & new together, note the new one also uses more bolts to hold it on and prevent wiggling:

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Holding up the MGF gasket shows the first issue - the ports are bigger:

vvc_Image179a.jpg

Second issue, not pictured, is that the injectors are different flow-rates. MGF ones are Bosch 280-150-749 which a quick google shows are 15.7lb/hr, whereas the standard one are 280-150-703 which are 14lb/hr. Just fitting the MGF setup would result in over-fuelling. If the car were going to be re-mapped or I had the time to megasquirt it then I'd fit the higher flow injectors, but for now the standard ones are being swapped across. The fuel rail is also different (MGF has a return line, Freebie doesn't) so that got swapped too.

So, let's see what needs to be done - using the old MGF gasket as a guide, time for the felt tips:

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Then it's time for a visit from my new die grinder - ports were blocked with rags, the one being worked on was blocked with a smaller bit of rag with a cable-tie round it to aid retrieval, vacuum cleaner was pointed at it while I was grinding to try and catch as much as possible:

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Since this was being done to make it work, not for performance, I didn't go too crazy. The main thing is to take the lip off, so a 5-10mm deep "blend" is fine and means minimal grinding.

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As I said, not a masterpiece of head porting but should at least smooth the path rather than having a ruddy great step in the way.

Anyway, time to stick the bottom half of the manifold on the "underneath" bolts either end are absolute b*ggers for clearance to get a socket or spanner on, I found I had to leave the manifold loose on the studs & tighten them in turn until it was on, then do the rest:

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I didn't have proper studs, so a couple of M8 bolts will have to suffice for now in the two extra holes:

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Top half then bolts in with another gasket, most pipes line back up again:

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...but some don't. Vacuum take-off for the ECU (quite important) teed into the line for the fuel pressure regulator, and the extra hole on the end blanked off. I will make a nicer blanking piece when I have more time, this one was hacked out in seconds to facilitate a test drive & cuppa:

vvc_Image189.jpg

After that, top up the coolant, try to blow as much swarf off as possible, and go for a test run. Initial indications are it's worked, low-down torque and smoothness are back, tomorrow's drive to work will show if acceleration has improved and by the end of the week I should have some idea about MPG. Previously it's managed ~26 when leaking and 30+ when healthy, so if you've got a leak it's well worth the £7 a genuine parts gasket will set you back.

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Cheers Les :)

While I think of it, tools used:

8, 10, 13mm sockets 1/4" drive

13mm deep socket 1/4" drive

1/4" wobble extension (~200mm total)

8mm ratchet spanner

Needle nose pliers (for hose clips)

Vacuum cleaner

Blow gun

Die grinder with small carbide burr

Excellent info on how to drive a die grinder is on the DVAPower website, plus everything you ever wanted to know about the K-Series.

For those wondering, here's where the injector part number is:

flapper_injector_pn.jpg

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Update so far - it's happier but still not right, we think it's a lean misfire possibly because of the improved flow of the new manifold, hopefully not an air leak or anything else (I've looked and can't find any reason for it).

I am going to try putting the MGF injectors in as they flow more fuel (+12%), but not too much that the ECU shouldn't be able to correct it for better MPG on cruising. We'll see how it goes. If it doesn't behave it's going to get MegaSquirted :lol:

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  • 2 weeks later...

i just finished doing this job yesterday,(also did a new cylinder head, cambelt, water pump and the VVC manifold)

i will say mine has no missfire and im running the freelander injectors. did you use the freelander or vvc throttle body and sensors? i used the vvc bits.

done 60 miles today and its great......

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Assuming the lambda sensor is working properly, any slight flow differences will be compensated for very quickly by the ECU adjusting the fuel trims. Installing the larger injectors is probably too big a step, and will likely result in the ECU running out of fuel trim adjustment.

Have you scanned it for fault codes? If there are no codes, and the car runs an airflow meter, try giving the sensor a clean with some IPA or similar and see if that helps. Often faulty AFM's will cause crappy running with no fault codes, as while the signals are wrong they're not out of range

Might also be worth checking/changing the coolant sensor, as they dont last forever, and a dicky one will throw the fueling away to hell.

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just a note. have done a full tank of fuel on my conversion and got average of 26mpg. that includes 60 miles of 80mph motorway driving, 30 miles towing a 1100kg caravan, and the rest the wife doing the school runs and shopping etc.

was quite happy with that and seem to be running great.

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