VX220 2.4L VVT ITB conversion

EcotecFiero

Interesting,

I must applaud you, because your the first person to break the LE5 ringlands!

I did it on my 2.2 L61, cylinder 2 broke a 2nd time and thats when things got nasty.

Typically this happens to people running boost or in my case to much timing. I had an Ignition control module that put out a base 10 degrees of timing, which I didnt know so when I had timing in my tables it added 10 degrees.

I was really hoping to see this updated with good news 🙁

If anyone is going to get the 2.4L crank, the rods for the 2.2 will not work with it.

alanoo

Rods could work... with a custom piston

hotpursuit

just to comment regarding no mid- high end torque, you most likely wont make any. my 2.4l has an opposit curve to the horsepower side of the dyno chart.

this is due to the VVT, it was designed to produce large amounts of high end torque at low rpm

this is an old dyno sheet before i was retuned with intake cam adjustments. (also my cut out was stuck closed and from previous dyno's the cut out open yeilds about 9whp and 13lb/f tq of gain.

trust me the 170lbft of tq at 3500 rpm is FUN. but tricky to get traction,

hotpursuit

try this for tunning..,

try running the engine by the VE tables for idle and up to 1500 rpm (or you'll get idle surge on cold starts) then after 1500 rpm run it based on MAF. very easy to run, and when doing so the car kinda learns for it self. for instance when my cutout is open rather than closed, my ECU senses larger air flow and leans the AFR out!

hope this stuff helps

rik1083

we can't map the ecu like you say - we're all running standalones 🙁
also no MAF on our engines
was there meant to be an images attached?

hotpursuit

yes, there was supposed to be an image, you'll have to fogive me, im at work and i get pulled around alot!

that sucks about running with out MAF! :wtf:

hotpursuit

heres the image..., agian old dyno, with cut out stuck closed lost about 9whp, and also a previous tune with out cam adjustments

rabidh

Hi, Sorry guys for not replying earlier but I didn't get e-mail for all the extra posts.

ATOM X : How much do you want for a head? I'd prefer Saab obviously, but if you have a Z22SE I'd be interested too...

EcotecFiero: When you trashed your pistons, it was purely boost? You were on a non-VVT engine? I'll have to check my cam lifts properly, but I'm wondering if my issues were related to VVT at all now as I don't see head trauma where the valves would have hit... As I did my own ECU for this, I have to admit the engine definitely suffered more than its fair share of backfires and premature ignition while I got things sorted, but I always figured these things were pretty bullet-proof so I never really considered it would be a problem (especially on an engine that had 7 miles on it when I got it!).

Does anyone have a good place for new Pistons in the UK? Looking at the current ones there's less than 1mm of metal between the rings and the piston top diagonally so I'd prefer some uprated ones if they're not masses more money.

Current plan is to replace the pistons and stick a new head on with the Webcon ECU and ITBs (still on order, thanks vocky 🙂 ), although I'm still toying with using the old head and making up a new Control Unit for just the Cams - I'll try and check the profile of the cams this weekend and see if I feel confident I can make hardware/software to stop it destroying itself again 🙂 I hate to admit defeat, but I kinda feel that it would take way more dyno time to make decent HP than if I just used a non VVT head (although it could be that I was getting low HP before because I had 3 sodding great holes in my pistons!).

On a slightly different note - I was half kidding before, but I had a look around and found that Oxford YASA motors do an inboard ungeared 500Nm electric motor that's 85kw = _114hp. That's actually pretty near to 147hp - drivetrain losses, and they're pitching for 2 per drive wheel. It's a bit more than I would have considered (£6k + all the rest), but if I can write it off as research through the company it would be awesome. It's definitely an option - I'm getting fed up unbolting cylinder heads 🙂

rabidh

I finally got a bit longer to look at the engine...

The cylinder liners are basically unscathed, however cylinder #4 has some deposits right at the top and it looks like that piston has been broken for some time. Looking more closely the other two breaks in pistons don't look as old, but they don't look shiny new either :o Cylinder 3 still had a bit of debris in so my guess is the bits from that caught a valve and bent it, and that's when the engine started running on 3 cylinders - pretty impressive it was still producing reasonable power up until the 3rd piston went 🙂

The valves are obviously a bit pitted/bent in places from all the stuff bouncing around, but I don't see any marks from them hitting the pistons. While I'll have to do the maths I still don't think it's possible for the VVT to do this - so most likely I'll put it back together with the VVT head, uprated pistons, Webcon ITBs and give it a whirl...

The valves themselves look identical to the ones from the 2.2,
The Pistons are stamped 2750 R1626, and the head gasket is EK 508428 12 597 769 - do these look even remotely like GM numbers? Can anyone think of a UK dealer that might be able to supply bits given these?

Honestly I don't want to put the same type of pistons back, so what's considered a reasonable choice to replace them with - Wiseco? Is there a UK distributor anyone's used? I'm fed up of getting done by customs 🙁

rabidh

One more update:

Decided to keep using the 2.4 engine and just replace the pistons
GM are hopeless. They have the part numbers for pistons on their system here, but they can't order them because the car wasn't officially imported here. The US parts importers want £150 per piston, which is more than the Wiseco ones, so I'm upping the compression from 10.4 to 11 with some nice Wisecos from Karo (although they'll take probably another month and a half to get here).
Checked the head, looks ok apart from some minor pitting and some slightly bent valves
Replaced and reground the valves in the head. They are exactly the same as the Z22SE valves on inlet and exhaust.
Finally got the ITB and ECU kit from Webcon. They took their time, but it was worth the wait - and every penny. It's sooo shiny and has an almost completely self-contained harness 🙂 Anyone interested in my home-made Z22SE ITBs? 🙂
The Z22SE coil pack doesn't bolt on as the rocker cover is a different shape for some stupid reason, but a bit of cutting and grinding sorted it out pretty easily. I'd like to use the COP, but at the moment it makes a lot more sense to use as much standard stuff as possible.

To be honest using the Webcon ECU is what I should have done at the start. Although I will still need to make a small control unit to handle the VVT, the engine will limp along with the base valve timings even if it fails (and Webcon has a trigger wheel so I can make a totally separate harness for the VVT ECU). The Webcon ECU looks a bit basic (90 degree trigger wheel pattern, no knock detection, semi-sequential, no wideband), but I imagine it's more than up to the job - and at least it's standard kit so I can get it tuned at a decent mapping place.

vocky

the webcon kit is certainly good value for money :thumbup:

looking forward to seeing the 2.4 wiseco piston pics 😃

alanoo

Update ? 😃

(Now that I have a dual continuous VVT-capable ECU, I may be interested in fitting a VVT head 😃 )

rabidh

Hi, sorry - it seems I don't get e-mail notifications from this site any more 🙁

The car's still off the road. I waited for around 13 weeks for the Wiseco pistons (I was told 6 at first 🙁 ). I have no idea what happened but after several weeks of having my e-mails ignored I got fed up and ordered the OEM bits and they arrived within the week! I've finally got the engine back together and the Webcon kit on, and I've just got to tidy up some wiring and re-fit the exhaust 🙂

I don't suppose anyone has a spare timing chain bolt plug (the one that fits below the inlet sprocket?) mine was so hard to get out I ended up stripping the 10mm allen key inner :o

The Webcon kit fits perfectly to the Gen II block, and I used a section of a replaced front rad hose to get a nice S bend that avoids the air filter. As for cam timing, I'll be building a small ECU that'll just handle that, but I'm going to get the engine started without it for now.

How do people fit the fuel tank vent? I've currently got mine connected to the vacuum feed via a MIG welder tip to reduce the airflow...

vocky

I have a spare upper righthand guide blanking plug, pm me a postal name and address and I will stick it in the post :thumbup:

I fit a filter to the pipe - after removing the solenoid

rabidh

You're a legend 🙂 thanks!

rabidh

Finally got to a rolling road today (Northampton Motorsport) with the Webcon ECU and my VVT unit. It was very driveable but I had to trailer it because of the lack of MOT (emissions).

With all the hassle from work I only had time to get the VVT ECU finished the evening before, and unfortunately it showed. The software had some timing issues and VVT angles were all over the place.

We got the car mapped with the VVT totally removed in the end. With it unplugged and the cams in the failsafe positions, we got 165bhp (fly), but with it on in guesstimate positions we were getting 180 (but there were holes everywhere). The guy doing the mapping reckoned I should expect well over 200 when it's sorted.

Hopefully I can finally get past the MOT on emissions now, and then I'll be able to do a bit more work with it on the road and get it mapped again once the VVT (and the app to map it) are better.

Still, I'm pretty happy with the day - it's crippled and it's still better than a std 2.2 - even at 60 degree inlet temps 🙂 If I'd had a few more hours to work on the VVT beforehand we'd be looking at much more interesting power now.

Unfortunately, while the car's been fine for everyday driving, the extended mapping with only a single fan at the front of the car has meant it looks like my gearchange cables have melted - suddenly it's hugely difficult to move the gear knob around 🙁

vocky

I would wrap the replacement gear cables with exhaust wrap or similar, I did mine with exhaust wrap :thumbup:

you should get some good bhp once you have the vvt sorted 😃

rabidh

Did your cables get damaged too, or did you just think about it a bit more than me? 🙂

Some kind of wrap is a good idea, that'd be a whole lot better than trying to pull the cable even further away...

vocky

I was lucky because mine were never damaged by heat, but during the last engine rebuild I decided to wrap them just in case

rabidh

Well, just gone for an MOT and it failed emissions again. It seems even worse than before!

It's probably some air leaks in the exhaust system so I'll have to have it all off, tape it up and check it under pressure - I couldn't find much in the way of leaks with it on the car.

I'm a bit pissed off really - I seriously expected that when I asked Webcon (and even suggested air leaks might be the trouble), or at the very least after spending hours on a rolling road after following their advice, I might be a little bit nearer getting past the emissions, or someone might have been able to pinpoint what the issue was.

I guess Northampton Motorsport may have noticed some issue, but they neglected to tell me that their exhaust gas analyser (the one that goes in the silencer) was broken until after they'd finished the mapping :/

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