Engine run in so time to up the boost and see what she's capable of. Back to Track N Road in Rainham.
But then something went very, very wrong and this shortly followed...
... Let me come back to that.
First I'll tell you about some other stuff that's been going on. A lot of this started some time ago and only recently got finished. Thought I'd share.
With great power comes a great need to be able to stop.
At the front we start with some fairly pathetic 282mm sliding calipers. they do the job, but I want more so I opted for "Brembodge" which is a kit available through Rovertech.
New discs are 326mm:
They're big but the colour's all wrong!
on with some nice new braided brake lines from Hel.
A nice snug fit behind the Superleggeras
At the back I'm using a ZR rear beam so have the 260mm discs. Nothing special but used refurbished calipers with braided lines here too:
Next job was to sort out some audio. I want this beast to also be a nice place to be on longer drives, so a decent sound system was essential. Nothing groundbreaking, just some mid-level equipment powered by an amp and a little sub for some bass-fill. I also thought I'd invest some time and money in sound deadening. Always money well spent.
I actually laid all the cables when I did the battery to boot conversion as I had the seats out and carpet out.
Nice meaty 0 Gauge cable running to the battery, which I terminated at the starter motor to avoid using any unsightly connector blocks in the engine bay.
Fuse holder and terminal block. excuse the cable tie - just a temporary measure because the bend is so tight and cable is very thick!
Something very satisfying about a pile of new audio equipment.
But first a bit of sound deadening. The R200 can be a rattly beast at the best of times so this is well worth doing. I opted for Silent Coat which is basically a 2mm thick foil-backed damping material. Similar to dynamat and works in the same way by mass-loading panels to reduce vibration and resonance. I used it to cover the holes - best practice would have been to first cover the larger holes with metal sheets secured with self-tapping screws but to be honest I couldn't be bothered! This will do for my modest install.
mids installed using spacers (required to clear window when it lowers)
Crossovers fitted behind the door cards.
managed to fit the tweeters in the stock housing for the standard look.
And onto the boot:
I'm hoping this also helps reduce some of the exhaust drone:
Amp installed on the back of the rear seats and sub slotted in. Amp has 4 channels so I'm using two to power the door speakers then bridging the 3rd and 4th channels to give me 180W to power the 10" sub. Again, not ground breaking but good enough for nice sound quality. I also installed some alpine co-axials in place of the stock speakers in the rear parcel shelf - just for a bit of rear-fill. The head unit is an Apline mechless unit (no CD). The bluetooth connectivity is great although I think the sound is richer when played on a USB stick.
(cables need tidying)
I'm very happy with the install. Considering it's a relatively budget setup it's actually very capable. The sub makes a massive difference and despite being quite low power, is surprisingly loud if you want it to be. I have the gain set fairly low though as I just want to add
And that brings me to the bad news.
So the mapping was going well and she'd been on the rollers for a few hours. As everything bedded in I found I had to add more fuel to the map. actually, it also turned out that my fuel pump had been dying. I upgraded to an in-tank Walbro 255 and that threw everything completely out. Anyway, once the chaps got everything running correctly again we started to engage the electronic boost controller through the Emerald in open loop.
Everything was looking good. We made small changes to see how they affected the top of the power curve. You will recall that at the top end we found the limit of the internal waste gate and so boost climbed from 7psi up to 10psi right at the top of the rev range. That can be mapped around with the controller but you have to make small changes to the solenoid duty and see what effect it has. It was looking good. Peak boost climbed to 12psi at the top, with about 10psi from 3rpm.
It happened at about 4k rpm. Everything was fine. I was sitting next to the guy with the laptop watching everything like a hawk at this stage. Temps and pressures bang on. AFR within range. Boost 10psi. Mapper immediately thought it sounded like head gasket failure between cylinders. I wasn't convinced.
We pulled the plugs to see how they looked. Plug 1 came out and the tip was smashed in. Not a good sign! My heart sank.
At this stage we think it must be a dropped valve, although peeking down the plug hole didn't show any debris or signed of damage. A compression test confirmed total loss of compression in cyl 1.
The rest of the plugs were fine. The colour indicated ideal combustion temperatures. So I called my breakdown cover and I waited dejectedly in the car park (for nearly 2 hours) for the recovery vehicle.
I wasted no time when I got home and whipped the head off. I expected to find a broken valve but as I put the head down I found this. My hear sank yet further as whilst there is obvious damage, it's not the source of the debris that's caused that patterning. It must be a piston.
I almost didn't want to walk back to the engine. But I did and this is what confronted me:
Ring land has broken away on 1/4 of the piston on the exhaust side. If you look at the inlet side, you can see where the very thin portion where the valve cutout is has started to bend in. this is obviously the original point of failure.
Whilst the other pistons appeared ok, closer inspection reveals that this is happening to all of them.
So, why did this happen?
No signs of detonation. The colours suggest the combustion temperatures were ok. Boost was only 10psi. I think it's a combination of two things.
Firstly, the piston is simply too thin by the valve cutouts. It's a weak point that fails easily if anything right. It also will become a hot-spot and a source of detonation because the lack of material can't dissipate the heat fast enough. However, given the other pistons haven't gone this way, and cyl 1 runs coolest of all, there's obviously something else going on.
So, secondly, there's some other problem specific to cylinder 1 that has contributed to this failure. I haven't found the answer yet. However, the cylinder wall has scoring all around, which I wouldn't have expected as a result of this failure. Especially when the engine was shut off immediately. Perhaps I got the ring-gaps wrong? Another possibility is that the injector went bad and cylinder 1 went lean. I need to get the engine out and try to get to the bottom of the issue.
I'm probably going to go 1.9. This will allow me to run 82mm Arias pistons. They have a great reputation and I can also get them with ceramic coated crowns and moly coated skirts. The block will be modified to accept custom ductile liners that are the same thickness as the 80mm liners except where they meet each other where they are squared off. They are also pressed in whereas the standard liners are a slide-fit. This setup has been run successfully on race cars at over 400bhp.
I might also change the turbo for the smaller GT2554. Indeed, I may have to change the turbo since most of the piston debris appears to have made it out of the exhaust and may have clouted the turbine. I'll probably be limited to 250bhp at the wheels but spool would be instant. With the extra torque from the added 100cc it should be a real midrange monster!
Finally, the head will require attention. I think the head itself is ok and just had a light peppering from the debris. The two (standard) exhaust valves on cyl are very bent but the (Paul Ivey) inlet valves seem fine - hopefully they are ok because you can now only buy them in sets of 8! So I'll upgrade all 8 exhaust valves to Paul Ivey. I also want to get the combustion chamber fettled a bit more. If I can remove 5cc from each combustion chamber I can run slightly less dished pistons (meatier and therefore more resilient). Also, with the extra 1mm all-around from the 82mm liners, you can improve the shape of the combustion chamber for improved flow and power.
So, whilst it's not the outcome I wanted, I don't feel too bad. It's not as bad as it could have been. interim results? Peak power increased from 220bhp at the wheels at 10psi when first mapped to 252bhp at the wheels at 12psi. I would have expected some increase from having run the engine in and change the oil to semi-synthetic. But that's very promising! At 16psi we could have seen nearly 300bhp at the wheels.
Watch this space!