Rover 200 BRM - 1.8 K-Series turbo project
Discussion
Could be.
When I removed the shim, my clearance was more or less head gasket thickness. This worked better than 1mm extra clearance.
Going completely the other way may really improve things. That flat wall on the edge of the combustion chamber reflects the shock waves too well if the wall to too high. In the area of positive interference of the waves near the wall knock is induced. Only if the gap is smaller than some 1.5mm, gases are cooled / quenched to a degree this does not happen.
One thing that helped me lot was direct port water / meth injection. Without it, I would have suffered the same piston failure as you, (I used the same pistons) a long time ago. Now that they pockets are machined, they should cope even better.
Place the jets a few cm behind the fuel injectors on the same side as fuel injectors, so the top of the bottom plenum. I used 4x 0.4mm Aquamist Typ c jets.
I can send you pictures if you want.
I have since got an other chap to install direct port water meth on a supercharged K and it works a treat even on track without knock and rather high IATs.
When I removed the shim, my clearance was more or less head gasket thickness. This worked better than 1mm extra clearance.
Going completely the other way may really improve things. That flat wall on the edge of the combustion chamber reflects the shock waves too well if the wall to too high. In the area of positive interference of the waves near the wall knock is induced. Only if the gap is smaller than some 1.5mm, gases are cooled / quenched to a degree this does not happen.
One thing that helped me lot was direct port water / meth injection. Without it, I would have suffered the same piston failure as you, (I used the same pistons) a long time ago. Now that they pockets are machined, they should cope even better.
Place the jets a few cm behind the fuel injectors on the same side as fuel injectors, so the top of the bottom plenum. I used 4x 0.4mm Aquamist Typ c jets.
I can send you pictures if you want.
I have since got an other chap to install direct port water meth on a supercharged K and it works a treat even on track without knock and rather high IATs.
Ive said:
Stuballs said:
will fit the new head. Considering running shorter rods for less compression and possibly milder cams. I noticed I have quite a lot of blowby so that'd be a good chance to have everything checked over (cylinders round, etc.
More to follow...
If you just fit shorter rods, you reduce squish/quench. I found my SC Rover K engine to be less knock sensitive AFTER removing a 1mm shim despite the now increased compression ratio. More to follow...
Quick little update. Took the old girl up to Santa Pod on Saturday. Whilst I've had a few issues with pressurising the coolant, I thought I'd chance a gentle run.
Video:
https://youtu.be/PUE4D1QAtWM
Ran a 14.7 at 96mph. Launched fairly easy. Never launched this car before and never been on a drag strip myself! It was serious fun I wanted to do more but didn't want to push my luck.
On the drive home I lost a fair bit of coolant out the expansion cap. So it's time to ditch this high compression setup and fit shorter rods to lower the compression. That can wait until after the respray which is starting next week!
Plan for the rebuild is taking shape. I'm actually considering a slightly bigger turbo at the same time to reduce back pressure - gt2871r. I have a low mileage vvc head which I'll port match and fettle slightly. It comes with the vvc mechs and cams so I'm considering going back to the vvc setup, at least use them for running in the bottom end before I switch to new solid cams. Spec still to be decided. I may need a clutch upgrade. And might fit a lightweight flywheel. I'll probably have everything balanced again too.
For now I'm just stripping done bits off the car ready for the respray.
Video:
https://youtu.be/PUE4D1QAtWM
Ran a 14.7 at 96mph. Launched fairly easy. Never launched this car before and never been on a drag strip myself! It was serious fun I wanted to do more but didn't want to push my luck.
On the drive home I lost a fair bit of coolant out the expansion cap. So it's time to ditch this high compression setup and fit shorter rods to lower the compression. That can wait until after the respray which is starting next week!
Plan for the rebuild is taking shape. I'm actually considering a slightly bigger turbo at the same time to reduce back pressure - gt2871r. I have a low mileage vvc head which I'll port match and fettle slightly. It comes with the vvc mechs and cams so I'm considering going back to the vvc setup, at least use them for running in the bottom end before I switch to new solid cams. Spec still to be decided. I may need a clutch upgrade. And might fit a lightweight flywheel. I'll probably have everything balanced again too.
For now I'm just stripping done bits off the car ready for the respray.
Stuballs said:
Quick little update. Took the old girl up to Santa Pod on Saturday. Whilst I've had a few issues with pressurising the coolant, I thought I'd chance a gentle run.
On the drive home I lost a fair bit of coolant out the expansion cap. So it's time to ditch this high compression setup and fit shorter rods to lower the compression. That can wait until after the respray which is starting next week!
Plan for the rebuild is taking shape. I'm actually considering a slightly bigger turbo at the same time to reduce back pressure - gt2871r. I have a low mileage vvc head which I'll port match and fettle slightly. It comes with the vvc mechs and cams so I'm considering going back to the vvc setup, at least use them for running in the bottom end before I switch to new solid cams. Spec still to be decided. I may need a clutch upgrade. And might fit a lightweight flywheel. I'll probably have everything balanced again too.
For now I'm just stripping done bits off the car ready for the respray.
How are you making the link from high CR to water loss? On the drive home I lost a fair bit of coolant out the expansion cap. So it's time to ditch this high compression setup and fit shorter rods to lower the compression. That can wait until after the respray which is starting next week!
Plan for the rebuild is taking shape. I'm actually considering a slightly bigger turbo at the same time to reduce back pressure - gt2871r. I have a low mileage vvc head which I'll port match and fettle slightly. It comes with the vvc mechs and cams so I'm considering going back to the vvc setup, at least use them for running in the bottom end before I switch to new solid cams. Spec still to be decided. I may need a clutch upgrade. And might fit a lightweight flywheel. I'll probably have everything balanced again too.
For now I'm just stripping done bits off the car ready for the respray.
If you buy a clutch which is hard work (like a paddle type) I would recommend keeping the std flywheel, the extra weight helps a lot setting off and with stop start driving.
Stuballs said:
Ive said:
If you just fit shorter rods, you reduce squish/quench. I found my SC Rover K engine to be less knock sensitive AFTER removing a 1mm shim despite the now increased compression ratio.
I did consider this. With my rod piston combo as it is, my squish clearance is too high for squish to be effective and I actually think that's a source of the epic detonation. To be honest Marko, I'm so det limited I can't imagine a setup that eliminates squish completely could be worse. With 2mm shorter rods and the head gasket I want to run, clearance will be more like 4mm - I.e. Zero squish.The stock rover k-series turbo is not a "detty" engine, and they have 1.5mm shorter rods and no squish. I've basically managed to build a forged engine that's less reliable that the stocker!
My only reservation about the shorter rods, is the increased side load on the thin liners. We'll just see what happens!
Saab did a heck of a lot of R&D with turbo engines and knock, this looks like an intelligent piston to me as it has a shallow well designed bowl and just a small squish band around the outside:
It looks like an old headlight bowl or satellite dish which were designed to reflect everything into the centre.
I wonder if tight squish has more to do with off-boost performance, something to do with emissions, moderate performance road cars or something needed more in N/A and less in a performance turbo engine?
You might want to read 'The Rover K Series 16V Engine' by Des Hammill, if you haven't already.
ISBN 978-1-910241-27-1 available via Evil Bay.
The damp liner engine particularly overheats because of poor block cooling due to the thicker liners, or have you had a custom set made to improve coolant flow?
According to Mr Hammill there is no margin for error and that is with the narrower wet liners fitted < 94/95.
I have to keep a close eye on the temp' gauge when on the motorway if I get stuck in a jam. This suggest that insufficient cooling flow takes place at tickover on an otherwise sound engine as mine is.
ISBN 978-1-910241-27-1 available via Evil Bay.
The damp liner engine particularly overheats because of poor block cooling due to the thicker liners, or have you had a custom set made to improve coolant flow?
According to Mr Hammill there is no margin for error and that is with the narrower wet liners fitted < 94/95.
I have to keep a close eye on the temp' gauge when on the motorway if I get stuck in a jam. This suggest that insufficient cooling flow takes place at tickover on an otherwise sound engine as mine is.
Mr Teddy Bear said:
You might want to read 'The Rover K Series 16V Engine' by Des Hammill, if you haven't already.
ISBN 978-1-910241-27-1 available via Evil Bay.
The damp liner engine particularly overheats because of poor block cooling due to the thicker liners, or have you had a custom set made to improve coolant flow?
According to Mr Hammill there is no margin for error and that is with the narrower wet liners fitted < 94/95.
I have to keep a close eye on the temp' gauge when on the motorway if I get stuck in a jam. This suggest that insufficient cooling flow takes place at tickover on an otherwise sound engine as mine is.
he has a full wet liner later engine like mine with westwood ductile liners, his issue is just to high compression, very mild cams and small turbo.ISBN 978-1-910241-27-1 available via Evil Bay.
The damp liner engine particularly overheats because of poor block cooling due to the thicker liners, or have you had a custom set made to improve coolant flow?
According to Mr Hammill there is no margin for error and that is with the narrower wet liners fitted < 94/95.
I have to keep a close eye on the temp' gauge when on the motorway if I get stuck in a jam. This suggest that insufficient cooling flow takes place at tickover on an otherwise sound engine as mine is.
If hes struggling with temperatures its because he doesnt have a good enough radiator/oil cooler setup rather than the engine structure itself
My old bottom end is now in an S1 Elise with a VVC head and active VVC mechs.
Runs 0.8 bar at 7000 rpm with a Rotrex C30-74.
With partially melted cat converter and a measured exhaust back pressure of 0.4 bar before the cat and no muffler, 0.7 bar with a restrictive muffler,
it was pushing 249HP and 299Nm at the flywheel. Air to air intercooler in the side pod. it sees about 70C IATs on track.
The cat did not survive as we were on the edge on what it can take anyhow plus the ignition timing was initially rather conservative. This is increasing cat temperature to rather high levels.
it now runs a proper 100 cell cat and a 2.5" exhaust system normally used for Honda K20 converted cars. It runs an adapted map of my old engine setup.
Goes like stink and should be around 260 or thereabout fwHP now
I don't dare to advance ignition any further without actually driving the car or him having it mapped on a dyno.
I did all the mapping though interviews and data logs. took a while to get it right. Part throttle VVC degree changes induced some misfires at part throttle.
That tok me some time to figure out as I never worked with a VVC before.
This is and was with a plain SAIC (N-series) head gasket and the JDM dyno 9.5:1 CR pistons, so plenty squish. No shims.
The valve pockets got machined by me before refit, so they don't melt and fail like thy did with Stu.
This is of course all with direct port water / meth injection on the order of about 500 ml/min. Jets near the fuel injectors, same side.
This makes it less sensitive to high IATs. The car has no knock. it is very easy to hear in a S1 Elise due to the lack of sound insulation.
Thing is that I have used the bottom end with 1 bar. Lee went even further. We both run quench. Lee's old TT setup uses shorter rods, but it also used custom low CR pistons with a high rim around the crown to get the quench/squish back.
The shim is part of your knock problem IMHO.
Runs 0.8 bar at 7000 rpm with a Rotrex C30-74.
With partially melted cat converter and a measured exhaust back pressure of 0.4 bar before the cat and no muffler, 0.7 bar with a restrictive muffler,
it was pushing 249HP and 299Nm at the flywheel. Air to air intercooler in the side pod. it sees about 70C IATs on track.
The cat did not survive as we were on the edge on what it can take anyhow plus the ignition timing was initially rather conservative. This is increasing cat temperature to rather high levels.
it now runs a proper 100 cell cat and a 2.5" exhaust system normally used for Honda K20 converted cars. It runs an adapted map of my old engine setup.
Goes like stink and should be around 260 or thereabout fwHP now
I don't dare to advance ignition any further without actually driving the car or him having it mapped on a dyno.
I did all the mapping though interviews and data logs. took a while to get it right. Part throttle VVC degree changes induced some misfires at part throttle.
That tok me some time to figure out as I never worked with a VVC before.
This is and was with a plain SAIC (N-series) head gasket and the JDM dyno 9.5:1 CR pistons, so plenty squish. No shims.
The valve pockets got machined by me before refit, so they don't melt and fail like thy did with Stu.
This is of course all with direct port water / meth injection on the order of about 500 ml/min. Jets near the fuel injectors, same side.
This makes it less sensitive to high IATs. The car has no knock. it is very easy to hear in a S1 Elise due to the lack of sound insulation.
Thing is that I have used the bottom end with 1 bar. Lee went even further. We both run quench. Lee's old TT setup uses shorter rods, but it also used custom low CR pistons with a high rim around the crown to get the quench/squish back.
The shim is part of your knock problem IMHO.
Ive said:
Thing is that I have used the bottom end with 1 bar. Lee went even further. We both run quench. Lee's old TT setup uses shorter rods, but it also used custom low CR pistons with a high rim around the crown to get the quench/squish back.
The shim is part of your knock problem IMHO.
I ran 1.8 bar on a stock turbo bottom end with no reliability issues with that bottom end, infact its sitting in my garage as a back upThe shim is part of your knock problem IMHO.
It did not have custom low compression pistons, they werent turbotechnics pistons, just simply VVC pistons with turbo rods which had no squish at all
here is the engine, you can see, not alot of squish in there
My forged engine again used turbo length rods and the same pistons as you with the valve cut outer section removed, as you can see very low amount of squish there being the entire piston is below the top of the liner, plus the 1.9mm of head gasket
the reason stuarts engine is such a high knock amount is big compression, short duration cams and small turbo.
As soon as he puts a better flowing turbine and a drop in compression that engine will really wake up
Thanks for the replies guys.
The only issue I'm actually having is pressurising the coolant. It's not actually overheating. It's getting worse so I'm working on the assumption that the high compression is giving me excessively high cylinder pressures - maybe that's lifting the head and/or killing the gasket.
227bhp thanks for the tip re flywheel/clutch combo. What you say about squish is very interesting. A lot of my own reading led me to the same conclusions - squish is nice to have on a turbo for off-boost performance and emissions but it's not essential.
Marko I've never run a shim. As Lee says my issue is primarily the high static compression ratio from these pistons, then a corresponding high dynamic cr from mild cams, then apparently compounded by relatively high back pressures. Added to that is that my "squish" clearance is too wide to actually squish and just causes det. My setup just doesn't work.
TB thanks for the reference I'll check it out. Cooling has never been an issue on my setup I run a pressure release thermostat and a massive copper radiator. I also run a thermal gasket on the exhaust side to prevent heat transfer back into the head. Even on track when oil shot up to 116 degrees, coolant only prodded 95. On the rollers it sat at 92, same story on the road however I drive it - always around 90. It's one thing I got right!
I knew I'd likely find myself in this situation when I decided to use these pistons I'd ended up with. It's made it through the year. I've been on the track, done a quarter mile at Santa Pod, been to loads of shows, and just really enjoyed driving it. It's going in for the respray next week. Once that's done I'll crack on over winter with fixing all the things I'm not happy with.
The only issue I'm actually having is pressurising the coolant. It's not actually overheating. It's getting worse so I'm working on the assumption that the high compression is giving me excessively high cylinder pressures - maybe that's lifting the head and/or killing the gasket.
227bhp thanks for the tip re flywheel/clutch combo. What you say about squish is very interesting. A lot of my own reading led me to the same conclusions - squish is nice to have on a turbo for off-boost performance and emissions but it's not essential.
Marko I've never run a shim. As Lee says my issue is primarily the high static compression ratio from these pistons, then a corresponding high dynamic cr from mild cams, then apparently compounded by relatively high back pressures. Added to that is that my "squish" clearance is too wide to actually squish and just causes det. My setup just doesn't work.
TB thanks for the reference I'll check it out. Cooling has never been an issue on my setup I run a pressure release thermostat and a massive copper radiator. I also run a thermal gasket on the exhaust side to prevent heat transfer back into the head. Even on track when oil shot up to 116 degrees, coolant only prodded 95. On the rollers it sat at 92, same story on the road however I drive it - always around 90. It's one thing I got right!
I knew I'd likely find myself in this situation when I decided to use these pistons I'd ended up with. It's made it through the year. I've been on the track, done a quarter mile at Santa Pod, been to loads of shows, and just really enjoyed driving it. It's going in for the respray next week. Once that's done I'll crack on over winter with fixing all the things I'm not happy with.
Christmas update!
Picked the car up from paint this week. Merry Christmas to me!!
The guy I went to specialises in restoring classic cars. He's a one-man-band and very familiar with rusty cars. Good thing as my BRM had it's fair share of rot (and dodgy MOT patch repair as you'll see). Not as bad as some but still needed dealing with appropriately. He took most of it to bare metal. Fitted new wings. Cut the rust out the rear arches and welded in new metal. Fabricated new sills on both sides front to back. shot blasted the roof drains and welded new metal in there.
I wanted to modernise the rear end as it's the only pat of the BRM I was never really a fan of. So went with a facelift Zr rear bumper. Whilst a direct fit, it has a number plate recess which needed filling. I taught myself plastic welding (which is easier than it sounds and basically involves melting plastic with a soldering iron) and made the best start of it I could so the paint man has as little to do as possible to make it nice. Very pleased with the outcome. You'll see I'm also running a ZR rear spoiler (which never would have looked right with the little Rover 200 bumper) and I'll also be fitting ZR facelift side skirts to match the bumper (paint man still has one of them - dropped it during final polishing!
All-in-all I'm extremely happy. I'll get some better pictures of the final product once I've got it all together. In the meantime:
Next: I need to fit my shorter conrods and new head so I'll be popping the engine out soon.
Picked the car up from paint this week. Merry Christmas to me!!
The guy I went to specialises in restoring classic cars. He's a one-man-band and very familiar with rusty cars. Good thing as my BRM had it's fair share of rot (and dodgy MOT patch repair as you'll see). Not as bad as some but still needed dealing with appropriately. He took most of it to bare metal. Fitted new wings. Cut the rust out the rear arches and welded in new metal. Fabricated new sills on both sides front to back. shot blasted the roof drains and welded new metal in there.
I wanted to modernise the rear end as it's the only pat of the BRM I was never really a fan of. So went with a facelift Zr rear bumper. Whilst a direct fit, it has a number plate recess which needed filling. I taught myself plastic welding (which is easier than it sounds and basically involves melting plastic with a soldering iron) and made the best start of it I could so the paint man has as little to do as possible to make it nice. Very pleased with the outcome. You'll see I'm also running a ZR rear spoiler (which never would have looked right with the little Rover 200 bumper) and I'll also be fitting ZR facelift side skirts to match the bumper (paint man still has one of them - dropped it during final polishing!
All-in-all I'm extremely happy. I'll get some better pictures of the final product once I've got it all together. In the meantime:
Next: I need to fit my shorter conrods and new head so I'll be popping the engine out soon.
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