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post #1 of 16 (permalink) Old 23-05-2012, 09:04 Thread Starter
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Compression ratio

I've asked for advice before and got great answers from you guys so thanks, not looking to repeat any questions I've asked but I'm currently starting to get all the bits I need to turbo my ZS 1.6 110

What I need to find out is what's the best way of lowering my compression ratio, I have the MLS thicker gasket (doesn't seem to have made any noticeable difference to how my zed runs) so I've been reading and it seems a 1mm shim is the way to go?

I'm only looking to run a LPT of the 1.8 k series lump

Could buying the turbo bottom end and fitting my 1.6 head with the thicker gasket be the way to go for lower cost and easier to do?

Thanks
Brad
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post #2 of 16 (permalink) Old 23-05-2012, 16:20
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in my opinion. ive done a mg zr turbo from the 1.8k series.

i put the 1.8 turbo engine in changing the inlet manifold for the original one.

made a downpipe for the existing system.

got my ecu back from z and f tuning

plugged in broom
--
the turbo uses a stock 1.8 k series head. no diff from what i could see.

so you can prob get away with putting the bottom end on (as the oil feeds are present) and run the standard turbo.

i was told if you dont get the correct map it will run like crap.
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post #3 of 16 (permalink) Old 25-05-2012, 02:57
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I am no expert but I have it on good authority that if you run the standard 1.6 pistons past 160bhp or 7200rpm that they will disintergrate. PTP are selling forged pistons at around 500.
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post #4 of 16 (permalink) Old 26-05-2012, 17:39
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three ways to do it,

Lower the comp ratio with a saver shim, not ideal but worked well on my 1.4 turbo, 1mm should be ok

Use the 1.8 turbo bottom end, good for 200bhp, as it has shorter rods

use the std comp ratio and run low boost and a bigger turbo. Its flow not pressure that makes power

MLS gasket will help lower comp ratio, but as said not by enough to notice
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post #5 of 16 (permalink) Old 02-06-2012, 20:59
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So basically if you drill a return feed into the block... And use some shims on the head, you can just smash a turbo on and heypresto?

Last edited by lukenobrains; 03-06-2012 at 12:01.
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post #6 of 16 (permalink) Old 11-06-2012, 16:41
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Quote:
Originally Posted by lukenobrains View Post
So basically if you drill a return feed into the block... And use some shims on the head, you can just smash a turbo on and heypresto?
Pretty well near enough but DO USE the thicker 1mm head shim with the MLS gasket which will give you between 9-9.5 - 1 C/R slightly higher than the standard turbo 8.5-1 but lower than the 10.5-1 of the NA engine. The inlet and exhaust turbo manifolds will bolt straight on and the standard turbo and downpipe will as well in a ZS (the downpipe needs modifying slightly on a 25/200/ZR). I know this for a fact as I have done it and have all of them here. If you want to spend about 150 more get a set of second hand turbo rods they are 2mm shorter and that is how Rover lowered C/R. The turbo oil return pipe requires the side of the crank carrier drilling and a 10mm spacer put in place between the carrier wall and return pipe flange and it will sit perfectly using the standard ZT pipework and oil filter housing. If you go that way I would think the standard ZT Mems3 should run it ok but either way Z&F can remap your standard mems3 for around 220 they have hundreds of maps so just give them the exact setup of your engine and they can do you something pretty good. The pistons are good for in excess of 160bhp so is the crank and I can't see any reason the rods would not be. The standard 1.8/1.6 pistons are running in engines upto 220 bhp, the rods in engines up to 250BHP as are the cranks. A turbo producing 160BHP will be doing so at around 1500 RPM less than a NA engine and the limit on the standard parts seems to be the RPM not so much the BHP. So with the Turbo conversion you have a better chance of seeing higher BHP than the NA on standard parts.
djwillma and RallyMatt are two of the guys that realy know their stuff on this they have done it and got the T Shirts mate.

Just as a note I have measured a large number of single layer and MLS gaskets both new and used as well as the so called turbo gaskets. On average the MLS is between 0.5-0.8 mm thicker than the single layer gasket so assuming your head is standard un skimmed it will lower the C/R by using the MLS. The shim used in the MLS gasket sets I have measured are 0.3-0.5 mm thick so by replacing that shim with the 1mm option you end up far closer to the 8.5-1 of the standard turbo engine than you do of the 10.5-1 of the N/A version. The shim was originally designed for heads that have been skimmed several times to restore the C/R. Using this combination you will keep below 9.5-1 C/R and I know for a fact there are a fair few turbo's running around at 9.5-1 very happily :-)

Last edited by Ian Roberts; 11-06-2012 at 16:55.
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post #7 of 16 (permalink) Old 12-06-2012, 07:13
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"slightly higher than the standard turbo 8.5-1 "
std turbo ratio is often quoted at 9.2:1
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post #8 of 16 (permalink) Old 12-06-2012, 16:55
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Quote:
Originally Posted by elise View Post
"slightly higher than the standard turbo 8.5-1 "
std turbo ratio is often quoted at 9.2:1
If that is the case then running at 9.5-1 as others have done is no problem what so ever. I seldom post on here these days I just get on with doing it. The point is 8.5-1 or 9.2-1 it is fairly easy to achieve and if as you say the C/R is 9.2-1 then is is even safer and makes it even more sense to increase the size of the shim to 1 mm as that will give you very close to 9.2-1 without changing to turbo rods the principle is exactly the same. Good luck to all those that go for it as it is a far cheaper way of gaining power using all but standard rover parts as long as you keep the revs down and are not looking for more than 200BHP. That said as I say I know for a fact a couple of cars are running nearer 220BHP on basically standard parts.

Last edited by Ian Roberts; 12-06-2012 at 17:43.
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post #9 of 16 (permalink) Old 12-06-2012, 21:40
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pistons and rods side by side 160vvc and ZT 1.8 turbo

Hope this helps clear up a few queries. I have both a 160vvc engine from my ZR 160 and the internals from the bottom end of a ZT 1.8 petrol 04 plate.

Cranks they are the same with identical id numbers

The rods are VVC 160 id number LFF101130
ZT Turbo id number LFF000410

The turbo rods are 1mm shorter and have more "meat" around the little end bearing.
The pin sizes are identical
The Big end bearings are also identical (although these can vary)

The turbo pistons and 160 VVC pistons are all but identical although believe it or not the turbo pistons have slightly deeper pockets for the valves. The turbo pistons have C ST stamped on them and the VVC have AR 160 on them. The depth of the crown of the piston is very slightly thicher to the top piston ring than the VVC piston BUT the overal dimensions of the pistons are the same with the lower scraper rings being lower and closer to the gudgeon on the Turbo piston than on the VVC piston ( this may account for the number of broken turbo pistons I have seen just above the gudgeon pin) maybe a good reason to use a 160VVC piston on a turbo build rather than a Turbo piston. With the pins fitted the top and bottom of both pistons lay in exactly the same position.

All in this means the Turbo engine block has been decompressed by 1mm compared to the VVC bottom end.
You need to factor into this the different heads and combustion chambers BUT assuming they are near enougth the same it would appear that is you use the MLS gasket with a 1mm shim you should be around the same CR as the ZT turbo lumps.
Whatever the standard CR is in reality on the NA or Turbo engine you still need to allow for any skimming etc increase in CR and for any work you may have done on the combustion chamber in the head decrease in CR but all said they would be very close in CR with a 1mm spacer (45) fitted or just use turbo rods on the VVC bottom end (150) the difference between the two is 95.
On close inspection the turbo rod being slightly shorter and having a beefier little end to the rod I would expect it to be very slightly stronger.

This is all taken from genuine rover parts I have here and the measurements are accurate.

Have a look at the pictures.

I have this clears up a few queries and myths for all that are going the turbo route either VVC or non VVC. Dont forget the VVC head has larger valves and ports so should give better overall performance and can be used with the VVC mechs and higher spec cams as is or converted to solid intake cam effectively giving you a VHPD head.

I hope this helps a few of you and have a look at the pictures ( turbo on the left VVC160 on the right) and good luck to all going for it :-)
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post #10 of 16 (permalink) Old 12-06-2012, 21:43
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More picture

final pictures
I have even now swaped piston rings between both types of piston and they appear to fit both and move freely. The biggest surprise was finding the Turbo pistons have deeper pockets than the VVC 160 items considering the sit 1mm lower in the bore due to the shorter rods and they run smaller valves. But on the downside they have less meat above the pins and the lower rings so that would be a slightly weaker point compared to the VVC piston. Remember all this is my personal observations but are based on measurements taken from original MG Rover parts.
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Last edited by Ian Roberts; 12-06-2012 at 21:50.
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post #11 of 16 (permalink) Old 13-06-2012, 08:34
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Thanks for posting the information above, I'm not sure you'll get much thanks for it but hopefully (assuming you're still doing this conversion?) it will become invaluable for other people who go down this route in the future. Hats off to you Mr. Roberts, a pioneer and inspiration.
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post #12 of 16 (permalink) Old 13-06-2012, 11:34
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Quote:
Originally Posted by Kameleon View Post
Thanks for posting the information above, I'm not sure you'll get much thanks for it but hopefully (assuming you're still doing this conversion?) it will become invaluable for other people who go down this route in the future. Hats off to you Mr. Roberts, a pioneer and inspiration.
Not looking for any thanks mate just trying to clear up a few myths by getting the parts and finaly confirming the differences. If reworked following Dave Andrews advice on his website "The Bible" as I call it and fitting a PRT you can overcome the overheating problems and get some good reliable power using mainly standard parts from the VVC and ZT/75 turbo cars. Plenty of people have done it so I am not re inventing the wheel just trying to get as much information in one place to help all going down the same route. The T16 is a heavy lump and an ever decreasing supply but there are thousands of K Series out there that can be converted fairly easily and relatively cheaply. These Turbo engines are to an extent an unknown quantity in regards to how far you can push standard parts. What I have learned from other who have done it is.
1. Standard pistons max out at 200-220 BHP
2. Rods max out at around 250 BHP as far as we know
3. Cranks max out at around 250 BHP as far as we know
4. Liners have been used upto 220BHP maybe more but Ductile liners are available and good for much higher RPM and BHP and hold their shape well
5. Engines are running happily at 9.5-1 and upto 220BHP on all but standard parts BUT that I would think depends on the quality of the build.
6. There are both VVC and solid cam turbo's running well and reliably BUT remember that there is a limit to how far you can rev the VVC mechs, so you need to decide how far you want to Rev your engine and the limits of these. Dave Andrews again knows the limits of these cams and can give very good advice along with others that have built turbo's. I have been told the VVC can be locked out by removing the solenoid effectively creating a non variable cam system but investigate this as I know nothing about it although if you look at the VVC it is clear to see how it can be done.
I am sure there will be engines out there that have pushed it more but these seem to be around the safe limits as far as I can tell from feedback from Guys that have built and run them.

Wossner DO MAKE steel rods and forged pistons for both NA and Turbo K series BUT it looks like the best way to obtain them is to go straight to them in Germany.
Others like Omega make pistons that you can use in either NA or in a turbo using a shim but they DO increase the CR by 1-1 so you need to allow for that in your build.
Maxspeeding steel Rods have been made for some builders but at the moment I have no feedback as to how well they perform.
Ductile liners in my oppinion are a must if you want to push the engine and are available from Westwood or Dave Andrews.
Arrow HAVE made cranks as have other manufacturers but the original MG Rover items appear to be better balanced although maybe a little light. It would seem that a well know 1.4 running 250BHP was running on an Arrow crank?

Finaly YES i have two engines on the go the first is running mainly standard parts although I may well use Forged pistons to give a bit of scope and safety for 200BHP+. The second engine I am using Ductile liners, Steel rods, forged pistons and a steel crank if I can find one for a decent price, M series hybrid intake system, uprated turbo and 3 inch exhaust and hope to find a suitable A series Mini to RWD.

Last edited by Ian Roberts; 13-06-2012 at 11:53.
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post #13 of 16 (permalink) Old 13-06-2012, 13:01
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Quote:
Originally Posted by Ian Roberts View Post
Not looking for any thanks mate just trying to clear up a few myths by getting the parts and finaly confirming the differences. If reworked following Dave Andrews advice on his website "The Bible" as I call it and fitting a PRT you can overcome the overheating problems and get some good reliable power using mainly standard parts from the VVC and ZT/75 turbo cars. Plenty of people have done it so I am not re inventing the wheel just trying to get as much information in one place to help all going down the same route. The T16 is a heavy lump and an ever decreasing supply but there are thousands of K Series out there that can be converted fairly easily and relatively cheaply. These Turbo engines are to an extent an unknown quantity in regards to how far you can push standard parts. What I have learned from other who have done it is.
1. Standard pistons max out at 200-220 BHP
2. Rods max out at around 250 BHP as far as we know
3. Cranks max out at around 250 BHP as far as we know
4. Liners have been used upto 220BHP maybe more but Ductile liners are available and good for much higher RPM and BHP and hold their shape well
5. Engines are running happily at 9.5-1 and upto 220BHP on all but standard parts BUT that I would think depends on the quality of the build.
6. There are both VVC and solid cam turbo's running well and reliably BUT remember that there is a limit to how far you can rev the VVC mechs, so you need to decide how far you want to Rev your engine and the limits of these. Dave Andrews again knows the limits of these cams and can give very good advice along with others that have built turbo's. I have been told the VVC can be locked out by removing the solenoid effectively creating a non variable cam system but investigate this as I know nothing about it although if you look at the VVC it is clear to see how it can be done.
I am sure there will be engines out there that have pushed it more but these seem to be around the safe limits as far as I can tell from feedback from Guys that have built and run them.

Wossner DO MAKE steel rods and forged pistons for both NA and Turbo K series BUT it looks like the best way to obtain them is to go straight to them in Germany.
Others like Omega make pistons that you can use in either NA or in a turbo using a shim but they DO increase the CR by 1-1 so you need to allow for that in your build.
Maxspeeding steel Rods have been made for some builders but at the moment I have no feedback as to how well they perform.
Ductile liners in my oppinion are a must if you want to push the engine and are available from Westwood or Dave Andrews.
Arrow HAVE made cranks as have other manufacturers but the original MG Rover items appear to be better balanced although maybe a little light. It would seem that a well know 1.4 running 250BHP was running on an Arrow crank?

Finaly YES i have two engines on the go the first is running mainly standard parts although I may well use Forged pistons to give a bit of scope and safety for 200BHP+. The second engine I am using Ductile liners, Steel rods, forged pistons and a steel crank if I can find one for a decent price, M series hybrid intake system, uprated turbo and 3 inch exhaust and hope to find a suitable A series Mini to RWD.
^
!
!

People need to start taking this guy seriously, he knows his stuff.
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post #14 of 16 (permalink) Old 13-06-2012, 14:52
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Originally Posted by gazzring View Post
^
!
!

People need to start taking this guy seriously, he knows his stuff.
Not realy. I just collected all the parts together so I have been able to compare and measure everything and have kept one of everything for reference. It has taken me 10 months and the original idea was to find a way of building a K Series Turbo using as many as possible Original parts and to do the whole job for under a Grand and get as close as possible to 200BHP WITHOUT breaking anything. I have been lucky enough to have the time to do it as my back is broken and people like djwillma, Dave Andrews, Rudder etc have lead the way. All I have done is collect the parts and try and collate the information and work out simple and easy ways of doing the job.
We did all this years ago on engines like the Ford CVH and Vauxhall 2.0l and the principles are more or less the same. People could do far worse than read a bit of the history on coversions like those and the ZVH (CVH turbo head/Zetec bottom end) and even the likes of the Saxo and AX turbo's all done using the same basics.
These K series engines have a lot of potential once the basic flaws are ironed out ie remote thermostats and opening up waterways as well as things like fitting Gaskets PROPERLY to clean and undamaged surfaces.
I would love to see a K Series Turbo forum and arrange a meet for all the turbo variations so that people can see IT IS a worthwhile and very cost effective alternative.
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post #15 of 16 (permalink) Old 13-06-2012, 19:31
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Quote:
Originally Posted by Ian Roberts View Post
Arrow HAVE made cranks as have other manufacturers but the original MG Rover items appear to be better balanced although maybe a little light. It would seem that a well know 1.4 running 250BHP was running on an Arrow crank?
mine/dylans?

was a DKE crank, now owned by Arrow. nothing wrong with the balancing.

Drew
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post #16 of 16 (permalink) Old 13-06-2012, 21:46
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Originally Posted by Roverdose View Post
mine/dylans?

was a DKE crank, now owned by Arrow. nothing wrong with the balancing.

Drew
I know your crank is spot on mate that is why I mentioned Arrow as I was told they had something to do with DKE but was not sure of the connection. The Rover originals by all accounts are very well balanced and from what I have read Arrow seem to be the people to match or improve on them hence why I mentioned them and no other manufacturer. If I were to go for a steel crank that is exactly what I would want to get as it is so bloody good. Others I can't and don't comment on as from what I have "read" dont seem to be as well balanced as either the Rover or DKE/Arrow items. It was Dylan that advised me that it may well be Arrow and I had already contacted them as they have a good reputation and are only 30 miles from me. The fact that it was manufactured by DKE may well explain why that is the only one I personaly know of although I am sure others exist and are in use. I would love to have one of their cranks for my 1.8 build but dont have the 2000 at the moment. Please don't think I am putting down the quality of their cranks far from it thats why I mentioned them.
All I am doing is sharing what I have found out from measurements, bolting things together and from knowledge shared with me buy people like Dylan and now yourself. It is all stuff that has been done before without a doubt but some of the parts are not easy to get hold of if you are building a higher spec engine like your 1.4 screamer. The fact that DKE made it and are now part of Arrow will helps others to track down manufacturers more easily. The Wossner rods and pistons are a classic case of tracking down the parts and there again Dylan was the person that told me to go straight to Wossner Germany and even made the enquiries to get a few sets that is why I also mention him djwillma as he is a top guy and helped me no end. It is great to have your input as well as it will make it so much easier for myself and others to make the right choices and find the parts for more powerful engines, if that is what they want.

http://www.arrowprecision.co.uk/details.php?id=70445

Last edited by Ian Roberts; 13-06-2012 at 22:11.
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