Basic info about tuning and different engine conversions available.

[bendjunkie]

Thought i'd do a little write up about the different engine conversions for the ZR/25/bubble range.

Please note, this is only a little brief of the basics.

The easiest and well known modifications for the k series are the breathing mods. (air filter, 52mm throttle body, exhaust).
There are many air filters available, and IMO, the best value for money option is a replacement panel filter for the standard air box, available from a few, inc K&N, mix this with modifying the airbox slightly and you get a decent, yet cheap set up, which visually doesnt effect the engine bay. I see a lot of cars with open cone filters inside the engine bay, and even though they may sound like the engine is running on throttle bodies or carbs, they commonly loose power and torque as hot air from the engine bay is taken in to the engine, (hotter air, less dense, less oxygen).
Exhausts are a more expensive option, but with the extra effect of the sound change, a little more money is usually spent, mandrel bent systems are always better for better flow, unlike compression bent systems that can reduce the bore area substantially at a bend. Be careful of the placebo effect. Sound is very good at giving the effect of more power or greater speed, when infact there is not.

1.4-1.6 conversions. We have done many of these converisons, although quite costly, if done at the same time as a head gasket repair, works out to be a fairly cheap modification with guarenteed increase in power and torque. The power doesnt seem a great deal on paper, but the extra torque spread from the extra capacity helps relieve the need for changine down gears as much for overtaking/hills. This is an increase in capactity and torque, with no external changes to the engine, using the same block and head.
This requires the pistons and liners to be replaced with 1.6/1.8 items, as well as a map to suit.

1.8 120 conversion. To change the internals of your 1.4 to a 1.8, it would require the engine removing, stripping down and rebuilding using the 1.8 crank, rods, pistons and liners. This is not a cheap affair, and usually works out cheaper to buy a complete 120 engine or bottom end second hand, along with ecu or ecu map. (the head and cams are the same as the 1.4/1.6)

1.8 160 conversion. This is similar to the 1.8 120 conversion, but with slight internal differences and a different head. It's usually much cheaper to buy a complete engine, rather than just a VVC head (even though the bottom end differs slightly to the 120, it can be done this way).
Not only is a head needed, but ecu (you cannot remap a non VVC ecu to use on a VVC as the ecu has parts missing to do this), wiring loom, timing belt covers, inlet manifold, exhaust manifold etc etc. You will need to get the ECU programmed into the vehicle using a T4, or fit a complete set (engine ecu, 5as/scu, key fobs). The problems with the VVC are the mechanisms commonly get noisey.

A 1.6 VVC is also possible.

All VVC engines come with an aluminium inlet manifold, these can be fitted to any 4cylinder k series engine, but to get best results the head needs to be port matched, as the VVC head uses larger ports along with larger valves. If you don't use a MEMS3 manifold, you will need to modify it to swap the MAP sensor over. By MEMS3 i mean rover 25 GTI, ZR 160, TF 160 etc (the MG TF 135 non VVC engine also comes with a suitable manifold).

The exhaust manifold can be changed, with an off the shelf manifold available from janspeed. Im not 100% sure on what is currently available as has changed over the years with regards to a different, larger bore available for the 160.

Cams are available, commonly from piper, although others do make them. This is where things get expensive.
These are in a variety of different specs. The higher specs requiring solid tappets that require shimming to suit.
For best results, adjustable pulleys are required so they can be dialled in for perfect timing.
With regards to cams, there are many different specs available, make sure your engine/budget will survive them. Some of the wilder cams will require the ecu to be remapped or an aftermarket ecu for mapping just to get the engine to run reasonable well. Others will run and you will reap many of the benefits and power of the cams without the remap, leaving mapping until after you have done the other modifications so not to have to pay several times, if you intend to pay at all.

VVC cams, there is a direct fit exhaust cam available from piper, which benefits, along with offset dowels.
To go further on the VVC, VVC blanking plates are required. This removes the VVC mechanisms, but retains the larger valves and porting used on the VVC head.

Larger valves are availble for the NON VVC heads, of which, +2mm are the most common. Its easiest to use these on a high port head and port to match. You'll struggle to find a low port head on a ZR/25/ZS etc running MEMS3. This, or find/purchase a VHPD head, which is basically a solid cam VVC head, but very expensive and extremely rare.

For serious tuning, along with internal upgrading, there needs to be some "matching" of parts to get the best gains.
For example, exhaust manifolds are designed to work around particular rev ranges, be them 4 into 1, for peak performance, or 4-2-1 to give a broader band, but lower peak. Its best to match these to the cams etc used. Compression changes also make a difference.

By mems3, i am refering to the engine ecu. This is the wedge shaped ecu as fitted to all the "Zed" range.

K-series turbo.

These are a reasonable conversion, with donor 75's and ZT's getting fairly cheap now. Be aware, they have limits as to what they can produce without serious money spent on the internals. However, they are fairly easy to fit and the turbo helps produce a decent torque spread, even though the peak power on paper is not much different to a 160 engine, you will find the turbo engine much faster. By retaining the lightweight K-series engine, the handing is barely effected, other than the extra weight of intercooler and turbo.
Be aware, if you have a 1.4, this conversion is not as cheap as many suggest. You would be best using a PG1 gearbox (as fitted to the 1.8's), to avoid blowing it up. You will also have to negotiate whatever intercooler and pipework you intend to use around the radiator.
There are tuning parts available for getting higher power from these, and we are currently developing thick wall exhaust manifolds for the K series to allow for larger turbos without fouling radiators etc.

T16 T-series turbo

The 2litre turbo conversion is well known for the ZR and bubble range. The engine is heavy, but what is gained in weight is lost (as such) by the extra power and torque produced. The handling of a ZR with a T series isn't quite as good as that of a K series engined car, but it's not as bad as many say, and what is lost around a bend is more than gained on the straight. Tuning the T series mildy isn't too bad. Boost controller, freeflow downpipe, decent exhaust and possibly a front mount will see good gains. The benefits of a T series are many parts are available for tuning.
The problems with a T16 conversion are, if a good donor car is not used, many issues can arrive later. My usual info for people interested is:-
-not to buy the cheapest donor car, shop around for a decent example, these are getting old now and there is uaually a reason for selling,
-Buy a 220 or 420, if you buy a 620 for example, you will have many parts from the first two still required.
-insure the car and drive it for a couple of weeks, if there are any faults, these can be sorted before or during the conversion,
-if your intending to mod it after, many times it works out cheaper to buy a modded donor car, if more expensive in the short run, however, many times a modded car has been owned by an enthusiast, and is better looked after than others.
Common problems include oil leaks, metal coolant pipes leaking due to rust etc etc.

The points above can be taken for any donor, including a 75/ZT 1.8 turbo.

To add, the 4 cylinder K series engine all have the known Head gasket problems, usually going every 40-60 thousand miles, keep this in mind if you intend on buying an engine/donor car.

There are other conversions available including KV6 from the ZS180 and the Honda B16, but these are a whole different ball game. It is also possible to turbo the 1.4, 1.6 and 1.8 engines. Many using the 1.4 due to the thicker liners.

Gearboxes.

Keep this in mind with any conversion.
The earlier 1.4's mid and pre 53 plate came with the R65 gearbox. This would hardly handle the torque of the 1.4, and many opt to change to the PG1 (as fitted with the 1.8's) if doing a conversion. The IB5 as fitted to later 1.4's seems to handle the torque of a 120 very well from our experence.

Most T16 turbo's come with an LSD fitted as standard (unless they have had the gearbox changed at some point). Both type of LSD can be fitted into any PG1 gearbox, including those for a 120, 160 or even ZS 180.

Adrian

www.AMWmotorsport.co.uk - MG Rover repair and tuning specialist.

[rakester]

fantastic post, stickied

[DannyZR]

fantastic post ade and great information given


guys if any of you are considering something along these lines, Ade is one of the best people in the country to do this and has been doing it for many years under a previous company name which im sure you all will know or of heard of at one point

[DannyZR]

fantastic post, stickied

dammit beat me to it jake

[sean2k]

i was looking at doin a 1.8 120 conversion with a 1.4 gearbox atleast now i know who to ask if i have any problems and has made it alot simpler for me as now i know wots involved

[Marc Kitchen Sr]

Seems like if you are just doing an engine change, say 1.4 for a 1.8 (120) it couldn't really be much easier, change engine/box and ECU, job done.

[JOHNDQ]

I don't no if you will be able to find a VHPD head ive been looking for a engine for ages and no luck at all. Only found a converted VVC engine guy wants £1500 engine was built few years back but is still running stock crank and liners which is no good at all

[Levaz]

I don't no if you will be able to find a VHPD head ive been looking for a engine for ages and no luck at all. Only found a converted VVC engine guy wants £1500 engine was built few years back but is still running stock crank and liners which is no good at all

I know a place that might be able to help with that.
Shipping to beds might be a hiccup though.

[Levaz]

http://www.hawkingevehicles.co.uk/

[JOHNDQ]

You think those guys will have a VHPD engine they only came in a few Caterham and Lotus models