The definitive guide to fitting

Vauxhalls 2 litre, 16 valve XE engine into the Opel Manta B

Some of this may seem basic but I just wanted to cover everything

Click on all pictures for a bigger version

Parts required

1 x complete redtop engine & wiring loom

1 x astra GTE clutch plate cover

1 x manta 1.8 gearbox

1 x manta 1.8 big wing alloy sump & oil pickup pipe

1 x manta 1.8 or 2.0 crank spigot bearing

1 x manta 1.8 or 2.0 clutch friction plate

1 x manta 1.8 sump gasket

1 x set of manta 1.8 engine mounts

1 x RWD conversion manifold

Assorted coolant piping

Fitting to a 1.8 or 2.0 GTE

Fitting the redtop to a GTE is preferable in my opinion as the fuel side is already there, whereas fitting to a carbed 1.8 manta requires you to fit the injection petrol tank, fuel pump as well as running another fuel line (for return), The only benefit to fitting this engine to a carbed manta is that the exhaust goes the same side, however you'll still need to modify the exhaust system to get it to fit to the 16v manifold, but of course the car will already have all the bits you need so there is that.

General fitting

This is a fairly straight forward conversion which took me 2 weeks to complete, this was longer than expected as I had difficulties finding wiring codes and I had other electrical problems.

The 16v engine will fit straight into the manta, there is not much clearance between the injection manifold and the servo reservoir but it's enough.

One place that does require some adjustment is the bulkhead, as the plug which comes out of the non-cosworth heads is in a bad place so to be able to get a pipe on comfortably you really need to take off around 3 inches then you'll have no trouble.

The standard SFI airbox (the one that's bolted to the injection manifold, not the air filter housing) requires a bit of adjustment to allow the bonnet to close and to clear the brake servo oil reservoir.

The heater also needs to come out as the distributor on the back of the engine needs to go there, so you'll need to either fit the Golf mk2 heater (smaller & better) or find some other method of heating the cabin, either with an electric heater or find somewhere else to mount the heater.

Redtop engines

There are 2 types of this C20XE engine available - the very early 'Coscast' head ones which apparently don't suffer from the porous head problems that the later ones can suffer from. These engines are 150bhp standard.

Of course there are the C20LET turbo versions (approx 210bhp) as well as the not so good Ecotec engines which have a measly 136bhp.

The Coscast head versions of the C20XE engine can be distinguished as the non-cosworth head has a core plug in the back (in a manta) and the cossie ones have a big casting rib here with no core plug, also on the head to block flange on the exhaust side on an overhanging part of the machined surface there’s the word 'Coscast' stamped.

Exhaust manifolds

When I rang around, Peter Lloyd had stopped stocking them; I could never get hold of Yukspeed so I rang Ashley competition exhausts, for £244 I got a 4-2-1 manifold finishing in a 2 & 1/4 inch end.

Yukspeed – www.yukspeed.com Tel. 01653 618540

Ashley – www.ashleycompetitionexhausts.com Tel. 01922 720767

Peter Lloyd – www.peterlloydrallying.co.uk Tel. 01656 724777

Air filters

The standard airbox requires a few mods to allow it too fit, this shall be covered in detail later on. However the filter box from the astra GTE was to big for my liking so a K & N 57i kit can be bought for the astra for approx £70 and will provide extra performance and is a lot more compact and nicer to look at.

Step 1

First remove the battery, you will obviously need the rip the old 8v out, even if your modifying a 1.8 I'd suggest removing the gearbox as well (fitting the gearbox to the 16v block before it's in the car is a little easier than trying to get them aligned lying underneath the car - this is unimportant though) don't forget your clutch cable and the 2 wires which plug into the offside of the gearbox (reverse selector switch).

Remove the old injection loom and ECU and don't forget to fill the hole where the loom goes through the bulkhead by fitting a rubber grommet etc. (If GTE)

Also mark the fuel lines (if GTE) which one is return and which is inlet.

Step 2

Remove the entire heater assembly, the piece that holds the little water matrix is a little difficult compared to the other 2 bits as you need to remove 4 screws from inside the car, these are right in the centre of the car and behind the dash, however with a little bit of a struggle and by removing some of the heater hoses you can get them access to all 4, they are 8mm.

Step 3 - Modifying the bulkhead

To do this firstly, very gently pull the brake lines forward to allow you to get an angle grinder in there so you can cut out the 3 inches required for the water pipe on the back of the 16v head, as the picture shows; you only need to cut the top ledge out and not the side section as this side piece can be cut down the centre and eased back with a hammer so you can then weld it back up in line with the top section, only a small piece of metal is then required to fill in the small central gap.

The brake lines then need to carefully be angled round to follow the curve and to hold them in position you can use the original plastic holders (If your careful enough when taking them out) as the holes will still be there.

Treat with appropriate rust inhibitor and paint/waxoyl etc.

This method will give you lots of clearance.

Step 4

With the engine out now is the time to weld up those hard to reach parts of the chassis rails and coat with waxoyl as well as sorting out the battery tray.

It's also a good idea to find a suitable location to mount the oil cooler now, I mounted mine where the original horn was as the pipes then did not need bending and it could easily reach the engine connectors.

Step 5

Decide what to do about a heater or do as I did and just put some thick plastic (cut to size) over the large hole where it goes through the bulkhead. To save drilling more holes there use the existing 4 holes and put 2 lengths off plastic on the inside of the car (vertically) and screw into them from the engine bay side (2 people required). Be sure to use sealant otherwise fumes will get through.

Step 6

Also just behind the battery there is the cold air feed for the centre dash vents, If left in this condition you may get fumes through as its getting air from inside the engine bay. I chose to pull this piece out and cut off most of the molding that sticks out and stick on a piece of plastic to block it off (use sealant here too).

Also where the old injection loom (If applicable) went through the bulkhead, make sure you seal up the rather large hole that’s left otherwise it’s gonna get cold inside.

Step 7 - 16v engine preparation

Firstly, remove any unwanted ally brackets from your engine, these were for air conditioning and power steering and no longer needed.

Fit your manta 1.8 alloy engine mounts

Now take off the 16valvers original sump, oil pick-up pipe and windage tray.

The above pick-up pipes are manta 1.8 (top) & 16v (bottom) note the length difference. Both may work - I didn’t try.

The windage tray needs a small section cutting away to allow it to fit into the 1.8 sump.

Remove this section from the windage tray and attach the manta 1.8 oil pick-up pipe along with the windage tray (these 2 items need to go on together as putting the pick-up pipe on first means the tray doesn't fit on after). Then attach the sump using 1 new gasket between it and the tray as well as the usual gasket sealant (I've read in some articles about this conversion that some people have used 2 gaskets, this is not required)

Now remove the 16v clutch cover plate from the engine along with the friction/drive plate and insert the small spigot bearing into the hole in the end of the crank using a little high melting point grease.

You can remove a spigot bearing from a 1.8/2.0 manta engine by using a piece of round bar that is tight fit into the bearing - pack the bearing full of grease and place the bar just inside the bearing so it's aligned with the roller bearing and strike the end with a hammer, the force applied on the grease will push the bearing out!! It works but may take some patience to achieve.

The round bar that I used was the end of an old CIH gearbox that was cut off with the angle grinder, this can then also be used to hold the friction plate in place while you tighten the clutch cover.

Now bolt on the a new manta 1.8 friction plate and bolt on the 16v clutch cover, use the above item to hold the friction plate in place if need be.

Both pictures: 16v on left, manta 1.8 on right

The manta 1.8 gearbox can now be attached if you wish.

However I soon discovered that the baffle plate which goes on the bottom of the gearbox; didn’t quite fit correctly, so this will need cutting slightly.

Before and after cutting

You'll also need to figure out what you intend to do with regards the coolant pipes on the injection manifold side of the engine.

I took the plastic pipe which bolts to the block off, made an angled reducer pipe from copper so it would fit directly onto the large 16v pipe that the original plastic one went to and then fit tightly into some standard manta hosing, this came out by the brake servo and was connected to a length of copper piping which then connected directly to the bottom of the standard radiator. My reducer pipe also had a small branch angled off which could be used for a heater system at another time however I just connected it directly to the water pipe on the back of the head with more spare manta hose.

My method would probably be frowned upon by some, but I did not have the time to look around and buy more ideal piping, this method works fine and overheating does not exist - the engine actually runs cooler than the old 2 litre CIH engine ever did (just below the half way mark).

Step 8

The 16v engine is now ready to fit into the car.

When the engine is in the engine bay and correctly aligned with the engine & gearbox mounts and the prop shaft is re-inserted with the spring in the end, you'll probably need to lift the engine back up a little as you'll find out that the nice new shiny exhaust manifold won't fit in with out either a suspension arm being taken off or the engine moved slightly, once on the manifold should have enough space either side to avoid any knocking when running.

The problem with my Ashley one was that the lip where the exhaust goes from 2-1 pipes was knocking against the gearbox cross-member mounting bolt, bending the 2 pipes down a touch was out of the question and I really didn't want to take the exhaust off to trim the lip, so I had to modify the cross-member, this meant I had to undo both bolts to get the one out and then cutting off about 2 inches worth of cross-member and then drilling the gearbox tunnel to allow my specially made bracket to be bolted on so I could then re-attach the gearbox cross-member!!!

This may not be the case with all cars and indeed all exhaust manifolds - beware!

Now re-lower the engine onto the mounts and tighten everything up.

Step 9

Do the usual procedure of re-attaching all the cables (clutch, speedo, reverse selector switch wires), the manta GTE throttle cable will fit directly onto the 16v injection set-up.

And then attach the coolant hoses.

Hoses I used for my conversion:

A top radiator hose from a manta 1.8.

This little beauty which is also off a 1.8 I believe.

2 top radiator hose’s from a manta 2.0 GTE – notice the one in the back ground connected to the bottom of my rad.

This was also used to join the 1.8 top hose to the 2.0 top hose piping; although it says 265mm length the true length needed was nearer 290mm – cut to your own judgment.

Step 10

Now the fuel lines need connecting, the 16v has bolt on fuel lines so you'll need length's of this line with the screw on end (The same screw on connectors are used on the modern ecotec engines), to join to your lines use a thin piece of copper piping about an inch long and small enough so that it's a tight fit into the 2 ends that need connecting; then just use some of the old fuel line jubilee clips from the old engine to clamp the pieces together tight.

Picture on left shows inlet line, right shows return

If the car is not a GTE then you'll also need to fit an injection fuel tank as well as an electric fuel pump either the standard manta GTE or an upgraded one, as well as another fuel (return) line.

Step 11 - Wiring the 16v harness to the engine

First push the long plastic piece down over the injector plugs, making sure it's the right way round and that all the spring clips 'clip' onto each injector. Also be sure to put the 2 separate plugs that are on a length of wire coming from the underside of the plastic multi connector; down between the injectors where they fit down best, these need to then be connected to the knock sensor (black) and idle speed adjustor (white).

If you find that the colours of the plugs don't match the connectors on the engine (like mine) you'll need to check the colours of the cables going to the plugs and position them as follows -

Knock sensor loom wires -          Black & yellow

                                                Brown & white

Idle speed adjustor -                   Red & blue

                                                Brown & dark blue

Water temperature sensor -        Blue

                                                Blue & light green

Mine did not match up exactly with these colours, my knock sensor wires were brown & white and brown & black. So long as one of the wires matches up it should be ok.

Next connect up the distributor and crank sensor; these are easy as they are both different plugs to anything else.

Connect up the 2 water temp connectors on the block, the small round one needs to connect to your old blue wire that was used for your temperature guage, the other connects to the spare plug that comes from the injection loom and is probably on a length of cable by itself.

Also mount the coil somewhere suitable and plug in the engine loom connections, straight forward as the plugs don’t fit anything else.

Step 12 - Wiring up the 16v harness to the car harness.

Connect the 2 looms together as follows:

Wires from the 16v loom:                                                Wires on the old injection plug:

Green –                         Tacho/rev counter                       Green -                                     Tacho/rev counter

Blue –                           Fuel pump                                 Red & Blue -                              Fuel pump

Black & Red -                Starter motor                             Black & Red -                            Starter motor

Blue & Green x2 -          Oil pressure                               Blue & Green + Blue & Yellow – Oil pressure

Black –                                                                         Black –

Blue & White -                                                               Blue & White –

Red –                                        Permanent +12v

 11 wires are in this plug 7 of them are required.

Step 13

Now’s a good time to connect the vacuum line from the injection manifold to the brake servo.

My method was to use the original 16v tube and non-return valve and connect some old manta sunroof drainage pipe (it’s all I had to hand) from the valve to the servo.

Slight heating of the pipe is required to get it over the connectors, once cooled down it makes a tight fit.

Step 14 - Positioning the ECU

Unfortunately there's not enough cable to allow you to mount the ECU inside the car, this is a matter of personal preference where you want to mount it, some have mounted it up by the windscreen washer bottle (If the smaller round one is fitted) but I chose to mount it down near the headlights. Where ever you choose make sure it has a good earth connection.

Then find somewhere suitable to mount the cable, I cut a chunk out of the radiator mounting panel and drilled 2 holes either side and used a cable tie to hold it in place.

Step 15

The car can now be started if you wish (if the airbox & airflow meter is attached), however the rest of the exhaust system will now require modifying to couple up to the manifold unless a custom made system is being fitted.

Step 16

The air-pre-volume box will now need modifying to allow the bonnet to close; alternatively a bonnet bulge could be installed. However the underside of the air box needs modding whatever just to clear the brake servo reservoir.

This is how far my bonnet stuck up with no mods to air pre-volume box

To adjust the air pre-volume box, extensive modifications need to be carried out to it.

First mark out the bottom section which needs cutting out.

Cut this out and use some method of sealing it (I used fibreglass).

The top will now require cutting as well as the inlet hole moving down by about 9mm.

Fit a decent air filter, don't be tempted to try and make a temporary one; it'll end it disaster as I found out and had to get hold of another air flow meter.

Final note

Good luck with this mod it’s not especially difficult and its well worth the effort.

If I’ve left anything out or there’s bits you think need improving and if you have any questions about the conversion, email me at - mlocke666@hotmail.com

Or/Also check out the forums on the manta owner’s club website for loads of technical advice - www.mantaclub.org

Loads of pictures and information are available about my mantas on my other websites - www.opelmanta.4mg.com & www.opelmanta24v.4mg.com