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Will A 2.4 Frontera Engine Bolt Into A Manta?


mantaboy89
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It is a straight swap mate, a very common conversion for the CIH models. Well not quite done as much as redtops but your GTE box will bolt on nicely and it saves having to spend out trying to find 1.8 stuff! The only complications I've heard of is trying to use mixes of injection systems.

I haven't done the swap myself as I'm looking to do a Monza 3.0 CIH at some point, so I let someone who has done it advise, but it's an easy one for certain.

Edited by Rick-Manta
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Doing this conversion for another club member as we speak. First thing you will have to do is factor in a re-build of the engine.

The raeson being is the 2.4 has an over square bore which means the pistons ware the bores on the sides so you end up with oval bores and round pistons.

Anything over 40,000 miles will need a re-bore and a new set of pistons. Valve seat will also need to be checked for pitting, these heads are lead free but the valave seat still don't like the lack of lead.

Other points to look for are the chain guides as these have a habbit of breaking up which can damage the chain. Or the other way is to drop the engine in and hope for the best.

Sump wise you can use the 20e one without a problem. The 20e flywheel and clutch will fit but if you are giving it a bit of hard the thats going to wear quite quickly. For the one i'm building we are useing a Monza flywheel and a 2.2e carlton Clucth kit.

Ign/wiring etc, The best set up is a 2.2 Carlton manifolds plus all the wiring, sensors and ECU's and Dissy, problem is they are getting very rare. You could keep the 2.4 system but you will need to cut a hole in the bonnet as the Fronerta Inlet mainfold sits to high in the engine bay. Or run a hybrid of 2.2 mainfolds with 2.0 wiring but you will need to drill out the back of the inlet so you can fit the fifth injector. 2.0 manifolds don't fit as the ports on the 2.4 are stepped instead of being in a straight line

Otherwise apart fron that its a straight swap. There will be a tread for the build once there is something to wite about

Cheers

Andy

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Doing this conversion for another club member as we speak. First thing you will have to do is factor in a re-build of the engine.

The raeson being is the 2.4 has an over square bore which means the pistons ware the bores on the sides so you end up with oval bores and round pistons.

Anything over 40,000 miles will need a re-bore and a new set of pistons. Valve seat will also need to be checked for pitting, these heads are lead free but the valave seat still don't like the lack of lead.

Other points to look for are the chain guides as these have a habbit of breaking up which can damage the chain. Or the other way is to drop the engine in and hope for the best.

Sump wise you can use the 20e one without a problem. The 20e flywheel and clutch will fit but if you are giving it a bit of hard the thats going to wear quite quickly. For the one i'm building we are useing a Monza flywheel and a 2.2e carlton Clucth kit.

Ign/wiring etc, The best set up is a 2.2 Carlton manifolds plus all the wiring, sensors and ECU's and Dissy, problem is they are getting very rare. You could keep the 2.4 system but you will need to cut a hole in the bonnet as the Fronerta Inlet mainfold sits to high in the engine bay. Or run a hybrid of 2.2 mainfolds with 2.0 wiring but you will need to drill out the back of the inlet so you can fit the fifth injector. 2.0 manifolds don't fit as the ports on the 2.4 are stepped instead of being in a straight line

Otherwise apart fron that its a straight swap. There will be a tread for the build once there is something to wite about

Cheers

Andy

Got 2 of these motors myself. Firstly the blocks are virtually identical apart from minor internal cut outs for the conrods to clear the block. Both the blocks i had were excessively worn at the top of the bore (only the top 10mm). This is down to the bad rod ratio and also the short depth of the pistons which causes the piston to rock at the top of the stroke. This could be attributed to the centre pin being offset by 90 thou which will make matters worse. Last time i priced up a set of std pistons they were about 90 quid each (Mahle). I went with a set of Wossner pistons instead, far better as they are forged, deeper cut outs so you can run wild cams, pin is in the centre and they also have a molycote spray coating to help with bore wear. Best thing was that i got them cheaper than the std ones.

The std pistons are pretty crap and have a low comp ratio as the pistons are dished, they are also prone to the top part of the piston breaking away. Personally i would rebuild with Wossners or similar.

I would definately not use the 2.2 carlton clutch...why you ask. Used one on a 2.2 tuned motor i built (180bhp ish) and it lasted 1 rolling road session and 2 6 lap 1/4 mile races before it was shot, slipping like a $%$£%^&*. That was a brand new LUK.

Use the 2.0 have it modded/lightened and use an XE non pot clutch. This should be ok, to be extra safe use the turbo calibra cover. I have had a steel flywheel made up (5.2kg) and will be using a Helix manta 400 cerametallic job.

I personally would not use injection as they are all very limited in the power output that they can go to. You can get the 2.0 plenum to fit a 2.2/2.4 head by drilling smaller 6mm holes to line up with the 2.2/2.4 ports and then smooth the ports out with a die grinder/dremmel. You will need to fab up some rectangular washers to get the manifold to stay in position and seal. Try lining it up and you'll see what i mean. The 2.2/2.4 injection systems are basically economy systems so tend to strangle the motors. this way you can stay with the 2.0 system which is simple and you won't need to do any mega mods/wiring. The thermostat housing will be a bit of a fiddle but you can make up an adaptor to use the 2.0.

The std manta exhaust will fit as the exhaust ports are in the same place.

Good point about the 2.4 is that the rods/crank are forged steel so are pretty strong.

You could use the 2.0 head on this motor and fit the larger valves to it. Have a bit of porting done and its not quite as good as the 2.2/2.4 motors but makes life easy fitting.

HTH

Chris

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The only complications I've heard of is trying to use mixes of injection systems.

And lack of a dipstick hole. I took the dipstick tube out of a CIH block and welded it into the side of the sump rather than drill the block. Kept height of tube the same so a standard dipstick will do. Similar idea to how the Frontera handles this point.

You need the injection system from a 2.2 as the 2.4 setup will stop you closing the bonnet!

You could keep the 2.4 system but you will need to cut a hole in the bonnet as the Fronerta Inlet mainfold sits to high in the engine bay.

The Frontera 2.4 plenum isn't part of the injection system any more than an inlet manifold is part of a carburettor. I have a 2.4 in the shed fitted with a 2.2 Plenum that is wearing the 2.4 throttle body and fuel rail and injection system.

It's also wearing a manta cold start injector in the rear "plug" so I can fail back to Jetronic in the case of a failure

Not sure, think the Manifold to down pipe flange is at 90' to the manta down pipe.

It vaguely points in the same direction as I spent many an hour comparing the two to figure out if I could use the GTE downpipe or whether it would need modifying. Conclusion was to be sure I would need to make a jig with ref to the engine rear mounting face.

The 2.2/2.4 injection systems are basically economy systems so tend to strangle the motors.

The Frontera injection system is, I think, a Motronic 1.5 system, which is a proper mapped system and a step change away from the analogue electronics of the Jetronic on the 2.2, and as such should be chippable if serious............

The Motronic 1.5 was also found on many of the 24V 3.0 motors around that time, Omega, Senator and I think Carlton. Also found on various lower performance motors too.

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  • 5 months later...
  • 2 weeks later...

OK, started the process with the 2.4 on the engine stand and stripped of anciliaries.

I am not looking for a big power motor, thinking more torque for my convertible which is never going to be a racing car.

I have a complete 2.0i as well as the C24NE. Two questions come to mind so far (just waiting for my membership to be reactivated, so sorry if this is covered in the main forum)

Oil pressure switch. On the 24 its on the front cover. Is this the best place to leave it, or do I remove the plug in the block and put it in the 2.0 position?

Head. I want to use the L system from the 2.0, so, as I want torque, and whichever head I use will be skimmed and rebuilt, does it make sense to use the 2.0 head?

TIA

D

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OK, started the process with the 2.4 on the engine stand and stripped of anciliaries.

I am not looking for a big power motor, thinking more torque for my convertible which is never going to be a racing car.

I have a complete 2.0i as well as the C24NE. Two questions come to mind so far (just waiting for my membership to be reactivated, so sorry if this is covered in the main forum)

Oil pressure switch. On the 24 its on the front cover. Is this the best place to leave it, or do I remove the plug in the block and put it in the 2.0 position?

Head. I want to use the L system from the 2.0, so, as I want torque, and whichever head I use will be skimmed and rebuilt, does it make sense to use the 2.0 head?

TIA

D

Oil switch - don't think that really matters but it is as close to the oil pump as it can be on the front cover.

The 2.4 engine is a long stroke motor so will give you torque anyway. Using a 2.0 head will restrict the flow into the engine. A std 2.4 head has the same flow characteritics as a well ported big valve 2.0 head so it seems pointless to put a 2.0 head on. Yes it would be easier to fit the L (isn't it LE) system with a 2.0 head but you can soon mod the intake manifold to fit. If your skimming the head remember that the cam timing will need adjusting back with a vernier pulley.

HTH

Chris

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Oil switch - don't think that really matters but it is as close to the oil pump as it can be on the front cover.

The 2.4 engine is a long stroke motor so will give you torque anyway. Using a 2.0 head will restrict the flow into the engine. A std 2.4 head has the same flow characteritics as a well ported big valve 2.0 head so it seems pointless to put a 2.0 head on. Yes it would be easier to fit the L (isn't it LE) system with a 2.0 head but you can soon mod the intake manifold to fit. If your skimming the head remember that the cam timing will need adjusting back with a vernier pulley.

HTH

Chris

My understanding is that the smaller valve sizes in the 2.0 head will increase gas speed at lower revs leading to more torque rather than less.

I think the official designation of the injection might be LE, but its an L system with tweaks, its not got emission control.

I would probably get a vernier anyway, but offset key would also do the job. Don't want loads off the head, just to make sure its flat.

Thanks for your help.

Cheers

D

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That's not strictly true as it's more related to the port cross sectional area and larger ports (typically associated with larger valves and vice versa) have lower air speed at part throttle which affects torque and pick up.

That's why 16 Valvers give away a lot lower down but fly if screaming.

If you were taking out a 2.0 to 2.4 you would probably be advised to use bigger valves to make the most of the extra CC and allow it to fill the cylinders better at RPM.

I seem to remember a load about using Carlton 2.2 inlets or something (may well be wrong).

If going for the 2.0 head you will need to accurately work out the required combustion chamber size, usually with glass, vaseline and a burette, but you already have a matched head that only requires the relatively crude work to fit an inlet.......

You pays your money and takes your choice. But consider that the 2.4 will probably have hardened valve seats that may well be an extra cost requirement of the GTE head.

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That's not strictly true as it's more related to the port cross sectional area and larger ports (typically associated with larger valves and vice versa) have lower air speed at part throttle which affects torque and pick up.

That's why 16 Valvers give away a lot lower down but fly if screaming.

If you were taking out a 2.0 to 2.4 you would probably be advised to use bigger valves to make the most of the extra CC and allow it to fill the cylinders better at RPM.

I seem to remember a load about using Carlton 2.2 inlets or something (may well be wrong).

If going for the 2.0 head you will need to accurately work out the required combustion chamber size, usually with glass, vaseline and a burette, but you already have a matched head that only requires the relatively crude work to fit an inlet.......

You pays your money and takes your choice. But consider that the 2.4 will probably have hardened valve seats that may well be an extra cost requirement of the GTE head.

I've got all the different heads fitted to these engines. The 2.2/2.4 combustion chamber in the head has a different profile to the 2.0 this was done to improve the flow with the bigger valves. I have measured (crudely) the cc of each including the race heads and to be perfectly honest when you calculate out the comp ratio its only small points of a difference so i wouldn't worry too much about that. Fitting a 2.4 head on a 2.0 will work fine as the 2.0 pistons are flat top whereas the 2.4 are dished, think its something like 3 or 4 cc, the only problem being if you fit a higher lift cam you may need to pocket the pistons, not always but you do need to check.

2.2 or 2.4 inlets can be fitted to the 2.0 head but porting work needs to be done around the bigger inlet for it to work properly.

The 2.2/2.4 were designed as std with 45mm inlets so why would you want to go smaller when GM have probably spent hundreds of thousands of pounds to change the head design to improve it.

If it was me i think i would use the 2.0 head as you can actually lose power using the different inlet manifolds. Picked this info up from a guy in sweden. They fitted the 2.0 manifold for 45s to a 2.4 head just to get the car out and racing. Later the proper 2.2/2.4 inlets were fitted and up went the horsepower and torque figures. This is due to the entry angle of the ports being different (something like that.. can't quite remember) and it messes up the flow into the head. Got myself a pair of the manifolds for the 2.5 race head and they are quite a bit different.

The cost of having the valves fitted will not be that expensive and a bit of a clean up of the ports and rounding of the valve guide protrusions will make a big difference.

Like Manta doc says you pays your money and takes your choice.

HTH

Chris

Edited by lamchop77
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