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i think its time to treat my manta to a new engine. I was thinking about the 2.4 comversion but i have heard that the bores turn oval because of the long stroke. i have a standard 2.0lt injection lump in my gte at the moment. im now thinking about keeping the 2.0litre lump in her so what sexy things could i do to her port polishing grumpy cam and so on. how easy is the 16valve head to fit onto these engines/ what timing gear will i have to use

any info will help

thanks alot jon

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Whatever you do with the manta engine is going to cost you. Personally i think that they are a brilliant engine, better than the 16v dare i say,. OK there an old design but they have loads of grunt.

I've done alot of looking around and the Std MAHLE pistons are expensive, the 2.2 ones i wanted were 127+vat a piece. Don't know what the 2.0 ones are but i would expect much the same. Wossner do a range of pistons and rods for the CIH, not cheap but the are forged pistons and will bump up the compression as well. Also the valve pockets are deeper so you can run hotter cams. These are available up to 97mm in 0.5mm increments. At 97mm though you will need to switch to a Cometic MLS head gasket which are £111+vat. If you stick at 96mm i think the std gasket can be used, but it would be better to use an Elring gasket which has a compressed size of 96.5mm I have got contacts that might be able to get the pistons slightly cheaper if you want.

Using 96mm pistons will give you a 2021cc motor, 97mm will give a 2063cc motor.

The 2.4 motors have a problem with the piston rocking at the top of the bore, this is due to the bad rod ratio. Not so bad if its a competition engine with limited mileage but not so good on a road motor. I've got 2 2.4's both meant to be low mileage and both engines have the same huge ridges at the top of the bore, and its only for the firts 5-10mm. You can see the honing marks further down. the pistons are weak around the top ring so break up and the pistons are dished so reduce the compression. You can get Wossner pistons for this motor with increased compression ratio and an anti scuff coating on the pistons. I have these and am building a 2461cc for competition use, very nice pistons!!

I'm also building a 2.2 based motor which will be a 2291cc for competition / road use. This is a 2.2 crank with 2.4 rods and custom pistons. The compression ratio works out at 10.87-1. This engine should rev alot harder than the std 2.2 bottom end that i used to run and give more power as the compression ratio was 9.75-1 before. The 2.2 i was running was rolling roaded at 175-180 bhp and revved up really quickly. I could order the pistons that i've had designed, mine are on order as we speak, if you want to go that route BUT they aren't cheap £500 plus rings at £122 and head gasket at £111, +vat!!!! you would have to source a crank and rods (you can get forged one through Wossner).

This all depends on how far you want to go. If your on a low budget then uprate with the wossner 2.0 piston, think they give 10.5-1 and there forged. Lighten and balence the engine and you'll have a good solid bottom end for not alot of cash. With decent carbs you should see over 160 with a std exhaust manifold, 2" system.

If you want to go 2.4 it might cost a bit more plus the needs modding on the combustion chamber to clear the piston ( slight design error on Wossners part but fixed with a Dremel!!!!) Check out opel GT forums. With this you'll have loads of grunt but the wear problem may still be there.

Or you can play like me and spend lots of cash. I can't tell you anymore so i hope this helps. If you want more info pm me for a chat :thumbup


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I'd also consider the 2.2 aswell...

the one in my i200 has had a lightened flywheel, high lift cam, the head has been ported, polished etc...

Goes really very well indeed, much quicker than a standard 2ltr gte etc.. ...especially in the higher rev ranges, you get that whoooosh feeling :thumbup

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