Answer: We have not worked on Group A Corsa engines for more than 10 years, the intake system is the biggest restriction & is one of the worst we have seen. This is the part that holds the power back in comparison with better intakes, such as the Peugeot. We did use much bigger cams than you are using & although the engine produced slightly more peak bhp, in our opinion the engine generally got worse meaning less driveable. Unless you can replace the intake system, your options are limited.

Our customer replied: 'Thank you for your e-mail. The customer had said that he would use this engine for one year just to get familiar with the car and develop the chasis and then he would go for a kit car spec engine with throttle bodies etc. so we did not spend time flow testing the head, intake etc. But the data I had during mapping and then on the dyno showed that something does not allow the torque to go at high revs and cam timing changes affected low but not high rpm performance. We tried a bigger exhaust but things were the same if not worse. So the only thing that was left to blame (we had a bad feeling for the intake from the begining ) was the intake which is very long with small chamber volume and many curves. Your e-mail confirms this impression. Thank you for your feedback.'

Answer: We do know of the problem. It isn't very common and usually only occurs in competition engines where the driver uses the gearbox instead of the brakes. What can happen under these conditions is that you get a shock loading through the flywheel. Sometimes the flywheel bolts will come loose, when this happens the shock continues on through the crankshaft. This will occasionally loosen the front crank bolt. On the 2.0L XE engine, the key way is only there for location, it has no strength. The gear itself is prevented from slipping by the extremely high torque setting of the crank bolt. The only other time we have seen the crank gears move, is if the correct torque procedure has not been used. Some people have even used loctite on this bolt and that is definitely wrong and is more likely to cause the crank gear to come loose because the loctite will usually prevent the bolt from clamping sufficiently on the crank gear. The thread of the bolt should always be lubricated and graphite grease should be placed on the underside of the head of the bolt. Then follow the torque sequence, which is laid down, on our web site (under set ups).
We have personally never experienced a crank gear coming lose on any engines we have put together, but on our 2.0L steel crankshaft we put in a second key. This means that the crank gear can then be modified to accept a stronger wood rough key. The same modification can be carried out to a standard crankshaft and we would normally mount the key 180 degrees away from the original.

Answer: The best thing to do would be to fit the new metal idlers onto new bearings & re fit the cambelt. Do a compression check to see if any of the valves are bent. If they are ok, then just fit a new cambelt If not, then i’m afraid you have to remove the head & go from there.

Links: 2.0L Metal Idlers & Cambelts | 1.6L Metal Idlers & Cambelts

Answer: Quite often when the hydraulic tappets get a bit older, you will usually find they rattle on cold start up. This should disappear after a few minutes of running. If the noise continues on after this, it usually means the followers are worn and I would suggest replacing the whole lot. The main reasons for this, is that they are considerably cheaper than they used to be and if you replace them one at a time, if you are lucky enough to find the ones that are rattling, I am sure the others won't be far behind. We do two versions of the hydraulic follower, the genuine version which is the INA and the pattern Eton version. The prices are available from our downloadable price list.

Links: 1.4L & 1.6L Vauxhall Valve Train Components | 2.0L Vauxhall Valve Train Components

Answer: Normally when we are fitting throttle bodies to a standard engine, for example the latest Ford Duratec, we leave the cam timing in its standard positions. There are several reasons for this. The first being, that when we supply a kit, we try and design the system to be as simple to fit as the end user. If we were to specify retiming the inlet cam, especially on the standard production engine where tolerances are very tight, there is a possibility that the inlet valves could come in contact with the pistons. Although advancing the inlet cam is almost certainly going to improve the performance of the engine, in our opinion the main reason why the inlet cam is fitted in a retarded position is for emission purposes on a production engine. If the cam were to be advanced on a standard intake system, it would be much harder to pass current emission standards and due to the restrictive nature of most standard intake systems, which are designed to produce as much torque as possible, advancing the inlet cam without improving the intake system is most likely to upset idle and in many cases reduces bottom end performance.
If your engine is of an earlier design (pre tighter emission control), such as a 2.0L XE engine, advancing the standard cam is likely to have little if any effect, since when the engine was designed the emission controls weren't as tight and therefore the cam was reasonably advanced to begin with.

Answer: The fact that you are using the car for grass track is always a tricky situation. If you produce too much power, quite often when the engine is off cam it will bog down and when it comes on cam, it will come on with a bit of a bang and break traction too easy. The camshafts I would probably suggest you run, are our SBD 295 profiles on both inlet and exhaust. These should give you a nice increase in peak power without sacrificing too much lower to mid range, making the car still driveable. Anything bigger than that, is likely to cause the problems I have mentioned.

Links: Camshafts