| Technical: 20XE and C20XE 16V Vauxhall engines. |
| The 20XE, a fine 2.0 16V DOHC SFI engine of the late 80's and early 90's, fitted to the Astra, Calibra and Cavalier. These days thay can be found in the Nova, Corsa, Tigra, Mini, Caterham and Westfield as they are such a powerful lump that can be picked up relatively cheapley. Thus good value BHP for your Ł. I'll be talking about known problems with them, and be writing about odd problems i've found but seldonm heard mention. |
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| 1 - Timing Belt The early model of 20XE shown at the right. 1 When removing the belt cover, great care has to be taken with undoing the cover bolts, as the studs (no.19) which are screwed into the block have a very thin shank... I've had one snap before, leaving the thread stuck in the head. Causing a nightmare! 2 The idler pulley (no.9)... If you look at the belt and how it sits on the pulley, it may be hanging off the front edge by about 1mm or 2... This isn't necessarily a problem, but it's still a worry. I've found the reason for this is the support pillar (no.12). The early type of pillar has a flat bottom, there is a later type of pillar (about Ł11) which is made with a recess in it's base. The early one sits slightly wonky. because it is in contact with the block right up to the threadded hole. The lip of the threadded hole isn't countersunk, and as a result of the bolts being tightened and stretched, the block metal stretches slightly too. This causes an uneven surface at the hole rim. The older type of pillar would sit on this uneven surface, causing the pulley not to be exactly in line with the others. After the belt has done about 4 or 5 revoloutions, it wil hang off. The latter, recessed pillar straddles the risen metal surface, thus curing the problem. |
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| 2 - Oil... The Classic 20XE problem! The old 20XE is typically a very oily engine, as i'm sure anyone reading this who owns one will agree! The problem is that when the engine ages, say 10 years, so do the o-rings, selas, and gaskets. The material gets hard, looses it's spongeyness, sometimes cracks and hence the seal is never as good as when it left the factory. - Easiest seals to replace (which cost in the region of about 60p) are the distributor and the oil cooler adaptor plate. These two may not seem like a lot, but they do make a lot of difference. - Another really easy one is the oil filler cap seal, just cleans up the top of the engine. - The gasket for the front steel Breather pipe: I've seen paper ones, which are rubbish, replace with compressable aluminium gasket- works work much better! - Next hardest is the camshaft cover gasket. The replacement gasket costs around the Ł20 mark, and just simply fitting a new one doesn't cure the problem!! I was disappointed to still have leaks, so off it came again, but this time used a thin smear of Flange Sealant on both sides. Result: jobs a good-un. - Following these on the Haynes Spanner number list is the Sump... The dreaded XE sump!!! Remove exhaust manifold for access and get busy with those little bolts (remembering to drain it first!!) With the sump, it seems that no matter how many gaskets you fit, how much sealant you squidge on, it'll still leak. Replacing the gaskets does help, but it's never fully cured. Although I have heard of another type of gasket used on an Isuzu diesel engine with the same sump pattern which apparently cures the problem 100%, I'm yet to try! - Next up on the spanner list are the sprung Lip Seals for the rotating components. Found on the Camshafts and both ends of the Crankshaft. I've only ever changed these with the engine out of the car - as to get to the flywheel end of crankshaft you've got to split the gearbox and remove flywheel anyway! Once you've got to the seals, the way to remove them is by driling a small hole, screwing in a self tapping screw, then pull them out with mole grips or use a claw hammer for leverage. Photo shows Screw in old seal. |
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| While the sump is off it's worth changing the oil-pickup-pipe O-Ring and the oil level sensor O-Ring. |
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| Low Rev Problems... Classic No 1- The Jolty / Jerky slow drive around town... caused by unmetered air getting into the intake from the rocker cover breather hose. This hose is designed to suck out fumes and oil vapour from the cam cover and crank case. This is fine, as the ECU knows how much unmetered air to expect from this hose, and can compensate for it. Now unfortunateley on older engines more air gets into the intake (more air creeping past piston rings) and the ECU gets it's nickers in a twist by over and undercompensating for the effect causing the up and down "reviness" and hence jolting. The fix is incredibly simple, and can cost you next to nothing! -Remove the pipe from the cam cover, block it up with a large bolt and jubilee clip. then add a hose from the cam cover to a catch tank (which must have a hole cut in it). this catch tank can be as simple as an old coke bottle! Supprisingly, this is commonly known as the "Breather Mod"! Other factors also affect this, mainly in the form of air leaks Downstream of the air mass meter... old perished rubbers, loose jubilee clips etc... Classic No 2- The stall after a fast drive.... Happens due to using a cone filter. When driving, the engine bay is kept cool by air flowing through it, hence the air going into the filter will be cool. When you stop at a junction, the bay temperature rises due to lack of airflow, the filter draws this in, air mass meter's temp sensor can't react quick enough to the sudden change in temp and the engine cuts out... Cure for this is to ditch the cone filter, and use a performance panel filter in the standard box with cold air feed from bumper intake. |
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