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Vauxhall 20x breaking valves

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Hi need some advice we recently bought an golf 1 with an 20x engine in it as an drag car car is doing good times but we have issue with it breaking the valves it still running its stock cams and hydraulic lifters what would be the right route to go in upgrade as the limiter is set to 9000rpm it is turbo charged as well

Are you getting valve float? Are you running sufficient valve springs and/or seat pressure for that RPM? If the valves float, you can find the hydraulic lifters try to make up the slack, and now your valves are opening too much and BAM! Since it's a race car, you might want to consider replacing the hydraulic lifters with a solid setup to eliminate that problem.

Or you might just need higher quality valves.

If this is a 20XE engine (AKA Cosworth KBA), I've no idea why you think running a hydraulic camshaft, let alone an OEM, and turning it that high is a good idea? Do you actually have any data suggesting that is a good idea as it's well past where the engine would be expected to be producing useable power - you should be maximising power under the curve.

There are numerous companies that can provide solid follower turbo' grinds and I'd strongly recommend you look at them. There are some high lift hydraulic options, but they are known to be hard on the followers, even the genuine INA type. Same with valves, the early engines were sodium filled for the exhausts and should be robust enough for almost anything you do but you can buy race SS, and even titanium, valves in stock diameters and +1 & +2mm oversizes if you want to go further. It was a common tuning aid with the LET (the factory turbo version of that engine) to swap out the LET intake for the XE inlet and retard (IIRC) it 7 degrees while keeping the LET exhaust - using the XE exhaust actually reduced power, because of the overlap and you may wish to look for an LET exhaust if you don't want to go aftermarket.

As David said, I would be very surprised if the actual problem wasn't loss of valve control rather than the valves themselves, as the engine is being turned way over what the valve train was designed for.

These are relatively strong (for a 1987 design) engine and were still being used to power the 2010 Chevrolet Cruze WTCC cars that won the Championship in the last year of the 2 litre class engines. In turbo' form with the XE inlet and LET exhaust camshafts and decent manifolds, and aftermarket pistons and rods, they were reliably producing over 500hp in street form, and suitably prepped drag race engines are producing over 1000hp.

Oh, while I remember, the oil pumps on these engines use sintered gears and they're not that reliable, often breaking and the resulting oil pressure loss will destroy the engine. There are aftermarket steel pump gears available, or there's a later oil pump that fits and is much stronger - can't recall exactly which, though.