simonray Posted March 27, 2002 Share Posted March 27, 2002 The main valve spring on valve No. 2 on my crossflow has broken. (The inner spring looks intact). Does anyone have a method of changing it without taking the head off? First race is a (working) week away and I don't have much time. Simon Link to comment Share on other sites More sharing options...
oilyhands Posted March 27, 2002 Share Posted March 27, 2002 You can use the rope trick. Slacken the two rockers off for that cylinder (or remove the rocker gear), get the engine at BDC on the cylinder and slip some nylon rope done the plughole, slip in a metre or so and make sure that the end is left protruding from the spark plug hole. Slowly bring the engine up to TDC until it wont go any further, the rope should than be hard up against the valves and this should allow you to compress tne spring/cap and remove the collets, then withdraw the broken spring and replace, assembly is the exact reverse, make sure you drop the piston down the bore before pulling the rope out gently. Oily Link to comment Share on other sites More sharing options...
F355GTS Posted March 27, 2002 Share Posted March 27, 2002 On the kart engines we used to remove the plug turn engine to TDC, put an Allen key (end wrapped in gaffer tape) down the plug hole, rotate it so it is touching the underside of the valve, then change/repair the springs Really needs two fo you or an octopus! ps make sure the gaffer tape can't fall off! Like the idea of the rope trick though may try that next time! Mark Link to comment Share on other sites More sharing options...
stevefoster Posted March 28, 2002 Share Posted March 28, 2002 The springs esp the new ones going back on are quite stiff. Give each valve retainer a sharp tap with a suitable sized socket to free the collets that get worked in tight. I have used compressed air successfully on two occasions to hold up the valves. Pop the cylinder up to the top = both valves shut, in gear and HB on. Chock the wheels. 8 bar of air across the piston face will move the car if the piston is not perfectly at TDC. With the airline on press down on the valve spring retainer to allow the collets to be removed. This can be easier said than done. Esp with stiff double springs. We used a normal valve spring compressor with the end that seats on the valve spring retainer turned around to allow the clamp part to be a handle. One chap on this, another pushing down for all he was worth using a wooden hammer shaft and the third chap to whip the collets out. By the 4th one you have the hang of it! Refittment is the reversal of removal.. Link to comment Share on other sites More sharing options...
Big Brother Posted March 28, 2002 Share Posted March 28, 2002 "Refittment is the reversal of removal.." Only a little more fiddlysmile.gif This might be a "stupid" question.....but what are the symptons of a broken valve spring? Steve www.Se7en-Up.co.uk id=green> Link to comment Share on other sites More sharing options...
Graham Perry Posted March 28, 2002 Share Posted March 28, 2002 Have done the same as Steve Foster, but my father had a spark plug that he modified by removing the centre (insulater and electode) and braised a airline high pressure coupling to it, so you just screwed it into the spark plug hole and clipped on the airline. No air leaks and Worked a treat. Link to comment Share on other sites More sharing options...
edmandsd Posted March 28, 2002 Share Posted March 28, 2002 Don't tell me it's a vs1 spring with 244 cam Link to comment Share on other sites More sharing options...
simonray Posted March 28, 2002 Author Share Posted March 28, 2002 The broken valve wasn't a VS-1, but I've been advised by Roger King to replace them with these. Is there something I should know? Simon Link to comment Share on other sites More sharing options...
edmandsd Posted April 2, 2002 Share Posted April 2, 2002 Talk to Aaron Tucker or Roland Hayes at HT Racing and they'll tell you 01474 872888. Link to comment Share on other sites More sharing options...
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