scotty Posted May 24, 2005 Report Share Posted May 24, 2005 Finally finished the car today . was off the MOT station in next town & the b^%$£" cam shaft broke . It sheered where the sprocket is bolted on . It was all running free and going well then that . Dont know why . Am really pi££%^ off . Anyone got a match ? Quote Link to post Share on other sites
malcolm Posted May 24, 2005 Report Share Posted May 24, 2005 Very sorry to hear it Scotty No recourse from the guys that built the engine, or did you do it yourself?? Malcolm. Quote Link to post Share on other sites
scotty Posted May 24, 2005 Author Report Share Posted May 24, 2005 down to me Im afraid . I hag trouble with the drive dog which goes between th dizzy & oil pump , am wondering if it did not connect fully with the oil pump . does any one have the measurements of the required length of this dog ? Quote Link to post Share on other sites
Phil Kirk Posted May 24, 2005 Report Share Posted May 24, 2005 Scotty, Sorry to hear about your trouble,hang on in there in it will all be worthwhile in the end Best of luck Phil. Quote Link to post Share on other sites
Tom Fremont Posted May 25, 2005 Report Share Posted May 25, 2005 How bizarre! Never heard of such a thing. Can't imagine the shaft shearing at its thickest section. If the bolts were involved perhaps they weren't torqued suitably ( a critical operation ).... Quote Link to post Share on other sites
marvmul Posted May 25, 2005 Report Share Posted May 25, 2005 . It was all running free and going well then that . Before the oilpump and dizzy driving gear was fitted? Camshaft gear and oilpump driving gear are square to each other and this is not ideal when the driven gear is highly loaded when something is going wrong like gripping oil pump, or when the oil pump/dizzy gear has no clearance. I believe this clearance is determined by shims under the distributor pedestal(it is in the TR 4 cylinder engine). Take consolation : I 've got 2 ruined camshafts in one month on my TR3A : the gear on the camshaft (which drives the oil pump and dizzy) had razor sharp teeth, and some broken teeth after 3 races, a new camshaft had already some damaged teeth after only one race. After much searching and thinking, I suppose the camshaft is so heavy loaded (7000 rpm, 14.5mm valve lift,u/r valve spings) that the camshaft is vibrating/bending/fluttering causing this damage on its gear and the bronze driven gear. Other suggestions always welcome. Did other people experience damage of this gear? Quote Link to post Share on other sites
Guest ron Posted May 25, 2005 Report Share Posted May 25, 2005 Scotty If you know a metallurgist, or even a metallurgy student they should be able to tell you quite easily by looking at the shear why the shaft broke, ie was it overloaded or was there a flaw in the metal. And don't let it get you down, most resto jobs hit a few snags at the last minute. Ron Quote Link to post Share on other sites
scotty Posted May 25, 2005 Author Report Share Posted May 25, 2005 Thanks for the input guys . Ron - never thought of that my next door neighbour is a metalurgist for British Aerospace. Quote Link to post Share on other sites
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