Westfield Philippines Posted May 27, 2003 Share Posted May 27, 2003 We have a brand new Westfield Megabird (1100 CBR engine) that we have just finished building. However we have reached a road block. We are having a problem with the pulley for the oil pump drive for the Dry Sump Kit. We have the Westfield conversion shaft that is bolted onto the end of the sensor for the engine management. As you know it goes thro' a hole in a bolt on cover, and the pulley is bolted on the end of the shaft. It keeps coming loose when the engine is running. We have torqued it to the correct torque and put Loctite on the thread but it still comes loose. The problem seems to be that the allen bolt goes into the end of the shaft and there is no keyway. Hence the pulley tends to want to slip on the shaft. It also seems to be that the thread is the "wrong way" so that it tends to unscrew as the engine turns. What is a simple solution for this as we can't risk driving the car as the engine will seize? Quote Link to comment Share on other sites More sharing options...
Kit Car Electronics Posted May 27, 2003 Share Posted May 27, 2003 I'm not familiar with this part, but the following info may be useful Keyless non-splined fittings - there are two common approaches: (1) Tapered shaft where slip is prevented by friction between taper and attachment (2) clearance fit where slip is prevented by friction between pulley faces and stepped shaft on rear, screw head on front. This is what you have. For this to work, there obviously needs to be sufficient friction - it sounds like there isn't. Don't be surprised that threadlock doesn't help - the torque transmitted is higher than the resistance from threadlock. I'm surprised that you have an Allen head bolt - normally you would use a bolt with an integral flange/ washer to provide more grip. Front pulley bolts had a similar tendency to slip on the first Duratecs due to poor surface hardness on the pulley- the fix was to fit a diamond impregnated washer between pulley and bolt head to improve grip. So - make sure that front and rear sides of pulley are clean and grease free, with a good metal surface. Make sure bolt has enough head surface area and is also clean. Other than that, I'm stuck. Good luck! Quote Link to comment Share on other sites More sharing options...
Kit Car Electronics Posted May 27, 2003 Share Posted May 27, 2003 Oh, and if you post the question in Techie Talk, you'll probably get plenty of answers Quote Link to comment Share on other sites More sharing options...
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