trowa47 Posted February 9, 2008 Share Posted February 9, 2008 if i us the l24 crank and rods in a l28et 83 can I still us the cam or will i need a custom cam made ? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted February 9, 2008 Share Posted February 9, 2008 umm... the cam will be fine. If you use L28ET pistons they will stick above the deck 1mm. They could be cut down a little to compensate though. Quote Link to comment Share on other sites More sharing options...
trowa47 Posted February 9, 2008 Author Share Posted February 9, 2008 I will be using custom pistons any way so thats ok Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted February 9, 2008 Share Posted February 9, 2008 i wouldnt use the l24 crank its a common practice to use the l24 rods with the l28 crank and then special pistions. it has something to do with rod to stroke ratio. Quote Link to comment Share on other sites More sharing options...
ozconnection Posted February 9, 2008 Share Posted February 9, 2008 Changing over to L24 rods and crank will change your rod to stroke ratio...this is true. Why?.... the theoretically optimum rod to stroke ratio is 1.75. The way this figure is calculated is to divide the length of the rod by the stroke of the crankshaft. L24 specs: 133mm/73.7mm = 1.80 rod/stroke ratio now, lets look at the L28 130mm/79mm = 1.65 These numbers reflect the inherent 'revability', the higher the number (like the L24) the higher the redline of the engine. On the other side of the coin, a lower number (like the L28), the more low speed torque is produced. It's a mechanical thing. Many papers have been written on the topic, so I will suggest you read some of them off the 'net. They will give you far more insight into what's happening inside your engine than I. The advantage you have in building such an engine is that H/D rods are available off the shelf (from Carillo for example) in this size. You are custom building pistons, so that's cool. There's heaps more in it, like the instantly lower compression for boosting using the same cylinder head, large valves compared to the swept volume of each cylinder and the H/d parts available. Cam timing shouldn't be an issue, and MSA has some bigger turbo cams if you need them. However, the stock turbo cam will work well if you so choose.Don't worry about capacity, wind in a little more boost, that'll cover it!! Interesting project, I considered something like this for my P230 Cedric, instead using an L20A crank I have sitting in my shed. BTW, that rod to stroke ratio works out to be 135mm/69.7 =1.94. Easy 8k rpm motor there, if it was built correctly, of course! (valve springs, rockers, port sizes, good quality valves, pistons, bottom end balance, flywheel material etc etc etc) Good luck mate with your project... Quote Link to comment Share on other sites More sharing options...
trowa47 Posted February 9, 2008 Author Share Posted February 9, 2008 ya i really want to us the l20a crank but do to the fact i can get l24 stuff much faster i think i'm going with it Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.