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Brett asked: The 1310cc engine I got with my S has high lift rockers, with reasonably large Rimflo valves (have to check sizes tonight) and twin 1.5" SUs. The cam with it is a Kent 276, has anyone got experience with a similar setup and could make some comments on the performance/driveability? |
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Comments from Arnoud: I had a 276 in an MG metro engine with an HIF 44, Maniflow LCB and RC40 and it was great. Idle doesn't have to be lopey (unless you want it to be;) and it pulls strongly from 2k all the way to wherever you want (I never go past 6.5k). If I ever build a fast road engine again, this will probably be the cam of my choice. Arnoud Comments from Jacob Cash: The Kent 276 is a good cam, but was a "theoretical" cam when it was designed. Viz didn't test all the cams he designed, and in that range he only tested the 266 & the 286. Despite what might be said in TBASE, the 276 was NEVER tested on the dyno with 1.5's Be careful with 1.5's on a 276 - the 1.5's increase the amount of lift on the valves during overlap - which kills low and mid range. Not a problem for some engine specs, but if you are trying to retain "road manners" definately not a good thing.[READ THIS NOTE!]. If you want to use the 276, sell the 1.5's and buy some 1.3 roller tips. This should give plenty of power but retain some decent manners. Cheers, Jacob Toby commented: My 1293 had a 276 cam... but a std head! No a good set-up. (I didn't build it ;-) The idle was lumpy, midrange torque was good and top end power was quite poor! It really needs a good head to work properly. I was going to try a MG Metro head as they are quite a lot better but never got around to it. Sounds like your head should be good. I'm now running a 1098 with a big valve 998 cooper head (same valves as std 1275) with a MG metro cam. Pulls like a train from idle all the way up to 5000+rpm (when the mixture is right) I think it makes more top end power than the 1293 and is certainly easier to drive! Toby. Tom Francis commented on Jacob's note: Don't be silly.. (or as Scott would say "whoever wrote this must be talking out of their arse") the high lift rockers cannot warp the space-time continuum. The duration of overlap will be the same regardless what rockers you have, BUT the high lift ones will make the valve lift greater during the overlap period, which will affect the mid range and low range torque as you said.. but NOT cos of a longer overlap.. Tom |