SlowMoe Posted March 1, 2011 Report Posted March 1, 2011 Hey whats up. I've got a set of drag ported 350 cylinders done by Dave Moore (DMR), and since I don't have a degree wheel or dial indicator ect I hoped I could get someone to help me figure out the port timing on these things. The exhaust port is 25.78mm from the deck, the transfers are 42.56mm. I will be using a standard base gasket and I do not believe the cylinders are decked. If I'm not mistaken the exhaust duration is around 202*; have no clue on the transfers. The exhaust port is 72% of bore and has a very flat top. I have a stock head that has been milled and rechambered for race fuel and I plan on running 100ll in it (not too serious about being super competitive right now). I have vitos fat [censored] pipes. My first thoughts are that the duration will be a little high for my pipes and fuel but I'm not sure. Actually the Vitos are supposed to be real close to the Shearers...Dunno.. Also I was thinking about enlarging the piston windows some and also opening up the sides of the piston skirts a little to kind of match up with the sleeves; I have seen this done before but am not sure if it will be worth my time....? BTW this is my first set of drag ported cylinders; how does the porting look? To me the transfers could stand to be opened up some, but I know bigger isn't always better...? Quote
mopar1rules Posted March 1, 2011 Report Posted March 1, 2011 Ok, so I ran your measurements.... Assuming .017" (.43mm) deck height 25.78mm exh is 200.9deg 42.56mm trans is 124.87deg 38.01deg blow down Your blow down is too long IMO for trail and dune riding and by the looks of the pics and seeing your durations, I would say there is room for repairs/improvements in those cylinders. I don't see much port chamfering and some of the work looks shaky. I don't know how well the port timings are gonna work w/your vitos pipes. I do port work and could fix some of your porting for you. Quote
SlowMoe Posted March 1, 2011 Author Report Posted March 1, 2011 Ok, so I ran your measurements.... Assuming .017" (.43mm) deck height 25.78mm exh is 200.9deg 42.56mm trans is 124.87deg 38.01deg blow down Your blow down is too long IMO for trail and dune riding and by the looks of the pics and seeing your durations, I would say there is room for repairs/improvements in those cylinders. I don't see much port chamfering and some of the work looks shaky. I don't know how well the port timings are gonna work w/your vitos pipes. I do port work and could fix some of your porting for you. Greeeat. I just measured 55.5mm from deck to bottom of transfers. Quote
SlowMoe Posted March 2, 2011 Author Report Posted March 2, 2011 Yeah so I bought a set of 4mm cylinders. Great. If I can't get a refund, I'm thinking about pie cutting the piston crown to bring the transfer duration up to about 132. How much would I need to cut to get there? About 1.5mm? Quote
mopar1rules Posted March 2, 2011 Report Posted March 2, 2011 What cylinders are you planning on cutting the piston crown for? Why not just port the cylinders? Like I said, I can do the port work for you. When you don't have the right tools, it makes for a real pita to do the job. Quote
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