big cam question
big cam question i have a 239/245 duration, 604/576 lift cam on a 109 lsa. will i need to fly-cut the pistons with a stock short block and un-milled 241 heads? any help would be greatly appreciated.
considering your cam is smaller in size and duration than a trex and an ms4, which both fit without flycutting, i would assume no flycutting is necessary. thats assuming u are using the stock 241s and head gaskets
My guess is that you would most certainly need to flycut with that cam. That cam is pretty large and on a tight LSA, you didn't mention if the cam was ground with any advance which would also cut down on PtoV clearance. These large cams that many others mention clear, but with minimal clearance, minimal room for installation error, and not anywhere near the amount clearance many would deem necessary. My cam is much smaller then that and on a wider LSA and is about as tight as i would want to run on the street. I believe the average clearance for a G5X3 on a 112 LSA was approx .070"/.110" and that cam is 5*/3* smaller.
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check it anyway but i doubt youll need flycutting. use a .055 head gasket. my ms4 has a .650 lift on the intake with a 239 duration and a 111lsa. the exhaust is a .609 lift on a 242 dur.
nope, not on the old motor. I am on the new one, thats why I said check first. it worked for me with unmilled heads and stock thickness gaskets. Its on xer lobes and i dont know if that changes much as far as clearance it just has a fast ramp rate. Tsp designed the ms4 to have about .0060 on the intake and about 0.0080 clearance on the exhaust side. hope this helps.
nope, not on the old motor. I am on the new one, thats why I said check first. it worked for me with unmilled heads and stock thickness gaskets. Its on xer lobes and i dont know if that changes much as far as clearance it just has a fast ramp rate. Tsp designed the ms4 to have about .0060 on the intake and about 0.0080 clearance on the exhaust side. hope this helps.
thanks for all the info guys. i know that some have cams with more duration and more lift than mine with no clearance issues. but none of those cams are on a 109 lsa. i will probably just take hvyhttter's advice and have him wack the pistons with a hammer just to be sure it will clear.
well not that i know much but there is an article where carcraft took a 6.0 stock short block and installed a comp xer287 cam thats 238/242 and the lift is over .608+ on a 114ls and they clayed the stock pistons and used L92 heads with bigger valves and had more than emough room to me it looked like they had .150+ on both. Also on the exhaust it barely touched the clay ? You can google (L92 heads dyno) and you will see the build and where they clayed the pistons.
