Mill my 317's or get some 243's?
08-05-2012, 10:40 AM
#24
TECH Senior Member
08-05-2012, 12:12 PM
#26
It's actually entirely possible, just a little troublesome. For example, that much milling would have made the 317's chambers small enough to put the compression ratio on a stock LQ9 shortblock well above pump gas territory, but if you flycut the pistons enough, you're probably just fine.
BTW, there actually is a difference between .1, .10, and .100.
BTW, there actually is a difference between .1, .10, and .100.
08-05-2012, 01:04 PM
#27
It's actually entirely possible, just a little troublesome. For example, that much milling would have made the 317's chambers small enough to put the compression ratio on a stock LQ9 shortblock well above pump gas territory, but if you flycut the pistons enough, you're probably just fine.
BTW, there actually is a difference between .1, .10, and .100.
BTW, there actually is a difference between .1, .10, and .100.
08-05-2012, 01:34 PM
#30
It's actually entirely possible, just a little troublesome. For example, that much milling would have made the 317's chambers small enough to put the compression ratio on a stock LQ9 shortblock well above pump gas territory, but if you flycut the pistons enough, you're probably just fine.
BTW, there actually is a difference between .1, .10, and .100.
BTW, there actually is a difference between .1, .10, and .100.
.1=tenth
.10=tenth
.100=tenth
.1000=tenth
.10000=tenth...and so on
08-05-2012, 03:38 PM
#32
.001" is not the same as .0010" because one is less accurate than the other. Can you measure .0010" with a micrometer that reads in only .001" increments?
Google "significant figures" and you can get more information on the subject.
08-05-2012, 05:21 PM
#35
TECH Addict
iTrader: (2)
so doing all that work on 317s(cost+porting+shipping) isnt benefiting much instead of going straight to 243/799?
so unless you pretty much get the 317s FREE or close to it, all the extra work for an N/A application is mute and should look into better aftermarket heads or 243s at the least.
thats what im gathering.
317s are more for the boosted engines due to compression and flow improvments right?
so unless you pretty much get the 317s FREE or close to it, all the extra work for an N/A application is mute and should look into better aftermarket heads or 243s at the least.
thats what im gathering.
317s are more for the boosted engines due to compression and flow improvments right?
08-05-2012, 05:47 PM
#38
08-05-2012, 06:31 PM
#39
But does that mean it looses power? Depending what else is done with the valves, valvejob, port work, etc I don't think you can know for certain. I know people have had problems on the flowbench from making the chambers to large too.
For about the price of a set of used 243/799 heads, you can have a set of 317 heads with a fresh valve job and freshly machined deck that could very well outperform the 243/799 heads, depending on how good the valvejob is. What it comes down to is how much P-V is needed?
so doing all that work on 317s(cost+porting+shipping) isnt benefiting much instead of going straight to 243/799?
so unless you pretty much get the 317s FREE or close to it, all the extra work for an N/A application is mute and should look into better aftermarket heads or 243s at the least.
thats what im gathering.
317s are more for the boosted engines due to compression and flow improvments right?
so unless you pretty much get the 317s FREE or close to it, all the extra work for an N/A application is mute and should look into better aftermarket heads or 243s at the least.
thats what im gathering.
317s are more for the boosted engines due to compression and flow improvments right?
08-05-2012, 08:21 PM
#40
What i did was , mill heads.. Took I/e valves .. Did a std drop test, did some math, and with a lindy cutter I flycut them.. And performed another drop on them till I had clearance for max lift +.030.. Knowing the thickness of the piston helps as well obviously you cannot go too crazy you will eventually make a window in the piston .. I did this with every cylinder.. Lot of time, but at least nobody's gonna meet..