hi all. i was wondering if anyone has the dimensions of the ports on a stock blaster cylinder? the cylinder that i have here is bored out to 67.5mm, so i'm thinking that some of my dimensions are going to vary from the stock bore. of course the distance from the cylinder deck to the boost port roof will for surely be greater on this cylinder, than on a stock bore cylinder, due to the angle of the port entry into the cylinder. what i'm looking for guys, are the dimensions from the cylinder deck, to the port roofs and port floors, on the exhaust, main transfer, secondary transfer, and boost port. any dimensions or specs that you guys can provide, will be greatly appreciated.
Stock Porting Specs
- Thread starter mopar1rules
- Start date
just a heads up most pros dont go by whats already(that can vary) and scribe off lines accordingly ... they have their own specs they use ..most engine builders are far more concerned with mapping it out to their custom proven layouts .is there a reason in particular why you want the crappy stock port layout ?you do realize due to the manufactring process that these stock measurments can vary a good deal
i'm only looking for the dimensions of the ports on a stock bore, so i know what the dimensions are from the cylinder deck to port roofs and such. right now i have a cylinder that i'm thinking about coming up w/my own port spec/setup, but i just want to know what the dimensions are on a stock cylinder, as the one i'm working on is @ 67.5mm already. you and i both know that the boost port roof height is going to be way down. now, if i know the stock dimensions, i can see how much time/area that i lost. i went to macdizzy, but his port timings of the exhaust are coming up to 4* hotter than mine. the exhaust port i don't think gets lower as the bore gets larger, cause of the straight cut exhaust port thru the sleeve. know what i mean? i have TSR software, so i can come up w/my own specs, but as we all know that $hit in is $hit out. so, do any of you just have the dimensions on each port roof, to the cylinder deck, on a stock bore? how about port widths? chordal/flow width that is.
youve got the cylinder,you need to degree the thing and that will tell you what you need to know,plus you can get all your port widths and sizes from the cylinder you have.Im not sure whatelse anyone can tell you,but if you cant do these things yourself your TSR software is going to be useless to you.Tom should have sent you info on how to properly measure you port widths ect.
i know how to measure up the port widths correctly. tom did send me the info. no, the TSR ain't going to be useless to me. i was mearly asking for port width measurements and dimensions on the port roofs to the cylinder deck, on a stock unmolested cylinder, so i would have some dimensions to compare to.....as boost port roof dimension from the deck, will drop considerably, as the cylinder is bored out....which mine is. if i was given the stock boost port roof dimension from the deck, i could compare that to my found dimension and see how much lower the boost port roof got, from boring the cylinder out. understand now?? also, some of the port widths may change as the cylinder gets bored out, so the other reason i was asking for port widths on a stock cylinder bore, so i would have the other dimensions to compare too.....i could see which ports got wider or skinnier, as it got bored out. understand yet??
also, i can't degree wheel this thing in, as i got the engine in pieces, in a box, with the crank shot, etc. also, don't have a degree wheel.....i know i could easily buy one tho.
also, i can't degree wheel this thing in, as i got the engine in pieces, in a box, with the crank shot, etc. also, don't have a degree wheel.....i know i could easily buy one tho.
a degree wheel is your best bet.. many factors affect port timing.. if you want true "stock" figures make sure to use stock base gasket thickness.. being the parts are mass produced there are variances.. if say the cases are at the high limit for acceptable and the cylinder is at the tall limit as well that will read different than cases and cylinder that are at the low spectrum of "acceptable"
macdizzy has the stock port specifics on his site,if they jive with your numbers or not i think his are factory numbers(i could be wrong)that all anyone can tell you,i can grab a cylinder,degree it in and measue all the port areas and time areas and its going to be different from yours.You need to assemble your bottomend buy yourself a gasket kit and start to degree your cylinder as it is,then you measure you port widths and radii and your set.
hat chutzel is saying is that because of variances your may be different.. now even though most times those variances are very slight... if you have 2 or 3 slight variances compunded they can make a significant difference.. also watch the port chamfering.. if your new at this it can sometimes throw you off as well..
yep, i payed attention to the port chamfering, or "lack" of it on this overbored cylinder....lol.
