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I sent my 243s for hand porting out of state.. When I got them back I took them to a shop in indy for a valve job and assembly...he also flow tested them for me, this is valuable info for Pat or anybody to spec your cam..Anyway, the bench was set for 3.900 bore, no pipe on exh which I understand knocks off a bit when compared, be sure to look at those tidbits at the bottom of flow charts. These were tested at a totally unrelated shop..for neutrality. To be honest I think the guy wasn't too thrilled I didn't have him port them but at the time I didn't know he even did that kind of work. They CC'd about 230-231cc on the I runner if I recall.
I paid $750 for the port work.
We'll see what they make, I had a cam spec'd by Pat based on these #s and a 11.5:1 LS1. It's def a labor of love, the guy I sent them to does nothing but port LS intakes and heads.
Hey KLowR6 what is the throat diameter on the intake , valve seat insert . And on the exhaust side too.
oh man, I coulda measured this for you 2 days ago with my snap gauges. I just swapped out my checker springs and torqued the heads on tues night lol. Sorry
fwiw they are factory 243 seats, the ports are obv blended, I don’t believe there was any cutting of this area of the seat but I’ll take a look
edit..yep the throats are opened up
oh man, I coulda measured this for you 2 days ago with my snap gauges. I just swapped out my checker springs and torqued the heads on tues night lol. Sorry
fwiw they are factory 243 seats, the ports are obv blended, I don’t believe there was any cutting of this area of the seat but I’ll take a look
edit..yep the throats are opened up
Yeah they appear to be opened up from the pics. Guess I am a day late and a dollar short .thx for reply back .
Most hand Porters can get decent results on the exhaust side , but the intake is a little more difficult. Most hand ported Non-243s with stock valves sizes will not get much past 280 cfm .and hand port 243 about 290. One of best experienced hand Porters Lloyd Elliott gets his 243 to 295cfm intake and 210 ex. This is with stock valves. LE1
i ported my own 243's and didnt make the port very much bigger. Heres my numbers:
intake ex no pipe
.200 138 100
.300 200 146
.400 245 177
.500 280 193
.600 300 201
.650 301 204
of notable mention. his bench is stingy on exhaust and also he sent me s heet where he flowed with a pipe at .650 it did 208 and add a pipe it did 244. so mines at around 240. not bad for a shade tree lol. stock valves too btw.
I think those numbers for that price (the op) is pretty damn good. ive got weeks in mine and multiple trips to he flow bench.
i ported my own 243's and didnt make the port very much bigger. Heres my numbers:
intake ex no pipe
.200 138 100
.300 200 146
.400 245 177
.500 280 193
.600 300 201
.650 301 204
of notable mention. his bench is stingy on exhaust and also he sent me s heet where he flowed with a pipe at .650 it did 208 and add a pipe it did 244. so mines at around 240. not bad for a shade tree lol. stock valves too btw.
I think those numbers for that price (the op) is pretty damn good. ive got weeks in mine and multiple trips to he flow bench.
Thats pretty impressive what volume are your runners at.
Thats pretty impressive what volume are your runners at.
thx. Honestly I wasn’t worried about that. I was concentrating on fixed the short turn, removing the rocker bolt bumps, widening the pinch a little. They do work very well because I did the cam senate from the heads. I did just heads at that time and from what I could remember, I was impressed with the difference they made. I’d say it felt like 60hp but most Dyno tests say about 30hp. I did not have 243’s originally. I had stock ls1 heads. I’ve done quite a few heads but these were more challenging to get to 300cfm and not hog them out. I wanted to retain low speed tq and I did. I had less trouble getting 300cfm out of a set of truck flow r 23 degree sbc heads than I did with these. I do keep forgetting I did that with stock valves. I did reshape the exhaust valve rim on each one and picked up an average of 5fcm just from doing that. I tested the untouched valve back to back. Interesting what attention to detail does!
thx. Honestly I wasn’t worried about that. I was concentrating on fixed the short turn, removing the rocker bolt bumps, widening the pinch a little. They do work very well because I did the cam senate from the heads. I did just heads at that time and from what I could remember, I was impressed with the difference they made. I’d say it felt like 60hp but most Dyno tests say about 30hp. I did not have 243’s originally. I had stock ls1 heads. I’ve done quite a few heads but these were more challenging to get to 300cfm and not hog them out. I wanted to retain low speed tq and I did. I had less trouble getting 300cfm out of a set of truck flow r 23 degree sbc heads than I did with these. I do keep forgetting I did that with stock valves. I did reshape the exhaust valve rim on each one and picked up an average of 5fcm just from doing that. I tested the untouched valve back to back. Interesting what attention to detail does!
When you say you reshape the exhaust valve rim ....... are you putting a radius on the margin chamber side of the valve , ... or something else ? Did you add any back cuts .
When you say you reshape the exhaust valve rim ....... are you putting a radius on the margin chamber side of the valve , ... or something else ? Did you add any back cuts .
no back cut. I rounded the edge of it facing inside the chamber. My theory was it would allow the exhaust to flow around it easier. Buddy with the flow bench said I was wasting my time. Until I saw a nice improvement for no money spent and maybe 30 extra minutes. I always do this on my heads anyways but I wanted to see if it actually worked.
no back cut. I rounded the edge of it facing inside the chamber. My theory was it would allow the exhaust to flow around it easier. Buddy with the flow bench said I was wasting my time. Until I saw a nice improvement for no money spent and maybe 30 extra minutes. I always do this on my heads anyways but I wanted to see if it actually worked.
For whatever reason I can't tell much from the pic in the link, and it redirects so I'm not sure if it's the same one. But it sounds like you essentially did the same thing as a back cut. Sounds like you're saying you smoothed the valve instead of actually cutting a back cut angle in it with a cutter
For whatever reason I can't tell much from the pic in the link, and it redirects so I'm not sure if it's the same one. But it sounds like you essentially did the same thing as a back cut. Sounds like you're saying you smoothed the valve instead of actually cutting a back cut angle in it with a cutter
its not the back side (port side) that I cut. I rounded the edge that is in the combustion chamber. It allows flow to go around that edge easier with no negatives in the flow curve. Here’s the pic I tried to post a link to. DONT do this on the intake valve, exhaust valves only. dont reduce the diameter of the valve when you do it. I chucked it up in my drill and rounded against my bench grinder and the smoothed it with 400 on my belt sander and then polished it to get rid of scratches (potential hot spots)
Yes he's putting a radius on the chamber side of the margin . I believe it helps more on low and mid lift .
It is interesting and it should help. Never heard of that one, learned me something new today!
I don't see why it won't help on the intake too. I think most of us by now know that the airflow rolling off the back of... say a car or motorcycle, is less turbulent if the exit point is rounded/smooth. Picture the rear of a busa vs a pickup truck for example.
It is interesting and it should help. Never heard of that one, learned me something new today!
I don't see why it won't help on the intake too. I think most of us by now know that the airflow rolling off the back of... say a car or motorcycle, is less turbulent if the exit point is rounded/smooth. Picture the rear of a busa vs a pickup truck for example.
Did you try it on the intakes and flow bench it?
nah I didn’t, for good reason too. Think of it this way. If you allow the intake to “backflow” better then you’ll get more reversion. The thing to do on the intake valve and helps with better cams to deter reversion is to cut a flat angle on the edge at about 45 degrees. Gases in the chamber hit the chamfer (you’ll notice most aftermarket valves have it already but smaller) and are deflected back into the chamber.
Btw, your your broke like me, you gotta learn all these little tricks!
It is interesting and it should help. Never heard of that one, learned me something new today!
I don't see why it won't help on the intake too. I think most of us by now know that the airflow rolling off the back of... say a car or motorcycle, is less turbulent if the exit point is rounded/smooth. Picture the rear of a busa vs a pickup truck for example.
Did you try it on the intakes and flow bench it?
It doesn't work on the intake side . You have to keep in mind the direction of flow . It works on the exhaust because the flow has to hit the face of valve move around it turns goes down past the seat into the bowl. This why many do not put a back cut on the exhaust valve.and a tulip shape works well on the exhaust. The reverse is happening on the intake.side.
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