LS2, G5X3-114 lsa, AFR 205 heads 59 cc. Flycut or not?
Safety Car
Joined: Dec 2005
Posts: 4,157
Likes: 37
From: North Carolina
St. Jude Donor '07-'08-'09-'11-'12
Even the 100 degree heat of the garage, my buddy still smiles strong...even though he has to use a "Ford" tool as we used to call it 
Cranking the bolts to the exact degree
Ed...if you're listening, we need a suction cup tray with a magnetic section to put on the window to hold stuff while we work....
He wouldn't let me help though...guess he is smarter than even I give him credit for LOL...could it have been those huge 2 for 1 Margaritas we had at the beach the night before??
It was great to see you guys...cant wait until I get back down...permanently!
Cranking the bolts to the exact degree
Ed...if you're listening, we need a suction cup tray with a magnetic section to put on the window to hold stuff while we work....
He wouldn't let me help though...guess he is smarter than even I give him credit for LOL...could it have been those huge 2 for 1 Margaritas we had at the beach the night before??
It was great to see you guys...cant wait until I get back down...permanently!
Thread Starter
Tech Contributor
Joined: Jul 2002
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From: St. Louis, MO
St. Jude Donor '08
Craig funny story on that magnetic tray from Harbor Freight...so I get done with the job and I'm missing one of those f&7(&ing bolts for the power steering bracket.....can't find it anywhere. I get the everything else done, and still can't find it. Next day I'm cleaning the garage and putting tools away, and lo and behold...the bolt was stuck to the bottom of that tray! Never had that happen before. 
Safety Car
Joined: Dec 2005
Posts: 4,157
Likes: 37
From: North Carolina
St. Jude Donor '07-'08-'09-'11-'12
Craig funny story on that magnetic tray from Harbor Freight...so I get done with the job and I'm missing one of those f&7(&ing bolts for the power steering bracket.....can't find it anywhere. I get the everything else done, and still can't find it. Next day I'm cleaning the garage and putting tools away, and lo and behold...the bolt was stuck to the bottom of that tray! Never had that happen before.
Burning Brakes
Joined: May 2006
Posts: 1,110
Likes: 16
From: stuart fl
Thread Starter
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
Yes I should have cleaned up a bit before the pictures. It does indeed look like I should clamp that line.
You can see the beautiful cnc work by Tony Mamo & crew on that shot....those AFR heads look like artwork.
Last edited by Joe_G; Aug 7, 2011 at 03:35 PM.
Burning Brakes
Joined: May 2006
Posts: 1,110
Likes: 16
From: stuart fl
i been eager for a while now, if i wouldnt have tore up my trans about a year and a half ago i think i would already have the 10's. o well i guess i'll get it this year sometime.
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Melting Slicks
Joined: Jun 2005
Posts: 2,396
Likes: 52
From: Sicamous BC
Did Tony port those cylinder heads?
My experience with the AFR 205's is that you can run more timing than the stock heads even with the SCR increase. I've always ended at or very near 30*. Never gone past 30*, the power always kept improving on the dyno as I increased the timing.
My experience with the AFR 205's is that you can run more timing than the stock heads even with the SCR increase. I've always ended at or very near 30*. Never gone past 30*, the power always kept improving on the dyno as I increased the timing.
Thread Starter
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
It was a fun day swapping heads between two vehicles; now that I've done it once I could do it much faster next time. These cars are amazingly easy to work on compared to my Oldsmobiles I'm used to....no turkey trays to leak vacuum, and the heads are so much lighter! The reusable gaskets are great too. Hard to believe you can swap heads and only need to change the head gaskets, nothing else. Only bad think is that power steering bracket. It stinks.
Did Tony port those cylinder heads?
My experience with the AFR 205's is that you can run more timing than the stock heads even with the SCR increase. I've always ended at or very near 30*. Never gone past 30*, the power always kept improving on the dyno as I increased the timing.
My experience with the AFR 205's is that you can run more timing than the stock heads even with the SCR increase. I've always ended at or very near 30*. Never gone past 30*, the power always kept improving on the dyno as I increased the timing.
I have been getting some knock at part throttle so I've backed a little timing out there.
Melting Slicks
Joined: Jun 2005
Posts: 2,396
Likes: 52
From: Sicamous BC
Part throttle timing I found the same, I chalk that up to how much more efficient the cylinder filling is at that point. It will be awesome to see what happens to the under curve torque, hopefully you will be able to compare the two combo's, same dyno.
You already commented regarding traction, that must be the improved torque & throttle response....clutch killing stuff
You already commented regarding traction, that must be the improved torque & throttle response....clutch killing stuff
Thread Starter
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
Part throttle timing I found the same, I chalk that up to how much more efficient the cylinder filling is at that point. It will be awesome to see what happens to the under curve torque, hopefully you will be able to compare the two combo's, same dyno.
You already commented regarding traction, that must be the improved torque & throttle response....clutch killing stuff
You already commented regarding traction, that must be the improved torque & throttle response....clutch killing stuff
I was surprised that WOT timing had ZERO knock...but I'm running 22 degrees, which is my summer timing and it all I could run with stock heads without knocking. Interesting to hear about your experience.
I always get the .drf files from the dyno, so I'll be able to show before and after curves for each phase of my modding, stock, bolt on, cam only, FAST, now AFR's.
I'm
chuckling at you guys who've chalked up my stock clutch...it's been a month of daily driving now, still fine. And, I snuck out to the 1/8 mile track last Saturday, made 3 passes, no problem, clutch felt the same as always. I've got faith in old reliable!
Hoping for the best anyway. So far so good.
Melting Slicks
Joined: Jun 2005
Posts: 2,396
Likes: 52
From: Sicamous BC
No before & after dyno's, I'm very rural so dyno's & tuners were a min. of 6 hours away. So school of hard knocks for me. I have after dyno's & some of that progression.
I did the HCI first, then proceeded to kill clutches & diff's. I'm much wiser & poorer now, my first modification would have been the 4:10's.
As far as your WOT timing, I would going to at least 26* & if you are still clear of KR then bumping by 2* from there.
My cam was smaller I'm sure 228/228 113+2, I'm not familiar with your spec.
BTW that was a great tip on the valve drop TDC, I'm re cam-ming another motor & that is a very easy test to do.
I did the HCI first, then proceeded to kill clutches & diff's. I'm much wiser & poorer now, my first modification would have been the 4:10's.
As far as your WOT timing, I would going to at least 26* & if you are still clear of KR then bumping by 2* from there.
My cam was smaller I'm sure 228/228 113+2, I'm not familiar with your spec.
BTW that was a great tip on the valve drop TDC, I'm re cam-ming another motor & that is a very easy test to do.
Thread Starter
Tech Contributor
Joined: Jul 2002
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From: St. Louis, MO
St. Jude Donor '08
That TDC drop tip only works if you've got someone, like LG in my case, who has done the R&D on the cam and engine setup to know what a safe TDC drop figure would be.
Thread Starter
Tech Contributor
Joined: Jul 2002
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From: St. Louis, MO
St. Jude Donor '08
Spinmonster says it better than me...linked for those interested. NOTE the information below is from a ls3 head on an ls2 engine.
http://forums.corvetteforum.com/c6-t...cam-specs.html
http://forums.corvetteforum.com/c6-t...cam-specs.html
FLY-CUTTING 101-back in session
In most L92 set-ups like this one, the pistons would have to be cut. Each car is different and every cam, even the same grind, will vary. The Manley race flow valve has a thicker margin than the stock valve by .030”. Yes I measured them. In the picture below the various parts of a valve are labeled.
The margin takes away from P/V clearance therefore by about that amount. The heads being milled, and thinner gaskets are other factors. This install also advanced the cam 2 degrees from the original. Before everyone gets confused, my cam is a 230/234 XER on a 114LSA. The last cam I had was a 228/232 and it was stronger in the mid-band. These are very small differences but a man knows his ‘tool’. Duration takes away from P/V clearance too as it grows. I wouldnt be a bit surprised if a 226/230 or a 226/232 would do as good or better than this cam did. Data from various sources suggests that smaller works better on this head.
When you determine what clearance you need and decide to fly-cut a certain amount you have to realize that there is a difference between the fly-cut cut depth and the usable depth. Just because you cut a certain amount doesn’t mean the depth is the needed depth where the valve actually touches.
Taped up prior to fly-cutting:
Completed fly-cuts:
Pistons were cleaned by Craig before reassembly.
TECH POINT (NEON LIGHTS)
In the following hand drawn diagram, (because I care about all of you), shows the place where a valve actually touches a piston and where the cut is actually made. First thing to note is that when a piston is close to a valve that’s off the seat, the piston is not at top dead center (TDC). The intake valve’s contact (or near contact) occurs between 0 and 15 degrees after TDC when the piston is heading down. On the top diagram, the cut made is at TDC which is made with a 2.25” cutter. Since the valve is 2.165”, the cut has a wasted space of about .0425” that isn’t where the valve would touch. The deepest part of the cut is actually too high for the valve because of two reasons: The cutter is bigger than the valve and the piston has to be cut higher in the cylinder bore than where the piston would be if it would contact the valve at 0-15 degrees past TDC. Diagram 2 shows the piston further down the bore during contact IF YOU HAD THE PISTON TOO LOW FOR THE FLY-CUT and the edge of the valve touches the edge of the cut. Unfortunately you cant take a chance of putting the cut too far down the piston. What this amounts too is that the cut is unlikely to be deepest where the valve would touch and so the real cut depth is deeper than your actual gained clearance distance. Since the piston is limited in how deep you can cut, the distance must be discriminated. LG has had experience with deep cuts that worked fine and Louis’ Jr’s accuracy can be banked on. If you get an .080” cut, the usable depth is less. How much? You guess. While compression is your friend, the ring lands get close to the cut at the edges.
Craig was cut .075” at the deepest but at TDC so the effective depth is more like .055". The depth wasnt really needed but if things work out on a future grind, it may benefit from the added available space.
In most L92 set-ups like this one, the pistons would have to be cut. Each car is different and every cam, even the same grind, will vary. The Manley race flow valve has a thicker margin than the stock valve by .030”. Yes I measured them. In the picture below the various parts of a valve are labeled.
The margin takes away from P/V clearance therefore by about that amount. The heads being milled, and thinner gaskets are other factors. This install also advanced the cam 2 degrees from the original. Before everyone gets confused, my cam is a 230/234 XER on a 114LSA. The last cam I had was a 228/232 and it was stronger in the mid-band. These are very small differences but a man knows his ‘tool’. Duration takes away from P/V clearance too as it grows. I wouldnt be a bit surprised if a 226/230 or a 226/232 would do as good or better than this cam did. Data from various sources suggests that smaller works better on this head.
When you determine what clearance you need and decide to fly-cut a certain amount you have to realize that there is a difference between the fly-cut cut depth and the usable depth. Just because you cut a certain amount doesn’t mean the depth is the needed depth where the valve actually touches.
Taped up prior to fly-cutting:
Completed fly-cuts:
Pistons were cleaned by Craig before reassembly.
TECH POINT (NEON LIGHTS)
In the following hand drawn diagram, (because I care about all of you), shows the place where a valve actually touches a piston and where the cut is actually made. First thing to note is that when a piston is close to a valve that’s off the seat, the piston is not at top dead center (TDC). The intake valve’s contact (or near contact) occurs between 0 and 15 degrees after TDC when the piston is heading down. On the top diagram, the cut made is at TDC which is made with a 2.25” cutter. Since the valve is 2.165”, the cut has a wasted space of about .0425” that isn’t where the valve would touch. The deepest part of the cut is actually too high for the valve because of two reasons: The cutter is bigger than the valve and the piston has to be cut higher in the cylinder bore than where the piston would be if it would contact the valve at 0-15 degrees past TDC. Diagram 2 shows the piston further down the bore during contact IF YOU HAD THE PISTON TOO LOW FOR THE FLY-CUT and the edge of the valve touches the edge of the cut. Unfortunately you cant take a chance of putting the cut too far down the piston. What this amounts too is that the cut is unlikely to be deepest where the valve would touch and so the real cut depth is deeper than your actual gained clearance distance. Since the piston is limited in how deep you can cut, the distance must be discriminated. LG has had experience with deep cuts that worked fine and Louis’ Jr’s accuracy can be banked on. If you get an .080” cut, the usable depth is less. How much? You guess. While compression is your friend, the ring lands get close to the cut at the edges.
Craig was cut .075” at the deepest but at TDC so the effective depth is more like .055". The depth wasnt really needed but if things work out on a future grind, it may benefit from the added available space.
Last edited by Joe_G; Aug 27, 2011 at 11:39 AM.
Melting Slicks
Joined: Jun 2005
Posts: 2,396
Likes: 52
From: Sicamous BC
But be careful with that tip.....remember, the intake valve comes closest not at TDC but a few degrees after as the piston is going down the bore and the intake valve is opening.
That TDC drop tip only works if you've got someone, like LG in my case, who has done the R&D on the cam and engine setup to know what a safe TDC drop figure would be.
That TDC drop tip only works if you've got someone, like LG in my case, who has done the R&D on the cam and engine setup to know what a safe TDC drop figure would be.
. Now that I thought a little, checker springs & dial gauge while the degree wheel is still on I should be able to figure it out.
Thread Starter
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
Be sure and post up a how to thread with pics!
Pro
Joined: Apr 2006
Posts: 737
Likes: 24
From: Edwardsville IL
Thread Mark / absorbing ideas. THANKS!!!
I recently found out a Neighbor used to Race Cars and has built many engines including the one he now placed in his 67 Camaro Vert.
I may have RUINED Him by letting him drive my car? But he deems he is skilled in this arena and would provide his assistance to me if needed / When needed on the evolution of my car. This is wonderful news to me if I can source the $$ for the mod's. I bet I can squirrel away something in the coming months!
I recently found out a Neighbor used to Race Cars and has built many engines including the one he now placed in his 67 Camaro Vert.
I may have RUINED Him by letting him drive my car? But he deems he is skilled in this arena and would provide his assistance to me if needed / When needed on the evolution of my car. This is wonderful news to me if I can source the $$ for the mod's. I bet I can squirrel away something in the coming months!
Last edited by gsx1300r; Aug 29, 2011 at 07:09 PM.
Thread Starter
Tech Contributor
Joined: Jul 2002
Posts: 14,950
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From: St. Louis, MO
St. Jude Donor '08
Some preliminary results to report
I haven't had the chance to hit they dyno yet, but I did make three passes at the local 1/8 mile track. The track prep wasn't perfect and my tires are getting long in the tooth so I was spinning every pass to a 1.8 60. I stopped beating on the equipment after 3 tries.
DA was 2047, but I ran 94 & 95 mph in the 1/8, which compares to 92 & 93 in the 1/8 with my stock heads back in June with 2000 DA. So the gains my SOTP meter reported are real.
Since I scan my delivered torque with HP Tuners, I can demonstrate this another way too. See below - at torque peak of around 5300, my stock heads on the right showed 413 lb ft in June (similar to my last dyno measurement of 408 lb ft) vs my AFR heads on the left showing 438 lb ft.
DA was 2047, but I ran 94 & 95 mph in the 1/8, which compares to 92 & 93 in the 1/8 with my stock heads back in June with 2000 DA. So the gains my SOTP meter reported are real.
Since I scan my delivered torque with HP Tuners, I can demonstrate this another way too. See below - at torque peak of around 5300, my stock heads on the right showed 413 lb ft in June (similar to my last dyno measurement of 408 lb ft) vs my AFR heads on the left showing 438 lb ft.
Le Mans Master
Joined: May 2011
Posts: 5,022
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From: Tampa FL (formerly Justinjor)
Tech Contributor
St. Jude Donor '11-'12-'13-'14
Outstanding Joe, congrats on the new found power. That's always exciting.
Any idea when the first big track day is for you and your 'crew' over there? I'm really looking forward to making the trek across the state to finally meet up.
Any idea when the first big track day is for you and your 'crew' over there? I'm really looking forward to making the trek across the state to finally meet up.