biggest cam w/ AFR 59cc milled heads
08-15-2010, 12:51 PM
#2
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this topic has been beat to absolute death. 
Do a search. It literally took me 2 seconds to come up with this.
https://ls1tech.com/forums/generatio...-v-issues.html
https://ls1tech.com/forums/generatio...style-pps.html
Do a search. It literally took me 2 seconds to come up with this.https://ls1tech.com/forums/generatio...-v-issues.html
https://ls1tech.com/forums/generatio...style-pps.html
08-16-2010, 07:58 PM
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Sounds like your in the same boat as me. I already have a 231/237 589/595 on 112 installed in my vette and Im looking for a set of heads. Every set I find have been milled to 59cc. With my cam the minimum size chamber I can go with on a head with out fly cutting will be 62cc. Ireally don't want to fly cut so Im either holding off until I find unmilled heads or I will just buy new prc ls6 2.5 heads unmilled. Im pretty sure with 59cc heads your going to be limited to a cam with duration some where in the 224 or 225 range to keep safe piston to valve clearance.
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08-17-2010, 04:03 AM
#8
I have the AFR 6016 cam (224/228) and with the heads milled to 60cc and Cometic 0.040" gaskets my intake clearance was slightly below minimum. I would say with XER lobes that going over 222 in the intake side with 59cc heads and GM gaskets is going to put you below 0.080" on the intake so it will be a matter of how comfortable are you with those clearances. My exhaust side was fine.
08-17-2010, 10:14 AM
#9
Thanks for the posts guys. The reason I'm trying to find out is because I'm lookiing at a set of AFR 205cc heads that have been milled to 59.5. I'm debating on getting these or just holding off till I can afford a new set of either AFR or Trick Flow as cast heads. I want to be able to run a pretty aggressive cam without having to flycut.
08-17-2010, 12:01 PM
#11
The cam I am running is small if compared to some of the cams with names, but it has instant snap at almost any RPM. Some if this is because I can push the compression more with the smaller cam. There are trade-off's with any cam setup, so make sure you understand what a larger cam will do and not do. I would also contact Tony on the heads.
08-17-2010, 01:00 PM
#13
230 is going to be the max duration on a head milled .030 without flycutting...at 230 I would make sure and check the P to V clearance with some clay for sure..because it is going to be close ... if you are going to run a 228 or lower duration cam you should be good to go...
A 59CC chanmber with a .040 cometic head gasket will make around 11.4 to 1 compression that combined with a 228 duration cam that will make very nice power for a head/cam street car..mine makes 452/418 with a simalar set up.
PS Just an FYI for those who do not know ... Lift is not what you worry about when it comes to piston to valve clearance it is the duration of the cam that will determine what your clearance is going to be.
A 59CC chanmber with a .040 cometic head gasket will make around 11.4 to 1 compression that combined with a 228 duration cam that will make very nice power for a head/cam street car..mine makes 452/418 with a simalar set up.PS Just an FYI for those who do not know ... Lift is not what you worry about when it comes to piston to valve clearance it is the duration of the cam that will determine what your clearance is going to be.
Last edited by slt200mph; 08-17-2010 at 01:07 PM.
08-17-2010, 01:45 PM
#14
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or you could get an indexable timing chain and move your installed intake centerline up a bit. like if you're on a 108 now maybe a 110 or even a 112. with that though you will lose a hair of bottom end, but with the added compression i bet its very near offsetting.
08-17-2010, 02:59 PM
#15
230 is going to be the max duration on a head milled .030 without flycutting...at 230 I would make sure and check the P to V clearance with some clay for sure..because it is going to be close ... if you are going to run a 228 or lower duration cam you should be good to go... A 59CC chanmber with a .040 cometic head gasket will make around 11.4 to 1 compression that combined with a 228 duration cam that will make very nice power for a head/cam street car..mine makes 452/418 with a simalar set up.
PS Just an FYI for those who do not know ... Lift is not what you worry about when it comes to piston to valve clearance it is the duration of the cam that will determine what your clearance is going to be.
A 59CC chanmber with a .040 cometic head gasket will make around 11.4 to 1 compression that combined with a 228 duration cam that will make very nice power for a head/cam street car..mine makes 452/418 with a simalar set up.PS Just an FYI for those who do not know ... Lift is not what you worry about when it comes to piston to valve clearance it is the duration of the cam that will determine what your clearance is going to be.
Solid post but I need to correct you on the sentence I boldfaced above.
More like 11.8.....what your not taking into account is zero volume being displaced from valve reliefs. Even 61 cc's with a .040 gasket (assuming the piston is .007 - .008 out of the hole) is almost 11.5 to 1 with no valve reliefs in the piston
This combo (a 59 cc head with no valve relief pistons) would need a minimum of 92 octane to expect a reasonable amount of detonation resistance and reliability with 93 octane being much more preferable.
Regarding cam, a 114 LSA is a must and a 228 would be the absolute largest....even that netting you alot less than the textbook .080/.100
My guess is you would have around .050 on the intake and .070 on the exhaust...possibly a little less. Will it run.....sure....it will run good but you don't have a very large window in the event the RPM's flair up quickly or your valve springs start to get weak. Your just taking a bigger chance running them that tight....in a perfect world you would never have a problem but sheeeet happens, springs fatigue (or break) and at the least you have to head into this knowing your rolling the dice a little or burying your head in the sand and plowing ahead on blind faith that "everything is going to be OK".
If you really want "an aggressive" combination a 59 cc head is what you need, but you need to make the proper room for it via flycutting or swapping in forged pistons for even more reliability. Pay now or pay (potentially more) later....thats a good one liner applicable to this situation.
And the problem with going with even less cam is your dynamic cylinder pressure is too high....even 93 octane would be pushing it with 11.8 to 1 CR and a 224/228 stick (hypothetically speaking).
My advice is to bite the bullet on the flycutting or better yet pick up an aftermarket piston with 2 cc valve reliefs....the entire combination improves dramatically. It leaves you with 11.5 CR....more user friendly on pump.....you will have plenty of room to install an more aggressive cam in the mid 230's or even more if you want it really "chunky", and you will have a ton of P to V clearance and a much stronger piston. Alot of factory pistons fail in the ring land area under extended high RPM use....such as would be the case with a big cam to take the most advantage of it....once again the reason Im advocating the best solution here being a forged piston swap. Long term it probably saves you money and alot of time in the event a factory slug fails.....and that scenario is more common than you think.....ask me how I know....LOL
-Tony
08-17-2010, 03:04 PM
#17
08-17-2010, 03:06 PM
#19
For the others reading this my post above joking about the Bat signal was typed before I saw this response
Man.....that was hilarious.....and I was like WTF....I didnt even hit send yet!
