afr head?
Compression...
Originally Posted by pdd
when i get my afr 205cc 66cc heads should i mill them or just through them on as is.
If you don't live in CA or AZ I wouldn't hesitate for a minute to mill them down to 62 cc's or so....with an .050 head gasket your just under 11 to 1, with an .040 gasket your just above it. Even in the 91 octane states (which I happen to live in) I still advise a compression bump if your trying to get the most out of the head swap....it just takes a very good tuner to minimize knock retard etc., but the AFR chamber design seems to show better resistance to knock anyway. Either way you go, you will be smiling.....
Hope this info helps you out...
Tony M.
Originally Posted by Tony Mamo @ AFR
If you don't live in CA or AZ I wouldn't hesitate for a minute to mill them down to 62 cc's or so....with an .050 head gasket your just under 11 to 1, with an .040 gasket your just above it. Even in the 91 octane states (which I happen to live in) I still advise a compression bump if your trying to get the most out of the head swap....it just takes a very good tuner to minimize knock retard etc., but the AFR chamber design seems to show better resistance to knock anyway. Either way you go, you will be smiling.....
Hope this info helps you out...
Tony M.
Hope this info helps you out...
Tony M.
Teching In
Joined: Jul 2002
Posts: 25
Likes: 0
From: Nixa, Mo. USA
Originally Posted by Tony Mamo @ AFR
If you don't live in CA or AZ I wouldn't hesitate for a minute to mill them down to 62 cc's or so....with an .050 head gasket your just under 11 to 1, with an .040 gasket your just above it. Even in the 91 octane states (which I happen to live in) I still advise a compression bump if your trying to get the most out of the head swap....it just takes a very good tuner to minimize knock retard etc., but the AFR chamber design seems to show better resistance to knock anyway. Either way you go, you will be smiling.....
Hope this info helps you out...
Tony M.
Hope this info helps you out...
Tony M.
Thanks,
Originally Posted by rsmith
Tony, Thanks for the reply to some of the questions we have about your new heads. My question relates to valve to piston clearance with the lifts & timing events that are close. I thought I saw posted that unmilled your heads have the valves farther away from the piston than on stock unmilled GM castings. If this is true how much milling on the AFR heads to equal stock GM casting valve clearance. I hope this question is understandable to help figure out how much milling would be needed to make valve clearance. This could help the ones that have a cam that is recommended for unmilled stock heads.
Thanks,
Thanks,
Your very welcome....To answer your question, you will have .010-.015 additional piston to valve clearance with an un-milled out of the box AFR 205 versus a STOCK LS6 head....but I would never NOT check P to V and assume your OK. Keep in mind, an LS6 head is 65 cc's so you would have to mill .006 off the AFR to have the exact same compression ratio....Now you have .004-.009 additional room at the same chamber volume. Hope I'm explaining it properly for you to understand.
Bottom line, the AFR 205 should yeild close to the same P to V as a stock LS6 head (and maybe a little more), and P to V must ALWAYS be checked unless you like rolling the dice with expensive engine components.
Regards,
Tony M.
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Teching In
Joined: Jul 2002
Posts: 25
Likes: 0
From: Nixa, Mo. USA
Originally Posted by Tony Mamo @ AFR
RSmith...
Your very welcome....To answer your question, you will have .010-.015 additional piston to valve clearance with an un-milled out of the box AFR 205 versus a STOCK LS6 head....but I would never NOT check P to V and assume your OK. Keep in mind, an LS6 head is 65 cc's so you would have to mill .006 off the AFR to have the exact same compression ratio....Now you have .004-.009 additional room at the same chamber volume. Hope I'm explaining it properly for you to understand.
Bottom line, the AFR 205 should yeild close to the same P to V as a stock LS6 head (and maybe a little more), and P to V must ALWAYS be checked unless you like rolling the dice with expensive engine components.
Regards,
Tony M.
Your very welcome....To answer your question, you will have .010-.015 additional piston to valve clearance with an un-milled out of the box AFR 205 versus a STOCK LS6 head....but I would never NOT check P to V and assume your OK. Keep in mind, an LS6 head is 65 cc's so you would have to mill .006 off the AFR to have the exact same compression ratio....Now you have .004-.009 additional room at the same chamber volume. Hope I'm explaining it properly for you to understand.
Bottom line, the AFR 205 should yeild close to the same P to V as a stock LS6 head (and maybe a little more), and P to V must ALWAYS be checked unless you like rolling the dice with expensive engine components.
Regards,
Tony M.
Thanks for the good info on your products ~~~ looks like I will be getting milled .024 for 62 cc chambers.
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