BTR stage 3 cam with milled heads question
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BTR stage 3 cam with milled heads question
I have some 243 port and polished heads that are milled .028" and was wondering if anyone knows what my piston to valve clearance would be? Cam specs are 231/242 .617"/.592" 112+2. I would be running stock head gaskets .051"
Just trying to figure out if I would be ok with such cam or no
Just trying to figure out if I would be ok with such cam or no
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Just from my own experience, I would say that's a little to big for that much mill. I have 243's worked over by AI. They were milled .020 and they suggested something in the area of a 228- 232 or 230-238. Of course type of valve job and a few other factors play in. Your mill is .008 more so that cam might be a tad big. If you haven't installed those heads yet you could always flycut and run whatever size cam you want. Maybe someone else on here who has more experience could chime in also.
Last edited by black sky; 12-05-2016 at 08:17 PM.
#4
I put a set of PRC heads that were cut .017 with BTR stage 3 cam in my 02 TA.I didnt measure for ptv clearance.BTR said it would be close but that I should be ok.Runs like a scalded dog.Installed a ported FAST intake and throttle bodyand it put down 448/400.I'm happy.
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blsnelling (12-27-2019)
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I think comparing a GM 243 factory casting to a PRC casting would be a bad idea. Especially when considering ptv clearance. PRC heads are cast with a thicker deck than 243's from the start. More material to mill from means more PTV. You have to be a bit more mindful of how much you mill 243s because the lack of extra material. Both sets milled to a say......62cc combustion chamber will give very different ptv measurements. To the OP,,,,,that's cool if you are not into flycutting. Well if you are dead set on that cam, I would either consult Brian tooley and get his feelings or clay your heads to see if it hits. I'm going with a new cam motion cam myself and will go through the same process.
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#8
Not the same cam, but for ref: Stock deck 243 heads, OE head gaskets, 235/240 .629/.615 lift on a 111 LSA and I was at 0.100" and 0.080" on a stock bottom end with 14k miles. I'm approx 0.020" under the "normally accepted" PTV clearance. Car turns 6800-7000 RPM quite often and sees a road course about 20-30x a year...
#9
While you didn't say what engine I thought I would add to this info for anyone putting this in an LS2.
I put the BTR stage III in a 6.0 LQ9 with 243 heads (basically an LS2) that are milled .020 with LS9 gaskets. My measured P2v at the closest point in rotation is E= .076 I= .067. I was concerned that this was too close but both the guy who ported and milled my heads and BTR said that this should be fine and that the cam would benefit from the bump in compression. Mind you this didn't come from Bryan himself but one of the people in his shop.
I haven't started the car yet so I can't say but I figured the measurements may be helpful for someone who is going down the same road.
I put the BTR stage III in a 6.0 LQ9 with 243 heads (basically an LS2) that are milled .020 with LS9 gaskets. My measured P2v at the closest point in rotation is E= .076 I= .067. I was concerned that this was too close but both the guy who ported and milled my heads and BTR said that this should be fine and that the cam would benefit from the bump in compression. Mind you this didn't come from Bryan himself but one of the people in his shop.
I haven't started the car yet so I can't say but I figured the measurements may be helpful for someone who is going down the same road.
#11
While you didn't say what engine I thought I would add to this info for anyone putting this in an LS2.
I put the BTR stage III in a 6.0 LQ9 with 243 heads (basically an LS2) that are milled .020 with LS9 gaskets. My measured P2v at the closest point in rotation is E= .076 I= .067. I was concerned that this was too close but both the guy who ported and milled my heads and BTR said that this should be fine and that the cam would benefit from the bump in compression. Mind you this didn't come from Bryan himself but one of the people in his shop.
I haven't started the car yet so I can't say but I figured the measurements may be helpful for someone who is going down the same road.
I put the BTR stage III in a 6.0 LQ9 with 243 heads (basically an LS2) that are milled .020 with LS9 gaskets. My measured P2v at the closest point in rotation is E= .076 I= .067. I was concerned that this was too close but both the guy who ported and milled my heads and BTR said that this should be fine and that the cam would benefit from the bump in compression. Mind you this didn't come from Bryan himself but one of the people in his shop.
I haven't started the car yet so I can't say but I figured the measurements may be helpful for someone who is going down the same road.