Valves and bore size
08-23-2002, 01:12 PM
#1
Re: Valves and bore size </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by racer7088:
<strong>No not really. I don't even know that you can get those in with stock valve spacing or at least both of them at once!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I have heard that 2.10 & 1.60 valves can be used on stock spaced heads. Just wondering if these could be used also.
<strong>No not really. I don't even know that you can get those in with stock valve spacing or at least both of them at once!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I have heard that 2.10 & 1.60 valves can be used on stock spaced heads. Just wondering if these could be used also.
08-23-2002, 01:12 PM
#2
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Re: Valves and bore size There is a good rule I heard once from one of the engine builders at Rheir Morrison Racing Engines, and it's that you should look for a Intake Valve size that is 52-54% of the bore. So a 2.05-2.10 Intake valve would be ideal for a bore of 3.90 but if you can fit that in there is another problem.
Bret
Bret
08-23-2002, 03:57 PM
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Re: Valves and bore size There's diminishing returns in that size range. I doubt you see too much additional flow. Plus, with that size you run into all different kinds of performance issues. (Ideally, you would want to change the valve angle due to the increased surface are (you want to keep the bowl as round as possible for more uniform combustion, etc.), this leads to more interfearance during valve overlap). I'm not one to discourage innovation...you might want to try it with the C5-R heads. I believe they have wider valve spacing--what cam would you use though? At a certain point you hit "undriveable" because the flow characteristics dictate the optimal cam profile, which will probably force your pwoer curve WAY up in this case. Somehow I don't think spinning 8k+ would be too fun all the time. You better have a strong valvetrain!
08-23-2002, 05:24 PM
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Re: Valves and bore size MMS uses 2.055 intake and 1.57 exhaust valves in their Stage III heads. These heads are designed for a 4.125 bore. I don't think that you need to go any bigger than these...especially with a 3.90 bore.
