Re: need valve lash advise if I don't know the cam
There you go again. You know, for someone who is always critical of others' writing style, ability, punctuation, syntax, and usage, you certainly do resort to speaking in colloquialisms whenever you are angry. This, of course, occurs with regularity whenever you are challenged in your pontifications. You should concentrate on the business at hand, rather than trying to divert attention by testing others' knowledge. I'll respond to your "smoke and mirrors" discourse, in kind. I trust that most folks on board, here, will follow along.
As you know, a cam's LSA (lobe separation angle), defines the number of camshaft degrees separating the intake's POML (point of max lift) from that of the exhaust, and since the camshaft rotates at one-half the rate of the crankshaft, then a hypothetical camshaft with 110 LSA would be one in which the POML of the intake and exhaust would be separated by 220 crankshaft degrees. When a camshaft is neither advanced nor retarded relative to the crank, its intake's POML is the same number of crankshaft degrees ATDC as the exhaust valves' are BTDC.* So, the hypothetical camshaft whose LSA is 110 degrees, and is installed neither advanced nor retarded, would be one whose intake valves' LCL (lobe centerline), or POML are 110 crankshaft degrees ATDC, and whose exhaust valves' LCL, or POML are 110 crankshaft degrees BTDC.
When a camshaft is specified as having a certain LSA, this does not in itself define the opening and closing events of the valves. The cam's timing relative to the crank must be specified, and most camshafts are manufactured with some degree of advance built in, generally between 2 and 8, with 4-6 being the most common. Look again at the hypothetical camshaft with 110 degree LSA, assume that it is ground with 4 degrees advance. If it is installed in the engine with its index mark directly opposite that of the crankshaft, then its intake POML is 106 crankshaft degrees ATDC and its exhaust POML is 114 crank degrees BTDC.
*This assumes lobes with symmetrical flanks. Camshafts having asymmetrical lobes with do not necessarily have LSA's which are co-incident with [(intake LCL) + (exhaust LCL)]/2, because their POML do not necessarily occur at the centerline of the lobes.
There you go again. You know, for someone who is always critical of others' writing style, ability, punctuation, syntax, and usage, you certainly do resort to speaking in colloquialisms whenever you are angry. This, of course, occurs with regularity whenever you are challenged in your pontifications. You should concentrate on the business at hand, rather than trying to divert attention by testing others' knowledge. I'll respond to your "smoke and mirrors" discourse, in kind. I trust that most folks on board, here, will follow along.
As you know, a cam's LSA (lobe separation angle), defines the number of camshaft degrees separating the intake's POML (point of max lift) from that of the exhaust, and since the camshaft rotates at one-half the rate of the crankshaft, then a hypothetical camshaft with 110 LSA would be one in which the POML of the intake and exhaust would be separated by 220 crankshaft degrees. When a camshaft is neither advanced nor retarded relative to the crank, its intake's POML is the same number of crankshaft degrees ATDC as the exhaust valves' are BTDC.* So, the hypothetical camshaft whose LSA is 110 degrees, and is installed neither advanced nor retarded, would be one whose intake valves' LCL (lobe centerline), or POML are 110 crankshaft degrees ATDC, and whose exhaust valves' LCL, or POML are 110 crankshaft degrees BTDC.
When a camshaft is specified as having a certain LSA, this does not in itself define the opening and closing events of the valves. The cam's timing relative to the crank must be specified, and most camshafts are manufactured with some degree of advance built in, generally between 2 and 8, with 4-6 being the most common. Look again at the hypothetical camshaft with 110 degree LSA, assume that it is ground with 4 degrees advance. If it is installed in the engine with its index mark directly opposite that of the crankshaft, then its intake POML is 106 crankshaft degrees ATDC and its exhaust POML is 114 crank degrees BTDC.
*This assumes lobes with symmetrical flanks. Camshafts having asymmetrical lobes with do not necessarily have LSA's which are co-incident with [(intake LCL) + (exhaust LCL)]/2, because their POML do not necessarily occur at the centerline of the lobes.
Both of you obviously know your stuff and just have different perspectives on what constitutes performance.
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