Cam and valvetrain longevity....??? low duration high lift...
10-01-2016, 04:14 PM
#871
Registered
MT listed a couple howards grinds about a dozen pages back that looked about the best I've seen for off the shelf. I noticed howards always list lift depending 1.60, 170, 1.80 rocker ratio. I realize many don't like to use 1.8's however is there anyone has had any real known issues with running them. I can see perhaps a little harder on valvetrain with geometry but... Again anyone here that's had real issues with them?
10-01-2016, 04:21 PM
#873
Registered
MT listed a couple howards grinds about a dozen pages back that looked about the best I've seen for off the shelf. I noticed howards always list lift depending 1.60, 170, 1.80 rocker ratio. I realize many don't like to use 1.8's however is there anyone has had any real known issues with running them. I can see perhaps a little harder on valvetrain with geometry but... Again anyone here that's had real issues with them?
10-01-2016, 04:44 PM
#874
Registered
So, what are you guys thinking ?
Something like this ? NArrower centers ? Something larger ?
Brand:Crane Cams
Manufacturer's Part Number:168771
Part Type:Camshafts
Product Line:Crane Hydraulic Roller Camshafts
Summit Racing Part Number:CRN-168771
UPC: 021174045079
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,600-6,200
Intake Duration at 050 inch Lift: 240
Exhaust Duration at 050 inch Lift: 248
Duration at 050 inch Lift: 240 int./248 exh.
Advertised Intake Duration: 302
Advertised Exhaust Duration: 310
Advertised Duration: 302 int./310 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.621 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.632 in.
Valve Lift with Factory Rocker Arm Ratio: 0.621 int./0.632 exh.
Lobe Separation (degrees): 114
Computer-Controlled Compatible: No
Grind Number: HR-240/365-2S-14 IG
Valve Springs Required: Yes
Quantity: Sold individually.
Notes: Camshaft incorporates an integral cast iron distributor drive gear. An aluminum-bronze distributor drive gear not required. 10.5 to 12.5 compression ratio advised. Also fits 502 c.i.d. engines.
Something like this ? NArrower centers ? Something larger ?
Brand:Crane Cams
Manufacturer's Part Number:168771
Part Type:Camshafts
Product Line:Crane Hydraulic Roller Camshafts
Summit Racing Part Number:CRN-168771
UPC: 021174045079
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,600-6,200
Intake Duration at 050 inch Lift: 240
Exhaust Duration at 050 inch Lift: 248
Duration at 050 inch Lift: 240 int./248 exh.
Advertised Intake Duration: 302
Advertised Exhaust Duration: 310
Advertised Duration: 302 int./310 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.621 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.632 in.
Valve Lift with Factory Rocker Arm Ratio: 0.621 int./0.632 exh.
Lobe Separation (degrees): 114
Computer-Controlled Compatible: No
Grind Number: HR-240/365-2S-14 IG
Valve Springs Required: Yes
Quantity: Sold individually.
Notes: Camshaft incorporates an integral cast iron distributor drive gear. An aluminum-bronze distributor drive gear not required. 10.5 to 12.5 compression ratio advised. Also fits 502 c.i.d. engines.
This type of cam will revert h2o
Last edited by Black Baja; 10-01-2016 at 04:48 PM.
10-01-2016, 04:53 PM
#875
Registered
That cam is too small. Need mid 250's on intake high 250's exhaust 109 lsa cam needs to go in 10 degrees advanced. Something along those line in mid 5xx" motors with 320range heads will be in the 725-750hp range a tic over 6,000 rpm's with compression in 9.5:1 range. They really make a bunch more torque if you put a dome piston in them around 10.3:1
This type of cam will revert h2o
This type of cam will revert h2o
10-01-2016, 05:32 PM
#877
Registered
I hate to say this but having been born a gear head and a lot of experience racing and wrenching on all sorts of racing stuff. I always kind of new Bob really didn't have any hands on experience. I could tell it was all text book talk which is ok but the text book only gets you so far and hands on real world experience is what really matters. I've been in and around some really bad azz stuff some was designed/ engineered buy guys that couldn't even read or write. So at the end of the day I really can't fault Bob cause he is what he is (textbook) and I had always really known.
baffles me every time. Then when the game is up they discredit actual knowledgeable people and businesses . But eventually the Bullchit is scooped out and the truth becomes clear.
10-01-2016, 06:34 PM
#878
Registered
My controlled induction 2016 cam software, suggests for Tim's engine, max rpm of 6000, A 252/260 108 LSA 654/680 lift cam.
My dyno simulator, with tims 241/246, 112 LSA cam, shows a peak HP of 658HP at, 5500 with his components( prob not far off if tim had dynoed with no accessories and dyno headers). Switching to the cam softwares 252/260, hp peak goes up to 699 at 6000RPM. Switching that 252/260, from a 108 LSA, to a 112 LSA with a 110ICL, the HP climbs again, to 711hp at 6000. Going to a 114, with a 110 ICL, drops it big time, to 683HP at 6000rpm.
So, back to the 252/260, 112 LSA setup. Sim say 711HP at 6000RPM. Thats with a CFM rating of 1000CFM. Bumping that, to a 1250 CFM, the engine is now making 728HP at 6000RPM. Peak torque, still in the 4500RPM range.
Now, granted thats just pplaying around with a software program, but that certainly seems fairly in line with this guys claims?
Here is a few that I have built for power boats. 540-548 bbc's, ported Iron eagle 308 heads, not radical porting, but detail work, chamber work, ex port work, the intake received attention thru the whole runner, about 320cc ish when done. 10:1, the Dart single plane that came on the boat originaly, on the mecruiser HP 500 502, Custom comp hydraulic roller, 252-260 at .050, .640 lift, 112 lobe sep. For numerous reasons. Did like 8-10 of those, either 540's or 548's out of the original 502 blocks. THey would make 715-730 hp, and about the same for tq, peaked about 5800 for hp, in the 4500ish for tq, depending on carbs used. And they rocked. Also built similar engines, but made them 509's, using the stock crank, they would make about 680hp and about 665 for tq, but, I would pull the duration back to 248-256,to keep the same rpm range.They would actualy go 6000-6200 for peak hp, same lobe family, so the lift was the same, and the same 112 lobe sep.
My dyno simulator, with tims 241/246, 112 LSA cam, shows a peak HP of 658HP at, 5500 with his components( prob not far off if tim had dynoed with no accessories and dyno headers). Switching to the cam softwares 252/260, hp peak goes up to 699 at 6000RPM. Switching that 252/260, from a 108 LSA, to a 112 LSA with a 110ICL, the HP climbs again, to 711hp at 6000. Going to a 114, with a 110 ICL, drops it big time, to 683HP at 6000rpm.
So, back to the 252/260, 112 LSA setup. Sim say 711HP at 6000RPM. Thats with a CFM rating of 1000CFM. Bumping that, to a 1250 CFM, the engine is now making 728HP at 6000RPM. Peak torque, still in the 4500RPM range.
Now, granted thats just pplaying around with a software program, but that certainly seems fairly in line with this guys claims?
Here is a few that I have built for power boats. 540-548 bbc's, ported Iron eagle 308 heads, not radical porting, but detail work, chamber work, ex port work, the intake received attention thru the whole runner, about 320cc ish when done. 10:1, the Dart single plane that came on the boat originaly, on the mecruiser HP 500 502, Custom comp hydraulic roller, 252-260 at .050, .640 lift, 112 lobe sep. For numerous reasons. Did like 8-10 of those, either 540's or 548's out of the original 502 blocks. THey would make 715-730 hp, and about the same for tq, peaked about 5800 for hp, in the 4500ish for tq, depending on carbs used. And they rocked. Also built similar engines, but made them 509's, using the stock crank, they would make about 680hp and about 665 for tq, but, I would pull the duration back to 248-256,to keep the same rpm range.They would actualy go 6000-6200 for peak hp, same lobe family, so the lift was the same, and the same 112 lobe sep.
