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Can 310's (as per Canfield)
Lift Int/ex (% ex to int)
.100 72/74 (102%)
.200 138/123 (89%)
.300 204/176 (86%)
.400 266/205 (77%)
.500 318/237 (74%)
.600 347/260 (75%)
.700 353/273 (77%)
.800 355/284 (80%)
average % ex to int=82%, average above .400"=76%
were these #'s off your heads or an avg they use from their testing?
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These are Canfield's numbers.
VALVE LIFT .100 .200 .300 .400 .500 .600 .700 .800
Intake Port 72 138 204 266 318 347 353 355
Exhaust Port 74 123 176 205 237 260 273
Here's a side by side comparison using my average left-right numbers.
lift Can# My#
.100 72 74
.200 138 166
.300 204 243
.400 266 289
.500 318 320
.600 347 335
.700 353 341
.800 355 343
ex
.100 72 66
.200 123 135
.300 176 179
.400 205 216
.500 237 251
.600 260 279
.700 273 298
.800 --- 312
Next...designing the cam.
Is there much value to lifting this valves much more than .600? Seems like the heads are about done around there. A .600 lift seems like it would make valve springs live better than an .750 or so.
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If the head doesn't flow....holding valves open is a waste of Hp. You make no power with a valve open.
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Although the "numbers" don't show that there would be much advantage of opening the valve much further than .600, there's more to it than that. The cam that's been designed for my particular application, where I'm looking for max power in the 6500-6800 range, and will realistically run between 6200 and 6300 will have an intake lobe over .700, but an ex lobe of less than .700. Lift alone is of no use without considering duration as well, and duration will dictate the rpm range. The duration will be relatively short as compared to conventional tinking on this app, which might hurt power above 7000, but it will pick it up more down where I'm using it. If this was a v-drive, where I could gear it to what ever rpm I wanted, the cam would be completely different. That's one of the fun parts of building a good running jet...getting the power where you're limited to using it. I could cut the crap out of the impeller for more rpm, but then you begin losing impeller effeciency, trading pump performance for engine performance, At some point, you begin to have diminishing results.
I've been working with Chris Straub on designing this cam and I have to tell you, this guy's sharp! He's also about one of the nicest guys I've ever had the opportunity to work with. There's a lot of information that has gone into the profiles we (he) came up with and i'm looking forward to getting this thing on the dyno to see what we've got. He's had very good results so far, and I'm hoping this to be just another. I'll post the results as soon as I have them...probably toward the end of summer.
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I might add this, although I'm not positive, but I think to keep the valve open for a measured duration, especially when the valve opens as late as possible (like with IR cams) and stays open for as long as it does, even thjough you don't "need" to open it that far, you have to continue opening the valve...you can't just reach max lift, then flatten the lobe, hold it there, and then start letting it down. You'd have "corners" on the lobe, and you'd throw the lifter. The lobe has to remain relatively consistant with a smooth radius, which might have to add lift, just to get through the cycle. Don't know if that makes any sense....
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Can 310's (as per Canfield)
Lift Int/ex (% ex to int)
.100 72/74 (102%)
.200 138/123 (89%)
.300 204/176 (86%)
.400 266/205 (77%)
.500 318/237 (74%)
.600 347/260 (75%)
.700 353/273 (77%)
.800 355/284 (80%)
average % ex to int=82%, average above .400"=76%
were these #'s off your heads or an avg they use from their testing?
These are Canfield's numbers.
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Bump...any news to report? :cool:
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Not yet...still waiting on cam, and a few other parts. Scored a very clean set of 1050's. (earlier 6464's) Will need to check v/p clearance with new cam, and probably have to fly cut pistons on the intake side. Still have lots of work to do. I'll keep updating as I go. :D
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You won't be disappointed.
I had a set of 310s worked over by Jim Valako. Mild port on intake and full port exhaust.
L/Int/Ext
.200/150/140
.300/230/181
.400/297/225
.500/342/258
.600/360/280
.650/---/290
Engine makes over 900hp in the boat with 7-8 lbs of boost :D :D
Have Fun!!!
Dave
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Dave...that's pretty interesting. Thanks for that. I got about the same on the exhaust, but I'm wondering what he did on the intakes to get the numbers up above .300? What happened above .600? I studied these ports quite a bit and I didn't see much that could be done to pick up the top without making them considerably bigger. I was able to improve on Canfield's numbers up to .500, but my heads didn't even meet Can's advertized no's above .500. (I'm sure they flowed on a 4.500 bore, where as I flowed on a 4.31.) What's interesting is the exhaust...you say full port on the ex. yet our numbers are almost identical, and all I did was basically cartridge roll and blend the ex. I didn't change the port at all. (well, maybe a little :D)
Making the int. port bigger is no big deal for a blown app, but I wanted to keep it as small as I could for what I'm doing.
I always enjoy these comparisons. Thanks again!! :cool: