Off the shelf cam options for marine engines
02-16-2016 | 08:23 AM
#243
Frank's Marine Service
Joined: Sep 2002
Posts: 11,959
Likes: 142
From: Elkton, MD
i was just thinking about this, and looked up that crane solid roller you mentioned.
That Crane solid roller profile, is VERY mild for a solid roller cam.
304/312, 254/262, .636/.636 valve lift (.374 lobe).
You switched it out for similar duration, .671/663 (.394 lobe) hydraulic roller.
Without having all of the camshaft details, I'd be willing to bet that the hydraulic roller you switched to, not only has more lift, probably also has a more aggressive lobe than that particular solid grind you mentioned.
Now, try putting that hydraulic roller up against a solid lobe, that is comparable, and I think you'd find the results would have been a bit different. Just because a cam is designed for a solid, doesnt make it more aggressive, and just because a cam is designed for a hydraulic, doesnt make it less aggressive. I'm not a cam guru, but plugging those basic numbers off the cam card from that solid crane there, into my simulator, shows its lifter acceleration to be, very tame. I've seen off the shelf hydraulics more aggressive than that as far as lifter acceleration goes. Its spring recommendation of 190lbs on the seat, kinda says something in my opinion as well.
That Crane solid roller profile, is VERY mild for a solid roller cam.
304/312, 254/262, .636/.636 valve lift (.374 lobe).
You switched it out for similar duration, .671/663 (.394 lobe) hydraulic roller.
Without having all of the camshaft details, I'd be willing to bet that the hydraulic roller you switched to, not only has more lift, probably also has a more aggressive lobe than that particular solid grind you mentioned.
Now, try putting that hydraulic roller up against a solid lobe, that is comparable, and I think you'd find the results would have been a bit different. Just because a cam is designed for a solid, doesnt make it more aggressive, and just because a cam is designed for a hydraulic, doesnt make it less aggressive. I'm not a cam guru, but plugging those basic numbers off the cam card from that solid crane there, into my simulator, shows its lifter acceleration to be, very tame. I've seen off the shelf hydraulics more aggressive than that as far as lifter acceleration goes. Its spring recommendation of 190lbs on the seat, kinda says something in my opinion as well.
The idle quality of the hydraulic is better than the solid was. The torque improved substainitally in the mid-range and had a pretty sizable gain on the top end. We expexted the power to increase a little bit over the solid roller but not as much as it did.
My point is that the cam selection and design was a success and I'm very happy with it.
02-16-2016 | 08:30 AM
#244
Frank's Marine Service
Joined: Sep 2002
Posts: 11,959
Likes: 142
From: Elkton, MD
I was told 3-4wks when I put the order in, which would have worked well with my schedule but on week 5 I threw in the towel. I had an upcoming poker run and wound up taking a JE piston and cutting a dish in it and adjusting the weight to match. Ran that engine with the milled JE piston for 5 years.
The "Weisco" pistons showed up at my doorstep 2 weeks after the poker run.
Last edited by Panther; 02-16-2016 at 08:33 AM.
02-16-2016 | 08:32 AM
#245
Registered
Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
I think it's fair to say that if I put a 700 lift (680 minus .020 lash) solid roller in, it definitely would make more power, they usually do. That wasn't my point. If I wanted a more aggressive solid roller with higher lift, I would have run it. The solid roller that was in there was not aggressive which is what I wanted at the time (2007) because there were a lot of hydraulic lifter issues back then. I was sick and tired of lashing valves so I had my new cam modeled around my solid roller with more lift to take advantage of the AFR's head design. I had been looking at several shelf cams but I wasn't finding what I was looking for.
The idle quality of the hydraulic is better than the solid was. The torque improved substainitally in the mid-range and had a pretty sizable gain on the top end. We expexted the power to increase a little bit over the solid roller but not as much as it did.
My point is that the cam selection and design was a success and I'm very happy with it.
The idle quality of the hydraulic is better than the solid was. The torque improved substainitally in the mid-range and had a pretty sizable gain on the top end. We expexted the power to increase a little bit over the solid roller but not as much as it did.
My point is that the cam selection and design was a success and I'm very happy with it.
Has anyone cam doctored one of the .680-690 ish lift cams that guys seem to be having issues with? Seems like they are the ones with duration at .050 in the 240 range ....maybe with more info one can help see what the lobe is like.
