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Originally Posted by SB
(Post 4359943)
As most know now, Cup and some other forms of endurance racing go one step much further, and that is to 'flood' the valve covers with oil.
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I like what Reher says here.... "In my experience, an extremely smooth profile is unlikely to win drag races. It might be suitable for a NASCAR stock car engine or an endurance racing application...."
We're certainly not drag racing here and not stock car racing or endurance racing----but obviously the engines need to live/survive in everyday normal wear and tear......and I know I am not saying anything profound here, but what I have observed over the years is that aggressive valve opening/closings will hardly make any noticeable difference in a hi-perf offshore boat engine. |
I'm guessing that having a lifter out of adjustment (i.e. too loose) or collapsing would also hammer the valvetrain the same way that valve float would, since the clearance ramps can't do their jobs. Am I on the right track with my thinking?
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Originally Posted by ICDEDPPL
(Post 4359937)
See I told you your seats are getting beat up with that wimpy 140# pressure.
Once they heat up it`s probably more like 115, I think you need some spring oilers I like my spring pressure like a like my mountains.. HIGH! and I like my springs like I like my Beer .. COLD We can talk about high or low spring pressures all day, but whats high? Whats low? Whats high? For example, a GM truck big block, might have 90lbs of seat pressure. Merc 525's, had what like 120lbs of seat pressure? Crane/comp/howards/lunati, etc, normally seem to recommend anywhere from 140-160lbs of seat pressure on a bbc hyd roller off the shelf cam. Then all of a sudden, we are talking 225lbs of seat pressure, and nearly 600 over the nose on a hyd roller. At one time, that was serious solid roller spring territory. I guess its simply a guess, unless you take you engine combo to a spintron, and see what it really needs for adequate valvetrain control with your combination of parts. Or, take a chance, and tear it down after couple hundred hours, and see what things look like. Like seats, lobes, lifters, etc. I think most cam companies, do the majority of the testing for us, and hence why they may recommend xxx part number springs, with xxx cams. I am sure they arent pulling those numbers out of thin air. I certainly don't know more than the guys at crane, crower, or comp cams. I can only take their word for it. My guess is when you really start getting into stuff like 55mm+ cam cores, big body lifters, custom designed lobes, higher lifts, larger pushrod diameters, big valves, different valve materials, untraditional style springs, and so on, a trip to the spintron, is worth the money. My gut feeling, is a basic traditional, mild lobe, off the shelf hydraulic roller from crane, designed for marine applications, isn't requiring 600lbs of spring over the nose, at 6,000 RPMs, to keep the valve train under control. But, thats just a guess, and I certainly dont know that for sure. I do know, there are lots of guys who've ran those cams, with much less spring here on oso, for lots of hours without issue since the late 90's. |
Originally Posted by Keith Atlanta
(Post 4359976)
"flood the valve covers with oil" How can that have a positive effect for us? Wont that just cause more problems? Plus, cup cars are runnind a 2000++ RPM higher than we ever see.
Was not suggesting the Cup Car deal. |
Read Grumpy's response to the first question:
http://garage.grumpysperformance.com...gine-oil.6491/ Chris Osborn from PAC springs: http://speedtalk.com/forum/viewtopic.php?f=1&t=4595 |
Originally Posted by abones
(Post 4359736)
This is what i'm refering to if you take away the 14# boost pressures would be 176/476, so we can't say what the perfect presure is for a hyd roller. it should be engine specific.
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Originally Posted by MILD THUNDER
(Post 4360001)
Mine are 165 at the seat. Maybe this winter we will tear mine down, and see what things look like in there. But you're right on about the temps, that certain can change the pressures as the spring heats up. One of the reasons I cringe when i see guys saying "my oil temps are 260, but its ok, my 12 dollar a quart oil can take it". I dont care about the oil, I care about the engine parts!
We can talk about high or low spring pressures all day, but whats high? Whats low? Whats high? For example, a GM truck big block, might have 90lbs of seat pressure. Merc 525's, had what like 120lbs of seat pressure? Crane/comp/howards/lunati, etc, normally seem to recommend anywhere from 140-160lbs of seat pressure on a bbc hyd roller off the shelf cam. Then all of a sudden, we are talking 225lbs of seat pressure, and nearly 600 over the nose on a hyd roller. At one time, that was serious solid roller spring territory. I guess its simply a guess, unless you take you engine combo to a spintron, and see what it really needs for adequate valvetrain control with your combination of parts. Or, take a chance, and tear it down after couple hundred hours, and see what things look like. Like seats, lobes, lifters, etc. I think most cam companies, do the majority of the testing for us, and hence why they may recommend xxx part number springs, with xxx cams. I am sure they arent pulling those numbers out of thin air. I certainly don't know more than the guys at crane, crower, or comp cams. I can only take their word for it. My guess is when you really start getting into stuff like 55mm+ cam cores, big body lifters, custom designed lobes, higher lifts, larger pushrod diameters, big valves, different valve materials, untraditional style springs, and so on, a trip to the spintron, is worth the money. My gut feeling, is a basic traditional, mild lobe, off the shelf hydraulic roller from crane, designed for marine applications, isn't requiring 600lbs of spring over the nose, at 6,000 RPMs, to keep the valve train under control. But, thats just a guess, and I certainly dont know that for sure. I do know, there are lots of guys who've ran those cams, with much less spring here on oso, for lots of hours without issue since the late 90's. |
Originally Posted by KAAMA
(Post 4359985)
I like what Reher says here.... "In my experience, an extremely smooth profile is unlikely to win drag races. It might be suitable for a NASCAR stock car engine or an endurance racing application...."
We're certainly not drag racing here and not stock car racing or endurance racing----but obviously the engines need to live/survive in everyday normal wear and tear......and I know I am not saying anything profound here, but what I have observed over the years is that aggressive valve opening/closings will hardly make any noticeable difference in a hi-perf offshore boat engine. |
Great info from all parties here. If nothing else, great tech conversation :coolcowboy:
I don't know why I havent put spring oilers on yet, looks like another add on this winter coming |
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