SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: 2savage4you on September 10, 2008, 03:57:57 PM
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What are the pro's and con's of a solid cam vs hydraulic.....
Dont be shy let me have it ;)
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From what I have read, hydraulic cams on a big block tend to want to go into valve float at around 5800RPMs. You can use stiffer valve springs in combat against that, but then you're beatin' the cam up by having to fight stiff ass springs. Also if you're running hydraulic roller and trying to use really stiff springs to make it work, it's really hard on the roller axles.
If you plan on staying below 5800RPM, hydraulic is the way to go, but if you plan on spinning faster than that, I'd definitely go solid lift.
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If you want dependability and are willing to give up a little rpm.....My choice would be HYDRAULIC,
Just get a GOOD ONE. CompCam or ClaySmith etc. Top it off with Roller Rockers.
Do your research!
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This subject is very debateable, with alot of different views.... I don't think there is a single correct answer....
But I say solid ;D
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Agreed..... Just depends on what is expected for performance. ;D
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If you just want a good running river boat and aren't going to abuse it, go hydraulic.
If your looking to get the most performance possible out of your combination, go solid (will require adjustments & inspections more often).
You can also look into a hydraulic roller cam. You get the added performance of a bigger cam without the headache of having to adjust it every time you take it out.
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I can tell you from first hand experience, the solid lifter cam will be less prone to valve float at higher RPM (6000+) and will eat up less HP do to less mechanical work needed, make the oil windage problems subside a little too, but for an endurance type application a mechanical type lifter beats the living crap out of everything, think of hydraulic lifters as little shock absorbers, so if your looking for a "set it and forget it" with a solid, IMO I wouldn't go that route.
A hydraulic on the other hand has it's limitations as well, the action of valve float is a "catch 22", yeah it causes problems with valvetrain parts, but at the same time limits engine RPM, keeps from breaking bigger stuff, "Little rev limiters" ;D
Best of both worlds, again IMO, mechanical roller, very expensive, but worth every penny for a bulletproof valvetrain pretty tuff stuff.
I agree with PW, open to way too much debate to be right or wrong, I just hate adjusting valves :-\
Ultimately, the engine needs to be built around the valvetrain, not the other way around, which unfortnately I have screwed up everytime.... :screwy:
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I am going to take a guess and say that you probably are not going to be turning more than 5500ish and that you are probably not going to be racing and probably (if you are like me) are not going to want to screw with valves all the time. So, I would suggest a good Hyd. cam and a set of roller rockers. After the initial adjusting and tinkering, put gas in boat and go to lake (or river in your case) ;D
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Once again.... It all depends on what the customer wants.....
I been building Engines, full time for the last 30 years, and
I know from customer follow-up that customers do not like
to mess with the valve train.
I good friend of mine "76 Nordic" is running a custom hyd. cam
and I know he is happy with it...... Once again , this subject
is very controversial............ Contact Isky Cams or another
CamGrinder and get their input. Good Luck ;D
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what does adjusting the solids "all the time" mean? every year, month, or week? i got 50 days on mine with out checking them. am i asking for problems? :banghead:
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What are the pro's and con's of a solid cam vs hydraulic.....
Dont be shy let me have it ;)
what is the intended use and application ??? those ?'s will have to be addressed first. the camshaft is the last thing i pick in any build.
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what does adjusting the solids "all the time" mean? every year, month, or week? i got 50 days on mine with out checking them. am i asking for problems? :banghead:
you say 50 days, but, how often/far are you running the engine? if you have to keep adjusting your valve train there is something wrong. i check mine once on race weekends seldom adjust even 1 rocker. mostly for peice of mind and to catch something before it goes wrong. oh yeah its on my race motor, solid roller same but different.
edit, in the late 60's cars came off the show room floor with solid cams with a valve adjustment every 3-5k, not sure on that but that should put it into perspective for you.
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you say 50 days, but, how often/far are you running the engine? if you have to keep adjusting your valve train there is something wrong. i check mine once on race weekends seldom adjust even 1 rocker. mostly for peice of mind and to catch something before it goes wrong. oh yeah its on my race motor, solid roller same but different.
Totally depends on how hard and for how long its run, Ralph is right on the "checking them", most times dont need to do anything, especially on the rollers, flat tappets a little more (way more impact), I would say worst case scenerio one time a year for a lake boat.
Roller rocker arms help this too (again less impact) not the roller tipped delios, full blown rollers, shaft mounted preffered...Again IMO...
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Steve, with a B impeller, and a decent motor capable of some good power (upper 500's) then I would put solid in it for piece of mind
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Steve, with a B impeller, and a decent motor capable of some good power (upper 500's) then I would put solid in it for piece of mind
x2
B impeller= more rpm
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With a solid lifter, the cam profile can be more aggressive and can accelerate the valve off the seat and open it fully more quickly, resulting in "more area under the curve"
Hydraulic lifters are subject to this thing called "hydraulic intensity" which limits how quickly the cam can open the valve without "collapsing" the lifter mechanism
Rollers can have the most aggressive ramps and you dont have to worry about cam break in.
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In the old days I would agree - however with the issues with the lack of zinc and other essential additives that allow a flat tappet cam to survive, I won't build an engine nowadays without a roller cam in it. You can do a mild hyd roller cam, not beat up parts, and not worry about the cam going flat.
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Solid , roller preferably . You should be snooping around your motor maintanace wise anyways . It wont kill you to whip out the feeler gauges for a few minutes . It'll probably take you longer to take the valve covers off than it will to check the valves .
-beerjet-
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So Im shooting for 500 hp or more . I have a 454 .030 over, flat tops 10:1 comp. ported polished 781 heads roller rockers . I am down to cam choice and cant make up my mind. Any suggestions? I dont mind checking the valves or anything. I wouldnt have a boat if I didnt want to work on something right.
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So Im shooting for 500 hp or more . I have a 454 .030 over, flat tops 10:1 comp. ported polished 781 heads roller rockers . I am down to cam choice and cant make up my mind. Any suggestions? I dont mind checking the valves or anything. I wouldnt have a boat if I didnt want to work on something right.
one of the cheby guys will have to give you specifics but, i would think that you could get to your target hp (500) with a hyd cam. you say ported and polished, do you know what they flow ??? that would be the optimum way of choosing a camshaft for any application.
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So Im shooting for 500 hp or more . I have a 454 .030 over, flat tops 10:1 comp. ported polished 781 heads roller rockers . I am down to cam choice and cant make up my mind. Any suggestions? I dont mind checking the valves or anything. I wouldnt have a boat if I didnt want to work on something right.
336781 ~ 73-85 ~ oval port ~ open chamber ~ 454 ~188cc chamber ~ 256/114cc ports
I'm no cam guy so I cant help you there . I choose a cam based mostly on RPM range since all your componenets should compliment/match each other . Like Ralph said , the lash on a solid lifter cam shouldnt change and going over all your bolts and pulling valve covers off before every trip out should be part of routine maintanance (sp?) anyways . 500 hp shouldnt be a problem with those heads and 10:1
-beerjet-
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So Im shooting for 500 hp or more . I have a 454 .030 over, flat tops 10:1 comp. ported polished 781 heads roller rockers . I am down to cam choice and cant make up my mind. Any suggestions? I dont mind checking the valves or anything. I wouldnt have a boat if I didnt want to work on something right.
What piston part #'s are you using? With the open chamber 781 heads, you would need a domed piston to achieve 10:1 compression. Probably be closer to 8.5:1 with the flat tops.
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I dont have the part # for the pistons , I talked to my Dads friend I got them from and he said that they are more like 9: 1 comp. and he planned on milling my heads very little too. So as far as flow on the heads I know that they are 119cc and oval ports. Ive got a cam picked out (I think) extreme marine comp cam 244/254 dur....570/575 lift. Do you think that cam will sound nice and have a good lope. I know it will perform well, but I want it to sound good too.