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| Hydraulic cam...benefits? https://www.slantsix.org/forum/viewtopic.php?t=9409 |
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| Author: | sleddogg [ Wed May 26, 2004 1:17 am ] |
| Post subject: | Hydraulic cam...benefits? |
Greetings from Oregon! New to the board, I have been reading for about 2 days and finally got off my duff and registered. Well, here's my question. I have a 71 Demon, 225, with complete rebuild (new crank, pistons, cam, etc) clifford 4 bbl manifold and an unknown set of split headers (clifford maybe?). Around $5000.00 was dropped in the drivetrain previous to my purchase, with engine work and tranny rebuild and exhaust. The invoice that came with the car lists all the new parts but some are a mystery. Machine work listed "bore block" but did not say how much, also "machine head" but what I don't know. The biggest mystery is the "performance cam" but no specs. The car runs great on the freeway, it is geared high at the moment and has too much carb (600 edelbrock). I plan on lower gears and a 390cfm holley. I am looking for more low end. This is my first /6 and I want to race on the weekends. The motor makes great power, but there is one thing I dislike. Since I will be changing gears and possibly torque convertor I would like to install a camshaft that I know more about the specs other than just "perf. Cam". How about the clifford hydraulic cam sets? And I know this is petty but will the hydrualic cam get rid of that solid lifter noise that this motor makes? Or is this a /6 thing and I should stop whining and get over it? Actually though, is there a significant advantage to a hydraulic or should I stick with a solid lift? I know it's long, but there is so much to cover when your new!! Thanks alot!! Jesse |
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| Author: | Michael_Cuda [ Wed May 26, 2004 2:56 am ] |
| Post subject: | |
I'm glad to hear your changing the carb to something smaller... To many people use way to much CFM's it kills throttle response and eat gas with no befit... One of my friends has a hydraulic /6 and I can tell right away most the lifter noise is gone. |
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| Author: | 72Duster [ Wed May 26, 2004 5:13 am ] |
| Post subject: | |
What will he need when switching to hydraulic? Cam, Lifters, pushrods, rocker arms. Rocker shaft? Rear bolt for rocker shaft? Christian |
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| Author: | Super6 [ Wed May 26, 2004 9:12 am ] |
| Post subject: | |
Quote: What will he need when switching to hydraulic? Cam, Lifters, pushrods, rocker arms. Rocker shaft? Rear bolt for rocker shaft?
That about covers it. Honestly, you are better off with a solid cam in terms of aftermarket cam choices. There are only a few grinds made for hydraulic setups, amny more for solid.Christian About the only benefit I see with hydraulic lifters is not having to adjust your valve lash every 15k or so. -S/6 |
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| Author: | DusterIdiot [ Wed May 26, 2004 9:35 am ] |
| Post subject: | Get a good friend with tools... |
If I wanted to know what I had in there, I'd pull the timing cover (not too hard), and the valve cover and use a degree wheel and dial indicator with magnetic mount to look at cam event vs. lift at the pushrod/rockers to see what profile you have most of us have a good set of specs of common cams that could be ordered unless you have a reground unit from Redline in Albany, OR.... Most guys don't have these items, I have a wheel, but tend to borrow my buddy's mic's and precision tools for those one off measurements. The lifters are like that, but they may need to be properly lashed, you'll need to identify the cam before you can do that... Holley 8007 is a good start for a 390 cfm carb and if you have several holley carbs laying around you have lots of good spare parts to work from, but if you 'up your cam' to a bigger stick and find that the guy put in larger valves you'll want to keep the 600 cfm carb handy. The nice thing about hydro lifters is you don't have to lash them and they are quieter unless they don't pump up properly...The solid cam choices are more plentiful and in ranges that are more beneficial to what you are about to do... Sounds like a cool car, check the 'club schedule' section there are a few events happening this summer that you may want to take the drive northward to Salem and attend (get to meet some of us face to face!!!!) welcome to the board, -D.Idiot |
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| Author: | sleddogg [ Wed May 26, 2004 11:32 am ] |
| Post subject: | |
sounds good. I will check into gettting a degree wheel to see exactly what I have in there. You would think that a shop would at least give a PN or something on their invoice, but oh well. Definately need to lknow what I have so I can adjust.... I will definately check into the events schedule to see when something is going on around the Salem area..I go up there all the time. Anyone going to the Mopar National show up there at Woodburn Dragstrip? July 18th I think..I 'm definately going. Take care |
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| Author: | Slant Cecil [ Wed May 26, 2004 11:46 am ] |
| Post subject: | |
Without getting into the reasons, give me a solid cam in my slant6. Cecil |
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| Author: | MitchB [ Wed May 26, 2004 12:44 pm ] |
| Post subject: | |
I guess you do not know what the recommended lash is on this cam since you do not know what cam you have. If you are going to degree the cam to document the valve timing events, you need to check this at the advertised lash and/or at .050. If you do not know the lash, I guess the .050 would probably be more meaningful. If you come back with what you find, I'd bet someone on this board will know what cam you have. In a slant, I'd run only a solid. Mitch |
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| Author: | sleddogg [ Wed May 26, 2004 1:43 pm ] |
| Post subject: | |
The science of cam dynamics has always confused me, exactly how would I come up these numbers a .050. To be honest I don't know what you mean by .050. I have always used the cam manufacures recommendations on RPM and gearing when selecting a cam. I am thinking maybe just purchasing a new camshaft that I know what the specs are on?? Hope I don't sound like an idiot here, but I am sorely confused. Anyone have recommendations on where I can read up on this matter and educate myself? 
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| Author: | MitchB [ Wed May 26, 2004 3:15 pm ] |
| Post subject: | |
You can probably find info at some of the cam manufacturer's web sites. .050 is simply a measure of the lobes profile or duration above .050 lifter rise. So if you have a dial indicator on a lifter that is in the lifter bore resting on the camshaft lobe, you would measure how much the crank would turn in degrees after the lifter had risen .050. Mitch Quote: The science of cam dynamics has always confused me, exactly how would I come up these numbers a .050. To be honest I don't know what you mean by .050. I have always used the cam manufacures recommendations on RPM and gearing when selecting a cam. I am thinking maybe just purchasing a new camshaft that I know what the specs are on?? Hope I don't sound like an idiot here, but I am sorely confused. Anyone have recommendations on where I can read up on this matter and educate myself?
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| Author: | sleddogg [ Wed May 26, 2004 5:46 pm ] |
| Post subject: | |
Ahh, I see. Very helpful. So instead of going wacko and purchasing a new camshaft, then the trouble of installing it, I will take your advice and do this. Thank you for clearing this up for me. It makes perfect sense now. |
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| Author: | Doctor Dodge [ Wed May 26, 2004 9:45 pm ] |
| Post subject: | |
You may want to pull-off the valve cover and try re-lashing the valves. First check them all, hot, and record the readings. Take special notice of the two intake valves which are "side by side" in the center of the row, those can throw you out of sequance. If the lash is over .022 on any exhaust valve, they need adjusting. Intake valves should be set in the .010 to .016 range. The key will be to get all the valves adjusted to the same lash as sets. I would shoot for all intakes at .016 and all exhausts at .022 as a starting point. (If all the valves are already tighter, pick an average number to lash to, then try going a little tighter. Bottomline, get in there and "play with it", even if you don't know the exact lash setting for your cam. You may find-out that your current valve lash adjustment is waaaayyy out of wack. The trick is to find the "clearance ramp" of the cam lobe. This is a short area of slow cam lobe movement, designed to take-up the lash, before going into fast lift rates. If the lash is set too loose, the lifter misses the clearance ramp and smacks right into fast lift, that makes the ticking noise. If the lash is set too tight, the valve will not seat fully and you get a miss or rough idle. Try turning the idle way down on the running engine and tightening the valve lash until the ticking noise stops and the engine starts to miss and run rough. Find that adjustment point, then back-off .002 or so, you should be in the clearance ramp of the cam lobe at that point. Just be sure to work with all the intakes and all the exhaust valves as "sets", each set should have all their valves set to the same lash. Search this message board for "valve adjustment" to get lot's of good info on the adjustment process. DD |
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| Author: | sleddogg [ Wed May 26, 2004 10:45 pm ] |
| Post subject: | |
In the case of Me and my Slant.....Ignorance is definatley damning. I am incredibley pleased that I found this forum. When I bought my car 3 months ago, I was disheartened that it didn't have a 340....but it WAS a Demon, and that slant just looked too cool with the eddy and headers, but still I thought, "what the hell, I'll just build a 360". Well, I am building the 360, but I am gaining an immense interest in my slant.... Maybe enough to save the 360 for something else. I will check out the valve adj this weekend...get in touch with the motor-learn it's moods I cannot wait to get in there and start playing with it, get into the carb, etc. Thanks for all the info... I am slowly coming around 
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