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#1
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cam break-in
This weekend I'm going to fire up my engine with a new cam (MP .474"). This is my first cam swap. A few questions:
How do I prime a 600 cfm edelbrock so it fires right away? (mechanical Fuel pump) How long, what rpm to do break in? Do I have to baby it after this, or is it just change oil and letr rip? Thanks, Keith |
#2
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To fill the float bowl, you could hook up a hose to the fuel inlet and hold a container of gas above the carb. This will gravity feed the bowl till it's full. You can also get priming fluids. They usually look like carb cleaner. You just spray some in while cranking.
As far as cam break in, don't you have the manufacturers instructions for cam break in? You really should have those and follow them. Usually you run the motor at 2000 - 2500 rpm for 20 - 30 minutes for cam break in. Once you break in the cam you shouldn't have to baby it unless you also replaced other engine components. |
#3
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I'VE NEVER RUN A NEW MOTOR AT 2500 RPM FOR 20-30 MINUTES?
WHAT YOU NEED TO DO UPON FIRE UP (ASSUMING YOU HAVE OIL PRESSURE!) IS HOLD IT AT 2000 RPM'S FOR MAYBE THE FIRST FEW MINUTES (2-3) THIS ALLOWS THE CAM LOBES TO GET A GOOD COAT OF OIL. YOU DID ASSEMBLE THE CAM/LIFTERS WITH THE PROPER CAM BREAK IN LUBE RIGHT? ALL THE BREAK IN LUBE DOES IS LUBRICATE THE NEW PARTS UNTIL THE ENGINE OIL HAS TIME TO GET TO THE CAM/LIFTERS, AFTER THAT IT IS WASHED AWAY AND BREAKS DOWN INTO THE OIL. THIS HAS BEEN MY METHOD FOR MANY A BIG BLOCK MOPAR AND IT HAS'NT FAILED ME YET! |
#4
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I did use the lube that came with the cam/lifters. I also thought you could fill the carb that way but I wasn't sure. CL440, I think you have a good point. It doesn't seem like such a long break in time is really nessesary. Of course, it couldn't hurt either.
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#5
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Running the motor at 2000 RPM for 20 - 30 minutes isn't for oiling purposes. This RPM on the motor allows the cam to wear in the lifters. You are right about the assembly lube getting washed away with the first coat of oil, and that is why breaking in the cam and lifters on the first start-up is so important. If you do not run it long (or fast) enough the first time, the next time you start your motor, your cam will be dry and the lifters (which aren't worn in) could wipe your lobes. This is the recommended procedure by both engine builders and Cam manufacturers.
Here is a quote from the crane cams instruction manual: Quote:
What would exactly be wrong with this? Can your engine not handle this? |
#6
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I alaways add a can of chevy E.O.S. (Engine Oil Suppliment) as this is what Crower recommends with their cams. The EOS has some anti-scuffing compounds and stuff? I think Mopar sells a simular EOS for engine/cam break-in.
If this is a dual spring flat tappet cam only run the outer valve spring for break-in. If a new engine, or oil was changed, remove distrubitor and prime the oiling system with a priming rod and drill. While priming the oiling system slowely rotate the engine a few turns so oil get up to the rocker arms. Re-install the distrubitor. I also pre-set the ignition timming at 10 degrees before TDC. Put #1 cylinder at 10 before TDC on the compression stroke. Remove distrubitor cap and rotate distrubitor so the magnetic pickup lines up (or points just open with point system.) Make sure distrubitor rotor is pointing at the #1 spark plug wire on the cap too. Fill the carbs fuel bowl with gas / prime engine with fuel, screw in idle speed screw a few extra turns so engine won't die if you let off the gas. Check fluid levels, oil, radiator fluid, trans fluid, etc. Start engine and let run at 2,000 to 3,000 RPM for 15-20 Minutes. If dual springs are used, re-install the inner valve springs. Leave the oil with the EOS in the engine for at least 500 miles if street driven, or at least several trips down the drag strip. The reasons for the fast RPM break in is two fold. The high RPM splash oils the cam for good lubrication, and the higher RPM will "spin" the lifter easier on the lobe. The cam lobes are machined with a taper to them so they will spin the lifters for correct wear, if a lifter sticks you can wear out the lifter and cam lobe quickly. |
#7
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What about hydralic roller cams? I will be replacing the cam in my Magnum 360. I would think the hydralic roller lifters would need less time at speed. Does anybody know of any special instructions for rollers?
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#8
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Roller cams don't need to be broken in. The cam lobes have no taper (this is why you need a cam button on big blocks), and the lifters don't spin (they better not or you'll destroy the cam/lifters, etc.)
You may want to dip the roller end in some oil so the roller has oil before start-up. |
#9
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Right on kekoakeakane.
Hey CL440 where did you get the information on the cam break in? ALL cams (Except roller as 451 mopar said) should be broken in around 2500 rpm for at least 20 minutes. This is to get the correct wear pattern on the lifters to prevent premature lobe failure. |
#10
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I got my car started this weekend. I did have some trouble getting it to start immediately. I had to turn it over with the starter for probably 20-30 seconds before I got it to fire. I ran it at 2500 RPM for 20 minutes with some rev blips interspersed throughout the 20 minutes, then I timed it and took it for a drive. It ran well and reved easily to 6K.
Should I be worried that it didn't fire up right away? Would a compression test reveal any problems? I am planning on doing this anyway soon. Keith |
#11
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Keith - you are fine with the 30 sec of cranking. You should only be worried if it was excessive, say over 5 minutes. It would take time to gas into the carb, etc. so don't worry about 30 seconds.
If the motor is completely new you will want to change the oil right after cam break in, then 100 miles, then 500, then 3000. The best rule of thumb is to watch to make sure it doesen't get dirty, this will tell you if your jetting in the carb is correct. |
#12
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DART - IVE NEVER HAD A PROBLEM WITH MY METHOD OF BREAK IN, YOU MAKE A VALID POINT ON LIFTER WEAR TO THE CAM TAPER, BUT MY METHOD HAS NEVER FAILED ME, MY ENGINES DO RUN LONGER THAN THE 2-3 MINUTES @ 2000 RPM I STATED FOR THE PROPER OIL SPLASH TO OCCUR JUST NOT AT THAT RPM. BUT I HAVE NEVER HEALD 2000-2500 RPM FOR 20 MIN. NOT THAT, THAT MAY NOT WORK ALSO I JUST HAVE'NT HAD THE NEED TO DO THIS.
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#13
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Keith, you should run your motor in a bit more before you go revving it to 6K.
I usually run mine for 1000 kilometres (600mile) before I go racing them. |
#14
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Cam break in
Keith,
Three things, 1. I agree with Jims451, especially the EOS. 2. I would not follow CL440s advise, it may work for him but I would follow the cam manufacturers directions. After all they should know, they made the cam. 3. Run it like you stole it! FYI, been building engines professionally for 14+ years with 0 cam failures on break in. |
#15
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Hey blownhemi:
Most engine builders will tell you otherwise on the break-in time. The last motor I broke in I did as follows: 20 min @ 2500 rpm for cam break in Change oil Check for leaks etc. Drive out to the highway 1/4 throttle blast Check for leaks etc. 1/2 throttle blast Check for leaks etc. 3/4 throttle blast Check for leaks etc. Full throttle blast Change oil Drive as normal, try not to hold at one rpm for extended period. The biggest thig is to keep the oil clean and get the carb jetted correctly so it doesn't foul the oil. |
#16
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Do both a lean and rich condition make oil dirty? My oil always seems to get dark quickly. I think I've always been lean, but I just bought a carb tuning kit so I could tune it after this cam swap. About 10K street miles on motor. Good compression on all cylinders.
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#17
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Only if you are rich will the oil foul. The long chains of unburned hydrocarbons from the unburned gasoline foul the oil. you may be rich on the secondaries or the primaries. If you motor is completely new it may take some time for it to clean out, but the trick is to change it whenever it looks dirty.
If you have an edelbrock carb it may be lean on idle and then rich off idle when the rods lift out of the jets. You will need to replace the rods to get the correct mixture. Usually the jets are fine. What carb do you have? It was a pain to get my 360 jetted correctly... |
#18
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One other thing...
If you are excessively rich you can prevent the rings from sealing correctly. You should get this resolved quickly, especially if you have chronically dirty oil (Which tells you that you are rich). You can sniff the exhaust to tell if you are rich...or buy a tailpipe sniffer. |
#19
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Dart,
My carb is a 600 cfm edelbrock. Its in the out of the box state now. My plugs are always white also. Any tuning advice would be appreciated. Keith |
#20
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What you want is a light brown on the cermic part of the plug. If you are white (no coloring on the caraminc part of the plug) you are lean.
You need to pull the the rods (the two small discs on top of the carb) that are held down by a torx screw. The rods are spring loaded, pull one out and read what the rods numbers are (printed or stamped on the side). Some are hard to read, but they tell you the diameter of the rod say 47x72. The lower number would be the smallest diameter part of the rod and the higher would be the largest diameter of the rod. Since the rod is down in the jets at idle, tha larger part of the rod is in the jet. If you are lean at idle, decrease the diameter of the fat portion of the rod, say go to 47x68. this would give you more gasoline getting between the jet and the rod at idle. If you are ok at idle and say lean or rich off idle (when the vacum of the motor pulls the rod out of the jet) you will need to increase or decrease the diameter of the smallest portion of the rod. You can also put different springs in the holes to adjust when the rods get sucked out of the jets. This is all based on having the timing set correctly, especially the advance in the distributor. If you are small block you need to be around 32-36 total advance. You may need a lighter spring or more distributor work to get it right. Electronic ignition is a big help also. I can give you more information on your carb tuning (rod diameter), but I need to know the details on your motor and where you live (elevation). |
#21
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You can also call me at home if you want. I will be home after 5:30 MST. 970-613-8747.
Blake |
#22
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Hey Dart, Can't say I agree with your run-in recommendations.
It might be fine for a race motor but I would do that to a street motor, especially if I was going to drive any distance with it. I guess there are 100 different way to run your engine in and it's what works for you that's the best. After all it's you that has to foot the bills later on if it breaks. |
#23
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Hey Blown Hemi:
I am fine with agreeing to disagree, but I would like to know more. Is your position because of experience or something you read? I am not out to slam you or make you look stupid, I was just wondering about how you derived your opinion. |
#24
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Pure experience mate.
I build and race my own cars, I'm also editor of a new Australian Chrysler magazine. seeSlick 6 Packs magazine I've done 440/"A" body conversions, blown small blocks, blown sixes, and pretty much every engine/gearbox/diff conversion you can think of pertaining to Chryslers, other than hemi426's. I'm trying to be a smart ar*e or take a "My d*ck is bigger than your d*ck stance" I'm just giving you a run down of where I'm coming from. Remember being in Australia it's alot harder than working on your Mopars in the States because we don't have the access to the same range of parts as you guys do. My current projects are an EFI/Turbo 360 in a 65 Valiant Utility and a 6/71 supercharged 360 in a 1970 "A" body station wagon. So no, I'm not a 13 year old with a computer and an attitude (And yes they p*ss me off as well!!). I'm just a guy who likes to help people out with their Mopars and spends way to much money and time on them, much to the disgust of my wife and child. As for running an engine in. I know alot of guys who think a lap around the block and a couple of burnouts are a great way to run in an engine!! Hoever I"m a little more sympathetic to my driveline, so I let everything bed in nicely AND THEN drive the cr*p out of it. |
#25
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Prelube it
Prelube the engine b4 starting through the distributor shaft hole then you dont have to worry about starting it ,waiting for the carb to fill up
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#26
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Blown Hemi:
As you would say: "No worries mate" I have built a few on my own and haven't had any problems with my break in procedure. I will say that erring on the conservative side will do you well when breaking in a motor. I gotta imagine that getting parts is a pain the the ar$e down there. What do you do? |
#27
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Yeah your not wrong, when it comes to parts it's pretty hard. the guys in the speed shops don't know anything when it comes to chryslers. Case in point: I went in today to pick up a set of 340+.60 rings I ordered. Trouble is that they were 318+.60!!
"Oh, aren't they the same??" All our parts are alot more expensive than the chev and ford guys and the fact that $1 australian only = $.53 US. So you guys pay $80 US for a set of Mopar Rocker Covers, while we pay $299 Australia for a pair. The only good thing I've noticed is you guys pay around the same for machining as we do. IE: boring a block is about $170AU and that sort of thing. A set of Edelbrock small block aluminium heads are $3000au when you guys pay about $1200. so no complaining about the price of parts OK!! That's why we decided to start the magazine, so we can more interest in the hobby here and hopefully the price of parts will drop. |
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