What cam should I get?

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The more I think about it, it has to be on the exhaust stroke. Are you sure you are looking at #1, sorry but thats the first cly. in front on the driver side-left side. Yeah you should know that but I am just trying to think of everthing. This not being there stinks. Look at the cam lobes also, maybe the cam lift is very little and with no oil pressure and the crank turning very slow the valves are NEVER opening at all.
 
Did you pull the dist. out yet? If not the easy way is to look at the rotor to see which cly. should be firing. When the rotor is at the #1 plug wire post on the cap thats TDC for sure if the motor was runing before and you did not move the dist. at all
 
dodge freak said:
Did you pull the dist. out yet? If not the easy way is to look at the rotor to see which cly. should be firing. When the rotor is at the #1 plug wire post on the cap thats TDC for sure if the motor was runing before and you did not move the dist. at all
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Yes I have pulled the dist out now. But when it was in I made sure the rotor button was on the #1 clyinder, the piston was at the very top of the bore, and both valves were closed. Then I removed the dist, dist cam gear, and then removed the cam. But the marks were not lined up. ???
 
moper said:
There is now way to tell what static compression ratio you have with a compression tester. You need to pull a head and measure some stuff. MUllin, you will want to keep the cam coice mild until you do some digging. You cant run stock springs with a lot of cams. Even the milder ones I install. They get matching springs. That 484 is so wrong for your car, you need to stop reading magazines, and start reading tech books. YOu said in another post the car tried to come around on you when you drove it recently..Too big a cam will give the sound you want, but you wont need to worry about it ever coming around unless it's raining. The less you knwo about your exact engine, the less likely any choice will give you what you want. And the more likely a change will hurt you.
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After reveiwing this post and seeing where I'm now (cam out,intake off) I figured that I might as well pull the heads and find out all the info I need. I just don't trust what the guy that rebuilt the motor is telling me. He said it had a Crane cam and it didn't. He also said it had a 9:8 to 10:1 compression ratio but after doing a compression test I'm only getting 105 to 115 cranking compression. So I can get the heads shaved maybe to bring the compression up and also make sure I have plenty of valve guide clearance for a bigger cam. I will be talking to the machine shop on this stuff also and the guy that does the head work aroung here will set me up right. So you was on the money about doing some digging. I will now make sure the cam I will chose will exactly what I need and not to big. And I will get the cam,timing chain,valve springs, valve seals, kit also to do it right.
 
Makes sense, this way you know you have the right springs. Hey if you can find out the max. lift without shorting the valve guilds. I look again at hughes site, they claim ALL 318 & 360 motors are max. .450. I tell you right now thats wrong, how much is max IDK but its more than .450. Maybe more than .500 cause many mag. storys have ran over the years and none ever said that the guilds need to be shorten. Thats racing stuff, like for those .570-.600 cams. Those cams to me have too much lift for the short openings, can't believe they last a long time. Good luck and keep us posted.
 
Mullin, first things first. You now have the timing chain exposed. Do yourself a favor. Stick your finger over the #1 cylinder's spark plug hole (all plugs removed) and have a friend turn the engine clockwise. When you feel pressure on your finger tip and air pushes out, turn the crank until the dot on the crank's timing gear is pointed straight up. The keyway will end up in the 2:00 position or so. You are now at TDC on the compression stroke. The dot on the cam's timing gear SHOULD be exactly straight up. I use a steel ruler to verify both dots are lined up and exactly centered over each gear. My feeling is, the cam gear's dot will be tothe left of center. Meaning the cam timing is retarded. The pressure reading you got has NOTHING TO DO WITH STATIC COMPRESSION RATIO. It has to do with dynamic compression ratio that again, cannot be figured by using strictly the pressure reading. You dont need to think about shaving heads or retainer to guide clearance. You need to do some checking. Post a pic of the ruler and dots either lining up or not. Witht he timing cover off, you can ignore where the rotor points, if you can see the piston top, etc. use the dots. Crank dot points straight up, cam dot should also be slightly ahead or in line with crank dot. It's that easy.

Now, as far as cam size goes...They changed the mechanical cam for hydraulic, so they probably just replaced the rockers for non adjustables for ease of maintenance. It's fairly common. You cannot replace a cam in some 360s with anything over .450, because some 360s have exh valve rotators and they are almost twice as "tall" as a std retainer. So they will hit the guide at full lift. You can replace the rotators withstd retainers, and run the same deals as a std mopar LA. In that case, I use .490 or so lift as max. I have run .484 cams with no retainer to guide issues on stock guide 340s. I also now make it a point to have the guides cut down for modern seals on every head I do to avoid that issue. Thier shop may not have been a performance type shop tho.

Good luck.... You're on the right track, just stay focussed. Worry about what you have, not what you need. Worry about what you need when you make sure what you have isnt put together wrong. It sounds to me like it is.
 
moper said:
Mullin, first things first. You now have the timing chain exposed. Do yourself a favor. Stick your finger over the #1 cylinder's spark plug hole (all plugs removed) and have a friend turn the engine clockwise. When you feel pressure on your finger tip and air pushes out, turn the crank until the dot on the crank's timing gear is pointed straight up. The keyway will end up in the 2:00 position or so. You are now at TDC on the compression stroke. The dot on the cam's timing gear SHOULD be exactly straight up. I use a steel ruler to verify both dots are lined up and exactly centered over each gear. My feeling is, the cam gear's dot will be tothe left of center. Meaning the cam timing is retarded. The pressure reading you got has NOTHING TO DO WITH STATIC COMPRESSION RATIO. It has to do with dynamic compression ratio that again, cannot be figured by using strictly the pressure reading. You dont need to think about shaving heads or retainer to guide clearance. You need to do some checking. Post a pic of the ruler and dots either lining up or not. Witht he timing cover off, you can ignore where the rotor points, if you can see the piston top, etc. use the dots. Crank dot points straight up, cam dot should also be slightly ahead or in line with crank dot. It's that easy.

Now, as far as cam size goes...They changed the mechanical cam for hydraulic, so they probably just replaced the rockers for non adjustables for ease of maintenance. It's fairly common. You cannot replace a cam in some 360s with anything over .450, because some 360s have exh valve rotators and they are almost twice as "tall" as a std retainer. So they will hit the guide at full lift. You can replace the rotators withstd retainers, and run the same deals as a std mopar LA. In that case, I use .490 or so lift as max. I have run .484 cams with no retainer to guide issues on stock guide 340s. I also now make it a point to have the guides cut down for modern seals on every head I do to avoid that issue. Thier shop may not have been a performance type shop tho.

Good luck.... You're on the right track, just stay focussed. Worry about what you have, not what you need. Worry about what you need when you make sure what you have isnt put together wrong. It sounds to me like it is.
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Well now I have the cam out and will be starting everything far as timing fresh when I finally get the cam that I need. I plan on getting the total Comp cam kit with there retainers so will that make sure that I will get full lift without cuting down the valve guide? I have noticed that they have the umbrella type valve seals installed already. If so all I need to do is figure out what compression the motor is 8:1,9:1 etc to determine what cam I can go with. The XE268 likes more compression than the cam that was in it which is a .420 lift.
 
The retainers are not what determines the max lift ona stock head 273, 318,or 340. The height of the stock guide does. 360s need new retainers, or replacement of the exh rotators if equipped. I just put 8 used stock retainers on my '87 360 replacing the rotators when I swapped the springs and cam with XE262 and IIRC 901 springs. To get your comression ratio as built, you must pull off a cylinder head too. Then you have someone cc a head chamber, and measure where the piston is in relation to the deck surface of the block and grab the part number for the piston. Then you can figure the true compression of what you have. It also lets you see what you have for valve releifs and if you need to worry about piston to valve clearance.
 
moper said:
The retainers are not what determines the max lift ona stock head 273, 318,or 340. The height of the stock guide does. 360s need new retainers, or replacement of the exh rotators if equipped. I just put 8 used stock retainers on my '87 360 replacing the rotators when I swapped the springs and cam with XE262 and IIRC 901 springs. To get your comression ratio as built, you must pull off a cylinder head too. Then you have someone cc a head chamber, and measure where the piston is in relation to the deck surface of the block and grab the part number for the piston. Then you can figure the true compression of what you have. It also lets you see what you have for valve releifs and if you need to worry about piston to valve clearance.
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After you installed the XE262 does the motor have a noticeable idle to it? Another words does in have a lopey idle or just a rumble? I have been beating around with the xe262 and xe268 and I think I will go with the xe262 since I do have a 273 not a 340 or 360. I am going to get the cam lifters retainers timing chain etc. so I will have everything that will match. The pistons already have the valve releifs but do you think I really need to pull the head just for valve to piston clearance. I don't really want to pull the head after all but I will I if it is really necessary with the ex262.
 
I myself would use the "rope in the cylinder" trick to change the springs but some like to check. With small valves and valve releifs it should be fine. You can log on to www.compcams.com and listen to sound clips of different camshafts. Guess many are like you thats why they have it. Remember what I said about that 1967 hot rod story, they ran a .510 lift cam with stock pistons and no valve releifs and had .018 clerance, ha ha. Now of days they say .060 min. but that was 1967 for you. Didn't they also drive 80 mph with drum brakes back then? Oh I had the name of the story wrong its "Building Mopar Muscle" still was in 1967. I scaned it to my computer but it was too large to put on here, must be a way but IDK how to. Hey, this stinks-they do not have a XE262 cam sound. Go to tech. and you should see the cams but they are all big ones
 
Well, the 262 has no real noticable lope..BUt it's also got no exhaust or mufflers..lol. The 368 I had ina 9.8:1 360 had a hint of an idle. But I think in a 273, you will hear the 262. Just my opinion tho. The XE cams are designed to have a nice idle, so "hearing it" is not on the top of the list. You dont have to pull a head unless you want to figure compression ratio. You wont have valve to piston trouble with the 262, the 268 you should also be ok.
 
Well I talked to a friend of mine that has fooled around with muscle cars and told him what I wanted to do to my ride. He said that I should go with what I know will sound and perform good and that is the Mopar "Purple Shaft" cams. He also reminded me that I have a 4-speed and can go a little wild with the cam options.He helped me install a Mopar cam in a 383 Charger I once had. So I bought a 238 duration @ .50, .474 intake, .474 exhaust cam. It has 34 more duration @ .50 and 54 more lift than the cam I had. So I fired it up tonight and DANG IT SOUNDS GOOD! When I fired it up I let it run 2000 rpms for little over 15 minutes, fooled with the timing some and took it for a test drive. I didn't dog it but could tell that she wanted to go if you know what I mean. I think I picked a good cam like I did before for the 383. I was like burning myself out trying to pick a cam and got tired of looking I guess. How long do I have to wait before I can let it roar? I can't remember if I took it easy for awhile on the cam change on the 383 or just gunned it. I will change the oil this weekend. Thanks everyone for your help!
 
Think about it, it does not matter how "hard" you drive it. Pistons and bearings yes but the cam just opens and closes the valves. Now rpm's might matter a little but if you say keep it under 5000 rpms for the first 100 miles it might be helpfull maybe not. Change that oil fast, get that cam lube and any other junk that might have gotten in the motor out of there. I myself would change the oil agian after 1000 miles or so. Right after you change the oil and the motor warms up you can drive it as hard or soft as you want, the cam could care less, the big thing is the fist 1/2 hour till the lifters and cam mate. Once the wear patterns are set then thats it. As long as you use good oil the cam should last. That cam sounds big but I am not sure if it is really a 238@ .050. Maybe Mopar is pushing those # a bit. With .474 lift that should work out to around 228@ .050 with most cams, which should work good for it. Lets us know after a while how it idles and drives, ok?
 
dodge freak said:
Think about it, it does not matter how "hard" you drive it. Pistons and bearings yes but the cam just opens and closes the valves. Now rpm's might matter a little but if you say keep it under 5000 rpms for the first 100 miles it might be helpfull maybe not. Change that oil fast, get that cam lube and any other junk that might have gotten in the motor out of there. I myself would change the oil agian after 1000 miles or so. Right after you change the oil and the motor warms up you can drive it as hard or soft as you want, the cam could care less, the big thing is the fist 1/2 hour till the lifters and cam mate. Once the wear patterns are set then thats it. As long as you use good oil the cam should last. That cam sounds big but I am not sure if it is really a 238@ .050. Maybe Mopar is pushing those # a bit. With .474 lift that should work out to around 228@ .050 with most cams, which should work good for it. Lets us know after a while how it idles and drives, ok?
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I will pick up the oil today and change it either tonight or tomorrow. Here is the numbers:

Brand: Mopar Performance Parts
Product Line: Mopar Performance Purple Camshaft Kits
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 2,000-6,000 RPM
Intake Duration at 050 inch Lift: 238
Exhaust Duration at 050 inch Lift: 238
Duration at 050 inch Lift: 238 int./238 exh.
Advertised Intake Duration: 280
Advertised Exhaust Duration: 280
Advertised Duration: 280 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.474 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.474 in.
Valve Lift with Factory Rocker Arm Ratio: 0.474 int./0.474 exh. lift
Lobe Separation (degrees): 110
Camshaft Gear Attachment: 1-bolt
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.
Computer Controlled Compatible: No
Lifters Included: Yes
Lifter Style: Hydraulic flat tappet
Valve Springs Included: No
Retainers Included: No
Locks Included: No
Valve Stem Seals Included: No
Timing Chain and Gears Included: No
Assembly Lubricant Included: Yes
Pushrods Included: No
Rocker Arms Included: No
Gaskets Included: No
Quantity: Sold as a kit.
Notes: Single-bolt camshaft.
 
Sounds like Comps' 280 magnum cam. That cam has 280 duration and ..480 lift and Comp's rates it at 230@ .050. Same rpm range too. Anyways its still big for a 273 but I really think those small intake and exhaust ports will help out. Hey in 1967 those hot rod guys stuck a .510 lift cam in their 273 motor-no @ .050 # cause they did not use it at the time-and they loved it. Saids the motor idle sound was whap-whap-whap-whap
 
You should "dump" the oil and filter either right after the cam's break in cycle, or very soo thereafter. Dont wait for 100 miles. The additives to help the cam break in and the asociated bits of cam and lifter (very small particles) should be removed as soon as possible to keep everything else healty. I know many guys that run break in oil for months..I change it and the filter before the engine is cooled off after a cam break in..
 
moper said:
You should "dump" the oil and filter either right after the cam's break in cycle, or very soo thereafter. Dont wait for 100 miles. The additives to help the cam break in and the asociated bits of cam and lifter (very small particles) should be removed as soon as possible to keep everything else healty. I know many guys that run break in oil for months..I change it and the filter before the engine is cooled off after a cam break in..
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OH YEA! Dang straight!
I myself go crazy on filter and oil changes on a new engine or cam change. It can'y hurt. One thing about many cam lubes is there heavy and sit in the pan. The more you change the oil, the better off you'll be.
I do mine like this;

Break in cam, Change oil (C/o)
(Re) Tune carb, drive about 100 miles. C/o
Drive around and test wheel traction, butt meter and general engine well being in everyday drivers mode. About 100 or so miles later, C/o and take notice of oil as it drains (Both times after intail cam break in) and smell for gas in oil, color and texture. It should be good at this stage.
 
Ok I ran the motor for a little while to get the oil hot and changed it with a new filter tonight when I got home. So now I will change the oil at later on but not sure when. I think a 1000 miles should be ok don't you think?
 
Well good oil not cheap anymore same with filters so yeah thats what I would do. It might be better to do it sooner but maybe not, its you call. Hey you ask us all what cam to get and I think not one member said to use the cam you did land up using, ssooo why ask us? I want to know how much vacuum you have at like 750 rpms and how it runs. I was thinking of use Comps 270 soild cam this spring but maybe that cam you went with would be better. Now I can't decide-Thanks
 
dodge freak said:
Well good oil not cheap anymore same with filters so yeah thats what I would do. It might be better to do it sooner but maybe not, its you call. Hey you ask us all what cam to get and I think not one member said to use the cam you did land up using, ssooo why ask us? I want to know how much vacuum you have at like 750 rpms and how it runs. I was thinking of use Comps 270 soild cam this spring but maybe that cam you went with would be better. Now I can't decide-Thanks
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I bought a Puralator filter and 5qts of Valvoline 10w40 and it ran $18.33. So I think I will go a 1000 miles before the next change. Well I think all of the members did a good job on chosing a cam but they seemed to mild for my taste. Actually I have learned more about cams from you guys than I have ever known before.The cam I chose has a good lick to it and I havn't dogged it yet but I know that it want be long. I might be able to kick it now but I want to wait a little longer and just to make sure everything is good. I did all the work and just listening to it run right now and putting around is good. People look before they can see me now so the sound of the car is a ear catcher if you know what I mean. lol. I know the throttle reponce is quicker and she idles like she is ready to rip some rubber. I didn't have adjustable rocker arms so I couldn't go with the solid cam. What size motor do you have? I went with a bigger cam than I would have if I had a automatic but I have a 4-speed. I don't have a tach yet but whatever the idle it is the vacuum is 9.5. That is low but I have no power brakes and like I said I have a manual transmission. Comp cams is a good cam but I went with something that I knew that was going to give me what I wanted. I know two Mopar Maniacs and they both said Mopar makes a good cam for our motors. It is kind of like chosing a head unit. If you like Sony and have had great success with it then you just want be happy with the JVC. I guess you know what I mean.
 
Well for you and your car it sounds fine. 9.5" of vacuum wow, good thing you don't have power brakes. Yeah I know the sound you are talking about, theres some guy down my street that has a 68 camaro that you can hear before you can see it. Thats not for me well maybe but I drive my car almost everday the roads are clean. I am up in Michigan and I still have it out, I don't care how cold it gets so long as theres no salt on the roads its going out and I don't need-make that want- anybody to hear me coming. Oh its a 318, with 3.91 gears-I am staying with that soild cam come this spring. I need more vacuum than 10" so thanks. I also use K & N filters which cost $10 and Valvoline VR 1 racing 20w-50 oil which at auto zone is $2.99 a quart so thats $25 a oil change. I think this is a great thread, I look at the whole thing tonight once agian. I am sure this will help many folks out. I notice you were at first going with the 284 cam so we did talk you in to going down 1 size so maybe we did get though to you, ha ha. The main thing is that YOU are happy, thats what counts.
 
dodge freak said:
Well for you and your car it sounds fine. 9.5" of vacuum wow, good thing you don't have power brakes. Yeah I know the sound you are talking about, theres some guy down my street that has a 68 camaro that you can hear before you can see it. Thats not for me well maybe but I drive my car almost everday the roads are clean. I am up in Michigan and I still have it out, I don't care how cold it gets so long as theres no salt on the roads its going out and I don't need-make that want- anybody to hear me coming. Oh its a 318, with 3.91 gears-I am staying with that soild cam come this spring. I need more vacuum than 10" so thanks. I also use K & N filters which cost $10 and Valvoline VR 1 racing 20w-50 oil which at auto zone is $2.99 a quart so thats $25 a oil change. I think this is a great thread, I look at the whole thing tonight once agian. I am sure this will help many folks out. I notice you were at first going with the 284 cam so we did talk you in to going down 1 size so maybe we did get though to you, ha ha. The main thing is that YOU are happy, thats what counts.
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Why do you need 10" or more of vacuum? Power brakes? I'm just curious. If you want to run a big cam that doesn't produce enough vacuum I have seen a pump that you can buy that will give all the vacuum you need. I had power brakes on my Charger and was running the 284 lift cam. It still stopped the car but it wasn't as good as it was before I did the cam change. At that time I didn't understand the specs of cams and didn't realize vacuum was important. I looked into the pump deal but never went any further than that. I can't really remember why I didn't get it.
Yeah I guess I did take some advice and dropped down one size. lol. I am happy with it. For some reason the vacuum advance wasn't hooked up so I got some rubber hose that I had and hooked it up. I don't know if it made a difference or not but I got it hooked up and took it down the road. I believe it did but couldn't tell a whole lot. Do you run the vacuum advance?
I have always wanted to run better oil and filter in my hot rods but never have. I figured that for those folks that have thousands of dollars in the motor and not close to stock like mine. Roller cam,lifters,rockers. I was however thinking about running some Mobil 1 synthetic maybe later but I don't know if I should stick with non-synthetic or not. Is the oil that you run synthetic? Will 20w-50 be better than good ole 10w-40? Questions, questions?
 
Yeah they make vacuum pumps, Summit racing has one but it $250 or higher I think. No vacuum advance, you get all sorts of opions. On the dodgecharger dot com site theres a big thread about it, some say that it just causes problems like spark knock and its just for smog motors, others swear by it. I have never use synthetic oil but again others swear by it. What I am going to do from now on is put 1 bottle of cam break in addivtive that Comps sells at each oil change. That has zinc and other good stuff thats no longer in the motor oil. Some like GM EOS stuff but I am not sure if that still has zinc in it cause its for newer cars and where its sold at. Comp claims you only need it for break in but they like you to keep buying new cams every few years. I don't know if 20w-50 is better then 10w-40 but thats all I use even the few weeks in the winter that I use it.
 
Price. That's why I didn't get it! lol.
I always thought that the vacuum advanced helped keep the timing more stable as you go up in rpm. If I remember correctly I didn't have it hooked up on the Charger.???
The way it sounds far as the above oil changes on this thread it sounds like the break-in stuff should be removed imediately or you will suffer engine damage. I mean that's the way they made it sound.lol. I don't know about it I never add anything to my oil.
 
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