Need help on centerlining my cam.

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Lars

Lars

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OK, while I'm waiting on my replacement bolts. I want to centerline my cam. I used my dial gauge to get the cam in straight up. The instructions that came with my comp cam said to use a solid lifter and have the heads bolted on the engine. I have just the short block setup right now, I didn't want to put the heads on until I had the cam degreed in. How do I go about doing this?
 
I made a 'solid' lifter out of an old hyd. lifter. pull out spring and flip bucket upside done...simple. Now you have 'solid' lifter to degree hyd. cams. Solid lifter is different length than hyd. lifter so this works really good with your pushrods if you have hyd. cam. Just FYI, Terry.
 
Also worth mentioning. Make sure the hyd. lifter you are using is not worn out but in good shape. Worn out lifter can give inaccurate results.
 
Actually its easier to do it with the heads off. I took a hydraulic lifter and took the guts out. find a bolt about 5-6 inches long that is a little bigger than the inside of the lifter. grind the threads down until you have a nice press fit and pound the sucka in. now place it in the number 1 cylinder lifter bore and use your indicator on the head of the bolt. didn't even cost you anything either.

don
 
Figures, I just tossed a bunch of old lifters out. DOH!

Edit: My local parts store has them for $4 a piece. Guess I could by one. Think I'm gonna go diggin through my shop's trash can first, maybe they are still in there...
 
I can fit my dial indictaor on the edge of a lifter by placing it in the valley area. If you can locate the plunger on the flat end, you're fine.
 
moper said:
I can fit my dial indictaor on the edge of a lifter by placing it in the valley area. If you can locate the plunger on the flat end, you're fine.
Click to expand...

Yep, I did the same thing when I degreed my cam.
 
That would be the number one (cyl.) intake lifter. Yes you can degree with the heads off, using the lifter body. I wouldn't say that way is any more accurate. Just another way to do it. But for those folks who don't have thier heads off, or are just changing cams, it can be degree'd 'in' without having to pull the heads or off the lifter body. Centerline of the cam can be found using the valve retainer as a good base for dial indicator. Very important to insure the indicator is in plane with valve stem. As with the lifter body if you use that method. If checking (verifing) duration use @ .050 off the lifter body or .075 off of the valve retainer using 1.5 rocker, and .080 using 1.6 rockers. You have to allow for the rocker ratio if checking duration at the valve. I just prefer to 'see' what the engine is seeing. Good luck. Terry.
 
Using the retainer you have to use a solid body lifter or a modified hydraulic (locked solid). Otherwise the lifter will collapse under the weight of the spring, and the rate of collapse will not be consistant enough for measuring by the .001". If the collapse is not consistant, the measurement will be off by a bit. It only takes a few thousanths to change the degree reading significantly. BTW, like Terry said, you'll be amazed at how much less lift the valve actually gets after you get thru the poor pushrod angles and rocker ratio issues. In a small block LA or Magnum, you may loose .020 of lift just with pushrod angle because it's so bad.
 
OK, I did TDC, mounted the dial indicator and everything. I rotated the engine till I got to .050 before maximum lift and got 61 degrees. I continued rotating until I got to .050 after maximum lift which was 149 degrees. Add those together and divide by 2 = 105 degrees. My cam card says my centerline is 106 degrees. So if I understand correctly, I need to advance the cam 1 degree? Please tell me I did this right. :p And how do I advance the cam 1 degree? Do I need to order an offset key for one degree?

Thanks
 
Lars you are advanced 1 degree. 105 is 1 degree advanced from 106 degrees. You did good. Isn't it fun too. Knowing where it is, is important. Insure you have piston to valve clearance. Advancing the cam closes up clearance on the intake valve and opens up the clearance on the exhaust. retarding does the opposite. Good luck there, you do learn fast. Terry.
 
Also please note: smaller number = advancing the cam and larger number = retarding the cam. (in relation to where it is at that point). Using intake lobe of number 1 cyl. Think about this, when I degree in the cams on my Suzuki pro street bike I have two cams and they each have to be degree'd, and they have to be 'moved' in opposite direction's. Intake is advanced by moving in the direction of engine rotation and the exhaust has to be advanced by moving in opposite direction of rotation. Retarding is the opposite for both cams. I would rather be 'moving' my mopars cam.....LOL,LOL. Good luck, Terry.
 
OK, so I can leave it as is? Cool, it's not a very big cam (.480) and with the pistons I'm using I'll have enough P/V clearance. I just wanted to make sure it was in well, never did a cam before.
 
I'd leave it as installed. One degree advanced isn't worth the trouble of installing an offset key. A little more cylinder pressure is always better than not enough. :thumbup:
 
Yeah I'm going to leave it as is. If it was retarded I would go through the trouble, but since it is advanced I'll leave it alone.
 
Nice work. You're perfect. 2° can make a feelable difference. 1° is not worth the effort. I always do the procedure twice, just to make sure they come out the same...But I'm a little crazy about stuff like that...lol.
 
moper said:
Nice work. You're perfect. 2° can make a feelable difference. 1° is not worth the effort. I always do the procedure twice, just to make sure they come out the same...But I'm a little crazy about stuff like that...lol.
Click to expand...

Yeah, I checked it three times to make sure my numbers were right. :D
 
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