273-318 rocker shaft differences

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63dartman

63dartman

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I am converting to adjustable rockers from a 273 and do not have 273 shafts. Will the 318 shafts work? I know that the 273 shafts have two small oil holes verses the 318 with only one larger hole. Also the 273 shafts have small oil grooves in the lower hole and the 318 do not. I understand that the shafts are different since the rocker arms oil differently. I just need to know if the 318 shafts will work. Thank in advance for the help guys.
 
If it were me I would op for the new hardened shafts,as the adjustable rockers use a harder shaft than that of a hyd. cam shaft of the 318. Also it's money well spent as the new shafts will help to stop the flexing of the rockers and valve train and making the engine not operate properly. As we know Mopars have problems with this from the factory it's a inhearent problem.



BJR Racing
 
BJR where do I get those hardened shafts? I checked jegs and summit. I could only find shafts for big blocks....Are they the same?
 
Also, I noticed that when I pulled the old rocker shafts I can push down on the pushrods into the lifter and several but not all of my lifters are not holding oil. I can depress the lifter and felt the spring tension. I thought that once they are filled they shoud be pretty solid. Do i have a couple of lifters going that might be causing the tapping?
 
63, This is possiable that the lifters are going down, most stock lifters do go down to help with start up. (less lift and less duration) But after the engine has been run and up to temp. that the lifters should hold the oil, if this occurs after the engine has been run then the lifters are more than likely bad.
As for the shafts there are a number of places that you can get them, but check with mopar 1st, then if you still can't get them let me know and I'll get them for you and send them to you at what they charge me and shipping, they generally run $90-100 but they are better than the stock shafts and will support both rockers setups. Summit, Jegs, Doug Herbert, Harland Sharpe all offer shafts but this is your choosing, pick the best and go with it.


BJR Racing
 
Also they do make different shafts for the small blocks but they are for the more advanced engines such as the W-5 s,7s,8s,9s P-5, P-7s W-2 race. They are offset .100 or .150 with valve train to match. So yes they do offer others but most so called parts houses don't offer much for Mopars. So just let me know and I'll get them for you or I'll let you know where you can get them from.



BJR Racing
 
63dartman said:
BJR where do I get those hardened shafts? I checked jegs and summit. I could only find shafts for big blocks....Are they the same?
Click to expand...

No they aren't the same, the length and the bolts are different. 5/16 verses 3/8s on the bolts and the BBD is about 1/2 " longer.


BJR Racing
 
Thanks for the info BJR. I borrowed some 273 adjustable rockers and tried them out. Still getting that annoying ticking. I replaced the questionable lifters with new ones and still no change. I swapped all my old gear back on and changed the oil. Was running mobil1 10/30 now running quaker state 20/50 blend. noise did quiet down alot but is still there. will the crane ductile iron shafts work with my stock rockers? I think those are the ones I will be getting.


CRN-69619-2

Application Show All

Brand: Crane Cams
Product Line: Crane Pro-Series Rocker Arm Shafts
Rocker Arm Style: Ductile iron
Rocker Arm Shaft Offset: None
Rocker Arm Shaft Material: Steel
Rocker Arm Shaft Finish: Natural
Quantity: Sold as a pair.

Rocker Arm Shafts, Pro Series, Steel, Chrysler, Small Block, Pair
 
I'm not familiar enough with the 273 shafts to be positive, but I have read that you must use 273 shafts for them. I dont know if the Crane shafts will work with the factory arms, but I doubt it. If you are using the adjustable rockers ona hydraulic cam You may need to experiment a little to get the proload right. You're setting preload on the plunger, not lash, and there is a "sweet spot" where you'll quiet things down and not hurt the cam. If your heads have been worked, like a valve job or milling, then the amount of preload will be hard to find. The best way to find it is to pull the intake, and use a wire feeler gage to check the preload on each lifter. It'sa lot of work, but then you KNOW its right. I normally will adjust things to 1/2 turn tighter than the point where the pushrod cannot be twisted by your finger tips. If things are noisey, I'll re-adjust to 3/4 and see if things quiet down. I wont go tighter than that, because yo ucan wipe the cam easy. Also, you must be sure the engine is at running temperature when the valves are set. I do one side, then put the valve cover back on, and run the engne again, then go back and do the other side. Then it stays warm. Also, be SURE the cam is on the base circle (not any lift from the lobe) or you are doing it wrong, and can leave you way loose.
 
Mechanical rockers are going to be somewhat noisey anyway if it's not bad then I would let it be, as long as the engine is running fine. Rollers sound like a bunch of bolts being shaken around in a can when they are right.


BJR Racing
 
BJR Racing said:
Mechanical rockers are going to be somewhat noisey anyway if it's not bad then I would let it be, as long as the engine is running fine. Rollers sound like a bunch of bolts being shaken around in a can when they are right.


BJR Racing
Click to expand...


Yup..I find a lot of guys arent used to that "normal" noise.
 
thanks for all the help. I guess I am going to leave it....It doesn't seem to be broken so.....I ain't going to fix it. I do believe that I will invest in a good aftermarket adjustable rocker system for my 360 build though.
 
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