PRW Roller Rockers

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pdcs

pdcs

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So I went out and bought PRW Roller Rockers for my 340. Only to find they hit the top edge of the valve spring. Has anyone else run into this problem.... Luckily the place where I bought them took them back and ordered me another set.
 

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yes i had the same issue, also tried on several different heads, I tried using spacers to gain some height , but still didn't work. I sent them back and decided NOT to use prw .
 
I have 2/sets ,and still have the old 273 rockers on because of this ,I though it was from installing longer valves(.100)plus. I think the only fix is bee hive springs/retainers.
 
Thats what spacers and a grinder is for...aint nothing wrong with those rockers...have some myself for bblk...also have buddies running them[bblk] dont know about smblk but appears to be same,he had to grind his for clearance I did not all tho it is close...they are tough even tho he had to replace his adjusters when he 1st purchased them which the company he bought them from did cheerfully[KMJ PERF] the rockers themselves proved to be good performers[stainless steel roller rockers]has ball and ball style pushrods same as mine or you could get the reg ball and cup style also..his were 1.5's and mine are 1.6 ratio...I've ground several sets of rockers and seen it done on many others with no issues ever....
 
I have ground lots off the 273 rocker for clearance, but these I'm not sure of .but there still sitting in the boxes so I will grind 1 set and see how it goes . I was waiting for someone to say they have done this before so I wouldn't be first .
 
I bought the alum. prw rockers had to grind and buff worked great.Lets face it very little of this stuff is replace and go seems like a little or a lot of fabrication in all parts,Kevin.
 
yep....same issue, some people fixed them by grinding additional clearance , myself I took them to work and machined some of the "Web" area on the underside where it contacts the spring. I used a ball endmill, not to leave a sharp corner where stress fracture could occur...did 2 sets actually
 
did anyone check for correct ratio /I heard that the 1.5 was really like 1.44
 
I'm rather curious to know that myself, but I'm pretty sure the stories of ratios not measuring up were more directed at factory stamped rockers. Some have been measured at over 1.5, while most were under. I recall reading in HR and PHR many moons ago that the typical observed ratio was closer to 1.45:1...but that goes for MOST domestic engines. Some SBC rockers they (HR) had measured in the past calculated closer to 1.42 or 1.40!
 
If they are sending you the same brand rockers, you're going to have the same issue as they are all made the same. Almost nothing is bolt on and go with a Mopar. Just clearance the under side. Or you could get Harland Sharp.
 
txstang84 said:
I'm rather curious to know that myself, but I'm pretty sure the stories of ratios not measuring up were more directed at factory stamped rockers. Some have been measured at over 1.5, while most were under. I recall reading in HR and PHR many moons ago that the typical observed ratio was closer to 1.45:1...but that goes for MOST domestic engines. Some SBC rockers they (HR) had measured in the past calculated closer to 1.42 or 1.40!
Click to expand...

You are right this is referring only to factory stamped rockers, a modern aftermarket performance parts company would be embarrassed to sell parts with that much tolerance in the dimensions. And if they did sell them I sure as heck wouldn't buy them...
 
How big are your springs? I have 1.6 PRW's on mine and they clear fine. Big springs are the problem when you gotta bust out the grinder.
 
I went with Comp Cams! And they clear the valve springs!

The height and diameter of the springs are within stock specs!
 
when I was racing all the time ,I went to a mopar salvage yard and pulled 4 complete sets of 273 rockers cleaned them up and mocked up the engine with a .450 lift cam with .300 lobe lift /then checked every rocker arm for ratio /almost every one was 1.5 only 5 or 6 were out of specks 1 of them changed the lift to .510, the rest just under 1.5 by a little.so this isn't too bad .
 
lil red said:
yep....same issue, some people fixed them by grinding additional clearance , myself I took them to work and machined some of the "Web" area on the underside where it contacts the spring. I used a ball endmill, not to leave a sharp corner where stress fracture could occur...did 2 sets actually
Click to expand...

Yeh he did my set,great cut good work to bad I didn't take pictures,had zero issues with them so far
 
bought the aluminum rockers from kmj perf and had same prob called the company and they said you can clearance them so i did motor saw 6800rpm on a reg basis sb 340 with 528 purple shaft
 
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