Thread: Roller rocker lash- too loose?
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04-13-2011 09:05 PM #1
Roller rocker lash- too loose?
I hope someone can answer this or help. I am building a motor and getting ready to degree the cam- BBF V-8-- the pushrods I have come up with are 8.8" long, using EDL-60679 alum. heads, .048 compressed thickness head gasket and a set of FMS roller rockers. When I set 0 lash + 1/2 turn, the roller tip is of course in contact with the valve tip- My concern is the rockers "side to side" movement, when valve is not being depressed. It seems loose to me- hydraulic lifters/ cam by the way. Cam is Comp Cams 34-250-4. Will the movement go away after engine is fired up and the lifters pump up? PICTURE OF VALVE TIP is in 429-460 FMS Roller Rocker thread. (Showing center pattern) I just recieved the Trick Flow pushrods today, and am hesitant on going any further until i'm sure it's right. Thank you in advance.'77 Tbird/ 460 BBF, '70 Camaro RS split bumper w/ 4spd Muncie/ 350 2BBL
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04-13-2011 11:59 PM #2
side to side movement is controlled most of the time with guild plates . some side to side you can live with but you need to track as close to center line side to side of the valve stem.valve lash has nothing to do with side to side movement of you rocker armsIrish Diplomacy ..the ability to tell someone to go to Hell ,,So that they will look forward to to the trip
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04-14-2011 07:20 AM #3
As usual Pat is on the money. Your gonna need pushrod guide plates.
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04-14-2011 10:35 AM #4
My heads have the plates, it's the roller tip I'm worried about.'77 Tbird/ 460 BBF, '70 Camaro RS split bumper w/ 4spd Muncie/ 350 2BBL
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04-14-2011 01:07 PM #5
yep the guid plate stop some of the side to side movement of the roller tip on the rocke arm as well as the tracking of the rocker a cross the valve stem .you can have alot of side to side movement if you have the wrong size push rod for guid plates like 5/16 push rods with guid plates made for 3/8 push rodsLast edited by pat mccarthy; 04-14-2011 at 01:18 PM.
Irish Diplomacy ..the ability to tell someone to go to Hell ,,So that they will look forward to to the trip
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04-14-2011 07:34 PM #6
Thank you guys! I was worried over nothing! I cleaned and dropped in pushrods; did the solid lifter- cam degreeing, had 106 centerline, came out at 107 degrees. Called Comp Cams tech rep, and he told me the cam could be off by up to 1.5 degrees. Also with my high comp ratio, it should work just fine. Threw oil pump, shaft, and oil pan and front cover on tonight. Batten her up tomorrow. Thanks again.Last edited by parpart; 04-14-2011 at 10:08 PM.
'77 Tbird/ 460 BBF, '70 Camaro RS split bumper w/ 4spd Muncie/ 350 2BBL
Welcome to CHR. I think that you need to hook up your vacuum advance. At part throttle when cruising you have less air and fuel in each cylinder, and the air-fuel mixture is not as densely packed...
MSD 8360 distributor vacuum advance