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valve springs
#1
Hi there again. Today I installed the new cam and lifters in my 1973 351 Cleveland, I bought from Summit..... I naturally had to undo the nuts on the springs that hold the push rods in so I could remove them and change lifters. The time has come now to retighten springs, hence my problem, how much do I tighten the springs? is there like a torque rating or something? Thanks again for the help!
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#2
Read this, especially starting at step 11 and non-adjustable rocker arms.
http://www.compcams.com/technical/instru...es/145.pdf Chuck
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#3
Assuming you mean the rocker arm bolt, the torque for it is 18 to 25 ft.-lbs. After you get them tightened, make sure the rocker arm tip contacts the top of the valve stem in the center, other wise you'll need to change the pushrods, for a different length. Does the new cam have more lift than the old one, will your old valve springs handle the new cam? How about the torque for the cam sprocket and thrust plate, the bolt that holds the damper to the crankshaft, etc.? Do you have the torque specs for them?



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#4
Hello again.... Bad luck has struck (or I made a mistake) I was out in my garage attempting to torque the rocker arm bolts to 22 ft-lbs. All of a sudden the torque wrench slipped off the head of the bolt... with the bolt head in the socket Sad Now I am in a pickle! I suppose I must remove the head and take it to a machine shop unless I can drill it out, any ideas guys? any ideas why it would have snapped? I started on Number one cylinder with both valves down all the way as the video says and the timing marks said 0 on the damper, I thought I was good to go, but alas now I have a bigger problem....
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#5
You shouldnt have to take the head off if you take your time getting the broken bolt out. You can either drill into the bolt and try to use an "easy out" to get the bolt out, or if there is any of the bolt still sticking up you can try to set a nut on top of the stud left sticking up and weld the nut to the stud, then just back the bolt out. Whichever way you go make sure you cover all around the broken bolt with rags so no debri goes into the motor. if you drill it out coat the drill bit in grease to help catch the shavings. you could even put grease on the rag under where you are drilling to catch the shavings too. Hope this helps and good luck. im sure some other guys will have some ideas for you too.
Kevin

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
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#6
I've heard of rocker arm bolts breaking while the engine was running but not by applying 22 ft/lb of torque. It could happen I guess if the bolt was defective and already about to sheer.

Sounds like you need to drill it out and use an easy out - shouldn't be too much trouble. Then replace the bolt and retorque.

Chuck the expert, though, and should be along with the correct way to do it. Smile Good luck!

Doc

EDIT - while I was typing this Kevin was submitting his previous post. Sorry for the duplications.

Doc

[Image: 6y14ea.jpg]

Project started 8-7-10
Completed: All new suspension, rebuilt 351C H Code bored .030 over with mild cam and intake, new 3.50 TracLok, custom exhaust system
Current "mini-project": interior upgrade Undecided
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#7
I broke a rocker bolt head off when I assembled mine too. lucky could use visegrips to remove..Though my torque wrench was bad. Replace and tightened it in 2 steps and was ok.

Alan L

[Image: 1_30_09_13_10_12_32.png]
Alan L
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#8
not2old;63009 Wrote:I broke a rocker bolt head off when I assembled mine too. lucky could use visegrips to remove..Though my torque wrench was bad. Replace and tightened it in 2 steps and was ok.

Alan L
I think the torque wrench I borrowed is defective .... My bolt is broken off flush so no luck on the vice grips, I think the bolt might have been defective as well because I can still turn the push rod with my fingers with no great effort, so it couldnt have been that tight to sheer off a bolt.
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#9
Make sure the new valve springs have the correct installed hight.
If it's a head bolt consider new head bolts or studs.
If it the rocker bolt that's different deal.
Make sure to check the spring hight!
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#10
Joe Stang;63016 Wrote:Make sure the new valve springs have the correct installed hight.
If it's a head bolt consider new head bolts or studs.
If it the rocker bolt that's different deal.
Make sure to check the spring hight!
Hi there, I didnt put new valve springs in, yes it is the rocker bolt!
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