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| Author: | moondog [ Sun Jun 14, 2009 7:00 pm ] |
| Post subject: | valves keep backn off |
have a 1915 with stock heads, new valves, solid rocker shaft, 1.25 ratio rockers with swivel feet, 110 engle cam. motor was just rebuilt in april, broke it in with valvoline with zinc additive, brought the rpms up 2 2000 for 20 minutes. been on 3 "real" rides but mostly round the house and so one.. the problem is my valves keep vaking off. i have adjusted them over 10 times since i broke it in. the exhuast valves seem 2 loosen up the worst. sometimes as much as 1/4 in. it might take a couple days of hard riding or just a few minutes around the yard but they keep coming loose.if it is the cam wouldnt 1 and 3 back off the same amount and 2 and 4 be the same? it seems that 3 and 4 r usually worse than 1 and 2. #4 exhaust is usually worse than any. any 1 got any idea what might b goin on |
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| Author: | gasman [ Sun Jun 14, 2009 7:12 pm ] |
| Post subject: | Re: valves keep backn off |
looks like if you set them and locked them down theres no way they could back off,but the screw is backing out of the jam nut? might be the swivel feet doing it,as it lashes across the top of the valve stem it is turning and then its turning out the set screw maybe just a thought.chad 
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| Author: | moondog [ Sun Jun 14, 2009 7:27 pm ] |
| Post subject: | Re: valves keep backn off |
well i had stock rockers and stock screws on it but it was doin the same thing then. it dont seem 2 be the screws and jam nuts. but then again it dont seem 2 b the cam 2 me either.ive adjusted them so much it looks 2 me like if it was the cam it wouldnt be enough left on the lobes 2 run good when they r adjusted. but i dont know i could b wrong. i just cant figure it out. when they r adjusted it runs great!!! it seems 2 me it would b runin bad all the time if it was the cam or lifters or am i wrong |
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| Author: | redrail1915 [ Sun Jun 14, 2009 7:37 pm ] |
| Post subject: | Re: valves keep backn off |
make sure you adjust them when the engine is cold let it set over night and try if that dose not work check your monting studs nuts and the shims |
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| Author: | Stevo [ Sun Jun 14, 2009 7:42 pm ] |
| Post subject: | Re: valves keep backn off |
Make sure the flat part of the swivel feet is against the valve when adjusting them, I had one move on me before. |
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| Author: | moondog [ Sun Jun 14, 2009 7:52 pm ] |
| Post subject: | Re: valves keep backn off |
i make sure 2 adjust them while th e motor is completely cold. could it be lifters stickin?? |
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| Author: | redrail1915 [ Sun Jun 14, 2009 8:14 pm ] |
| Post subject: | Re: valves keep backn off |
i dont think that would be the prolbem did you shim the shafts are they stock or solid shafts ball or big foot adjuster like subysteve said make sure you have the flat part to the valve |
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| Author: | gasman [ Sun Jun 14, 2009 8:18 pm ] |
| Post subject: | Re: valves keep backn off |
i always set mine cold then let it warm up and recheck them and reset if needed,have i been doing this wrong?if you have adjusted these as many times as you say and the screw and jam nuts wasn't backing off you would be out of screw by now.have you checked your pushrods to see if they have bent any at all.i cant see a cam wearing down that quick that shouldnt be your problem.chad
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| Author: | redrail1915 [ Sun Jun 14, 2009 8:55 pm ] |
| Post subject: | Re: valves keep backn off |
valve lash should all ways set with the engine cold i think 0.006 is the spec but i set mine on 0 if i set for someone i will go 0.006 |
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| Author: | moondog [ Sun Jun 14, 2009 9:02 pm ] |
| Post subject: | Re: valves keep backn off |
before i changed 2 solid shafts with the swivel feet, i was out of screw on #4 and had very little left on #3 and the next time they backed off the jam nut on #4 came off (due 2 runnin out of threads on the bolt) droppin out the screw and breakin 3 rods. my cam calls 4 them 2 be set at .004 but i usually set mine on 0. they backed off last night and my #1 exhaust had backed off to.015 my #4 is atleast 1/8 in off |
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| Author: | redrail1915 [ Sun Jun 14, 2009 9:18 pm ] |
| Post subject: | Re: valves keep backn off |
did you use the red break in lube with the cam if not then it might be the cam they need to mash togather for proper breakin change the oil see if there is any metal in it |
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| Author: | Odyknuck [ Sun Jun 14, 2009 9:36 pm ] |
| Post subject: | Re: valves keep backn off |
What procedure are you using to adjust the valves? |
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| Author: | Stevo [ Sun Jun 14, 2009 10:39 pm ] |
| Post subject: | Re: valves keep backn off |
Are you sure your geometry is correct? You may want to check it, that may be why your haveing issues with running out of bolt threads. Are your pushrods the correct lenth also? |
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| Author: | moondog [ Sun Jun 14, 2009 10:42 pm ] |
| Post subject: | Re: valves keep backn off |
i bring up #1 top dead center on the compression stroke. adjust 1 intake and exhaust turn the motor over counter clockwise half a turn to bring up #2 adjust it half a turn counter clock adjust 3 half a turn counter clock and adjust 4 |
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| Author: | turboblue [ Mon Jun 15, 2009 12:05 pm ] |
| Post subject: | Re: valves keep backn off |
I'm thinking the cam is going flat. |
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| Author: | Stevo [ Mon Jun 15, 2009 5:15 pm ] |
| Post subject: | Re: valves keep backn off |
turboblue wrote: I'm thinking the cam is going flat. Im thinking the same, also if the geometry is that bad mabey it should have lash caps. |
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| Author: | redrail1915 [ Mon Jun 15, 2009 5:47 pm ] |
| Post subject: | Re: valves keep backn off |
i thank it is cam to if you like to come by my house i would be happy to try to help you with it you only about 40 miles from me |
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| Author: | moondog [ Tue Jun 16, 2009 5:04 pm ] |
| Post subject: | Re: valves keep backn off |
i took it 2 tim at southern bug yesterday and we tore it down. turns out the pushrods had worn through the lifters. must of been a bad bach of lifters. (never seen that before  ) but im pretty happy thats all it was. the cam is still in perfect condition yea 4 melol |
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| Author: | gasman [ Tue Jun 16, 2009 5:29 pm ] |
| Post subject: | Re: valves keep backn off |
cool glad it wasn't that major,i couldnt see a cam wearing out that fast but you never know.did you take some pics i would like to see this i have never heard of that either.them some tough push rods  lol.chad
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| Author: | redrail1915 [ Tue Jun 16, 2009 5:54 pm ] |
| Post subject: | Re: valves keep backn off |
cool
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| Author: | moondog [ Tue Jun 16, 2009 6:07 pm ] |
| Post subject: | Re: valves keep backn off |
i keep one of the valves ill try 2 get a pic on here later |
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| Author: | Odyknuck [ Wed Jun 17, 2009 8:32 am ] |
| Post subject: | Re: valves keep backn off |
Thats a first for me too. It would appear they case harden the lifter ends and missed those. |
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| Author: | bruce 1 [ Wed Jun 17, 2009 6:08 pm ] |
| Post subject: | Re: valves keep backn off |
Scat had a bad batch of lifters for a while. I know several people that had the same problem. |
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| Author: | Dave Winterburn [ Thu Jul 02, 2009 2:47 am ] |
| Post subject: | Re: valves keep backn off |
When did Scat have the problem? I've got a Scat cam and lifters that I have n't run yet, they're about 2 1/2 yrs old. Thanks Dave. |
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| Author: | sammmmmm [ Sat Jul 04, 2009 1:09 pm ] |
| Post subject: | Re: valves keep backn off |
I had trouble similar to that once and it turned out to be the cam gear came loose. it was amazing how good it still ran while I was trying to figure out what the problem was. |
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