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302 Valve train

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Old 07-05-2014, 04:12 PM
lm987 lm987 is offline
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302 Valve train

Greetings to all.
I have a 1971 Ford 302 installed in my Ford F-1. My issue is with adjusting or doing the initial setting of the valves. It has hydraulic lifters and standard length pushrods. The engine has just been rebuilt and this is the initial run-in. I did the initial valve/rocker arm adjustment just as the shop manual and other references specified. This engine has non-adjustable rocker arms that just require an initial pre-load and then torqued to the specified torque (18-20 ft-lbs). A mild Compcam cam has also been installed. The heads were planed but I do not know how much.The issue is that when I start it the thing sounds like a threshing machine and upon reving it up to about 1500 rpm or so some of the rocker arms will come off the pushrods. I have redone the adjustment 4 or 5 times but this obviously not the problem. My thought now is that I don't have the correct pushrod lengths.
Any suggestions or help would be greatly appreciated before I just shoot it and be done!!
Thanks
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Old 07-06-2014, 12:25 AM
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crazy96863 crazy96863 is offline
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Is there a gap between the rockers and pushrods or valves when everything is torqued? If so measure the gap with a feeler gauge on post the size of the gap.
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Old 07-06-2014, 09:19 AM
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What heads are on the motor(casting number) and do you have the correct rockers on them? Early heads used rail style rockers and if you put later pedistal style rockers on there is nothing to keep them aligned on the valve stem. Rail rocker is on the right in the pic below.

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Old 07-06-2014, 10:39 AM
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Valve train Issue

Thanks for your reply. I have the rail type rockers as shown on the right in your photo. They are new but the nuts that were supplied with them are apparently not doing their job and allow the rocker to come loose. The rockers are the same as the originals.
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Old 07-06-2014, 11:05 AM
lm987 lm987 is offline
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Valve train

I checked for any gap between the rocker arm and pushrod when torqued but there is none on any of them.
Perhaps I should just let it run after replacing the rocker arm nuts????
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Old 07-06-2014, 09:18 PM
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Sounds like you need a fresh set of lock nuts. As you stated before, there is no adjustment for your setup. If not mistaken the nuts are 3/8"NF on your studs.
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Old 07-06-2014, 09:19 PM
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Also might want to look at the slots in your rockers to see if the higher lift cam is causing them to bottom out. If you see wear at the ends of the slots, you'll need new rockers with longer slots.
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Old 07-06-2014, 09:19 PM
 
 
 
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