Lifter problems new 460 build
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Lifter problems new 460 build
I am rebuilding a 1983 460 out of a one ton to put in an old 1/2 ton tbd.
Got everything back from the machine shop heads and valves needed little work he barely touched them. I installed my new cam, new hydraulic lifters, old pushrods and old non adjustable rockers. Book says to compress lifters at Tdc compression and make sure gap is .100-.150. I did this all the way around and had a couple I wanted to double check as they seemed a touch over .150 as I was using a rough stack of shim stock. I ground a .151 piece of steel and went back thru to double check today and two lifters will not compress again. I am 100% sure they all did yesterday when I checked them. I primed them all with a pump oil can before installation. What’s going on? I’m not an engine builder but I’m pretty confident with a wrench but am not sure why the compressed yesterday and today a couple will not. I’m also concerned that since I have rotated the crank I am loosing my molly on my cam, should I re molly the bottom of my lifters again ?
Thanks in advance guys. Been lurking but never had a reason to post
Got everything back from the machine shop heads and valves needed little work he barely touched them. I installed my new cam, new hydraulic lifters, old pushrods and old non adjustable rockers. Book says to compress lifters at Tdc compression and make sure gap is .100-.150. I did this all the way around and had a couple I wanted to double check as they seemed a touch over .150 as I was using a rough stack of shim stock. I ground a .151 piece of steel and went back thru to double check today and two lifters will not compress again. I am 100% sure they all did yesterday when I checked them. I primed them all with a pump oil can before installation. What’s going on? I’m not an engine builder but I’m pretty confident with a wrench but am not sure why the compressed yesterday and today a couple will not. I’m also concerned that since I have rotated the crank I am loosing my molly on my cam, should I re molly the bottom of my lifters again ?
Thanks in advance guys. Been lurking but never had a reason to post
Lead Driver
Joined: Mar 2004
Posts: 8,924
Likes: 153
You need to check the preload on the lifters, there should be .020-.060. Forget checking them the way you were, that will just get you in trouble. At tdc and the push rod just seated, there should be .020-.060 more to go before the fulcrum seats, that's your preload. Also make sure the machine shop set all the valve tip heights exactly the same height.
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