Engine build - Camshaft Endplay?

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JAndrea

JAndrea

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I'm assembling my 1968 383. I just installed the timing chain set, degreed the cam, etc. All went well except I have some concerns about how much camshaft (hyd flat tappet) endplay that I have. I haven't been able to find a spec for it in my manual, but one of the books I have says it should be .006". Well, I have way more than that... I have probably just over an 1/8" movement from front to back. Is this common? Do I need to correct this? If so, what are the recommendations? I'm not building a race engine or anything like that... just a strong HP motor for street driving.

Thanks!!
Jay

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Don't big blocks have a cam plate like the small blocks do?
 
Big block flat tappet cams rely on lobe bevel to keep cam toward the rear and spin the lifter while in motion. So no plate behind the timing gear. The cam gear should have a bearing on the engine side as well.
 
Yep, I know about the angle of the lobes keeping the Cam in place. I started with a bare block when building this, so all I have to go on is word of mouth, manuals, videos, and other web resources... I've never seen a cam bearing behind the cam gear. Can anyone elaborate on this? Image links, etc? Anything I've ever seen was cam gear bolting straight to cam.
 
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My mistake. Stock cam gears have a solid surface that contacts to block. This is where they take the thrust. Double rollers and many aftermarket gears have a bearing that contacts the block in the same manner. I don't believe there is an endplay measurement as the cam gear is thrust back to the block.
 
gear drives have a torrington bearing back there as the cam is pulled back onto this bearing, stock cogs have a smooth machined surface with an oil channel. They sell thrust buttons (more like a spacer) but they just butt against the stamped front cover, not real exact. I understand you dent the front cover to set endplay? WTH?
 
AJ/FormS said:
I'm the kind of guy that would do something about it, even tho it is said to be a non-issue, Kindof like a married guy wearing a condom.
Click to expand...
flat tappets don`t require anything special, as stated above, unless something has been machined or messed with on it. rollers need the thrust controlled w/ a buton on a r/b. bearing behind the gear is good. I like .008 -.010 thrust on mine.
 
I decided, as Bob said, general knowledge is that with flat tappet cams, it's not critically important. I also talked to Summit Racing and their tech said the same thing.

Thanks everyone!
 
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