# Camshaft



## Hotsticker1 (Aug 20, 2017)

Is it normal for the lifters to ride off center on the camshaft lobe 1965 GTO. After looking closer looks like some of the lifters are at an angle I think I've answered my own ?


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## bigD (Jul 21, 2016)

Yes, flat tappet lifters are off center so that they will rotate.

"...With “flat tappet” pushrod engines, the bottoms of the lifters appear to be flat. But actually on most applications the bottoms of the lifters are slightly convex. The center is about .001 to .002˝ higher than the edge. Also, the lobes on flat tappet cams are not perfectly flat but have a slight taper (.0007 to .002˝) to one side. In addition, the centerline of the lifters are offset slightly with respect to the cam lobes. This makes the lifters rotate as the cam turns, which helps to reduce friction and wear...."

"...While operating, any flat tappet is allowed to rotate in the bore as it moves up and down. To get there, the cam lobe is tapered slightly. Ditto with the camshaft contact face of the lifter (it’s slightly crowned and not exactly “flat”). The rotation of the tappet within the bore evens out the wear of the lifter (particularly at the edge where it comes in contact with the camshaft lobe)..."

http://www.sweethaven02.com/Automotive01/fig0349.gif

Roller lifters roll centered on the cam lobes. They do not rotate.


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## Hotsticker1 (Aug 20, 2017)

Thanks for your reply


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## BearGFR (Aug 25, 2008)

Yes, flat tappets are not supposed to be centered so that they'll rotate - as BigD said. If you have the engine out of the car, one thing to check is the fit on the front of the cam drive gear, behind the fuel pump eccentric. The cam is supposed to 'stick out' a little past the face of the cam gear in order to center the outer ring for the fuel pump eccentric.

Bear


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## ‘Vid (9 mo ago)

Quick side question on the same topic. After a HFT cam is well broken in with ZDDP motor oil and say it has a few hundred miles under it’s belt, is a ZDDP oil (or additive) still necessary or can a straight modern oil be used?


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## Jim K (Nov 17, 2020)

‘Vid said:


> Quick side question on the same topic. After a HFT cam is well broken in with ZDDP motor oil and say it has a few hundred miles under it’s belt, is a ZDDP oil (or additive) still necessary or can a straight modern oil be used?
> 
> 
> Sent from my iPhone using Tapatalk


With any flat tappet cam, yes you will need either an oil with the correct type and amount of ZDDP or add a ZDDP additive to oil that does not have it.


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## O52 (Jan 27, 2019)

Valvoline VR1 Racing Oil 10-30. 









Amazon.com: Valvoline VR1 Racing SAE 10W-30 High Performance High Zinc Motor Oil 1 QT, Case of 6 : Everything Else


Amazon.com: Valvoline VR1 Racing SAE 10W-30 High Performance High Zinc Motor Oil 1 QT, Case of 6 : Everything Else



www.amazon.com


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## Jared (Apr 19, 2013)

Running Driven in mine.


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## Jim K (Nov 17, 2020)

I run Lucas oil for classic muscle cars in mine.


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## Baaad65 (Aug 29, 2019)

Jared said:


> Running Driven in mine.


Sames 👍


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## geeteeohguy (Feb 2, 2008)

You will need to do as these gents say. I personally run diesel-spec in mine for the ZDDP package. No issues in 20 years using it and many, many miles driven (100,000 +)
About 2002, the ZDDP was mostly removed from conventional oils because it would clog up and disable catalytic converters on high mileage cars that burned oil (300,000 mile Hondas, etc.) So no longer an option. The classic car specific oils are an excellent choice for no-worry operation.


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## ‘Vid (9 mo ago)

Jim K said:


> With any flat tappet cam, yes you will need either an oil with the correct type and amount of ZDDP or add a ZDDP additive to oil that does not have it.


I figured as much and definitely wouldn’t risk my new 455 otherwise. I’m pretty sure the previous owner of my car ran Castrol synthetic without any added ZDDP in the original 350 motor is why I was asking. Thanks all for your suggestions. 


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