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Beautiful Drive Ends with Pushrod Failure

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cobrapatrol Avatar
cobrapatrol Gold Member Jim Harris
Quartz Hill, CA, USA   USA
In reply to # 1499036 by Tonyfixit
I agree on the shockingly low quality of many replacment parts, and how vowed not to replace parts for the sake of replacing, or sorce OE parts (even used) ifpossible.

Yeah, I guess I tend to agree. The original pushrods have some slight pitting in the contact surfaces. But, after all, I didn't throw them away, did I? The rocker pivot ball measurements came out in a range of 0.3120" +/- 0.0018. I'm surprised at the variation but the #1 that broke was not an outlier.



Jim Harris
Quartz Hill, CA

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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
I think I might be looking at the witness marks on your other pushrods.

I is common practice when disassembling an engine to keep the valve train components in their matched sets.

I guess you could call your new pushrod/s severely miss matched! If I were to use them it might be an idea to lap the new rods to the rocker ball with lapping compound (or at least, pre-seat the rod cup by lapping it to a surplus rocker ball to first get an aproximation of a fit)

It is things like 'what you have experianced' with 'new' components that really pi$$ me off. Moss used to be a trusted name in our parts business.

cobrapatrol Avatar
cobrapatrol Gold Member Jim Harris
Quartz Hill, CA, USA   USA
Tony, Wes

I think we all agree and I am putting the original pushrods back in. Although its SOP to replace and run-in the valve train components together I think in this case the original pushrods will be a better choice.

Thanks to all for your help! Jim



Jim Harris
Quartz Hill, CA

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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
I hope you send the broken pushrod and the other 11 back to Moss.

Did the other cups show the same witness mark?

South San Frncisco, CA, USA   USA
Jim, Tony
Please report how the conversion to roller rocker goes, and nature of engine behaviour, if any, changes.
you have had quite an adventure, nice that nothing else got destroyed by bad pushrod.
wes

poolboy Avatar
poolboy Ken D
Sandy Hook, MS, USA   USA
I think that's Rex A Lott that's going to the Roller Rockers, Wes.
Nothing wrong with higher ratio RR's but you have to have the proper springs, and pushrods especially with a performance cam or else:



Edited 1 time(s). Last edit at 2017-12-11 12:59 PM by poolboy.


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spring bind .jpg

Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
I admit I did wince when he mentioned the roller rockers. Such parts HAVE to work in conjunction with other components AND be set to the correct geometry.

Not just a bolt on! Despite what vendors might advertise. Which kind of come back to what Jim was talking about with 'up graded' parts.

MUCH of what we see from our vendors is 'marketing' they make money by selling parts. An Up sell increases their profit margine.
Perhaps you should not blame them for this....that is their busness. The buyer SHOULD be aware of what he is buying. (In my teens I put a full race cam in a bog standard Herald :-( )

Now the grip I have is when a part is NOT suitable for the use advertised weather is is of the wrong dimension or unsuitable material/design.

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