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General Category => General Discussion => Topic started by: SmithSwede on January 17, 2017, 02:56:12 PM

Title: What keeps Guzzi pushrods straight?
Post by: SmithSwede on January 17, 2017, 02:56:12 PM
I really need to take apart a small block and figure this stuff out.

What constrains the movement of the pushrods?  What keeps them from flopping around laterally?   Is there some sliding bearing somewhere is the push rod tube to ensure that the rod just moves straight up and down as it follows the cam contour?
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 17, 2017, 03:07:22 PM
 Well , we could take your V7 apart at CV and show you  :shocked: :laugh:

 Really , the push rods aren't flopping around on the cam , but on the followers  :laugh:

 Bud , are you bored today ? :grin:

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 17, 2017, 03:26:01 PM
 Uh , whatever Kirby said  :huh:

 Prescott , there is a cup on the rocker end of the pushrod that runs in a ball on the rocker , the cam end has a ball that runs in a machined cup on the cam follower . If you have ever removed an airhead pushrod and heard the pop as it disengaged from the follower this would all make sense . Guzzi pushrods do the same thing .

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: SmithSwede on January 17, 2017, 03:57:49 PM
Thanks, that makes sense.  I've seen the little cups, but wasn't sure if that was all there was.

I'm not bored today, just extra special curious.
Title: Re: What keeps Guzzi pushrods straight?
Post by: rodekyll on January 17, 2017, 04:11:25 PM
Internal case pressure.    EVERYBODY knows that.   :whip2:
Title: Re: What keeps Guzzi pushrods straight?
Post by: jcctx on January 17, 2017, 04:25:39 PM
SEXYrocker arms!!!!!!
Title: Re: What keeps Guzzi pushrods straight?
Post by: rodekyll on January 17, 2017, 04:35:24 PM
MUCH better thn mine!   :bow:
Title: Re: What keeps Guzzi pushrods straight?
Post by: tazio on January 17, 2017, 06:20:22 PM
Bad hair day?
Use your pushrod comb!!
Title: Re: What keeps Guzzi pushrods straight?
Post by: mtiberio on January 17, 2017, 08:14:06 PM
Compression stronger than tension.
Title: Re: What keeps Guzzi pushrods straight?
Post by: Triple Jim on January 17, 2017, 09:02:46 PM

Hooke's Law & Young's Modulus...keeps things straight.

:-)

I think Euler deserves some credit too.  :)
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 17, 2017, 09:10:01 PM
 Keebler Elves ??

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: Tom H on January 17, 2017, 09:28:24 PM
Keebler Elves ??

 Dusty

 :1: :1:

But maybe an Italian super model :evil: :thumb:

Sorry :grin:
Tom
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 17, 2017, 10:10:28 PM
:1: :1:

But maybe an Italian super model :evil: :thumb:

Sorry :grin:
Tom

 Good one  :laugh:

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: Sasquatch Jim on January 17, 2017, 10:47:08 PM
morals.
Title: Re: What keeps Guzzi pushrods straight?
Post by: Arizona Wayne on January 18, 2017, 12:42:56 AM
Depends what year small block Guzzi you're referring to.  How many miles on it's odometer and if it's a 4 valve Lario or not.  :undecided:
Title: Re: What keeps Guzzi pushrods straight?
Post by: beetle on January 18, 2017, 01:07:39 AM
Not only are they straight, they're also narrow.


Title: Re: What keeps Guzzi pushrods straight?
Post by: tris on January 18, 2017, 03:35:28 AM
Keebler Elves ??

 Dusty

I had to Google that one  :wink:
Title: Re: What keeps Guzzi pushrods straight?
Post by: John A on January 18, 2017, 06:17:51 AM
Rev limiter :evil:
Title: Re: What keeps Guzzi pushrods straight?
Post by: chuck peterson on January 18, 2017, 07:11:42 AM
 :popcorn:

Lead in their pencil?

 :popcorn:
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 18, 2017, 09:36:22 AM
I had to Google that one  :wink:

 All this time I thought the Keebler Elves were Yorkshiremen  :laugh:

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: Tobit on January 18, 2017, 12:33:10 PM
Rev limiter :evil:

  :bow:

But I appreciate the Hooke's law and Euler references.  Gives me something to read tonight.

Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 18, 2017, 12:37:42 PM
 The OP's question was a bit confusing . Seems he wasn't asking what keeps the pushrods from bending , rather what keeps them from flopping about . Two different questions .

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: rodekyll on January 18, 2017, 12:43:08 PM
That makes sense.  Nobody likes a floppy pushrod.
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 18, 2017, 12:56:28 PM

Oh, that would be spring pressure....not to be confused with peer pressure.

:-)

 Once again , not quite what he was asking . The OP has a degree in fisics  :huh: His question was what actually hold the pushrods in place . The answer is the ball and cup present on both ends .
 Hey Kirby , what is the term for the sticky situation created by the oil present in the aforementioned ball and cup ?

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 18, 2017, 01:03:24 PM
 Ugly ?

 Wasn't trying to be snarky , just that sometimes it takes one of us , er , less intelligent guys to decipher a question .

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: Triple Jim on January 18, 2017, 01:19:59 PM
  :bow:

But I appreciate the Hooke's law and Euler references.  Gives me something to read tonight.

If anyone really looks up Euler, he did a lot of stuff during his life.  I was referring to his work in estimating the load a column can support before it buckles, now referred to as the Euler buckling load, among other variations.
Title: Re: What keeps Guzzi pushrods straight?
Post by: Muzz on January 18, 2017, 01:59:11 PM
  Hey Kirby , what is the term for the sticky situation created by the oil present in the aforementioned ball and cup ?
 Dusty

I would have thought simple suction Dusty. They are probably machined close enough that capillary forces come in to play as well.
Title: Re: What keeps Guzzi pushrods straight?
Post by: twhitaker on January 18, 2017, 03:11:58 PM
That suction sound is because nature abhors a vacuum.
Title: Re: What keeps Guzzi pushrods straight?
Post by: Muzz on January 18, 2017, 08:22:16 PM
That suction sound is because nature abhors a vacuum.

So do I. 'Orrible noisy things, always need emptying. :wink:
Title: Re: What keeps Guzzi pushrods straight?
Post by: SmithSwede on January 18, 2017, 08:41:26 PM
Ok, thanks. 

As Aristotle noted, "horror vacui," or as the medievals said centuries later, "natura abhorrent vacuum."

So anyway, I get-eth oil in mine cups of my pushrods, on both the cam and the rocker end.   Straight and narrow and moral are thy pushrods kept, with capillary action leading them not into temptation to stray into crookedness.

I'm still wondering about the Coriolis effect and how that could create a torque abscess that might lead to quantum proton tunneling. 

Say, has anyone else noticed it's cold and wintery?

 
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 18, 2017, 08:46:57 PM
 Of course Aristotle didn't know that less than .01% of nature is anything more than a vacuum  :huh:

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: Guzzistajohn on January 18, 2017, 08:47:41 PM
I always thought a naked Ducati kept a Guzzi's pushrods straight?
Title: Re: What keeps Guzzi pushrods straight?
Post by: Kiwi_Roy on January 19, 2017, 03:31:01 AM
It was a good question.
I thought Hooke was all about the extension of a spring with load.
I can still quote Hook's Law as taught by my Physics master Spider Webber 50+ years ago
I got some homework to do
Title: Re: What keeps Guzzi pushrods straight?
Post by: Zoom Zoom on January 19, 2017, 05:13:12 AM
You guys are putting way to much thought into this.

They're not made out of cardboard or another paper derrivitive. It is all really simple. :evil:

ZZ
Title: Re: What keeps Guzzi pushrods straight?
Post by: Triple Jim on January 19, 2017, 08:28:11 AM
BTW 98% of the world drive on the correct side of the road...go figure!

That sounds about right, or maybe a little high.  I'd say at least 2% of the cars I see are across the center line when I'm on a curve.
Title: Re: What keeps Guzzi pushrods straight?
Post by: John A on January 19, 2017, 11:11:51 AM
to get  back on the rails, when I said the rev limiter kept the pushrods straight I was mostly joking. I've never bent a pushrod on a big block by over revving it. I bent an intake pushrod when an errant piece of aluminum from porting jammed the valve. when I got done with that engine I could wind the needle off the tach and never bent a pushrod. Other big blocks I haven't experienced a bent pushrod.I use aftermarket pushrods, never had an end come loose on one of those. stock pushrods sometimes loose a tip but I always caught that by extra noise. the original post was about a smallblock and I haven't gone  wild on one of those, yet. so I was wondering if you guys that hop up smallblocks bend pushrods? remember if you're not breaking parts you are not putting out enough power :evil:
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 19, 2017, 11:23:18 AM
 Kirby , I have no idea what you are apologizing for ? Being an engineer ? Pretty sure that isn't a crime  :laugh: Like you , I was attempting some humor directed at engineers . Probably missed the target  :rolleyes:

 Dusty
Title: Re: What keeps Guzzi pushrods straight?
Post by: Tom H on January 19, 2017, 11:26:17 AM
I really need to take apart a small block and figure this stuff out.

What constrains the movement of the pushrods?  What keeps them from flopping around laterally?   Is there some sliding bearing somewhere is the push rod tube to ensure that the rod just moves straight up and down as it follows the cam contour?

OK...

I'm not an engineer.

On a big block like my Ambo and Eldo there is a lifer that rides on the cam that has a cup in it for the push rod to sit in. Then on the rocker end there is a ball that sits in the cup on the push rod. My best guess is that the tension between the valve spring/rocker assy. and the lifter is what keeps the push rod from coming loose from those parts.

Hope this helps, but the topic was fun :laugh:
Tom
Title: Re: What keeps Guzzi pushrods straight?
Post by: oldbike54 on January 19, 2017, 11:58:44 AM

No you didn't miss a thing!

Should of put in more than just a couple of faceless/obscure names. You pop?? music fans are always calling out names that I have never heard of!!

Its all good.

:-)

 I feel the same confusion when folks start discussing movie dialogue  :rolleyes:

 Dusty