bugpack hd aluminum pushrods?

spyvsspy · Posted: Fri Jul 29, 2011 1:38 pm Post subject: bugpack hd aluminum pushrods?

I just want to let you guys know that these pushrods had a little more than (.020) flex on the shaft. I found out while I was testing the pushrods after they were cut to length and properly setup on my 1915cc engine. A dial indicator was setup midway on the pushrod to measure the flex while being hand cranked. The springs were hd single springs.

I can only imagine what difference in flex would be at 6000rpm under load. Now if this is good or bad, I don't know. I am just informing others on my findings and hope more knowledgeable posters add there thoughts on this subject.

I bought some Manton chromoly pushrods and will be using those instead.
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Glenn · Posted: Fri Jul 29, 2011 1:58 pm Post subject:

Next time if you want aluminum, get the AC.net ones.
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Max Welton · Posted: Fri Jul 29, 2011 2:04 pm Post subject:

Yep. Or Smith Brothers.

Max
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Clatter · Posted: Fri Jul 29, 2011 2:57 pm Post subject:

OK, this raises more questions than it does answer them...

How much do the Mantons flex?
It would also be good to check some stockers out, too.
And maybe even some ac.net ones, if somebody had one or some that were cut wrong or something...

See, there is going to be some 'side travel' as the pushrod actuates.
The rockers swing an arc as they travel through their stroke.
Are you measuring this 'flex' in addition to the lateral travel of the rod?

Im suspicious....

There's more going on here than meets the eye.

How are you determining what is pushrod flex, and what is the normal side-to-side movement of the pushrod?
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Type 5 Joe Wrote:
Gotta just love the opinions of a couple of the jokers on here... - and some of the funny thoughts that roll around in their heads, like a tin can with a couple marbles in it being shook up.

spyvsspy · Posted: Fri Jul 29, 2011 3:06 pm Post subject:

I'll tell you this; the pushrods flexed enough to where you could see them concave with the naked eye.
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Clatter · Posted: Fri Jul 29, 2011 3:09 pm Post subject:

I remember Scat used to sell some "HD Aluminum Pushrods".

They were smaller in diameter, and thinnner wall, than stockers.

And,they don't sell them anymore for some reason..

Are these Bugpack ones like that?

Can you stick in a stocker and see the same flex?

How about the Manton?
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Type 5 Joe Wrote:
Gotta just love the opinions of a couple of the jokers on here... - and some of the funny thoughts that roll around in their heads, like a tin can with a couple marbles in it being shook up.

spyvsspy · Posted: Fri Jul 29, 2011 4:16 pm Post subject:

Clatter, I don't know about the other pushrods since I didn't have a stocker to measure. The mantons haven't been measured either. I just happened to drop by the shop who is doing my rocker geometry when I witnessed the flexing. If anybody wanted to or has seriously perform a pushrod comparison please chime in. I don't have the time or the means to do it, I was just posting the results of what we found when adding stress to bugpack hd aluminum pushrods.
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mark tucker · Posted: Fri Jul 29, 2011 4:27 pm Post subject:

I was setting up one of my motors and trying diffreent pushrods& geo.tried a stock aluminum one and it skeered the crap out of me when I noticed how much it was bending/flexing,I promptly steped aside and removed it before it was to launch through me. my brother used some titaninum pushrods in his motor for a while till I told him how titanium splinters,(thou I dont know what grade he had or even what it takes to do it,he had sa set of smith brother the next week & still turned 9000+ rpm.
even using the 1.1 rockers with the stock pushrods & duel springs they flex a good bit, but ok for breaking in cam I reckon.

Clatter · Posted: Fri Jul 29, 2011 4:40 pm Post subject:

One other thing that could have an influence is how they shortened the pushrod.

If they did it with a hacksaw, instead fo an arrow cutter or lathe,
then the tip could be in a tad crooked, and influence how it decided to flex...

Sooooo, that .020" number was a manner of speaking, right?

How much do the Mantons flex?

I've got the hump right now over the Manton pushrods.
The balls on the end are a tad big for some adjusters,
So it makes it really hard to spin the pushrods and set that perfect 'loose zero'
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Type 5 Joe Wrote:
Gotta just love the opinions of a couple of the jokers on here... - and some of the funny thoughts that roll around in their heads, like a tin can with a couple marbles in it being shook up.

mark tucker · Posted: Fri Jul 29, 2011 4:55 pm Post subject:

I think a little big is better than a little small,add some oil and it should spin just fine,some pushrods dont have a flat on the end and the cups are not machined corectly and they both dont get along real well sometimes eating the end of the pushrod a bit and even the adjuster some neer the oil hole,I deburr& add a flat to the pushrod & depending on the cup shape I have also radiused the hole area, you dont need or want it seating on the very end, thats too small of an area. Ive seen nice cups and junk cups, and cups that dont have an oil hole likethe ones wth needel bearings in the rocker,those cups need some work up in there where the hole should be, to releave stress & let it seat around farther out, Ive seen them pull up a nub from the push rod hole eating into the cup when there is no flat on pushrod & no relief in the cup, you dont want any edges eating at any thing in your motor. CLEARANCE THEM!!!good luck
I even had some that fit like a ball socket,cb pushrods and cb rockers that snaped togeather !!! ok as long as there is clearance.

spyvsspy · Posted: Fri Jul 29, 2011 5:10 pm Post subject:

Pushrods were not hacksawed, they were machine cut and ends reamed to facilitate tip assembly. I think I will go write a letter to the owner of bugpack and send it to him along with the pushrods.
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It is what it is.

Ian Godfrey · Samba Member Joined: September 25, 2006 Posts: 500

AC.net straights don't flex with 375 lb springs. Tested turning over by hand against a straight edge. A much stronger alloy than bug pac.

RockCrusher · Posted: Fri Jul 29, 2011 10:24 pm Post subject:

How about carbon fiber push rods? Hint: at a given high RPM they literally vaporize....the engine shuts off and you tear it open to find out what happened and several pushrods are missing. True story. Needless to say, that was the end of the carbon fiber pushrod development at that shop.
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Type 5 Joe · Posted: Sat Jul 30, 2011 5:36 am Post subject:

Aircooled,net aluminum pushrods are Smith Brothers pushrods. = Same thing.

They have also built Gene Berg pushrods for many years.

Smith Brothers are just down the road from me.... I know those people down there pretty good.

They do work pretty well in a mild build.

I have a new set for sale in the classifieds

hooker · Posted: Sat Jul 30, 2011 8:24 am Post subject: push rods

Type 5 Joe · Posted: Sat Jul 30, 2011 8:41 am Post subject:

Yes, turbo boost will tend to push the intake valve open under boost....

Which requires a heavy spring set-up, and a heavy duty pushrod to reliably actuate it.

Smith Brothers push rods are top quality and they make several different tube thickness + and many different end styles.

I think the answer might be to install pushrod ends with no oil hole (Smith brothers offers these), then externally plumb a set of oil squirters in the valve covers.

Maybe build a set of custom heavy duty rocker shafts that are gun drilled / cross drilled and plumbed externally to oil pressure.

The additional weight that oil adds to a set of beefy pushrods can be considerable.

mark tucker · Posted: Sat Jul 30, 2011 9:48 am Post subject:

have you seen how thick the nascar pushrods are these days??.165wall tubing&more,.if you add a ratio rocker 1.1 to a 1.4 it changes the spring pressure that the pushrod/cam/lifter sees. 300 on the seat will see almost a 100# increase,thus the 2.2 ratio on this nascar stuff adds a lot more..there is a lot more to ratio than most think.and even more to the way the rocker is desigined&set up.

Type 5 Joe · Posted: Sat Jul 30, 2011 12:39 pm Post subject:

kielbasa · Posted: Sat Jul 30, 2011 1:05 pm Post subject:

There is nothing wrong with talkin "v8" vw motors have proven them selves again and again to need stronger parts, such as k800's there's a reason you can only get a set of 16.... It's for a v8!!!! I've seen some ones motor bend the Shit out of those NASCAR pushrods into a "L" I won't name names just cause. So stop whining about v8 Shit when its actually relavent. Good day and don't forget to pick up another pack of depends.
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RockCrusher · Posted: Sat Jul 30, 2011 1:22 pm Post subject:

Thank you Kielbasa....Mark may wonder around sometimes but usually has some relevant information if your willing to listen. I'd love to sit down with Mark and pick his brain sometime. He's done lots of things and had many experiences that some of us will never have. THAT makes him a valuable resource in my book. Does he know everything? No and neither do I. Does he know ALL the theory behind certain things and certain problems? No and neither do I. That doesn't mean I don't listen. While I don't always agree with Mark or many others here I STILL listen to every word.

RC
_________________
[email protected] Please use email for all general inquiries.

I will be happy to speak to anyone who has a serious inquiry (meaning real potential business for RC enterprises) or a parts order. Due to machining noise causing missed calls all calls will be returned promptly.
610-800-0569 (voice mail is Total Home Media.....soon to be changed)

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