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Lighten an I - beam rod

General engine tech -- Drag Racing to Circle Track

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Little Mouse
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Re: Lighten an I - beam rod

Post by Little Mouse » Tue Mar 17, 2020 8:43 pm

econo racer wrote:
Tue Mar 17, 2020 5:25 am
Sometimes I think me and little mouse outta have a 302 chevy contest. :lol: Those Hi RPM's were addicting weren't they
mouse :D

I always said this thing screams nice it's just not really getting anywhere that fast. It's all in the fun factor in life and then you die. After you get off the 13,500 rpm croutch rocket you think damn the 302 is a farm tractor engine or an 8 cylinder harley Davidson farm tractor engine. I stumbled on to a you tube video of a guy from CP/ Carrillo discussing rod and piston failure. He said people now refer to 5/64 and 1/16 rings as tractor rings. Got me to laughing. Saw somewhere the difference between a 1/16 to 3/16 oil ring pack and a 1.2 mm to 3 mm oil ring pack was 30 grams besides all the less friction.

David Redszus
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Re: Lighten an I - beam rod

Post by David Redszus » Tue Mar 17, 2020 11:50 pm

Little Mouse wrote:
Mon Mar 16, 2020 7:27 pm
I have a set of K1 rods I'm almost sure I will end up using there 6.250 long , 507 grams. Scary to look at them when I first got them. Howard's makes a new I- beam rod 6.50 long 680 grams. Have decided will do 3.00 stroke that long of rod could be used with 1.00 CH pistons. I would have to get a gram scale, then something to weigh the big end and small end of the rod, stuff shops have. Then I guess you could take a mic measure as you go. Be a hell of a long hour job to get it all right. I was thinking up above the curve of the big end and a ways below the pin end. Maybe take some off the length of the outside and some down the center. To me there's no such thing as to light of reciprocating weight as long as its strong enough.
If you are going to change the rod masses, remember that the rod gravity centers need to be matched.

englertracing
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Re: Lighten an I - beam rod

Post by englertracing » Wed Mar 18, 2020 10:42 am

Hmm
I wonder if that rod in the video stayed round...

Dan Timberlake
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Re: Lighten an I - beam rod

Post by Dan Timberlake » Wed Mar 18, 2020 1:02 pm

1972ho wrote:
Mon Mar 16, 2020 8:28 pm
This is video of a shop lightening a connecting rod
=============.

At 5:46 it looks like the finished rod will have :
- Seriously degraded fatigue strength due to the removal of the curved rib that wraps around the bolt head.
- Significantly reduced "foot print" at the rod and cap parting faces.

In my book Not a good exchange for what amounts to the loss of a few ounces of "flywheel" weight.

That rod, like many Honda rods in cars-n-bikes, appears to have been thoughtfully optimized for much Big End goodness with low weight.

Krooser
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Re: Lighten an I - beam rod

Post by Krooser » Wed Mar 18, 2020 1:42 pm

Krooser wrote:
Mon Mar 16, 2020 10:44 pm
I like his videos although I don't think he has made any in the last few years.
Just learned that John from Costa Mesa R&D passed away 12/25/17.

He was a machinist and an author of several books. RIP.
Luxemburg Speedway Hall of Fame Member Class of 2019

Cubic_Cleveland
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Re: Lighten an I - beam rod

Post by Cubic_Cleveland » Wed Mar 18, 2020 7:48 pm

Dan Timberlake wrote:
Wed Mar 18, 2020 1:02 pm
1972ho wrote:
Mon Mar 16, 2020 8:28 pm
This is video of a shop lightening a connecting rod
=============.

At 5:46 it looks like the finished rod will have :
- Seriously degraded fatigue strength due to the removal of the curved rib that wraps around the bolt head.
- Significantly reduced "foot print" at the rod and cap parting faces.

In my book Not a good exchange for what amounts to the loss of a few ounces of "flywheel" weight.

That rod, like many Honda rods in cars-n-bikes, appears to have been thoughtfully optimized for much Big End goodness with low weight.
I agree, not where I’d be looking to save weight either.

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