Club Cobra Gas-N Exhaust  

Go Back   Club Cobra > Engine Building, Tuning, and Induction > Small Block Talk

MMG Superformance
Nevada Classics
MMG Superformance
Main Menu
Module Jump:
Nevada Classics
Nevada Classics
Advertise at CC
Banner Ad Rates
Keith Craft Racing
March 2024
S M T W T F S
          1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31            

Kirkham Motorsports

Like Tree3Likes

Reply
 
LinkBack Thread Tools Rate Thread Display Modes
  #1 (permalink)  
Old 06-29-2013, 09:47 PM
Rick Parker's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2001
Location: California, Ca
Cobra Make, Engine: NAF 289 Slabside Early Comp Car with 289 Webers and all the goodies. Cancelling the efforts of several Priuses
Posts: 6,592
Not Ranked     
Default New engine on the horizon

Does anybody know the comparative weights of a Boss 302 Rod 5.155 c/c and that of a 5.400 Scat H beam for standard Crank Pin diameter and .912 Piston Pins?
__________________
Rick

As you slide down the Banister of Life, may the splinters never be pointing the wrong way

Last edited by Rick Parker; 06-29-2013 at 09:51 PM..
Reply With Quote
  #2 (permalink)  
Old 06-30-2013, 01:16 AM
Dimis's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2008
Location: Melbourne, Vic
Cobra Make, Engine: Some polish thing... With some old engine
Posts: 2,286
Not Ranked     
Default

Quote:
Originally Posted by Rick Parker View Post
Does anybody know the comparative weights of a Boss 302 Rod 5.155 c/c and that of a 5.400 Scat H beam for standard Crank Pin diameter and .912 Piston Pins?
That's well and truly beyond my knowledge...

But I'm interested to hear more about your new engine.
Will you still be running webers?

Your knowledge and posts about them has me learning plenty.
__________________
Reply With Quote
  #3 (permalink)  
Old 06-30-2013, 04:41 AM
Jac Mac's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2006
Location: Gore. New Zealand., SI
Cobra Make, Engine: DIY Coupe, F/T ,MkIV.
Posts: 808
Not Ranked     
Default

Rick , according to my Boss 302 Info...
Standard Boss 302 5.155" rods weight is :581/593 grams ( Same as 289 HP )
For balancing purposes the Big end weight is 421 grams ( per rod ), Small end is 166grams.

On the basis of those weights the total bobweight per journal for a stock Boss 302 being blueprinted with stock pistons etc was 1838.8 grams.( Thats for cross drilled crank- use 1827.8 grams for non- cross drilled to account for the oil weight factor )

Have a couple of Scat 5.4 rods here somewhere I could weigh, but they are all 927 pin variants.

Think we have discussed this motor already, are you trying or hopeing to work with your existing crank, in which case you should be able to weigh the old reciprocating components in order to figure what the original bobweight would have been....as long as your staying with the original damper/flywheel etc..
__________________
Jac Mac

Last edited by Jac Mac; 06-30-2013 at 12:53 PM.. Reason: additional bob weight info.
Reply With Quote
  #4 (permalink)  
Old 06-30-2013, 05:50 AM
Snakebit's Avatar
Club Cobra Member
Visit my Photo Gallery

 
Join Date: Nov 1999
Location: Salem,, NJ
Cobra Make, Engine: ERA 289 FIA #2100 Rio Red Wimbledon White Stripes 302 stroked to 331 Webers Richmond Road Race 5 speed
Posts: 779
Not Ranked     
Default

I did a 68 302 block stroked to 331 using a Scat forged crank with a 3.25 stroke, Crower 5.315 sportsman rods and JE pistons 188704 with a CH of 1.250, keeping the wrist pin out of the oil ring grove. Billet steel main caps 2,3,4. Canton main stud girdle, AFR 185 outlaw heads 58cc for a cr of 10.3, Miling blueprinted HV pump, Compcams 282S solid cam, and a Crower billet timing chain set. Running Webers with 40mm chokes.
prp289 likes this.
__________________
Snakebit

Last edited by Snakebit; 08-25-2013 at 01:30 AM..
Reply With Quote
  #5 (permalink)  
Old 06-30-2013, 05:50 PM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2001
Location: Louisville, KY
Cobra Make, Engine: I'm Cobra-less!
Posts: 9,389
Send a message via AIM to blykins
Not Ranked     
Default

Rick, give me a call.....you're worrying way too much about this connecting rod stuff.

Use the longer rod, keep the piston short. Don't worry about wrist pins intersecting the oil rings. It's a non-issue and has been perpetuated on all the forums for no reason.
__________________
www.lykinsmotorsports.com
Reply With Quote
  #6 (permalink)  
Old 06-30-2013, 10:19 PM
CC Member
Visit my Photo Gallery

 
Join Date: Mar 2003
Location: Arkadelphia, AR, AR
Cobra Make, Engine: Kirkham 427 brushed aluminum with Keith Craft 527C.I. all aluminum FE
Posts: 992
Not Ranked     
Default

I agree with Brent go with the longer rods. They are better and will keep the piston higher in the cylinder when at the bottom. I find this a bigger concern than the ring deal which is no problem. The shorter rods pulls the piston out the cylinder at the bottom for more piston rock.

Good luck, Keith
__________________
Keith C
Reply With Quote
  #7 (permalink)  
Old 07-01-2013, 03:53 AM
Snakebit's Avatar
Club Cobra Member
Visit my Photo Gallery

 
Join Date: Nov 1999
Location: Salem,, NJ
Cobra Make, Engine: ERA 289 FIA #2100 Rio Red Wimbledon White Stripes 302 stroked to 331 Webers Richmond Road Race 5 speed
Posts: 779
Not Ranked     
Default

I respect your opinions, but placing the wrist pin in the oil ring groove just isn't natural. As far as using a 5.315 rod vs a 5.4 rod, you are talking .085" difference. Just one more thing to help me sleep better at night knowing that the engine will not turn into an oil burner.
__________________
Snakebit
Reply With Quote
  #8 (permalink)  
Old 07-01-2013, 04:50 AM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2001
Location: Louisville, KY
Cobra Make, Engine: I'm Cobra-less!
Posts: 9,389
Send a message via AIM to blykins
Not Ranked     
Default

It wouldn't.

But peace of mind is a wonderful thing.

Think about how many fox mustangs there are across the us running 347's with 1.090" pistons. They are not rolling smoke shows. This is extremely common and even the 4.300" stroke bbf pistons come this way.

Once upon a time, I think someone jacked up the ring install or got the hone job wrong on a build and contributed it to the piston design. As you know, there are lots of bench racers on the Internet, so the idea stuck. :-)
__________________
www.lykinsmotorsports.com
Reply With Quote
  #9 (permalink)  
Old 07-01-2013, 07:56 AM
Rick Parker's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2001
Location: California, Ca
Cobra Make, Engine: NAF 289 Slabside Early Comp Car with 289 Webers and all the goodies. Cancelling the efforts of several Priuses
Posts: 6,592
Not Ranked     
Default

This will be a 3" stroke engine, essentially an overbored 302. I have a real nice professionally prepped Boss 302 Steel crank (thank you ERAChas) that will be internally balanced. I will use a 5.4 rod and am leaning towards the Scat H Beam with a .912 pin. I will probably use an ATI balancer. I want the reciprocating assy to be as light as feasibly possible, from my perspective this is an important issue, hence my concern.
__________________
Rick

As you slide down the Banister of Life, may the splinters never be pointing the wrong way
Reply With Quote
  #10 (permalink)  
Old 07-01-2013, 08:56 AM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2001
Location: Louisville, KY
Cobra Make, Engine: I'm Cobra-less!
Posts: 9,389
Send a message via AIM to blykins
Not Ranked     
Default

For something around your horsepower level, I would use a light I-beam rod. Crower makes a nice Sportsman rod that isn't too much more than the Scat piece. Light piston, light rod = light bobweight.
car4jim likes this.
__________________
www.lykinsmotorsports.com
Reply With Quote
  #11 (permalink)  
Old 07-02-2013, 03:36 AM
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2003
Location: West Bloomfield, MI
Cobra Make, Engine:
Posts: 717
Not Ranked     
Default

Quote:
Originally Posted by blykins View Post
Once upon a time, I think someone jacked up the ring install or got the hone job wrong on a build and contributed it to the piston design. As you know, there are lots of bench racers on the Internet, so the idea stuck. :-)
While I generally agree on it not being a huge deal, I will only pierce the oil ring groove on a race or performance package if it's the only way to satisfy other limitations - such as pulling the pin out of the bore or banging the counterweights on the pin boss. Or a checkbook limitation.

But if there is any other way I will avoid it. A narrower ring pack (.043-.043-3.0mm) coupled with reduced crevice volume can get you some good usable real estate up there (over .100") for modest cost and you end up with a nicer package as a result.

Consider the development budgets in the OE world and list the number of engines built with pin/ring groove intercepts.

That 5.315 rod ain't a bad deal either - it just never caught on with the bigger is better crowd. I do like the short CD for keeping the roll couple of the piston small - keep the ring pack squared to the bore and stable - don't need a long heavy piston since the working part of the skirt is all below the pin.
__________________
Survival Motorsports

"I can do that....."



Engine Masters Challenge Entries
91 octane - single 4bbl - mufflers
2008 - 429 cid FE HR - 675HP
2007 - 429 cid FE MR - 659HP
2006 - 434 cid FE MR - 678HP
2005 - 505 cid FE MR - 752HP
Reply With Quote
  #12 (permalink)  
Old 07-02-2013, 03:53 AM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2001
Location: Louisville, KY
Cobra Make, Engine: I'm Cobra-less!
Posts: 9,389
Send a message via AIM to blykins
Not Ranked     
Default

I don't know of many Cobra/Galaxie/Mustang engines trying to hit the 200k mark though...

OEM and what we deal with is certainly a good distance from each other.

With that being said, we may all have our theories/preferences, but again, I've never really seen any oil consumption or wear issues because of the oil ring placement. Most of my engines fall into the street/strip category, with some a little more strip than others. I do dabble with the LS crowd, BBF, FE, and SBF stuff, and it's not uncommon to see the oil rail support in the piston box.

While each point has its own merit, I do believe that the wrist pin/oil ring fiasco has really had its own evolution, carried on by most of the guys on The Corral and www.yellowbullet.com.
__________________
www.lykinsmotorsports.com
Reply With Quote
  #13 (permalink)  
Old 07-02-2013, 05:45 AM
CC Member
Visit my Photo Gallery

 
Join Date: Oct 2003
Posts: 4,078
Not Ranked     
Default

Great to have three pros weigh in with opinions. We need more of this on CC.
Makes for more educated engine customers for the builders too.
__________________
Chas.
Reply With Quote
  #14 (permalink)  
Old 07-02-2013, 10:52 AM
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2003
Location: West Bloomfield, MI
Cobra Make, Engine:
Posts: 717
Not Ranked     
Default

If you don't believe in OE development you can pop on over the "evilbay" and take a look at NASCAR take-outs. They have vacuum & dry sumps and still seem to leave the pin out of the groove when feasible.

The punched groove is a drag race specific deal that has migrated into the street world in order to accommodate the popular stroker crank & rod combinations. That said, there are eight hundred gazillion cars running around that way, so it obviously can work fine - just not my preference.
__________________
Survival Motorsports

"I can do that....."



Engine Masters Challenge Entries
91 octane - single 4bbl - mufflers
2008 - 429 cid FE HR - 675HP
2007 - 429 cid FE MR - 659HP
2006 - 434 cid FE MR - 678HP
2005 - 505 cid FE MR - 752HP
Reply With Quote
  #15 (permalink)  
Old 07-02-2013, 11:45 AM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2004
Location: Kansas City, KS
Cobra Make, Engine: jbl
Posts: 2,291
Not Ranked     
Default

Quote:
Originally Posted by Rick Parker View Post
This will be a 3" stroke engine, essentially an overbored 302. I have a real nice professionally prepped Boss 302 Steel crank (thank you ERAChas) that will be internally balanced. I will use a 5.4 rod and am leaning towards the Scat H Beam with a .912 pin. I will probably use an ATI balancer. I want the reciprocating assy to be as light as feasibly possible, from my perspective this is an important issue, hence my concern.
With only a 3" stroke and looking to go 'long' rod light piston with internal balance, aluminum rod comes to mind.
Reply With Quote
  #16 (permalink)  
Old 07-02-2013, 11:50 AM
Rick Parker's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2001
Location: California, Ca
Cobra Make, Engine: NAF 289 Slabside Early Comp Car with 289 Webers and all the goodies. Cancelling the efforts of several Priuses
Posts: 6,592
Not Ranked     
Default

NO aluminum, heat cycling affects it too much. Think rocker arm failure......

Save it for Beer cans
__________________
Rick

As you slide down the Banister of Life, may the splinters never be pointing the wrong way

Last edited by Rick Parker; 11-21-2013 at 09:30 PM..
Reply With Quote
  #17 (permalink)  
Old 07-06-2013, 01:27 AM
Caprimaniac's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2006
Location: Skjetten, No
Cobra Make, Engine: Unfortunataly ; none
Posts: 333
Not Ranked     
Default

Great to see you're putting together a new motor, Rick.

Agree 100% with Brent; look at I- beam rods like the Crowers. Maybe Howards have some as well. They may save you some weight and be PLENTY strong. I would even look at the Scat I- beams (will save more weifght, for sure). They can live to some HP and even some revs. May be less suitable for 7000+ revs?

The piston -pin in the oil- ring debate always pop up in these discussion. With Brent and others on this- it's a no- issue.

On your 3" stroke combo, this will be of no concern anyways, beacuse you will have more CH. Look at ICON (KB forged), they have shelf pistons for 3" stroke 5.4" rod combo. A flat top will save you some grms, but you'd need small chambers to get the comp. Probably other manufaturers have these pistons too?

An interesting project would be to use a shelf 347 piston with a longer rod for a stock stroke combo. Rods would have to be in the 5.5" area, custom rods most likely.
Reply With Quote
  #18 (permalink)  
Old 07-06-2013, 06:08 PM
CC Member
Visit my Photo Gallery

 
Join Date: Mar 2009
Location: Mendota, IL
Cobra Make, Engine:
Posts: 693
Not Ranked     
Default

Long ago I think they used 3 inch stroke 5.315 trans am rods with big bolts in boss 302 trans am engines.

Mark
Reply With Quote
  #19 (permalink)  
Old 07-06-2013, 06:17 PM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2001
Location: Louisville, KY
Cobra Make, Engine: I'm Cobra-less!
Posts: 9,389
Send a message via AIM to blykins
Not Ranked     
Default

Quote:
Originally Posted by Rick Parker View Post
NO aluminum, heat cycling affects it too much. Think rocker arm failure......
Rocker arm failure???

I use aluminum rocker bodies in almost every engine I do. But I agree, this is not the venue for aluminum rods.
__________________
www.lykinsmotorsports.com
Reply With Quote
  #20 (permalink)  
Old 07-06-2013, 09:58 PM
Rick Parker's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2001
Location: California, Ca
Cobra Make, Engine: NAF 289 Slabside Early Comp Car with 289 Webers and all the goodies. Cancelling the efforts of several Priuses
Posts: 6,592
Not Ranked     
Default

Quote:
Long ago I think they used 3 inch stroke 5.315 trans am rods with big bolts in boss 302 trans am engines.
Occcasionally these rods pop up for sale. They look DAMN heavy.
car4jim likes this.
__________________
Rick

As you slide down the Banister of Life, may the splinters never be pointing the wrong way
Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 07:59 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: CC Policy
Links monetized by VigLink