Which connecting rods to use

-
I'll take new offshore 4340 steel to 30 something year old 10 series carbon steel any day. If one knows the history of the forgings its one thing, but unknown rods ? Not saying I won't use a set of OEM rods, but then again I do my own machine work. Costs me nothing but my time, not everyone has that luxury. Here is a set of Magnum forgings that I'm planning on using in a low buck 500+ HP 360 build.

Balance pad ground off


Balance pad contoured/lightened
4bc72dce-2107-4e11-801b-275a2d2d6b87_zps63d162f2.jpg


Beams ground and polished then heavy media blasted. 683 grams total weight. Typical LA rods weigh around 740 IIRC.
64b7b045-c18b-4de3-a47d-ead1bd1e1b20_zpse750e5ba.jpg
 
ok I have been doing a lot of research on this because i'm in the same predicament. I'm in the middle of a 450hp build and decided on using the stock rods. Everything I have read and seen with pics is that the stock rods do hold up quite well. Most of the failures ive seen have been because of faulty builds and also heavy pistons. The point at which a rod would break would be high RPM, longer than normal stroke (stroker motors), and on the exhaust stroke because there's nothing pushing back at the piston (compressed air). Lightening the load on the rod by getting a set of lighter pistons and knocking off the extra weight pad on the small end is the best bet and goes for any rod used. now with that said on to 1970Duster's comment.

1970Duster said:
^Damn those rods heavier than my Eagle H-Beams
Click to expand...

They are heavy because they are high density forgings. Ma Mopar did it right back in the day. A stock set of rods prepped properly and lightened up will handle street/strip duty no problem. I bought up about 20 rods at recent swap meets and some from members here looking for unmolested rods that have very little extra weight on the small end of the rod. this means more material settled in the middle of the rod where it is the most and is the weakest point. I spent $60 in total for all the rods. I had the works done to them for about $160 and am very happy with the outcome. Now they look like an aftermarket $400 set of rods.
 
Something else to consider. You can use the 273/early 318 rods. They are much lighter than the later rods and with light pistons would be just as strong IMO. Just food for thought.
 
71Scamper said:
ok I have been doing a lot of research on this because i'm in the same predicament. I'm in the middle of a 450hp build and decided on using the stock rods. Everything I have read and seen with pics is that the stock rods do hold up quite well. Most of the failures ive seen have been because of faulty builds and also heavy pistons. The point at which a rod would break would be high RPM, longer than normal stroke (stroker motors), and on the exhaust stroke because there's nothing pushing back at the piston (compressed air). Lightening the load on the rod by getting a set of lighter pistons and knocking off the extra weight pad on the small end is the best bet and goes for any rod used. now with that said on to 1970Duster's comment.



They are heavy because they are high density forgings. Ma Mopar did it right back in the day. A stock set of rods prepped properly and lightened up will handle street/strip duty no problem. I bought up about 20 rods at recent swap meets and some from members here looking for unmolested rods that have very little extra weight on the small end of the rod. this means more material settled in the middle of the rod where it is the most and is the weakest point. I spent $60 in total for all the rods. I had the works done to them for about $160 and am very happy with the outcome. Now they look like an aftermarket $400 set of rods.
Click to expand...

Okay good to know. My rods are rated to 1400 hp, what are the factories rated to?
 
i like the lighter rods also..

scat I beam 590 grams...plus or minus

stock rods...as said 740 grams..

8 x 150 = 1200 grams...over 2.5 lbs.....makes life easier on a cast 360 crank too.
 
1970Duster said:
Okay good to know. My rods are rated to 1400 hp, what are the factories rated to?
Click to expand...

lol, well this is a touchy subject. Every person has a different opinion as there is no definite set number. There are alot of variables For instance, weight of the piston, intended RPM range, intended use of the engine. I would say they could handle upwards of 500 hp no problem if prepped right with quality bolts.

what kinda rods you running? couldn't of been cheap at all for that type of high HP security. :burnout:
 
I know my friend took his rods to 8500 rpm over and over running circle track, the stock rods are plenty strong. Btw what's the use of 1400 hp rated rods in a 450 hp motor?

Reconditioning rods cost 9-12$ a rod plus a set of 50 dollar arps
 
skrews said:
Its a dollars and cents thing. Press off the old pistons, disassemble, clean, magnaflux, polish beams, cut cap and rod, install new ARP bolts, resize, weight match/balance. This all costs $ at the shop. Now you've got a set of weaker forgings with an unknown fatigue history. Heavier than any I-beam aftermarket rod, pain in the *** press fit small ends, and inconsistent lengths.
Now compare that to a set of after market rods. Its false economy IMO.
Click to expand...

I do all that myself... other than resizing and balancing. But I had to resize and balance my new Eagles as well.
 
mbaird said:
I think the point is that mild builds dont need hyper rods...
Click to expand...

I'm with you my friend. I feel that if that engine isn't going a constant 8000 RPM for the majority of its time and the build is 500HP or under than properly prepped stock rods w/ good bolts are more than ample.
 
71Scamper said:
lol, well this is a touchy subject. Every person has a different opinion as there is no definite set number. There are alot of variables For instance, weight of the piston, intended RPM range, intended use of the engine. I would say they could handle upwards of 500 hp no problem if prepped right with quality bolts.

what kinda rods you running? couldn't of been cheap at all for that type of high HP security. :burnout:
Click to expand...

Eagle H-Beams with the strongest arp bolt possible and Eagle esp armor. They were checked out completely and thumbs up for them to be able to handle 1400 HP.
P.S. if they didn't checkout, those s.o.bs were going right back!
 
You must log in or register to reply here.
-

Back
Top