I got an old short block (10 passes on motor) I want to use for a bracket motor. It has Eagle SIR rods and Keith Black Hyperutectic pistons (4.060) and a factory 360 crank (3.58 stroke). I also have a new flat tappet cam sitting on the shelf that I never used from another build I'm going to use. I've lost the cam card and I have to call and find the exact specs but it's like .587/.612 lift and 260/268 @.050. I have also aquired a set of edelbrock heads that are ported. They flow 275CFM @.600 lift (intake). It will have a Strip Dominator intake and a Demon 750 CFM carb. My question is will this combo make to much power for that bottom end? The motor will be @ 12 to 1 compression with a standard thickness gasket.
How much power on SIR rods?
- Thread starter bignick
- Start date
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MRL Performance
Well-Known Member
Nope. Run it.
MRL Performance
Well-Known Member
:cheers:
My god,somebody gets it.
I figured as much MRL. Would it make any difference if I didn't turn it that hard? Bob weight piston/pin and rod is 1239. Just trying to build something from the leftovers that didn't get destroyed in Katrina. I would much rather have my 408" Diamond piston/H beam rod/4340 crank motor but salt water and engine parts don't mix. I'm just now getting my car back together and trying to do it with left overs since money is tight. It's going in my duster which at the moment isn't set up to turn it that hard anyway. 3000 pounds, 904w/ 4200 converter, Dana 60 w/4.56 and a 31x10.5w. And what pistons do you use in your builds all the forged pistons I have used Diamond, wiesco, srp are heavier than the hyper pistons in this motor? Unless you use chevy pin short shirt long rod combo's or something to that affect?
bad440
everything,all the time..
I'm skeered ....same setup,only ten to one,w2s cams good to 6500....damn you and your honest answers mike.....lol
Lmao!
bad440
everything,all the time..
my pistons don't weigh near as much as the op s and the rotating assembly got special attention from one of the best crank guys in the buisness,mike at ashland grinding.he's been there forever.and before forever his dad was the man.you guys shouldsee this place,he has signed handouts from the sixtys and seventys from a lot of big name racers thanking him for his work.
bad440
everything,all the time..
thats not heavy....
MRL Performance
Well-Known Member
:sign3:Yup
Mo-Par
Well-Known Member
Thats good to hear. My machine shop orderd Mahle instead of the Icons we were going to use. Some thing about the wrist pin area helping keep them light and thin rings causing less drag.
crazy 340
Well-Known Member
I ran for 10 years almost the same engine
SIR rod
.590 MP. cam
kb 191 piston
12.33 cr
915 J heads fully ported with 2.08 int 1.60exh
cast 360 cranck
strip dominator intake
this engine even ran with nitrous 125hp
blew the heads gasket twice before switching to sce copper
after that I tried to blew the engine so my wife coundnt yell at me
wanting a 408.
but I sold it to a friend told him that it need to be rebuild
he never rebuilt it and this engine still alive
but one thing for sure this engine was balance at best a guy can do
mine hold well,does the other one that built one like that will hold I dont know
to my idea it was suppose to blow the first time I hit the nitrous switch
my 2 cents
bob
SIR rod
.590 MP. cam
kb 191 piston
12.33 cr
915 J heads fully ported with 2.08 int 1.60exh
cast 360 cranck
strip dominator intake
this engine even ran with nitrous 125hp
blew the heads gasket twice before switching to sce copper
after that I tried to blew the engine so my wife coundnt yell at me
wanting a 408.
but I sold it to a friend told him that it need to be rebuild
he never rebuilt it and this engine still alive
but one thing for sure this engine was balance at best a guy can do
mine hold well,does the other one that built one like that will hold I dont know
to my idea it was suppose to blow the first time I hit the nitrous switch
my 2 cents
bob
1wild&crazyguy
Banned
I think it will hold together fine.
Scaredy cats...lol
Scaredy cats...lol
Well like I said there probably under 500 grams before you posted you use pistons under 500 grams. Like I said there slightly over 500 otb and they where flycut for valve to piston clearance. Crazy what did that combo run ET wise? And what rpm's did you turn it? Come to think of it 11-12 years ago I had a 11: 1 360 with a stock crank, mildly ported J's w/ 2.02/1.625 ferrea 6000's, stock rods w/ arp bolts and heavy hyper pistons. It had a .525 lift flat tappet Isky and I'd let it eat on the top end and it turned 7K rpm. It had 200-250 passes and some street driving and I took that one apart to use the block on another build. It went 11.50's in my duster that at the time was a all steel (3300#'s) leaf spring car with a terrible GER converter.
MRL Performance
Well-Known Member
Well there you go. You already know the answer to your own question. Just build it and run the crap out of it.
Its a solid power combo and it will make good power. I really like the cam/head/intake/compression combo.
Its a solid power combo and it will make good power. I really like the cam/head/intake/compression combo.
bad440
everything,all the time..
519 grams ,so yes 39 grams heavier than mahle . hell with it i'm gonna race it if it breaks going big block like i should have anyway.
39 grams, it's not like it's slinging the old trw pop ups that weigh in at ~750-800 grams.
From my old stoner days...
454 grams in a pound
divide that by 16 you get 28.375 grams per ounce
1.37 ounce difference per piston...
Now those old TRW's are 8-10+ ounces heavier, which is a bigger deal.
Light is good, but, at what cost?
From my old stoner days...
454 grams in a pound
divide that by 16 you get 28.375 grams per ounce
1.37 ounce difference per piston...
Now those old TRW's are 8-10+ ounces heavier, which is a bigger deal.
Light is good, but, at what cost?
bad440
everything,all the time..
alot of us learned fractions out of school,lol man 800 grams is a bunch.now that i think of it my .060 trw dome pistons were really heavy,but i spun it to 7000 for two years then sold it.still runs,but it has piston slap like a *****.....
1wild&crazyguy
Banned
This thread has more edits than Obamacare.
People are spoiled these days and half brain washed into believing you need top dollar race parts if you wanna playthis game..ha
Well... whatever you all do, just don't forget to lick nuts ;)
People are spoiled these days and half brain washed into believing you need top dollar race parts if you wanna playthis game..ha
Well... whatever you all do, just don't forget to lick nuts ;)
MRL Performance
Well-Known Member
Ya know what, ask Eagle if they recommend using their rod for what you are going to do with it. Go ahead, pick up the phone and ask them point blank and BE HONEST! Tell them exactly what your plan is. If they say "Sure thats the right rod for your application" then run it. But if they dont back it up and tell you Not to use that rod, then what?
Personally I think a stock rod w/arp bolts is better than a SIR rod. There is another inexpensive rod out there that is way better, the SCAT I beam rod. Why? Well Im going to tell you why. Stock rods and SIR rods are made from 5140 low grade forgings. They also have 3/8" rod bolts. Stock rods are around 700g(give or take a few g) and SIR rods are around the 580-600g mark. Yes they are a lot lighter, but they are not made from a stronger material, thats the big problem I have with them. Now on the other hand, the SCAT I beam rods are made from 4340, a high grade forging with a much higher tinsel strength. 4340 is about 40% STRONGER than 5140. This is a fact. Also the SCAT rods have 7/16" bolts. With the 7/16" bolt you put about 4-5000# MORE preload on the fastener over the 3/8". More holding power, less chance of the rod going out of round at high rpm. These are not high dollar race parts, just better suited for the higher HP, higher RPM engines. We are not talking about Oliver or Manley or any other $2000 sets of rods here.
I dont like Eagle rods. The last set of rods I got from Eagle were .0015 out of round on the big end and .0005" TO BIG on the small end. May not sound like much, but .0015" piston pin to rod clearance is to much for me. If yall want to run this stuff go ahead, dont matter to me.
You asked, I gave my opinion. Take it for what its worth.
Personally I think a stock rod w/arp bolts is better than a SIR rod. There is another inexpensive rod out there that is way better, the SCAT I beam rod. Why? Well Im going to tell you why. Stock rods and SIR rods are made from 5140 low grade forgings. They also have 3/8" rod bolts. Stock rods are around 700g(give or take a few g) and SIR rods are around the 580-600g mark. Yes they are a lot lighter, but they are not made from a stronger material, thats the big problem I have with them. Now on the other hand, the SCAT I beam rods are made from 4340, a high grade forging with a much higher tinsel strength. 4340 is about 40% STRONGER than 5140. This is a fact. Also the SCAT rods have 7/16" bolts. With the 7/16" bolt you put about 4-5000# MORE preload on the fastener over the 3/8". More holding power, less chance of the rod going out of round at high rpm. These are not high dollar race parts, just better suited for the higher HP, higher RPM engines. We are not talking about Oliver or Manley or any other $2000 sets of rods here.
I dont like Eagle rods. The last set of rods I got from Eagle were .0015 out of round on the big end and .0005" TO BIG on the small end. May not sound like much, but .0015" piston pin to rod clearance is to much for me. If yall want to run this stuff go ahead, dont matter to me.
You asked, I gave my opinion. Take it for what its worth.
66dartman
Well-Known Member
Well said, MRL! The scat I beams are no more money($300) for a set than the SIR eagles, but they are forged of better material. The scats are about as light too.
Yes..the scats are basically the same price...but IF YOU read his question...you will see that he has a used short block with the eagle rods all ready in it....
so everyone who is voting for the scat rods...send him 20 bucks so he can buy them...LOL
so everyone who is voting for the scat rods...send him 20 bucks so he can buy them...LOL
crazy 340
Well-Known Member
it ran 11.48 and 10.50 with the 125 hp of juice
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