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Discussion Starter · #1 ·
Im buying a set of BBC 3/8's rods on here. What would the power restriction be after putting in some ARP wave locs. Motor is going to be a "ski boat" motor for a jet. I think i have a set of ARP2000's laying around.

4-bolt 454
Gm forged crank 4.00
single plane intake
maybe some aluminum heads or a set of 049's
750 ish quickfuel carb

I don't plan on running the motor to hard, just a good ski, tube, cruising motor. I might put my foot in it once in a while.

Should I step up to 7/16 for the insurance?
 

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E-7 Sheepdog (ret)
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Well, IMO the bolts you intend to get are plenty.

I rebuilt my 2-bolt 1978 454 with 3/8" ARP Wave-Locks (the 8470 (r is it 8740, I never remember)) alloy steel and had them reconditioned.

I run 5400 RPM off nitrous against an Aggressor B impeller, 5900 on the gas, in a heavy old Taylor SS lake cruiser ski boat.
According to the charts, that's 500 and 650 HP ballparks, 4 years of running, no problems.

You do not need to go bigger IMO.
 

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Sit N' Spin
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1,345 Posts
With the cost of the rods themselves, the rod bolts, then having to pay a shop to install the bolts and resize the rods you'd be money ahead to just by a brand new set of aftermarket rods. They'll come with the fasteners and in all cases...have the shit checked for size and balance and corrected if need be. :D
 

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Discussion Starter · #4 ·
With the cost of the rods themselves, the rod bolts, then having to pay a shop to install the bolts and resize the rods you'd be money ahead to just by a brand new set of aftermarket rods. They'll come with the fasteners and in most cases will be sized and ready to go out of the box.
Yeah I have thought of that. I get everything at dealer cost to boot. These are already hung on mint TRW forged pistons for $150 for the set. Hard to beat that, considering I don't keep anything for more than
6 months
 

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Sit N' Spin
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Yeah I have thought of that. I get everything at dealer cost to boot. These are already hung on mint TRW forged pistons for $150 for the set. Hard to beat that, considering I don't keep anything for more than
6 months
Well I hope they work for ya. FYI, the rods will have to be removed from the pistons in order to resize them once the new bolts are installed.

Which TRWs are they? With the TRWs I wouldn't have the bigger valves installed in the 049s (another thing I learned the hard way). The reliefs in the ones I ran were not radiused big enough for them and there wasn't enough material on the piston deck to have them fly cut for them.
 

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I'm No Expert
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ready to go out of the box.
Negetive there, always have them checked! I think it cost me 20 bucks to have them dusted and i kicked the guy down another 20 because he did it while i waited!


If you have bolts laying around dont go out and buy new rods with bolts, like i said above your going to have to have them checked anyway. Not sure if taking the pistons off the rod is required for resizing but if it is and these are pressed be careful who you let do it. I was told it's alot harder to press a pin out of a piston than it is to press one in. On my last motor this is what killed it, i had a shop swap the pistons from one rod set to another and they gouged 3 of the pistons, i ended up burning up the pins. When you get them back, make sure all the pistons move on the rods easily with the same amount of force!!
 

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Sit N' Spin
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I got my whole rotating kit through my machinist, so as soon as they arrived at his shop my rods and crank as well as the pistons were checked to verify they were on size. Plus, when you get new rods you gotta take them in to balance/verify balance anyway so have them checked while the machinist has them.
 

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That was why I said "In MOST cases...". I got my whole rotating kit through my machinist, so as soon as they arrived at his shop my rods and crank as well as the pistons were checked to verify they were on size. Plus, when you get new rods you gotta take them in to balance/verify balance anyway so have them checked while the machinist has them.
So maybe you should not of posted "ready to go out of the box"!!

I sent my crower crank in to lopez when i Bought it, spent another 125 to clean it up to "get it ready to go out of the box"...lol

Same with my rods, cost me about 30 bucks to clean up and check before they were "ready to go out of the box"

:)hand
 

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Sit N' Spin
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I agree 100%. Never ASSUME that it's right...Always have shit checked, or if you're good with micrometers check it yourself. Post edited :D

On mine, everything was on size, but some had to be taken off the counterweights to balance.

Had I'd bought the kit from elsewhere, I would have taken everything to the machinist to verify size and balance.
 

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Sit N' Spin
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You know Shaun, it's interesting the subject of having new rods checked even got brought up. A friend of mine has a Ford 460 that he's been battling with since last season. Here is the history of the motor -

On a WFO run he came outta the water and unloaded, afterwhich he developed a 'knock' and had no oil pressure. Decided to limp it back at 1500 RPM with no oil pressure...#4 rod was ripped from its piston (he thought he had forged pistons...found out he actually had hypereutectics) and sent through the #8 cylinder.

Replaced block, pistons, a couple rods and the crank.

Rebuilt #1 - lost oil pressure. Teardown revealed the rod bearings were fine but the mains were shot. Block needed an align hone. #1 cam bearing spun...this is where it gets funny. While he was building the motor, he had two boxes of cam bearings on the bench. One set were for his motor while the other set was for an FE block. Grabbed the wrong box...didn't check the part number. He kinda thought they went in a little on the loose side but wanted to get the thing running so he rushed it and didn't worry.

Rebuild #2 - He had his heads converted to an adjustable valve train, roller rockers. He thinks a poly lock came loose...I speculate that he may have forgotten to tighten one of them. Needless to say, rocker came loose, then the lifter came out of the bore and he lost oil pressure. #2 and #6 rod bearings were the first to go. Come to find out...THE ROD BIG ENDS WERE TOO TIGHT! He figured since they were brand new rods that they didn't need to be checked.

Rebuild #3 - Had the rods resized, replaced crank (again...he seems to have an abundance of Ford cranks laying around) and installed a stud girdle. He got it on the water yesterday and ran it about 30 miles...seemed to do OK. We'll find out as time goes on.
 

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I'm No Expert
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THE ROD BIG ENDS WERE TOO TIGHT!
I'm no expert builder, my only experience so far is with BBC's and the 2 builds i've done. On my new rods, the rod shop said they where pretty good out of the box, he was actually supprised how good they where because they where engine pro rods (a knock off manely rod from what i've been told). BUT! checking bearing clearances in the rods before the check/dust vs after the check/dust was night and day! After the rods had been done my clearances where all pretty much the same +/- .0001. The small end is another story, with my rods they where on the tight side at .0007. Mahle wanted to see between .0008 and .001. Leason i learned was that every manufacture is different and just because it's new doesnt mean it's ready to go out of the box. Also just because it's new doesnt mean it's right! Cant remember who told me this but with rods i was told that alot of manufactures keep things on the tight side out of the box so that you can open them up to where you need them/want them.

Again, i'm no expert though.
 

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Sit N' Spin
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1,345 Posts
Which sparks another question for the builders/machinists...

On rods with a floating pin, since the piston pivots on the wrist pin, why would it matter what the small end clearance is?
 

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It's what we do
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709 Posts
One reason is that the piston may rotate on the pin, but if it is too tight on the rod it wont be able to move in the rod to center itself in the bore.
 

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Sit N' Spin
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Think I just had a Shaun moment (DUH!)

One reason is that the piston may rotate on the pin, but if it is too tight on the rod it wont be able to move in the rod to center itself in the bore.


Uh...I knew that. Just wanted to make sure everyone else did :D :D
 

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I'm No Expert
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Thats the difference between floating and pressed. Both styles the pin it still able to move in the piston's bore. The difference is that with floating the pin can also move in the small end of the rod where as with pressed the pin is pressed through the rod.

I would assume that the clearance between the pin and rod is for lubrication too.
 

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Sit N' Spin
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1,345 Posts
Thats the difference between floating and pressed. Both styles the pin it still able to move in the piston's bore. The difference is that with floating the pin can also move in the small end of the rod where as with pressed the pin is pressed through the rod.

I would assume that the clearance between the pin and rod is for lubrication too.
Well in my mind at first I thought "Rods with a press fit pin don't move at all so why would a floating pin rod need to move on the wrist pin?". I totally forgot that on a floating pin, the pin cannot slide side to side in the piston to allow rod alignment like a press fit rod can, so the rod has to have a way to slide on the pin itself.
 
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