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  #46 (permalink)  
Old 08-19-2010, 03:51 PM
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Did any of you guys huffing and puffing about the "big benifits" of long rods even read the Isky pages. It's all there in black and white. In particular look at the amount of movement away from TDC with the different rods.

I have yet to see anyone ,anywhere where someone has posted back to back testing proof of hp benefits attributable to just rod length. If you have the data, please post it up for all to see.

I know of one engine builder with a $1000 standing offer to anyone who can produce data to support their long rod claims, bounty has been up for 4 or more years and no one has claimed it yet.

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  #47 (permalink)  
Old 08-19-2010, 04:38 PM
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Quote:
Originally Posted by Dirty Biker
Thank you cobalt, I actually have seen that article on the 350 chevy should have built, Im sure it was one of the things that have helped form my intent on building this motor, especially the high compression part. I was just being silly with my opinions on the 400 sbc lol, I think that as long as you guys were spouting opinions I could dish out a few as well... hehe.. I met a guy with a 283 in his mid 1960s dumptruck, now I didnt run the numbers on the motor to verify it was a 283 and not a 327 but he said he was sure it was a 283 because it was his fathers and he had been around it all his life. Anyways he said that it did fine for such a small motor, even with 10,000 lb of dirt in the back. So, anyways, I started with the intent of putting this in my van because I am sure that it would work however I am hopefully going to trade it to my girlfriends mom for her van thats just like mine but a little newer and with a 6.2 liter gmc diesel. So I have an s10 that I can use this motor in as I was saying.. That would be a fast truck with any v8 in it compared to the iron duke it has in it now for sure.

here is a link to a 550 horse 302 chevy that got almost 25 mpg
http://www.hotrod.com/techarticles/3...une/index.html
My grandpa has a 63 dodge dump truck with a 361 and a 1bbl. Top speed is 35, wound out. Because it's geared to the max to move the weight
He has a early 70's c60 flatbed with a 350 crate motor, quadrajet, duels. it can run on the highway, but the motor is wound way up to do it, and it has alot of gears to get moveing. Same thing with his ford 900 with a 513 v8 and ford 2 ton flatbed with a 361 industreal, lots of gearing and gears in te trans so it can wind up.

My dad has seen many old farm dump trucks/grain trucks with IH 304's, and sixes in them. The small motors work, because it only has a top speed of 45, and the motor is screaming away to do it.
Your van needs a 10 speed+ manual hooked to that lil motor so it can wind up to get it moveing, then it will top out at 50.

I think this is a interesting idea, but all the vehicles set up in similar ways, have lots of gearing, lots of gears in the trans and top out at 50mph and get terrable gas milage.
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  #48 (permalink)  
Old 08-19-2010, 04:55 PM
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I personally thought the Isky article debunked the theory rather than bolster it. It didn't go into much depth- but I guess it's all in what you want to read into it.

The biggest "pro" for long rods comes from Smokey. He liked 'em- and that's good enough for me to at least give it some consideration. But the engines I build would not benefit enough from a "long" rod to make it worthwhile to use anything longer than 6".

BTW, some guys, (Jere Stahl among them) don't consider an engine to have a "long" rod until 1.81 to 2.0 rod/stroke ratio. That's a 6.3" rod in a 3.48 stroke engine.

FWIW, a VW Type 1 boxer 4-cyl. can be as high as 1.99! That's the equivalent of a 6.93" rod in a 350. A 283 SBC is 1.9, a 267/305/350 SBC is 1.64, a 400 SBC is 1.48. The BBC 454 is 1.53.
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  #49 (permalink)  
Old 08-19-2010, 05:03 PM
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The isky pages are comparing rod ratios on a 350 chevy with a 3.48 stroke and stock 1.64:1 rod ratio. So it really isn't the same thing since even with a 6.25 inch rod a 350 still has a measley 1.79:1 rod ratio not to mention the little skinny piston you have to use to get that. Little skinny pistons do not slide as well because there is less surface for oil film, and rock more because theres less wall keeping them straight in the bore, so they don't last as long plus the piston gets alot of heat that it must lose by transfering it to the cylinder wall that is cooled by the water jackets and less piston equals less surface to transfer heat. Uh oh for 400 sbc siamesed bores right? So its not really worth it with that particular motor in my opinion and here is why I think that: Lets compare a 400 small block with stock rods to my motor... muhaha.. Ok so a stock 400 sbc has a 1.46:1 rod ratio putting the angle of the rod to center at 90 degrees past tdc at 20 degrees to centerline. That means that the piston will be rubbing the cylinder wall really hard on the power stroke wasting energy in the form of friction and heat. Also piston acceleration puts a lot of stress on bearings and wrist pins, and causes vibration. Maybe thats why they had to use bigger bearings? hmm.. Now compare that to a 3 inch stroke with 6.25 inch rods, that would be a 2.08:1 rod ratio.. Now we are getting somewhere! The rod angle at 90 degrees past tdc would only be 14 degrees. That equals less drag against the cylinder wall, more thrust directly to the crank due to a straighter angle, less power lost thru friction and heat. So comparing the little steps of gain on that 350 really makes so sense that its not worth it. They are right, except the bigger difference on my motor compared to it makes it an entirely different animal. Hear me now, believe me later...

Here is a quote from another website,Some engines aren't happy at high rpm-and never will be. Their bearing diameters are too large, their strokes too long, and their head-flow capacities too poor to really work upstairs. As Olds expert Dick Miller points out, "The big-block Olds is incapable of living at high rpm. The 455 has the longest stroke of all stock big-blocks on the market. Its 3-inch-od main bearings are also the biggest. At 6,000 rpm the Olds main bearing [rotational] speed is nearly the same as a small-block Ford at 9,000 rpm!"

And:
What about changing the stroke but keeping overall engine displacement the same (the old long-stroke/small bore versus short-stroke/big-bore debate)? On a dual-purpose hot rod engine, juggling the bore and stroke won't significantly change the amount of torque at the peak, but the short stroke combo will usually raise the rpm at which peak torque occurs-which of course raises the top-end power potential at the expense of the extreme bottom-end.

I do not require extreme bottom end with a 5.13:1 rear end especially with a auto trans slushbox.. I could get even a stall converter if I dont convert to manual! You should see the double tranny fluid oil coolers, I have power steering fluid cooler even because the hydro boost brakes I spose, and oil cooler too. I bet I could run a pretty high compression because of the huge radiator without aluminum heads or reverse cooling retrofit... Especially with a motor that is incapable of creating all that extra wasted heat from friction...

Last edited by Dirty Biker; 08-19-2010 at 05:11 PM. Reason: left something out
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  #50 (permalink)  
Old 08-19-2010, 05:18 PM
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What heads are going on your world beater 302 (heretofore know as the WB302)?

And for the record- nobody builds a 400 SBC w/the 5.565" rods anymore. Like maybe 1/2%?
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  #51 (permalink)  
Old 08-19-2010, 05:38 PM
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Stock heads with the single hump, until I can get some decent vortec heads. What do you guys think of that? Vortecs are good right? And a high rise dual plenum edelbrock manifold?

Oh ya I forgot most people use 5.7 rods on the 400 sry. That brings the rod ratio up to 1.52:1 from 1.46:1, but thats not a big difference there man... I might stick with the short rods and and rv cam and just make a super low rpm motor out of it if I was kinda stuck with a 400 sbc that I spent money on. Longer pistons would at least sorta compensate for all that cylinder wall loading and maybe make less heat, and even more vacuum at low rpms making use of that low end power. The 400 sbc was not really designed by gm as a high performance engine btw... Be fun in a jeep I would think, putting around in 4wd alot. How low can one idle anyways? 200 rpm?
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  #52 (permalink)  
Old 08-19-2010, 05:50 PM
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We'll leave all the short piston/long piston and piston acceleration stressing things, etc. out of it for now- it would quickly get too off topic for me.

Now, if you'd have said you wanted to try a LT1-based 302, you'd have at least a fighting chance at redemption. Problem again, is it just doesn't work in the real world the way guys suppose it will on paper.

From HERE:
Quote:
An L99 crank in an LT1 block using the L99 rods and LT1 poistons will give you a super budget chevy 302 that lacks torque and the stock pcm rev limiter will stop you from spinning it high enough to ever make up for it in HP.

I sent a guy my old L99 rotating assembly and he tried it, even tried it as a milage motor in a Caprice and the lack of torque meant a lot of hunting and unlocking so it didn't even work for that. Was a cool application of backyard engineering though, as the L99 rods being longer(5.940) perfectly offset the shorter stroke allowing use of stock LT1 pistons.

One of the magazines did a LT4 heads on L99 build, again nothing but a novelty.
Be aware this guy isn't the only one who's been disappointed in the actual outcome from this one-off deal.

The only ways I can envision you having the proverbial snowball's chance in hell of making do w/a small, high winding engine in the 7-ton behemoth is possibly by using a Gen III 4.8L Vortec 4800 (293 cid)

OR if you'd have said a BBC-based engine built on a 454 or 502 Gen 6 foundation, using a 3" stroke and 7.4L heads. This would give a displacement of 340 or 382 ci respectively, and could at least get the truck down the road.
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  #53 (permalink)  
Old 08-19-2010, 06:10 PM
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Quote:
Originally Posted by cobalt327
I personally thought the Isky article debunked the theory rather than bolster it. It didn't go into much depth- but I guess it's all in what you want to read into it.

The biggest "pro" for long rods comes from Smokey. He liked 'em- and that's good enough for me to at least give it some consideration. But the engines I build would not benefit enough from a "long" rod to make it worthwhile to use anything longer than 6".

BTW, some guys, (Jere Stahl among them) don't consider an engine to have a "long" rod until 1.81 to 2.0 rod/stroke ratio. That's a 6.3" rod in a 3.48 stroke engine.

FWIW, a VW Type 1 boxer 4-cyl. can be as high as 1.99! That's the equivalent of a 6.93" rod in a 350. A 283 SBC is 1.9, a 267/305/350 SBC is 1.64, a 400 SBC is 1.48. The BBC 454 is 1.53.
Not to get in another short vs. long argument, but.......
1. I totally agree with cobalt on the Isky deal
2. Theory was , I feel, more than proven by Smokey,at Indy ,circa late n mid 60's stock block,pushrod chevy engines producing more than 900 H.P. all out of less than 210c.i.d.
So how many people that contradict Smokey's long rod theory, I wonder,have acomplished 1/10th of what he has.
Cant argue with sucess!
The only reason,I feel, manufacturers dont use higher rod ratios is. The engine has to fit under hood!
But this is kinda gettin away from the subject,which I think is already a dead dog!
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  #54 (permalink)  
Old 08-19-2010, 06:28 PM
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Yes I first wanted to build a big block chevy, as there are some 427 tall deck blocks for sale for couple hundred bucks. I was reading how people used the 348 w motor crank with bearing spacers, but I havn't had any luck finding any spacers like that, short of making my own with 60 over bb bearings then line boreing them to the cradle size of the w big block. I dont know for sure if that would even be small enough though and seemed so much trouble and expense that I decided to build a small block. A 427 tall deck motor would be better all around though I agree. I am limited on funds however.

On the topic of the new version of the 302, the cost is higher, the parts harder to get, the cranks are not forged like the 283, and I do not see the point of why I would want to do that really... I already have all the stuff to do this motor, all for less than 220 bucks I got 4 motors, one complete 283 that runs good, one 327 small journal block with crank, oil pan, oil pump, rods, and pistons, one rebuildable 283 with no heads or manifold but otherwise complete, a worn out 307 complete, 2different size pressure plates, flywheels, clutches, and a set of decent long tube headers with no dents. How do you beat that? Can I not retrofit reverse flow cooling on an gen 1 sbc? I wanted to try this motor in my van, its absurdly easy to swap motors in a step van, so no biggie if it doesnt work well for the application. I can stick it in the s10... I also have a 1965 ford van with 3 on the tree, no rust southern cali model I used to drive thats been sitting in a garage for 10 years... I saw a adapter to mount a chevy motor to a ford tranny on ebay, not cheap tho, like 300 dollars but it might be cool to have a scooby doo mobile that was fast and mean sounding. Its a motor that I want to build no matter what tho. Maybe I will put two saab turbos on it like that one guy on here... Maybe Ill just put it on a run stand and post 1001 ebay vids of me revving it up to the moon who cares.... lol geez
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  #55 (permalink)  
Old 08-19-2010, 06:36 PM
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Thank you topwrench, you posted while I was still typing. I think maybe you are the only one who hasn't told me not to build it, I do not want a 383 or whatever, I have made that perfectly clear from the get go, but thats all anybody has to contribute it seems. ~sniff~ Ok just kidding I dont really care, I like a good debate. I already have a great running 350 in my old suburban rust bucket I could pull out if I wanted to, and I might. I just wanted to talk about this motor that I want to build... Maybe get some advice on cams and stuff.. Unfortunatly it never got that far.... bummer
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  #56 (permalink)  
Old 08-19-2010, 07:52 PM
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For a good read try this:

NHRA Tech Specs

you can see all of the bore/stroke/rod length ratios use by everyone,
THERE IS NO MAGIC BULLET

if you want to check 'long rod' combos, see Pontiac, Olds, Buick, Chrysler, nothing stands out as ultra high-performance OR ultra high mileage motors. All of the long rod motors carry the BB dead weight penalty, so much for mileage.

Have fun with your build, post the results
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  #57 (permalink)  
Old 08-19-2010, 08:07 PM
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Quote:
Originally Posted by topwrench
Not to get in another short vs. long argument, but.......
1. I totally agree with cobalt on the Isky deal
2. Theory was , I feel, more than proven by Smokey,at Indy ,circa late n mid 60's stock block,pushrod chevy engines producing more than 900 H.P. all out of less than 210c.i.d.
So how many people that contradict Smokey's long rod theory, I wonder,have acomplished 1/10th of what he has.
Cant argue with sucess!
The only reason,I feel, manufacturers dont use higher rod ratios is. The engine has to fit under hood!
But this is kinda gettin away from the subject,which I think is already a dead dog!
That's just it, Smokey's long rod always better theory is 40 years out of date, modern information has blurred the lines on his hard and fast rules from those days quite a bit.

That 209ci 900 hp small block was under a great deal of turbocharger boost pressure, and on methanol, to reach those numbers. Would have been lucky to make 350hp naturally aspirated.

Current Pro Stock engines are using shorter deck blocks and shorter rods than even come in a stock 454, you don't see them all worried about rod length. Go and look at what Reher & Morrison has found out about rod length theory, it's on their web site.

Still looking for someone to post data for long rod superiority that can be proven to be just based off of rod length.

I'll agree, put the longest rod in you can for most of us and our performance or race engines at levels less than ProStock or Indy cars, the benefits of thrust loading and light pistons is there, but just throwing long rods into something is no "magic bullet" that us suddenly going to add 10 hp or 5 mpg.
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  #58 (permalink)  
Old 08-19-2010, 09:02 PM
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I do not think it is magic, I think it is just plain geometry. Isn't more horsepower per cubic inch one good indication of efficiency?
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  #59 (permalink)  
Old 08-19-2010, 09:24 PM
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Originally Posted by Dirty Biker
I do not think it is magic, I think it is just plain geometry. Isn't more horsepower per cubic inch one good indication of efficiency?
NO! There are many factors you left out. There are really powerful really inefficient engines. There are also really efficient engines that have low peak power.
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Old 08-19-2010, 09:44 PM
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Quote:
Originally Posted by turbolover
NO! There are many factors you left out. There are really powerful really inefficient engines. There are also really efficient engines that have low peak power.

Then in your opinion Turbolover, In stock form which would the 400 small block be and which would the 283 be?

Last edited by Dirty Biker; 08-19-2010 at 09:53 PM.
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