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6.0" con rods. . .will they work

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BowtieRed

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6.0\" con rods. . .will they work

i want to up my compression on my project motor. it's a gm goodwrench 350, can i simply use 6.0" rods to get the compression i want or will that cause valves clearance issues?
 
Re: 6.0\" con rods. . .will they work

To do it right, order new pistons for desired compression with what ever cc heads you are useing.
 
Re: 6.0\" con rods. . .will they work

6.0 - 5.7 = 0.3
if your piston is 0.3 in the hole at TDC then you could do it.
if your piston is 0.3 in the hole at TDC you have some problems.
 
Re: 6.0\" con rods. . .will they work

except i don't want to bore the motor any if possible, maybe i'll have to, idk. so does anybody know for a fact that they will or will not work?
 
Re: 6.0\" con rods. . .will they work

what all would i need for a roller camshaft? just the retrofit lifters?
 
Re: 6.0\" con rods. . .will they work

I'll tell you everything you need to know if you sell me your tires /forums/images/graemlins/thinking.gif
 
Re: 6.0\" con rods. . .will they work

how about the whole truck no engine for $1000 /forums/images/graemlins/grin.gif
 
Re: 6.0\" con rods. . .will they work

Increasing rod length has nothing to do with compression ratio. The only way to increase CR is by decreasing the combustion chamber volume or by increasing the stroke.

If you changed nothing else on your engine, but added 6.0" rods, the motor would not turn over. You would be pushing the piston out past the deck of the block by 0.3" like mj refered to. When a 6.0" rod is used, it requires a new set of pistons with a reduced compression height. In other words, the distance from the top of the pistion to the centerline of the wrist pin is decreased by 0.3" to account for the rod that is 0.3" longer.

If you want to increase compression, get pistions with less dish, change the heads for a set with a smaller chamber volume or both. /forums/images/graemlins/waytogo.gif
 
Re: 6.0\" con rods. . .will they work

[ QUOTE ]
except i don't want to bore the motor any if possible, maybe i'll have to, idk. so does anybody know for a fact that they will or will not work?

[/ QUOTE ]Why would you need too bore ??? I'm talking going from a dish piston to a flat top or even dome type piston. Depending on what cc your heads are, would determen what piston you would need for what compression you want. Boreing the cly is not needed unless the engine has alot of miles and you're getting blow by.
 
Re: 6.0\" con rods. . .will they work

i can't find any 4.000" bore 10:1 pistons, there's the problem. they are all 4.030" that i can find.
 
Re: 6.0\" con rods. . .will they work

Where are you looking ??? If all else fails, call Jeg's 1-800-345-4545. They have alot more then whats listed on thier website and in thier catalog.
 
Re: 6.0\" con rods. . .will they work

[ QUOTE ]
If you want to increase compression, get pistions with less dish, change the heads for a set with a smaller chamber volume or both. /forums/images/graemlins/waytogo.gif

[/ QUOTE ]

Or deck the block, which is cheaper than both of those and goes a long way to helping your quench distance.
 
Re: 6.0\" con rods. . .will they work

[ QUOTE ]
[ QUOTE ]
If you want to increase compression, get pistions with less dish, change the heads for a set with a smaller chamber volume or both. /forums/images/graemlins/waytogo.gif

[/ QUOTE ]

Or deck the block, which is cheaper than both of those and goes a long way to helping your quench distance.

[/ QUOTE ]

Uh-huh....
[ QUOTE ]
The only way to increase CR is by decreasing the combustion chamber volume or by increasing the stroke.


[/ QUOTE ]

You can only deck the block so far before the quench distance is too tight. Depending on the tolerances in his current motor, he may not be able to deck the block much at all.

What is the quench distance on your motor Tim? /forums/images/graemlins/thinking.gif
 
Re: 6.0\" con rods. . .will they work

or have the heads machined, it'll probably cost the same, have the same result, but wil be easier cause you only need to have 2 40lbs heads instead of one 200lbs block. you would need to take more material off the heads than the block to get the same result.

you can only go so far with the block. you can not go past the pistons, because then the piston would hit the head and it'll do some damage. but the heads you can go alot farther.
 
Re: 6.0\" con rods. . .will they work

[ QUOTE ]
i can't find any 4.000" bore 10:1 pistons, there's the problem. they are all 4.030" that i can find.

[/ QUOTE ]

Everyone makes them.

Speed-pro (Federal Mogul) makes some decent hypoeutectic flat tops with 6.1cc reliefs for about $120. So far, that's all I've run in all my motors.

EDIT: they make them in different piston pin heights... sometimes you have to cross over into Keith Black pistons though... same crap, different name.
 
Re: 6.0\" con rods. . .will they work

Please get a book that describes basic engine theory and performance modifications. A bad machine shop might take advantage of you. I would hate to see you spend a lot of money on something that plain does not work, or throws a rod through the pan on the break in.

Going to a roller cam is not that simple. Is that Goodwrench motor a roller block already?

What kind of compression are you looking for? What is the compression now? What fuel do you want to run, and what is the objective of this motor, street/some play, or all play all out?

What I am getting at, if you are looking for a 1/2 point increase, you are not going to really notice the difference vs. the cost/hassle involved....
 
Re: 6.0\" con rods. . .will they work

not much to gain in a roller lifter for the $$$
 
Re: 6.0\" con rods. . .will they work

going roller, i know the deal with it now, roller cam, and retro fit roller lifts, lotta money, but TONS of gain, atleast according to desktop dyno. i'm lookin at 10:1 compression and run 93 octane and octane booster. i want to go full roller, this will be a street/strip/mud motor. so high rpm. i built the engine i want on desktop dyno, now it's a matter of $$, i got 466hp and 449ft lbs.
 
Re: 6.0\" con rods. . .will they work

[ QUOTE ]
You can only deck the block so far before the quench distance is too tight. Depending on the tolerances in his current motor, he may not be able to deck the block much at all.

What is the quench distance on your motor Tim? /forums/images/graemlins/thinking.gif

[/ QUOTE ]

Not true, a Chevy can be decked to zero and running regular Fel-Pro perma torque gaskets gives you .042", which is right in the ideal of .039-.045.

As to what my quench distance is, I believe in the .065" range as the engine has composite gaskets and AFIAK not been decked although it has been rebuilt. I blew up the engine I built for this rig and haven't had the funds to build another yet, but when I do, it will be a 383 with 5.7 rods, balanced, decked to zero, with the fel pro perma-torques and aftermarket heads.

If ya decked to zero and tried running steel shims I'd say that's a no go, but decking to zero or +.002 or so and running composites and your choice of piston/chamber volume is the way to go IMO.
 
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