alright.. here's my problem. i was in the process of rebuilind a 305 HO engine when i changed my mind and decided to go with a 350. i was in a hurrying with tearing apart the 305 and did not mark the connecting rods. is there any mark on them to tell me which cylinder they went to. and if i get all new connecting rods. should i just get my old crank miced or go with a new crank?? thanks for the help.. peace.. and Much camaro luv

 

Welcome to TGO.

Connecting rods aren't as critical about putting in the same spots if you're going to be changing pistons and bearings, and having the crank ground down anyway. About the only thing you have to try and keep the same is the cap on the same con. rod. Even that doesn't matter either if they're going to be re-sized.

The MAIN CAPS are the ones you have to worry about. They are matched to the block. If you're gonna have the block alighn honed, then it may not be much of a worry. Although I ALWAYS make sure they're put back in the same spot. Maybe just piece of mind for me.


AJ

 

for one. i love your sig. gotta love the people that try to make **** burners "cool" though.. i mean you always gotta have someone to laugh at yanno.. .. anyhow.. what you said contradicts what i've been told. the block im buying has been completely re-done. it's been grinded down honed acid bathed everything. im buying it bare. the crank im using is out of an 82 305 HO. it's getting miced. i was told that if i dont put the rods back in the same cylinder it will screw something up because the way the crank wear's on the inside of the connecting rod. but your saying that if i get the crank miced that i wont have to worry about the connecting rods that they should be fine.. correct?

 

If you get the crank miced, then that should eliminate all wear marks/grooves that were left by the original rods attached to them. Also when you get the rods shot peened then that will refurbish and strengthen them also. It's like wiping the slate clean. No former grooves, nothing. You don't need to put the rods back in the same cylinder. A thing you might check out, or maybe you allready know and I don't, is whether you can use the 305 rods in a 350. Are they the same length? I do know you just don't need to put the same rods back in the same cylinder. So what are you going to put on the 350?

 

yeah.. the rod lengths for both are 5.7 inches... basicaly right now im just doing a mild rebuild. puting used parts from the 305 into the 350. new valves, pistons, seals, rings, bearings. the best will be yet to come. see. im graduating soon and most likely will be either heading to the air force or to college. so during that time i'll be putting money back to go ALL performance stuff. thanks again for the help.

 

one problem im thinking of. would shot peening the connecting rods make them bigger. so they would be looser around the crank? i was thinking since it would be makeing the surface flat like brand new it would have to take some of the metal out making the inside a bit bigger. thus creating a problem. but let me know. thanks again.

Keith Nepsa

 

All that shot peening does is to bombard the rod with little lead pellets, which vibrates it extremely, which forces the crystalline structure to relax and settle back into the shape it's designed into, rather than the slightly warped shape it assumed as it cooled after forging. It doesn't change the dimensions.

There is no such thing as a 82 305 HO. So you don't have one. If you have a 305 4-barrel, it's the LG4, 145 HP, low-performance. Even if there was such a thing as a 82 305 HO, it wouldn't matter as far as the crank; they're all the same casting (442), whether they came out of the LG4 std 4-barrel, or the HO motor that was introduced in 83, or whatever. But that doesn't mean they're the same piece.

305 rods are the same length and bearing diameter and stuff like that as a 350 rod. However, what your 82 has is regular 305 rods, which are much thinner along the beam than 350 rods, unless they're X rods from a 83 up actual HO 305. The crank casting for a 305 and 350 are the same, but the counterweights are machined differently because the rods are so different in weight. You can make a 350 crank into a 305 crank by taking metal off, but not the other way around. So, you can't put 305 rods in a 350, unless you use the 305 crank, otherwise it won't ever balance. (Unless of course you have a HO motor, with X rods which are 350 weight, and the crank tha tgoes with them, which is a 350 balance crank, since the rods are 350 weight).

Part of any decent engine machine shop rebuild procedure is to recondition the rods. I think that's what you have confused with shot-peening. That consists of removing the bolts, cutting a small amount of metal off the cap, and boring the now non-round big end back out to a perfect circle of the correct diameter. This shortens the rods a few .001"s, which is not a big deal in most cases, it just adds that little bit to the deck clearance (how far down in the bore the pistons are at TDC.) Any time you remove the bolts, the rods must be reconditioned, because the metal will change shape around them, which makes them out of round.

"Mic" ing a crank consists of measuring it with a micrometer. That doesn't change its size or clean up any wear. To do any of that requires grinding it. Again, part of any standard package of machine work while doing a rebuild.

I would not recommend going to all the trouble and expense of a rebuild, and failing to spend the extra $50 or so to put teh right parts into it in the first place. The amount of money you aer saving is trivial in the total cost of this project, and will do nothing but cause you trouble. Get a 350 crank a a set of rods, not just 8 rods, but a set; the best thing to do is to get the crank and rods out of a factory motor that's never been worked on, that way you don't necessarily have to do any balance work other than to make sure all 8 new pistons weigh the same.

 

Wow, so much I don't know. Thanks for the info. I hope it helped you because it sure cleared up some things for me! (And made me feel like an idiot at the same time, but it's all good.)

 

well i am using the 305 crank and 305 push rods so i will be alright correct? and i was tlaking to a guy at the machining place down by me and he told me that is what i was talking about. that when i take it in to get it shot peened he would re-condition it also. .. but doing all that would be fine and i would be able to use any of the rods in any of the cylinders then correct? that was all i was trying to figure out in the first place. how i would go about using any rod in any cylinder since they were not marked when removed. thanks

 

Sure... no problem ...... but they're called "connecting rods" not push rods.

Push rods are the ones that PUSH the rocker arm up.

AJ

 

talking about both of them at the same time.. that other guy said something about the HO model haveing x-rods(push rods) and the standard having lighter ones and if i used a 350 crank and 305 push rods it would bend them.. thats y i was talking about push rods.. thanks alot though..

 

You're confusing me. The "Push Rod" is what goes from your cam to your rocker arms and makes them open and close, with the lope in your cam. The "Connecting Rod" (which is the "X-Rod" he was referring to) is what ties your crank to your piston. (The X-Rod was a heavier connecting rod in the HO 305, which you don't have.) You will NOT reuse your push rods with the new engine, the connecting rods is what you are planning on taking along with your 305 crank. Am I correct or am I totally misunderstanding you?

 

X rods are not push rods, they're connecting rods. They have a "X" forged on them. They were one of the maximum possible rods available in their day. They have been superseded by several other varieties since then. But, they're the sdame ones that came in the hottest of the old 350s; just generally the best factory rod in their day.

 

ok.. you say the HO didnt start til 83. i have a 1982 305. (if i could remember the casting date off of it i would put it in but im at school so i cant get to it easily). with the connecting rods that have an x forged on them. which you say is the x-rod from the 305 HO correct. well this engine is a complete stock engine. nothing was ever done to it. explain that??sorry about being an *** on my comment. im not in the greatest of moods. and of course it has to do with women.