bearings

[hungryjoseph]

do I need to get align honing done to the block for new bearings? also, should I be getting machine work done to the rods? or can I just drop the bearings in without machine work if I've never spun a bearing?

[CSUPUEBLOTIM]

I would recommend checking the specs on everything to see if you should hone the cyclinder walls or if you need to machine the crank for undersize bearings. It would suck to throw new bearings in and spin a rod bearing a week later and have to take it all back apart. Also whats your reasoning for wanting to replace the bearings?

[hungryjoseph]

my block is apart and I'm about to bore and hone the cylinders. I am very new at rebuilding blocks, this is my first time. my reasoning is that since its all apart, I should replace the bearings that I have driven over 40k miles on, half of it at redline. the motor has been over heated a couple times and its been run on low oil a couple times, but its never knocked.

so, being that it never knocked and the bearing was working fine before the motor was pulled out of the car, should I even worry about replacing them? since its all lubricated by oil, they should never really make contact with any moving parts so there shouldn't be any real wear on a bearing. correct me if i'm wrong.

[CSUPUEBLOTIM]

Does the crank have any scarring or signs of excessive wear?

[hungryjoseph]

I actually haven't really pulled the bottem end apart yet, when I said it was apart I meant to say it's out of the car with the head taken off

[duffman1278]

If you never had a problem with it, I'm pretty sure you'll be able to get away with having the walls honed. As for the bearings. Its not too hard to take apart the block and put in new bearings. It also wouldn't hurt it. I mean, you COULD reuse the old ones since their apparently good.

If you're in doubt, get some plastigauge and double check it.

Are you boring out the walls for bigger pistons? Because if you're just going to keep the oem setup then theres no need to bore unless the walls warped.

Hell since you're in there I would suggest replacing the piston rings if you do take them out. But the job is tedious. I got frustrated after 4 pistons lol I can't even imagine how people do it on V12's lol.

But if you get OEM rings their usually already cut to spec on the ring gaps which is AWSOME. But I triple checked mine.

[hungryjoseph]

I am not sure if I want to get rods or not. so to replace the bearings, I shouldn't have to get any machine work done, correct? I've seen people do them and alot of the times they dont get it machined, but I also see people say otherwise.

if I did get eagle rods, would I just get bearings sized for the rods? what else is a part of that process? and I am getting forged pistons with a .5mm overbore so I would be replacing the rings, compression came out to be 140 142 60 145 and oil jumped them up to 150+ so the rings are worn

[duffman1278]

Since you're getting forged pistons you'll need the rods for them as well.

You shouldn't need to do anything with the crank, and you should just be able to drop in the new bearings. You could always check it with a dial if anything just to be sure but I highly doubt, from how you put it, that you'll need any machining on the crank.

[hungryjoseph]

thanks for the input duffman, but I don't understand what you mean by needing to get aftermarket rods with forged pistons, shouldn't the forged pistons work with the oem rods?

[duffman1278]

Nope they don't. Thats because of the wrist pin and how its held. When I was rebuilding my Honda motor I was thinking the same thing but I talked to a few shops and searched around and apparently you can't use the same rods.

[hungryjoseph]

that's strange, I saw a diy thread for rebuilding on here and the guy used his stock rods with his (i think..) weisco pistons. maybe its the type of piston you get?

[duffman1278]

I'm not 100% sure as I was working with a honda motor. It might be different, but that's what one shop told me and the guys there are legit.

Just look into it a bit I'm pretty sure you'll get your definitive answer

[CSUPUEBLOTIM]

thats because most of the aftermarket honda pistons you buy have a floating wrist pin rather than a pressed. the stock sr rods should work with your aftermarket pistons.

[idahotuner]

if you changes rods and pistions you need to have the whole rating mass blanced again.

that means flywheel, pistons, rods, and dampener

[hungryjoseph]

if you changes rods and pistions you need to have the whole rating mass blanced again.

that means flywheel, pistons, rods, and dampener

will they really throw it off balance by that much?

[idahotuner]

its a safe route to go.

[hungryjoseph]

what exactly constitutes a safe route though? I'm not doubting your experience, it's just that I see alot of people talk about safe routes without alot of backing behind it. I can understand bearing wear happening from unbalanced rotation, but how bad is this wear? the damage you see on motors that have 200k+ miles on them are almost always worn piston rings, I have rarely heard about a bearing going bad because of high mileage. and is the rotating assembly really unbalenced when pistons and rods are advertised to be balanced by the gram? which means it would add 2 grams of difference? can someone explain this to me, on why its a safe route that is worth the cost? I don't like to go do things without understanding what I'm doing. I like to go deeper than the, "because everyone else does it"

[idahotuner]

but not being balanced and being balanced rotating or balanced statically. rotating is the best.

if the balance is off. it will generate a wobble. which as at speeds can do all sorts of stuff. from accelerated wear.. from the vibrations. take somthing that is of balance and try to get it to spin and stay spining. now take something balanced and do the same test. it takes less momentum and and less power to spin it.

the main thing is the wobble or vibration you get from the weight of the pistons and rods being off from the counter weight on the crank. which can cause sped up wear because it is putting more pressure on certain parts. with a 4 cylinder engine that wobble is magnified because there is a power stroke less often compared to say a v8. so a the piston being off balance. and the firing not happening as smoothly. can cause the to wobble more which means clearances are not equal all the way around that can lead to spun bearings and other failures. generally making the engine to not last as long.

it can also be a noticeable vibration when driving.