lower crank bearings

If the lower crank bearings are no good, then the uppers are also no good, and you won't solve anything by changing the bottom ones and not the top ones. Rod bearings could be changed with the engine in the car, but what you can't do is any kind of machine work on the crank, and if the bearing is wiped, the crank will also need some attention, so new bearings will be a temporary fix at best.
 
The car runs just fine their is a very slight almost knock sound prob between 1300-1600 rpm. So i dont think their that bad heads were done last winter so i wanted to change them before it gets bad and if i could do it without pullin the heads off again or removing the motor.
 
If it is a rod knock, then you should at least check the crank and the rod journal to make sure they are still round and in spec. If one or both are out of round, and you just throw new bearings in, you will likely make the problem worse. If you want to drop the subframe and oil pan to just check the bearings to see if that really is your problem, that would be fine, but if any of the bearings are damaged, you will just be making double work for yourself by not pulling the motor out and rebuilding it properly the first time.
 
So if i pull the motor out can i put new bearings in have the crank checked hone and new ring it without pulling the top end apart. The heads were done last winter so they are fine have about 1,000mi on it. They are mls gaskets arp studs and the heads were shaved and all cleaned and straightend. Just trying to get around pullin them off. The gasket cost over 200. Let me know if it can be done.
 
K member do u mean subframe or a part in the bottom end. Or is this after motor is pulled. And can i hone cylinders from bottom or motor.
 
If you pull the motor, you can take the pan off, remove the crank to check it, and you can check all the rod ends, and if everything is good you can install new bearings and get it all back together. What you won't be able to do without pulling the heads is remove the pistons, which means you won't be able to rehone it and replace the rings. You technically could get the pistons out with the crank out of the way, but you'll never get them back in from the bottom.
 
Ok cool thanks. I just wasnt sure if they would come out of the bottom. So if compression is all good than dont worry about hone. Do u recommend oem bearings or is a aftermarket that works better
 
Ok last question will the pistons go down far enough so i can replace the upper rod bearings. Or will i have to remove heads to do the uppers.
 
Ok cool thanks. I just wasnt sure if they would come out of the bottom. So if compression is all good than dont worry about hone. Do u recommend oem bearings or is a aftermarket that works better

Wasn't sure what would come out the bottom? Make sure you get someone that has done this type of thing before to help you. It sounds like you may not be completely familiar with what you propose to be doing.
 
Yea i want to replace the pistion pin to but then i think ill have to pull the heads offthen. Want to do it right. Im gonna try and do it frim the bottom if not heads wil be ciming bacj off
 
Replacing the piston pin, the pistons, or the rings will require removing the heads. As I said, the pistons can come out from the bottom, but they will never go back in with the rings on due to the bottom of the bore not being flush, and therefore no way to compress the rings to reinstall them. Just out of curiousity, how many miles are on this engine, and what are your plans with it? I fully understand the cost of the MLS gaskets making you not want to pull the heads off. I actually had assembled a motor with MLS gaskets, then it sat for a few years uncovered in my garage and got a bunch of dust and crap inside, so I built another bottom end, but I wanted to use the ported heads off the motor I assembled, so when I built this motor, I ended up just getting regular fel-pro gaskets, and throwing away a $200 set of MLS gaskets that had been bolted down once and never fired. It was a hard pill to swallow, but in the end I decided that for my application, I didn't really need the MLS gaskets, and I would rather have new regular ones with the ARP head studs than risk re-using the MLS gaskets and possibly having to re-do the job.
 
Generally a bad rod or crank bearing will make noise all the time not at a certain rpm range. You would be best to have some one help you by holding the car at that rpm and trying to locate the source of the noise with a stethoscope. it could be caused by a number of different things. A sticky lifter won't make noise at idle and might pump up completely at a higher rpm. Pre detonation will also make an engine knock. Some of the problems your considering I feel would be audible at any rpm. These are just a few things off the top of my head but you may want to trouble shoot this problem further.
 
Some good and bad info in this thread.

1 - You can't remove the pistons out the bottom. It's not even possible.
2 - You can replace all the rod and main bearings without removing the crankshaft. Care must be taken to avoid damaging the rod journals, but it is absolutely possible to do this.
3 - I have not personally removed the crankshaft without removing rods/pistons first so don't assume this will be easy. You'll have to move all the pistons up to the top of the bores one at a time rotating the crankshaft as you go and hope that one bolt doesn't end up preventing you from removing the crank. Not even worth the risk. Just replace the bearings. If you need to go beyond this then a complete rebuild is in order.
4 - If the motor is knocking - and yes a knock from 1600-3000rpm heard mostly at no load or deceleration is a dead giveaway for a rod bearing problem. If this is indeed the case then a complete tear down is required anyway. A knocking rod (it's actually the sound of the piston hitting the head that you are hearing) will deform the connecting rod which means it will have to be replaced or reconditioned. Either action will require complete disassembly.
5 - Rod bearings do sound like the sound you are hearing, but it could also be a pin sticking depending on what it sounds like and under what conditions it is most prevalent. A sticking pin generally means new pistons and pins. You don't normally press a piston off and then back on without replacing it. But it has been done at times.
6 - Honing the cylinders and installing new rings is generally too little too late. On most SC engines by the time you have 100K+ on it the cylinder wall taper is over .005" and in some cases over .010" which means that if you hone it and install new rings you'll have piston rattle which will lead ultimately to cracked and broken skirts. Again, if you get this far then new pistons should be on the menu.
7 - Pre-detonation isn't even a term. Pre-ignition refers to the phenomenon where combustion begins before the spark is generated. This is only ever caused by a severe component failure and always results in severe engine damage. SC's don't suffer from pre-ignition. Detonation on the other hand is caused by excess heat and combustion pressure and it happens after the spark event, Detonation is common on SC engines, but only under boost. The SC engine is such low compression and runs on premium fuel that it isn't even possible to have detonation without also being under boost. You won't hear detonation or pre-ignition when the engine is not under load.
 
Yea the little noise i hear goes away completly after she warms up never does it at idel or over about 1700rpm. But i was thinkin of pulling it myself tearing it down keeping everything marked and in order and order new bearings gaskets clean it up and have a guy who builds racing engines in my town check the crank and put the short block back togeather. I can handel pytting the heads and accesorys back on and motor in. Dave u suggested new pistions i was going to go to advance auto and order that stuff any objections. Its supposed to meet or exceed oem. Not trying to spend thousands. I do plann on putting my late model ported blower and the nessacary add ons to make it work. I have arp head studs on so can i run the cheap felpro gaskets or when i add more power later will it pop thes cheap felpros. Will a miled cam give me any extra juice with only a 10% pully on. I just want to do it right so please point out the good and bad ideas.
 
Yea the little noise i hear goes away completly after she warms up never does it at idel or over about 1700rpm. But i was thinkin of pulling it myself tearing it down keeping everything marked and in order and order new bearings gaskets clean it up and have a guy who builds racing engines in my town check the crank and put the short block back togeather. I can handel pytting the heads and accesorys back on and motor in. Dave u suggested new pistions i was going to go to advance auto and order that stuff any objections. Its supposed to meet or exceed oem. Not trying to spend thousands. I do plann on putting my late model ported blower and the nessacary add ons to make it work. I have arp head studs on so can i run the cheap felpro gaskets or when i add more power later will it pop thes cheap felpros. Will a miled cam give me any extra juice with only a 10% pully on. I just want to do it right so please point out the good and bad ideas.

Don't put the cheap gaskets on, that's just silly. If you are going to replace the pistons, then do a proper rebuild. You can use replacement type pistons but they aren't better than stock at all. If you want something a bit better than stock then I can get you direct fit forged pistons and some 94/5 rods to go with them. Even replacement pistons I can save you money over a parts store. Email me about a complete kit.

A mild cam will help as will bigger valves, but that may be more than you plan to spend at the moment, however it would be much better to do it now than to go back in and redo it again later so you'll have to work that one out. If you do just a cam and not bigger valves then you will be limited with what you will gain.

The noise you describe does not sound like rod bearings. Any bearing noise is going to get louder when the engine is warm. This sounds like the other noise I mentioned which is a sticking wrist pin. As long as you are easy on it when it is cold and making that noise, it will continue to run a long time so no need to rush into it. Might get an oil pressure gauge and see what your hot oil pressure is also before doing anything.
 
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