Your "someone" knows little about engines.

Have your pistons/pins checked by a reputable shop. A very simple procedure.
Usually if the pins are worn, the pin bores in the piston are shot.

Back in the day. We used to buy .002" oversize pins and fit the assembly. Now however, the labor cost alone would almost exceed the cost of new stock pistons. If you could even find the oversize pins. I tried a couple of years ago and the only reasonably priced, over size stock pins, were from Badger. They only had a couple of sets and no plans to re-stock.

 

agree with Bob. If the pins need replacing,the pistons probably need replacing too.
If you are "rebuilding" then all measurements will be checked and all parts replaced as required.

 

The term "rebuilding" to me means all wearing surfaces and parts are renewed or replaced. That being the case the culinders would be rebored and finish honed to restore the wearing surface and the pistons would be repalced to match the overbore dimension. That would include new pins which are typically part of the piston package, and new rings that fit the overbore dimension, usually not included with the piston but are a seperate purchase item.

The 400 is hard on pistons and sylinder bores, not to replace pistons and resurface the cylinder walls of these engines is a waste of time and money as this is where the major wear problems occur. Ridge reaming and rehoneing the original bore then installing new rings on the old pistons simply does not due on this engine in particular and modern engines in general. The 400 is hard on bores and pistons because of the very short connecting rod and the odd cooling that results from the siamised cylinder walls. These conspire to effect an out of round and tapered bore that a simple ring replacement operation cannot restore.

Bogie

 

The motor is already .30 over and has5.7 rods. I was just trying to do a cheap rebuild to get it on the road again then do it all the right way soon when the money is there. It will only have to last a couple months before I redo it the right way. I was just wondering if the new rings would make it knock I hadn't herd of this til now. The motor wasn't knocking when disassembled that's why I wanted to ask someone's opinion if it would or not.

 

take it apart,take all measurements,see what it needs?
to freshen an engine it might need nothing more than bearings and a timing chain? take it apart,maybe some of the stuff is total junk?
for next build you will have time to plan it right,shop for parts,decide the end result wanted,,,

 

I got it apart now. Someone had told me they just had rebuilt it the right way not long before I got it. But had been ran hard sense then. I was just going to throw new bearings in it rings bigger cam and different heads. Until someone told me it might knock with the new rings this got me worried sense I hadn't planned to machine everything or spend alot doing it right this time, was just doing it to freshen it up and drivable then save up over a couple months and redo the hole thing right...

 

"MEASURE" all the engine pieces.Dont guess. If all is well put in w/e it "needs". Measure your deck height "exactly", measure the piston to wall clearance,"exactly",measure cylinder taper "exactly",measure bearing serfaces "exactly",,,post results,,,,biggest concern is block/piston to wall clearance,let us know what type of pistons are in the engine? Is the engine balanced? is the engine and external or internal type balance? what rods are in the engine? how did the rod bearings look(post a picture) why did you take it apart? what do you want from this engine? what intake are you using? what carb? what size headers are you using? where does this engine live?,,,,

 

I don't have away of posting pictures right now. The motor is a 2 bolt main 400. I pulled it apart because it had sat for a couple years and a couple lifters were ticking and just decided to freshen it up a bit. The motor just ticked a little didn't knock had amazing throttle response and about 45 pounds of oil pressure idling and well over 60 when reved. Not sure what size cam it had. It had stock 882 heads on it 202 valves. .30 over flat top pistons with stock 5.7 rods. I think the pistons are forged. It had a double roller timing chain a edelbrock performer intake and a 750 carb. It ran good on pump gas and had some torque. The truck has dual exhaust 2.5 pipes long tube headers. Not sure of the gears. The crank was still good it was turned 10/10 the bearings had copper showing but crank had no grooves rubbed my finger nail across all journals nothing caught it. I just want to freshen it up alittle bit without having to spin a tone maching everything and have a nice little street motor for a couple months til I save money to redo it right. I was going to just go through it put new bearings rings and gaskets in it I have a lunati can laying around that's 288/298 and lifts 540/560 I was gonna throw that in it use the same intake and carb with 1 inch spacer and hadnt decided on the heads yet thought about just gasket matching for now but didn't want to smother it with those heads. It's goin it a 85 c10 backed by a turbo 350 trans believe it has a 2500 stall..

 

"measure" the parts!
buy/borrow/rent proper measuring tools.

 

Better measure that crank. Sounds like journal wear if bearings are that bad.
Double check clearances with that cam/head combination. Spring stack, retainer to guide etc. It is a waste to use a cam larger than about .500" lift on 882 heads. They won't flow enuff to support the cam..

I had a customer bring in an aftermkt crank last week. Said he wanted it polished. Journals looked good to him...............It took a grind of .020" on the rods to make them round!!

These are the same type guys that swear you changed parts on them..