someone told me that now since i have the new pistons and the whole 455 engine is stripped down, it will be out of balance since i didnt buy a new crankshaft along with it? can someone help me out im confused and dont want to mess up this engine, and also how important is the ring gap?
thank you

 

My advise is to do a lot more research before you continue or your bound to run into problems. The classics don't get much attention so we will see how much help others can be.

 

Depends on the pistons you bought. I've rebuilt various brands of V8s, including 455 BBOs, using stock replacement pistons and had no noticeable balance issues. I think I read once that replacment piston manufacturers try to keep the weight close to factory so rebalance isn't a necessity. But once you go with a performance type piston, weights might be off enough to affect balance. But one thing for sure: the guy that told you you had to get a new crank if you R&R pistons is full of it. 455 Olds cranks are plenty strong and can take 500 hp plus, and can be balanced to the pistons used.

If you want to be on the safe side, just have the rotating assembly balanced. Around here it goes for ~ 150 bucks. Just take all the rods, pistons, crank, balancer, flex plate, rod bearing sample set, a sample ring pack to the machine shop and you will have peace of mind.

Ring gap is important to get max performance out of the engine. Too much gap = excess blowby = lost power. Too tight, the ring ends butt, hasta la vista cylinder walls. For a stock type rebuild, use the stock ring gaps. If you plan on using nitrous, you can add gap to prevent butting under load.

A couple of other things on Olds, been a long time since I've done one, but IIRC: the feed passages to the cam bearings are too large, so you can buy restrictors that you drive in the passages to redirect more oil to the mains. This is more for peace of mind, lots of stock engines live fine as is. The oil pump cover is a bit thin, can flex/leak. Aftermarket ones come with a thicker one, but you can also double stack the cover if you have a thin one. Use the cover off the old one on top of the new one to reinforce it + longer bolts. You can shim pumprelief spring .110" with washers to raise oil pressure ~ 20#s, not needed if you're using a high pressure aftermarket pump. This is for higher rpm use.

The stock oil pump drive rod is junk. I've seen them twist up like a licorice stick in stock apps. Use a chromoly aftermarket piece, cheap insurance, I think I used Milodon. The rods squeeze together at high rpm and restrict oil outflow, so in performance engines, I used to grind reliefs in the sides of the rods where the rod pairs met. .010" deep, about 1/2" wide IIRC. Some rods came with a relief hole where the rod meets the cap, so extra relief not needed on these.

If you put main bearing upper halves 2, 3, 4 in the block, you will notice that the oil holes in the bearings don't match the holes in the block. You can drill the oil holes in the bearings to 5/16 to remove the restriction. Deburr afterward.

If you are going to use performance rod bolts, your machinist will have to chamfer the bolt hole so it clears the larger radius under the bolt head or else the stock chamfers will damage the new bolts.

Olds rockers are not adjustable. If you use an aftermarket cam, mill heads, etc, preload will be off. You can shim the stands, or mill off the bottom of them to get the correct preload. Clearance under the stand needs to be ~ .035" at zero preload so pushrod depresses lifter plunger ~ .050" when you torque the stand bolts down.

Stock balancers usually have grooved necks = front seal leaks. You can buy a sleeve at the parts store that presses on to fix it. Tack weld the pickup to the oil pump so it doesn't vibrate off. Or use red Loctite. Make sure it's 1/4" or so off the bottom of the pan.

Add ~ 5 extra ft lbs to the cam bolt torque and use blue Loctite. If not, the damn thing can come loose. There are 2 oil galley plugs next to the cam. One has a squirt hole, install it on passenger side. Stock used a rope rear main seal, but you can buy a neoprene seal to replace it if your gasket kit didn't come with it.

Also I think the head gaskets are like Ford in that there is a large open passage that needs to go at the rear of the block, even if the gasket looks upside down. If you install that large opening to the front (either gasket), the water on that bank will go straight out that opening, not circulate to the rear of the engine = mysterious overheating. Not too sure on this one cause like I said long time since I've done an Olds, but something to keep in mind.

 

Now thats help!

 

wow thanks alot!! and i still have a few questions if you dont mind, where do you buy that rod for the oil pump, would you reccomend perdormance rocker arms, if i slide in the new rings and they dont have the reccomended ring gap what can i use to trim it down, and would you reccomend replacing the camshaft bearings?
thank you

 

Drive rod:

http://store.summitracing.com/egnsea...115+4294840139

If you're in a reasonable size city, your local speed shop might have one. As I said, I've used the Milodon unit b4, no experience with the Melling.

I've never used aftermarket rockers on an Olds as the stock type were fine for the cams I used, biggest had duration in the mid 230s, lift ~ .525" IIRC. Which cam are you going to use?

You use one of these to file end gaps:

http://www.muller.net/sonny/crx/rings/index.html

But you only need that on "file to fit" type rings. If you order stock replacement rings to fit a, e.g., 455 bored .030 over, the rings should have the right stock type gap, that is, within allowable range. I've never seen a stock replacement ring set not be right as long as the overbore is accurate. With the caveat of opening them a bit if you want to use nitrous. The file to fits are for experienced builders that want to have an exact gap for their application.

I always have blocks hot tanked, which means new cam bearings are required. Could you get away with not replacing them... considering all the work that would be required if they fail, why risk it?

I'll recommend what I always do: build the best short block you can afford, even if it means reinstalling stock heads, manifolds, etc. With a solid, reliable foundation, the other stuff can be changed later as funds allow. You skimp on the short block... chances are, you'll be pulling that puppy dog out again...