Alright, so I got 160 miles on a stock rebuild 350 c.i. Lt1 and spun another bearing. Well, it's pretty much tore apart again and just exactly what I expected to find. Gas in the bearings and spun all of them. Yes, all 5 main bearings and all 8 rod bearings. Unfortunatly, I downed a cylinder on the first test drive and like an idiot, figured I'd be safe to drive it back home.. BIG MISTAKE. By the time I had got home, I'd say it was a 50% mix of gas and oil in the pan and silver fake was everywhere. Well, I tried running a couple of oil changes through the motor but wasn't having any luck this week. By the time I shut her down, it was evident, I had definate knock. So now it's time to machine the crank, hone the rods and main caps, clean it all up and slap some new bearings in her. But I wanted to check a few things and decide if I should just go ahead and build a 355 now..

Alright, to the questions:

1 - How much W to P clearance should be good? Using stock hyperteutic pistons.

2 - Where's the proper place to measure the piston? I figured I would measure a couple different places in each cylinder wall to make sure it's not out of round or anything.

3 - How much end ring gap do you reccomend? Will be spraying 100-125 shot, no more but also, no less.

4 - Do you think I should have everything rebalanced again since the crank needs ground on every journal and the rods need honed? I just paid for all the parts to be internally balanced about a month ago and didn't need the added expense of ANOTHER rebuild. Btw, My harmonic balancer, flywheel, and pressure plate was neutrally balanced.

5 - How much clearance for the rod and main bearings is excessive? What's the minium I should run?

6 - What's the typical end play set at the crank? Isn't it somewhere around .003"-.006"? My memory is a little foggy, had enough time learning the proper assembly for the shortblock when I had an old-school engine builder help me last time, there's no way I could of remembered every single clearance. I think back and kick myself for not taking notes.

7 - What's a GOOD piston ring and also beairng set? I used some from a company called Engine Tech that a local reputable machine shop reccommended and had a nightmare getting the rings on right. I don't want to go through that again.

Alright, that's all I can think of for now. If you think I'm forgetting anything here, help me out and mention it.

 

Buying some reference material would be a good idea, IMO.

 

Was this rebuild done by yourself or a machine shop? I just got my shortblock done by a reputable shop here in town and I am going to pick it up tomorrow and have my dad come over and help me with checking all the clearances. If it was me, never trust a machine shop, no matter how reputable they are. You want to make sure you know all of the tolarances of that engine before you build it the rest of the way. That way you dont have to find out the hard way that the clearances were wrong from the get go. You can check them and take the block back if you suspect something is wrong.

I would highly recommend having someone with you that has rebuilt a few engines before that can help check the clearances.

Good luck with it.

 

if your gonna do a 355 i just say fork out the money for the 383 stuff

 

The last engine was rebuilt basically by me but I had tons of help from an engine builder along the way. We rebuilt it at his house but since he wasn't getting paid (just dinner for the nights he helped) he made me do all the b!tch work. Wasn't fun at all but I learned a ton of things. He knows all the clearances for everything I asked but I can't remember them off the top of my head yet. Plus, this time around I want to make SURE everything is perfect and triple check it all. There's no way I could do another rebuild after this. He did show me how to check all the clearances and assemble the bottom-end and then he checked them himself but this time around, he's not wanting to hold my hand all the way through this process, but will probally be willing to let me use his tools so I don't have to buy them. So any help I can get is needed. I am planning on buying the book "How to rebuild Lt1/Lt4 Small Block Engines" that's availible from summit. But like I said, all the help I can get will be appreciated. Thanks

 

There's some good advice.
Yeah, then buy bigger heads and cam and so on.


As far as your clearances go I'd talk to your machine shop. I personally run my rods a little loose on side clearance to help them live longer. For ring gap it depends on the piston and how big of shot you are going to run, a hypernutectic pistons requirs a lot more ring gap than a forged piston because of the high silicon prooerties it has and the high amount of heat it reflects back into the cylinder.

My machine shop has helped me a bunch and has saved me a lot of money in stuff that I thought I needed but didn't.

How did you wash the engine out with gas? I'm just wondering, I know **** happens. I installed the second piston ring upside down somehow on my 406 and it smoked like a b1tch, but it still ran 7.8's on street tires though can't wait to get some compression.

If you are going for a basically stock rebuild you can pick up a haynes manual that will have the info you are looking for. As far as performance parts the manufactur should have guidelines to help you with your intended application.

hope this helps some.