Can I efficiently rebuild an internal combustion engine?

Yes. I know this isn't a vehicle. But it may someday end up in one, if not as a coffee table. So I've always been facinated by building engines, by watching Engine Power on Saturday mornings and now on youtube, and Engine Masters among others. I got good at ripping apart lawnmower engines and never touching them again. So I decided a winter project for me will be to set my ADD ass down and learn how to rebuild an actual engine. I picked up a bunch of stuff from a friend for a smoking deal. Here's what I got:

-1975-1980 400ci SBC fully disassembled. Looks to me mostly there, needs bearings, a good clean, a magnaflux, and hopefully just a single ball hone and ridge ream before I can assemble. The provided crank is already .010 under as indicated by the crank bearings. I'll be interested to see what the bores are, as they are suspiciously clean for the age of the engine. The cylinder head casting numbers indicate they are 1969-1970 350 heads with 76cc combustion chambers, nothing special, but will need to have valve seats done to run on non leaded gas. Unknown aftermarket cam with a date from 2001 stamped on it, unknown stock looking 4 valve spot pistons. Crank does have a double roller gear on it.

- 2000 350 Vortec with I think 200k miles on it. Came from a guys work truck c2500. Fully complete minus harness, this I do know ran and drove. Now for this one, I have a new in box Jegs Vortec carb intake, MSD street Fire HEI dizzy (can be used on the 400) and a set of MSD plug wires. Not sure what head casting they have.

- unknown year 2wd 4l60e.

Plans?

Well if like to get the 400 into a short block. I have been gathering all the required tools to measure and assemble the engines. Also would get a set of junkyard vortec heads for the 400 for the 64cc chambers. I really don't want to split the 350 up for just the heads. This weekend I'm taking alot of parts to go get sonic washed, then I'll need to start measuring.

Sent from my Pixel 4 using Tapatalk

I'm a fan of displacement, but I'm wary of 400s. They're an older block - the newest is forty years old now, and they're still in demand, so people will recycle garbage. I'm not saying your friend's trying to cheat you - he may have been cheated and not know it. I'd pay the machine shop to put a critical eye on it.

Personally, I'd build the 350 first. It's straight forward with far less monkey business to watch out for. You also won't need a ridge reamer to rebuild it. If it doesn't have any damage, you're dealing with stock main bearings, stock rod bearings, and reusing the stock pistons. Cheap stuff that doesn't require machine work! I much prefer a $150 machine shop bill for a vat and magnaflux over a $400 bill.

Vortec heads? If it came from a running truck, it's either 906 or 092 heads, but "GM" so not everything's a given. There's plenty of internet bullcrap giving all sorts of wrong specs and "differences". The only difference I've seen (granted, I'm somewhat new to GM trucks), is that the heavy-duty trucks got pressed in hardened valve seats and the regular dutys got induction hardened seats. The pressed in seats sometimes fall out.

Take your time. During assembly, if you think you may have done something wrong, take the time to backtrack and fix it. Also, http://www.superchevy.com/how-to/engines-drivetrain/83818-block-plug-basics/

Erik the Awful said:

I'm a fan of displacement, but I'm wary of 400s. They're an older block - the newest is forty years old now, and they're still in demand, so people will recycle garbage. I'm not saying your friend's trying to cheat you - he may have been cheated and not know it. I'd pay the machine shop to put a critical eye on it.

Personally, I'd build the 350 first. It's straight forward with far less monkey business to watch out for. You also won't need a ridge reamer to rebuild it. If it doesn't have any damage, you're dealing with stock main bearings, stock rod bearings, and reusing the stock pistons. Cheap stuff that doesn't require machine work! I much prefer a $150 machine shop bill for a vat and magnaflux over a $400 bill.

Vortec heads? If it came from a running truck, it's either 906 or 092 heads, but "GM" so not everything's a given. There's plenty of internet bullcrap giving all sorts of wrong specs and "differences". The only difference I've seen (granted, I'm somewhat new to GM trucks), is that the heavy-duty trucks got pressed in hardened valve seats and the regular dutys got induction hardened seats. The pressed in seats sometimes fall out.

Take your time. During assembly, if you think you may have done something wrong, take the time to backtrack and fix it. Also, http://www.superchevy.com/how-to/engines-drivetrain/83818-block-plug-basics/

Click to expand...

Thanks for the info, I dealt with the stupid one difference with vortec heads when I had pieced together the engine in my truck. I inspected the 400 again tonight, and it seems to be freshly machined, with a few miles on it. The cylinders are clean with crosshatch, and it is bored .040 over, so the cleaning is getting done for free by my buddy at his work, then I'm fragging it to my work so I can magnaflux it for free. Then the cylinder walls will get checked for thickness to be safe. If all goes okay, I will bring it back, clean threads, gather all stock bearings and gaskets and start measuring. This 400 will be more stock than the engine in my truck, so stock crank, rods, pistons, the vortec heads will just be cleaned, and maybe just a thumpr cam to make it seem mean when it isn't. I'm not sure yet. I'm just focusing on the short block for now.

Sent from my Pixel 4 using Tapatalk

Forgot the pic

Sent from my Pixel 4 using Tapatalk

Make sure you understand the cooling passage differences between the 350 heads and the 400 block. You need the steam holes drilled for it to cool properly.

If the magnuflux and cleaning look good, go easy on the honing. .040 is already past where most builders would go on a factory 400 block. I have one that is .020 just because that's what it needed and i still have another .010 to safely remove in the future is I need it bored again.

"Ridge Reamers" are tools of Satan.

They're supposed to be used during DIS-assembly, in order to get the pistons out without breaking rings or ring lands on the piston when the ridge is so huge it'd hook the rings as the piston comes out..

REAL easy to screw-up a block by using a ridge-reamer.

And in the end...who saves pistons when the bore is that worn-out? That's 1930s thinking--the bore is totally ruined, but we'll put new rings on the old pistons, and everything will be fine. Bullshit. That engine is going to be an oil-burning low-compression pig.

Saving pistons when the bore is in good condition is one thing. Re-using pistons when the bore is totaled is another.

I don't know anything about the SBC 400, but was that a 2-bolt or 4-bolt main? The 350 should be a 4 bolt main if it came out of a C2500, and is considered a better engine than a 2 bolt. Probably doesn't matter for a stock application, though. If the 350 ran before, it will run again. Probably just some new gaskets.

But what are you going to use it on? That's the real question. But I will say go with the one that's most complete and known to be good, as your "first rodeo."

stutaeng said:

I don't know anything about the SBC 400, but was that a 2-bolt or 4-bolt main? The 350 should be a 4 bolt main if it came out of a C2500, and is considered a better engine than a 2 bolt. Probably doesn't matter for a stock application, though. If the 350 ran before, it will run again. Probably just some new gaskets.

But what are you going to use it on? That's the real question. But I will say go with the one that's most complete and known to be good, as your "first rodeo."

Click to expand...

Only if it was an 8 lug. 4 bolt small blocks are only 4 bolt on the middle 3. Converting a 2 bolt to 4 bolt with splayed bolts is stronger yet. I have a 4 bolt block on the shelf that wants to be a 383 when it grows up, but I don't see the current 350 blowing up any time soon.

The 400 4-boltblocks are considered weaker than the 2-bolt blocks, due to the extra holes in what is rather skimpy main webbing.

The first few years production ('70 to mid-year...'73, maybe) had 4-bolt mains and three core holes on each side of the block. The 2-bolt blocks showed up about the same time they deleted the extra core-hole on each side.

There's some other differences, but any 400 with decent cylinder walls is a keeper...if it's not cracked somewhere.