Technical Small Block Chevy 350 Rebuild

^^^^^^Yeah I agree with you on your ability and mine also .

However,,,,if He doesn’t mic #4,,,,, He’s gonna wish he had .
Just my observation ,,,I could be wrong .

Tommy

 

I’ve taken a crank in and had them polish just two journals before. Well, actually one took a polish and one had to be turned. Probably didn’t save me much after setup costs are concerned, but I felt better

 

I give the OP a ton and a half of credit for posting up here and sticking with it. It could have gone very differently and way too many post and run. Good on ya.
If this really is going to be a run stand queen, I wouldn't worry about the scruffy rod journal. If you were going to run it hard, that's a different issue. For this one, a dingle ball hone job and a hand polish on the crank journals, "twenty under" bearings R&R.
On the scruffy rod journal, I'd polish it with cut strips of wet/dry sandpaper and motor oil and get it shiny and plastigage it when I was done. As long as it's ballpark, you are good. I'm gonna post up a story from decades ago, but it's 100% true. And this motor was far more than a run stand queen.
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In the fall of 1984, My Uncle George had some trouble with his 1979 Chevy Tioga Motor home while returning to Bakersfield from Yosemite Nat'l Park. He pulled into my parent’s home in Fresno with a terrible knocking in the lower end of the engine.
My Dad was a fearless jack of all trades, truck driving Mr. Fix It. He said to George that to him, it sounded like a rod knock. He suggested that they should jump right into it and pull the pan and make a decision. Based on what they find he can decide whether to pay for towing or to patch it up well enough for him to get back to Bakersfield. So my Dad, my brother and Uncle George jacked it up and got after it.
Sure enough Dad was right, it was one rod cap that was very loose with a surprisingly large amount of free play. The guys pulled the cap, got one .010 under bearing, rod bolts and nuts. But before reassembling it, at my Dad's behest, he put the rod cap in the vise and filed on it with a flat 14" file. Not a precise machine tool procedure, but it might work. He filed on it until he thought it was about right. Then he crawled under the RV and using some 400 grit sandpaper, he polished the crankshaft throw.
The three of them put it all back together. No micrometers, not even Plastigauge, no measuring of the clearance at all other than by feel. My dad said that the repair was good enough to get George back to Bakersfield.
Surprisingly, it ran great all the way to Bakersfield. Ta daa!!! Rube Goldberg, jury rigged, Jerry built all rolled into one. Pretty amazing/surprising. That should be the end of the story. Full rebuild required, the rod was likely in need of resizing, the crank journal probably was out of round and needed ground to the next under bearing size. Rod knock is very damaging to the involved components.
Well, Uncle George was a ponderer and ended up thinking about what to do regarding the RV for about a week. While not a car guy he was an AT&T tech so he knew about testing and stressing components. He decided to run the Chevy really hard up the Grapevine the next Saturday. He buzzed the small block Chevy all the way to Tejon Pass. He decided it was sound and returned home. He ended up driving that Tioga for almost 25 years and finally sold it in 2008.
Later, not that many years ago, on a visit in Bakersfield he said to my brother " Tommy, the Tioga is still running." Tom replied, “I thought you sold it.” He said, “Yes to a neighbor...and he is STILL DRIVING IT!”

 

Lots of engines have been****embled using that method and worked just fine. I have used it in years past. What it doesn't tell you is out of roundness. If someone doesn't have their crank ground and mearly polishes it, there can be lots of taper and out of roundness. In the cylinder, lots of people just hone existing cylinders. They usually use a dingle ball hone. Its flexible nature allows it to follow high and low areas of the cylinder and appear to have a good round surface......when in fact it isn't round. If a camshaft seems a little too snug, you need mics or a dial bore gage to check the problem. Today, a little patience and searching will provide some of these precision tools very cheaply. I always look at it from the point of view that if I buy a used tool for a fair price, it will still be worth that price when I'm done with it. So I can recoup that money if I'm inclined to do so.....and they cost me nothing. As you say, there is more than one way to check things, and usually they work ok. It just depends on the individual and how precisely they want to work on things.

 

I’m getting g a little ahead but I have the camshaft in the block. There is nothing that holds it in place? I have a Cloyes timing kit (gears and chain). It did not come with bolts. I see on Summit I can order bolts that are 5/16-18x3/4. Some options are just the three bolts. Another option is the three bolts and a locking plate. Do I need the locking plate? What actually holds the camshaft in the block? Just the fact that it is connected to the timing chain and the crankshaft?

 

The timing chain and cover will kept the cam from slinging out.
I wondered the same thing on my first sbc

As far as cranks, many have been plasti-gauged and polished.
But turning a crank isn’t very expensive either

 

With a flat tappet cam, the slight back to front taper on the lobes keeps the cam pulled back in the block.

 

I don't use plastigauge on a used crank, and never considered using it for that purpose. I take my rotating****embly to the engine machine shop, along with the block to be checked, and align bored if needed.
But I wont****emble an engine when I get everything back without plastigauging the new bearings, and the crank and rods. I've checked after machine work and found occasions where the clearances weren't exactly what I wanted once everything was torqued down, and checked with plastigauge, so I've always considered it as important as all the machine work on the block, crank, and rods, regardless of who does the machine work.
My engine I purchased for my '39 Chev coupe was an****embled short block, and I was told it was rebuilt. But I still took it apart to check bearings, and rings, as I had no idea who did the work, and wanted to plastigauge the bearings, and check ring gaps prior to putting heads, etc. on and putting it in my project.

 

Nothing holds the cam except the timing chain and lifters. But I always use a cam*****on that simply slips into the end of the timing gear and touches against the inside of the cover. Most come slightly long, so I put a little piece of putty on the end of the*****on, and 4 bolts tightened down on the timing cover (with a gasket) to see how it clears. Pull the cover back off, and you should see the putty deformed, but not so much that you see bare metal in the center. If it's bare in the center it's too tight, and just remove some metal off the nose and check it again until you can see some putty remaining.
You can run without a cam*****on on a low performance engine, but I just like them, and they're inexpensive.
https://www.summitracing.com/parts/sum-g001

 

The locking plates are good, but I'd just use a drop of locktite before inserting the bolts. Be sure the bolts you get are the correct length and not too long.

 

Head gaskets. My cylinder bores are 20 over, so when I order head gaskets, I should get SBC 350 86 and up bore 4.020? What are the best cheaper end gaskets to get? I have seen some multi layer ones, some with a metal ring around the cylinder bore holes. Probably end up getting a gasket kit in order to get most gaskets needed for an overhaul.

 

If I were putting it together, I'd get a normal Fel Pro overhaul gasket set, which is likely to include the blue composition head gaskets with the ring around the cylinder bore, and they are designed to work with either standard or overbored engines. Don't overthink it....

 

Unfortunately, plastigauge won't tell you if a journal is round. I have also put engines together without even using plastigauge and they all lived. However, now that I know more, I mike everything and check all clearances.

 

I did Plastigage four sides of rod journal 3/4 (if thinking of a clock 12, slightly off 3, 6, and slightly off 9 o´clock positions ) with +30 bearings in place. I did the slightly off 3 and 9 because I did not want the Plastigage to squeeze out between the two halves of the bearings. All 4 positions look to be .0015. The other rod journals were .0015 - .0020 with +20 bearings in place. All fully torqued.

 

I'm going to****ume you just dropped a decimal place.....that those measurements should be .0015-.0020"clearance??

Because if it is actually .015-.020" clearance you definitely have a problem.

 

AGAIN. I use plastigauge after I get all my parts back from the machine shop to check things before I have machine work done, and after I get parts back. I certainly hope the machine shop doesn't turn my journals out of round, and so far it's worked fine.

 

Is there anything that goes in these two bolts holes and maybe a gasket? It looks like the timing gear will rub the block.

I purchased a Spectre 6 3/4" harmonic balancer. It came with a thick washer and a bolt. The bolt is too small for the crank, I believe it is a 7/16-20x2 1/2" bolt. As you can see in the picture, I found a bolt that fits (oddly enough painted orange from an Allis Chalmers project I did). It is not a grade 8, just a normal bolt, I think it is 1/2" with fine thread ( it actually measures 0.48"). I am having trouble finding a bolt and washer for the balancer. Update: on Summit I see a bolt that is 1/2-20 x 1.5" (under head length). It is listed as a Big Block Chevy fitment. Is this the one I need? Maybe my crank was drilled out?

 

The two holes in the block are not used for anything with the flat tappet cam. The sprocket rubs against the block. They last for hundreds of thousands of miles, like that.

The crank is supposed to be tapped 7/16-20. If someone screwed up the threads, then it might have been drilled and tapped oversize.

 

Chevy used a grade eight bolt on the crank dampers, is that what your bolt is?

 

Is that where a cam thrust plate would go? Thanks Squirrel and Fordors. It just seems weird that the timing sprocket will rub against the block, but the cam thrust plate is metal as well.

 

No, it was a bolt I found laying around in the shop. I know it needs a grade 8. I think I found one on Summit. I need to go to Tractor Supply and check the size of the bolt I have against there sizing tool.

 

Buying a new set of Cylinder Head bolts. They do not come with washers. Do I need to use washers? They are sold separately. The bolts have what I would call a flange head and they come with thread locker already on.

 

No Chevy with iron heads that I know of ever used washers...they did use flanged heads in later years, though

 

I bought my last set of bread bolts with threadlocker already on if you don't have that you will need to add it to the threads

 

There are lots of things that were done to engines and stories about those things during the Jurassic stage of Hot Rodding. People didn't have access to tools and parts and information. Most didn't have any money either. They were forced to try things and see if they worked.
People have literally ground every journal on a crankshaft to a different size, bored some cylinders and not bored others. Used a dingleball hone to finish unbored cylinders. Polished used bearings and ground rod mating surfaces. Used full floating pins in some pistons and not others. Used Different pistons or piston weight or compression ratios. Reused rod bolts or replaced them without resizing the rods. Different size valves in the heads and different valve springs on some cylinders. Reused the old oil pump and reused used oil. Almost no one owned a torque wrench. There are all kinds of things that have been done to engines and they still ran. Some lasted but many didn't. We hear about the ones that lasted. We don't hear as much about the ones that didn't last.

I remember the first engine I "rebuilt" when I was 15/16 and had no one to teach me and no real source of information. Didn't know a top ring from a second ring......so I put some one way and some the other way.
Yep, lots of dumb things were done in the 30s/40s/50s.

 

Don't just buy a bolt to hold the balancer on the crank! It also should have the correct washer too. The washers are a thick convex type that work like a lockwasher to help keep everything tight.

 

interesting, the washers I've seen on 350s are really thick and big, but they're flat, and there's also a split lock washer. Big blocks used a tooth lock washer.

 

The balancer came with a 7/16-20tpi maybe 2.5” long bolt, a 1/4” thick flat washer, and a lock washer. I found the 1/2x-20 bolt but it’s only 1.5” long with a thick flat washer and a lock washer.

 

That 1/2 bolt is probably for a big block, they use a shorter bolt since the crank snout is longer.

 

All I've seen were thick, but most older washers I've seen were slightly rounded on the top, but flat on the balancer side. But I looked at Summit Racing online, and appears they're all flat now as you mentioned.