Could we discuss all the steps, in great detail, concerning building a small block chevy. Specifically ANY/ALL machining operations concerning the block only for now. Discuss ALL of them and describe whether they are absolutely necessary and why or why not. i.e., Align-hone, Align bore etc.
There are MANY machine operations that can be done on a block most of which won't matter to a traditional hot rodder. Basic engine build process, billable hours or operations Remove cam bearings soft plugs galley plugs Clean Magnaflux crack check. Check deck for flat Line bore check , mains and cam tunnel Cylinder bore check IF it passes basic operations above then Basic- bore/hone/chamfer cylinders, option torque plate hone. Basic- install cam bearings/soft plugs Extras or failure of initial inspction Sonic check cylinder walls Line bore/hone Cut block deck flat option parallel deck or deck to a spec. All basic stuff for block build^^^^^^^^^^ repair threaded holes, drill tap modify for four bolt or splayed caps thread press in galley holes, oil restrictors lifter bore bushings, lifter bore keyways bore cam tunnel, oversize or BBC cam bearings drill/modify oil passages plus many more
Let's discuss cleaning first: For a new and/or aftermarket block i would ASSume that hottanking is not necessary? For a used block, we should go with hottanking (or better methods?) What is exactly involved. If the freeze plugs must be removed, then why?
1) chevy engines are so easy to find, it may be worth it to figure out what it will cost to repair damage..and then just buy another one. Maybe a crate engine that will give you 350hp if that's what you want. Instead of drilling for 4 bolt mains, just buy a block with it from the factory, unless you want splayed bolt mains (stronger), and then you may want to consider an aftermarket block that has everything already. spending money on sonic checks and magnaflux may put you ahead if you find cracked parts you were planning to reuse. also, there's a matter of core shift--those things people call "freeze plugs" aren't really for letting frozen water travel thru the block to find them. they are core plugs, designed to let sand cores to shake out after the block is cast. but if the cores shift around, the block won't stand up to high HP. so take a look at the metal that rings things like the core plugs or cam bearings. Is it a uniform circumfrence, or is it thicker on one side like things shifted about during the casting process? 2) if you're on a budget, focus on building the block and getting good reciprocating assembly first, save up to buy high flow heads to put on later. 3)boring the main webs brings the crank up closer to the camshaft, which can be an issue if you're playing with strokes and longer connecting rods, and will require a shorter timing chain as a result. It can be debated if its worth it if the crank spins freely already and you aren't planning to spin the engine past 5000RPM often. Cranks will flex no matter what, and oil is splashing on and off, balancing and unbalancing it. everyone has an opinion on this, but the point is this--measurements will be taken off the centerline of the crank. 4)some engine builders still say spraying Glyptol paint on the inside of the block helps. but paint doesn't smooth rough surfaces (for oil flow), only sanding does. nor does paint hold sand in place, spray some dirt then squirt water at 60 psi on it and watch things move. I find it to be another wives' tale, like oil pumps robbing HP (yet your drill can turn 'em). 5) deck the block first, THEN bore the cylinder. Chevies bolt their heads to the deck of the block, so boring it THEN reducing the deck thickness throws the work done by a torque plate (to replicate distortion by the heads being torqued down) out of whack. were this an aluminum block, i'd suggest an oil pump, starter, and the main caps and timing cover also put on to distort the block. 6)not everyone can do hottank, due to environmental concerns, so you may get the block baked, instead.
Hot tanking/spray washing gets most oil/sludge dirt/scale out of the block. Soft plugs oil galleries removed to get cleaner into all areas of the block. Usually leaves some rust stains and dyes used in production on block. Bake and blast.. Heats block in a commercial oven. This turns contaminants to powder/ash. Then block is shot blasted with fine shot. This surface conditions and removes any left on contaminates. Block is then tumbled to remove any left over shot and emerges looking like it just came from foundry. "5) deck the block first, THEN bore the cylinder." not always! Depends who and what equipment is being used. I have machines that use bore centerline and others that use the mains. Older stuff uses the deck for boring position. I also dis agree with the Glyptal comment.. Almost all of the big non automotive engines are internally painted. If the manufacturers thought it didn't work they damn well wouldn't pay for the extra step. 1) chevy engines are so easy to find, it may be worth it to figure out what it will cost to repair damage..and then just buy another one. Maybe a crate Also dis agree on this.. I work near (3 miles) where the vast majority of small block chevies were manufactured.. Most of the later engines were 305 in trucks. A good 350 block is getting hard to find here. A typical call to a bone yard will get you mostly 305 or a high mile 350 that needs work for only $950 +
As stated above remove all plugs so the oil passages/water jackets- can be cleaned during the hot tank session. Then =PERSONALLY=run your new set of cleaning brushes thru every one to remove sludge before the hot tank. Youd be suprised how many places did not remove the cam galley plugs at all during hottanking! a lot of engines are ruined by sloppy cleaning,some folks even sandblast to clean so imagine the potential for engine disaster there....find out how and what will be used and who is gonna do it[read that "be responsible"] for cleaning that block for you...... If a rare engine I would recommend marking your parts so they come back [the same] parts you brought in....
Look guy, buy yourself a copy each of HPBooks "How to Rebuild SBC's" and How to Hotrod SBC's" and be done with it. Both way old books but they will tell you everything that you want us to feed you. Kinda like a nooby that come's asking that picks our brains and in a couple a years thinks that he is an expert. I'm sorry, had a bad day.... pdq67
It's taken me like 50 years to learn this stuff and I will guarantee that if you get me to your place that I can put your SBC together in a NYM for free, you watching me. Ask mbrekke over on team Camaro. pdq67
1) First thank you to everyone for responding to the thread; i will respond further as time permits. 2) Secondly, no i agree-- i AM a piece of shit and yes i do want stuff for free. i'm a greedy turd. i'm not debating that. But it's not so much that---i do have and read hot to rebuild/hot rod SBCs. But do the books tell everything? For instance is align boring really necessary for a drag engine? That's why i'm being so anal about it. Smokey said do it regardless. i want to make sure i don't leave anything out.
seems a very interesting thread to me and should be made into a sticky ok i understand that people have many yrs experience on here and dont always want to share it but isnt this what rodding is all about, helping people ? a freind of mine got an awsome book about sbc's and has everything in there to do with boring and gaps and so on and im in no need to do mine or i would be doing it now Matt
Actually bob, I don't do the deck first for baseline measurement purposes, but b/c I want the deck to be its final thickness before I redo the cylinders. If the head bolts go into the walls of the block like a Pontiac, that's different. As for the Glyptal, you may find they're painting the inside of the block they expect to store, to prevent condensation from creating any "surface rust" after sitting on a shelf for a while. Plus the customer is used to seeing red paint on a block, so the customer buys what they expect. Like polishing a fruit at the produce counter, its wasted money except that the customer won't buy it otherwise. up north, 350's are cheaper b/c the car rusts out sooner in the end, what works for you...works for you.
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