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Hey everyone. Had this site referred to me by a bunch of people, and heard that it was really helpful. Anyway, I bought a late 70's 350 with the two piece rear main seal and im wondering where would the money be best spent? I'm just a begining tech, but really interested in pursuing this. I have the block, knocked out the freeze plugs, needs bored more than likely. What would qualify it has needed boring? I know that engines are really finicky about measurements but maybe a hone would do. Whats the amount of damage that a hone could fix?

The block seems ok, i had my uncle check it for cracks, but it has rust or just grime in most of the passages, and really needs cleaned in places where I just can't reach. Seems to have sat for a while, but I though it would be a good foundation to build from.

The pistons are shot, and the bearings dont show the abnormal wear that have looked at in books or other web sites. But I'm sure that those will need to be replaced too. So basically everything will need to ber re done on the short block. The heads are in horrible shape and would be better off going to scrap. But I disassembled them for the experience and the valves have horrible corrosion and just the chambers on in the ****ter too.

So what would be the best angle to approach this project from?
Any tips on anything would be helpful as well, because im just learning the basics.

Also, any books on the subject that would be of help?
Any Project journals that are aboput this? As this is a pretty popular topic I imagine.

Thanks
Drew
 

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01CamaroGuy said:
Hey everyone. Had this site referred to me by a bunch of people, and heard that it was really helpful. Anyway, I bought a late 70's 350 with the two piece rear main seal and im wondering where would the money be best spent? I'm just a begining tech, but really interested in pursuing this. I have the block, knocked out the freeze plugs, needs bored more than likely. What would qualify it has needed boring? I know that engines are really finicky about measurements but maybe a hone would do. Whats the amount of damage that a hone could fix?

The block seems ok, i had my uncle check it for cracks, but it has rust or just grime in most of the passages, and really needs cleaned in places where I just can't reach. Seems to have sat for a while, but I though it would be a good foundation to build from.

The pistons are shot, and the bearings dont show the abnormal wear that have looked at in books or other web sites. But I'm sure that those will need to be replaced too. So basically everything will need to ber re done on the short block. The heads are in horrible shape and would be better off going to scrap. But I disassembled them for the experience and the valves have horrible corrosion and just the chambers on in the ****ter too.

So what would be the best angle to approach this project from?
Any tips on anything would be helpful as well, because im just learning the basics.

Also, any books on the subject that would be of help?
Any Project journals that are aboput this? As this is a pretty popular topic I imagine.

Thanks
Drew
1) Strip it down to castings, crank, rods&pistons, cam, lifters, rockers, pushrods, fasteners. Really important is to number the main caps and installed direction to the front, and the rods both shank and cap; as this stuff has an order. If they are already numbered and the installed direction of the mains shown this is great, but not all engines are so internally identified.

2) Heavy parts get a rude inspection to see if they are serviceable, this doesn't mean you won't discover a disaster after cleaning, but there's no sense in paying to clean something that obviously will be trashed. Pistons, rings, rocker arms, pushrods, valves, camshaft and lifters most often can be immediately identified as junk or not.

3) Parts surviving paragraph 2 above get a shop cleaning whether hot tanking or baking. Once clean they can be inspected. Cast iron and steel responds to Magnaflux magnetic testing for cracks, aluminum castings like heads use a dye penetrant. Parts surviving cleaning and crack inspection move on to dimensional checking.

4) The crank journals are measured for diameter, roundness, and taper. This includes the distance between the thrust faces of the number 5 main. The crank can be fixed to standard undersize bearings if found to be under dimensioned, out of round, or tapered. Excessive wear or damage to the thrust faces is simply the kiss of death, but new cranks aren't too expensive for stock replacement and even some performance types. Rods are measured for twist, not uncommon and can be straightened, the big end is measured for out of round and can be corrected.

5) The block is checked for straightness thru the main bearing saddles and can be corrected by reboring if extreme, or honing if not too bad. At this time the main caps are checked for fit in their saddles, they must be a slightly tight side to side fit in the saddle, this can be corrected by peening if not too loose and the engine won't be asked to deliver high power outputs to where the mains will walk with the forces. The deck where the heads fasten is checked for flatness, waviness, and twist; errors are corrected by milling. The bores can be inspected, but in old engines they are usually gone, so just count on a rebore and new oversize pistons. Pistons with better shape dishes help the engine tolerate more compression without detonation than the factory's round dish fare, look for flat tops or D dish pistons depending upon your head selection of small or large chambers.

6) Heads, a subject for which entire books have been written. These days you need to put together a good cost estimate of repairing old heads against the cost of replacing them with new. With the advent of the Vortec heads in 1996 and the many similar aftermarket heads of the same concept where a so called heart or kidney shaped combustion chamber is used; the words fastburn or Ricardo may also be employed, these heads are markedly more efficient than the preceding generations of heads often offering an additional 40 horses with no other modifications on pre 1996 engines. They are in some cases available new at a cost very close to what it takes to renew old SMOG era heads.

Generally rebuilding an old set of heads means milling to get their decks flat, rebuilding the guides to correct guide to stem clearance, often redoing the top of the guide for a positive oil seal instead of using the factory umbrellas or O rings and hoping for the best, reshooting new seats, and probably replacing the valves, and their springs, retainers and locks. You'll probably also face replacing the rockers and pushrods as well, so this get to be pretty expensive which is why you need a reasonable cost estimate for rebuilding old less efficient and powerful heads.

7) Chevy's have a great appetite for cams and lifters so just figure at the outset that these get replaced.

8) Then there's all the totally consumable stuff, the timing set, gaskets, seals, oil and water pump, and many of the nuts and bolts.

It doesn't take long to rack up a pretty good bill on your Visa card.

Bogie
 

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You have responses from three of the best guys on this site already, so there isn't much I can add.

... but I will anyway :)

Any machine shop worth its salt will have a hot tank which is basically a dishwasher for big engine parts. What I like to do is use a solvent and a bottle brush set to clean out all the passages. That requires a good engine cleaning bottle brush set and it requires removing all of the threaded plugs and freeze plugs. I used to use hot soapy water, but the cast iron rusts so fast that I just use parts cleaner or an old can of stale diesel.

That way you loosen up all the crud and caked on gunk in any of those passages. Then when the shop "tanks" it they get it much cleaner than just tanking alone.

Otherwise it looks like the other guys have you handled.
 
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