OK here's the deal. I got a low mileage (under 10K miles) 1976 Chev 350 engine that a guy bought from a totalled Camaro in 1976. He had it on a pallet behind his garage under a tarp for a few years without plugging the intake and exhausts. A few years later he thought he was going to use it and thought that turning it over by hand was kind of difficult, s he pulled the heads to see if the bores had gotten rusty. They did have minor rust on them, so he decided to take the engine all apart, hone the bores, put new rings in it and put it back together. But once dis-***embled, it got put on the back burner (but thankfully stored inside). I was recently able to get it for pretty much nothing, BUT, although he kept the main caps in order, he had at one time put the pistons/rods (still together with the caps on them) in a box in some order so "he" knew which was the number 1, 2, 3, etc.....but somewhere along the line someone else moved them to a different box,and now neither he nor I know or can figure which pistron went where. So...the question...this is just going in a daily driver with no performance mods...can I just put any piston/rod combo in any old of the bores, or what should I do? Racefab? C9? Dr.J?
Usually on a new engine each bore is size matched to the pisto on ***embly- but since it is barely BUT probably broke in a little I dont think tht is critical as would be at ***embly time.All I know is what Ive learned from doing everything wrong so take this advice with a grain of salt- I think it would be all right any piston in any hole. As to the rods -as long as they have the correct rod cap still on the rod it belongs on and the main caps are where they belong you should be fine.[but what do I know?]
One more thing Jim be sure to check rod bearings and main bearings[mic the crank] that was the ERA when Chevy would have one main journal or one rod throw a couple thou over or undersize!!!![bearing will be stanped GM and marked so look]believe it or not it did happen. I noticed that over the years- it was fairly common around 73-74 and maybe even that year. so that would need to be check just in case.......
You can narrow down the randomness by seperating right bank from left bank pistons, ***uming the guy didn't take the rods off the pistons. The connecting rods will be ***embled on the pistons so that the con-rod bering tangs are facing away from the cam. The pistons should have a notch or dimple on them to ID front of engine. So you should have four with the notches to the right and four to the left. Sort them so the bearing-tang notches are towards the outside of the engine. Now look for any marks that might look like cylinder numbers, if not, I'd just measure tolerances like suggested above, measure bores and piston skirts, and match them up as close as you can to the bores. if two have to be a little tighter, make it the front two cylinders, (they run a taste cooler), but remember to keep the right bank ***emblie on the right and left on the left Write on a piece of paper with two rows of circles on it all the bores, and the piston diameters on "stickups" and play the match game!
[ QUOTE ] You can narrow down the randomness by seperating right bank from left bank pistons, ***uming the guy didn't take the rods off the pistons. The connecting rods will be ***embled on the pistons so that the con-rod bering tangs are facing away from the cam. The pistons should have a notch or dimple on them to ID front of engine. So you should have four with the notches to the right and four to the left. Sort them so the bearing-tang notches are towards the outside of the engine. Now look for any marks that might look like cylinder numbers, if not, I'd just measure tolerances like suggested above, measure bores and piston skirts, and match them up as close as you can to the bores. if two have to be a little tighter, make it the front two cylinders, (they run a taste cooler), but remember to keep the right bank ***emblie on the right and left on the left Write on a piece of paper with two rows of circles on it all the bores, and the piston diameters on "stickups" and play the match game! [/ QUOTE ] What DrJ said....... .Since you are putting new rings and bearings in it,and it has been honed,other than left or right sides and fronts facing fronts,that block really won't give a **** which piston was in which hole to begin with.One more bit of advise. When you are ***embling this engine,remember,CLEAN,CLEAN,CLEAN.
Can anyone tell when they stopped marking the rods at the parting line to identify the bore location? I've been collecting this stuff for years and everything I have has the bore no. stamped on the rod parting line. This is just one more indication that you are getting OLD. Frank
Thanks for the info everyone. I already knew about the marks on the piston tops indicating the foreward/front side. Wish the guy who took this engine apart would have gotten a set of metal stamps and marked the rod caps (hell, even a sharpie type permanent marker probably would have made marks that would have stood up after all these years). I have some micrometers and calipers to do some of the measurements and can borrow the rest. (My plastigauge days are over, not that it didn't work well for me in the past for checking bearing clearances). The rods are still on the pistons with the caps on the rods (someone asked). One more question: the guy oiled the crank and wrapped it in a plastic garbage bag, but upon recent inspection, a couple of the main journals have a faint hint of rust blossom on them (NOTHING BAD...you can just detect it was starting...it's not crusty or hasn't started any even minor pitting type damage). Is this something I can scotchbrite pad buff away, or what...send it to a machine shop for a quick polish job on the journals?
For a street beater, just rub that hint of rust off of the journals and you'll be okay. DR J's idea for matching up the pistons to the holes is exactly how I'd do it...should be good enough to get you by! New gaskets and carefull cleaning and ***embly will reward you with a motor that will get you around for a long time with proper care and upkeep. Another bargain mill for a Happy HAMBer!!
When I was in Highschool, I gophered for an old Mechanic during the Summers. The very first thing he taught me about rebuilding an engine was to Stamp numbers on everything as soon as I took the pan off.
As far as I know the numbers stamped on rod and caps were never on NEW GM engines /only a rebuilt engine done by an individual/or garage.....any one know different?
ford stamped the nunbers on didnt they? for the slight rust on the crank, take some emory paper, and do the shoe shine hustle on them. it sould clean them up real nice. but dont get carried away.
I'd just add that rather than looking for the tang on the rods make sure that the larger chamfer on the rod faces the cheek of the crankshaft counterweight. The larger chamfer corresponds to the fillet radius of the journal.
Don't use scotchbrite, it will scratch the journal. Go to your local Napa or whatever and get some crocus cloth, kind of like emery cloth but finer. have fun!!
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