Thread: Tear Down

Tweet

So i began tearing down my 350 today and expected to see some grime because it had a leaky valve cover gasket and was covered in oil, but i was not perpared for the horrors i found, its true you can learn alot about an engine during the tear down. First my dad and i discovered that it had been overheated, bad, all the intake manifold bolts were nearly stripped of theards and there was sever warpage, also, the rear main seal had blown and had not been properly repair, some ass just somethered the back of the intake in silicon. Then once we get the intake off we find that the heads are horrible, entire passages blocked firmly by metal shavings and grime, i had to take a screwdriver and pry on alot of crap just to see the water passage or intake runner, also, i have a question, a few of my rockers were bent to one side or another, what couldof caused this? I'm not sure what its called but between the heads on the block i guess was this sludge of grease, oil and metal shavings, i cant tait to find out what it came from, thanks for listining, i just thought i should share my first engine build with you guys, later

Sounds like you need to find another 350 to build.

i was thinking the same thing, i'll be sure to keep and eye out in the junkyards this weekend, it seems like this motor past its prime

The best blocks, heads, and cranks can be found at a machine shop, already done. Machine shops are all the time getting stiffed on jobs. Find a very large busy machine shop and ask if they have any chevy blocks that they got stiffed on. That is how I got my 350 4 bolt. They wanted to sell me the block on top of paying the machine shop bill. I told them they could keep it, that they got the block for free, and I was more than willing to pay for the machine shop work they put into it if it was a good block. The manager saw my point and agreed. I let them freshen the block for me, and mic out the cylinders etc... so I could get parts and bearing for it, etc... also had them line bore, and chamfer the block, and mag it for cracks.

Sounds like the block you have is a real piece of work. Could end up easily spending the cost of a GM crate motor to rebuild it. The waxy sludge buildup is from running Penzoil or Quakerstate in an engine that run hot. These oils use a parafin base to control viscosity, and breakdown and seperate under higher temperatures. The waxy greasy sludge is this product. I've seen this on other heads, and in the lifter valley, so bad that the springs looked like they were setting in holes made for them.

GP brought up a good source of parts!!!! I bought a 427 Ford short block a few years back, allready bored, honed, and decked with new pistons and rings allready fit and one good cleanup short of final assembly. Got it for a fraction of the real value, paid $500.00 for it. With all the guys doing chebbie stuff, there's got to be a ton of projects laying around unpaid for at shops. Might be worth your while to do some digging.

yeah, i'll definitly check out the local shops, this motor is burned up, the valves are all scorched, the exhaust on #8 is white while the rest have a crusty black substance one them, alot of passages in the heads are clogged, solidly with what i think to be carbon bild up, there was moisture in the cylinders because it sat outside for a month or so, the head gasket was also all cracked and corroded, there is a 454 with 0 miles in the paper for 1600, long block plus intake and the guy says it has 0miles, built for a boat then never installed in the 80's, been sitting in his garage on a stand since, I think we should get it but my dad thinks its "too much motor", does anyone know the stock specs for an 86?

Boat engines use 180 out cams to run backwards. Better ask the guy which way the engine spins. You can take any GM engine and put a marine cam in it and a marine starter and run it backwards.

Make sure. But even at $1600 - swapping the cam and a starter is a piece of cake. A 454 is only too much engine if you think so. It's all about hp not cubes.

ahh, right, i hadnt thought of that, oh well, my dad is set on rebuilding the 350, i'll take it to the machine shop and have it hot tanked or something and have em do what they do, and then just use trick parts to make up for the lost displacement

Before you shell out $$$ to a machine shop, ask them what it will take to bring the engine into spec for rebuilding. If it has to be bored - you are looking at a new set of pistons minimum. If the crank needs cut to much you might be looking at a new crank, but many shops will have good blanks (used one that is in good shape) that can be turned .010 to bring them into spec. Since the block has been fryed, you should consider getting it magged, and line bored. It is possible the block could just be a disaster. At any rate, ask the shop to take a look at it and see if it is economically viable to machine it for rebuilding. Have them mag it after it comes out of the tank, to keep your costs down if it is cracked. Then you'll only be paying for a tank job and a mag job that you get to have the shop throw away for you. Ask about brass vs steel freeze plugs. And don't forget to have the shop install your cam bearings for you. It's just safer to let a shop put them in.

Godd luck.

yeah, i am going to get an estimate for reworking the block and heads, if its too expensive or the block is cracked i think i'll but aa remanufactured motor from rebuiltautoengines.com they have remanufactured long blocks minus valve covers for about a grand. I think this would be the best way then bolt on goodies later when the buget allows or while i still have it out of the car, and correct me if i'm wrong but i'm pretty sure you can do a cam swap while the motors still in right, its classified as a bolt on swap right, i have been thinking of using the edelbrock performer package intake and cam, and heads later, with a 700ish cfm carb because i will probably put it on a 100horse shot of the bottle later, does this sound do able and does anyone see any potential problems?

I run a naturally aspirated 357 small block with a Speed Demon 750cfm carb.

The Speed Demon is definitely capable of feeding more fuel than an Edelbrock Performer of the same CFM.

Cam is a "bolt on" after you
take out the radiator,
all the engine accessories,
water pump,
harmonic balancer,
timing cover,
crank gear,
cam gear,
valve covers,
carb,
distributor,
intake manifold,
rocker arms,
pushrods,
lifters

so if you consider it a bolt on swap after all that - then I guess it's a bolt on.

Don't forget to degree the cam to make sure it's setup right using a degree wheel, and an a deflection or endplay gauge.

As noted in a post from Dr. Bowtie, your cam could easily be off by 4 degrees.

Also take extreme care not to draq the old cam over the cam bearings taking it out - or dragging the lobes across the cam bearings when you put the new cam in - this shaves and cuts grooves into the cam bearings.

You can use a cam installation tool to accomplish this or a very long bolt or piece of allthread that matches the threads of the cam bolt holes.

The Edelbrock Performer package is cam, lifters, pushrods, rockers, springs, intake, carb, heads. All of those items work together as a package. Usually you have to machine the heads to accept the oversize springs. If you put in oversize springs you should put in screw-in studs because the increased spring pressure will pull the studs out. If you put in screw in studs, then you will need to install guideplates. One thing leads to another.

You either do valvetrain, or you don't. Putting a cam in with more lift usually means putting in stronger springs. If you don't, the valves will float at the top end.


The picture of southern's engine is mostly stock with stock heads, stock valves, stock springs, stock rockers. I'd ask him if he thinks he'd feel safe putting a bottle on his newly rebuilt small block.

To see a 350 build - look here www.gpzilla.com I drive this everyday.

Guess I should post the engine building pics. Shows degreeing the cam, swapping valves, porting heads, etc...

wow, that was alot of help, I have 3932441 heads with 1.94intake and 1.5 exhaust with 76cc chambers, i think these will be good enough for my first build and plan on having them rebuilt because neither myself nor my dad have those skills, i think i may need a new crank because mine has grooves cut into a few of the journals i believe there called, i am thinking of using an edelbrock performer intake and 750cfm edelbrock carb, any suggestions on a cam manufacturer? This is all going thorugh a th350 with a mild shift kit to a stock g body rear, 2.50 or there about until it is gernaded then i am going with a 3.73 out of a monte ss or GN, by the way, that jeep is bad ass, and maybe a cam isnt as bolt on as i thought, i forgot about the accesories, oops

Cam vender should be the same as lifter, valve spring, crank gear, cam gear, chain, pushrod, and rocker arm vender. That way all the parts are designed to work together.

You have to replace the lifters if you replace the cam, they wear together, unless it roller. Non roller cams let the lifters drag across the cam lobes. They wear, nothing you can do about it.

If you replace the lifters you should replace the pushrods. Again...they wear together. And if you replace the pushrods. Pushrods wear into the rocker seats, rockers wear into the rocker fulcrums (unless they are roller).

I'd say if I had to skimp to save money, I would atleast put in new lifters with a new cam.

Roll the existing (clean) pushrods on a piece of (clean) glass to see if they are bent.

Bottom line, you should inspect each part for wear. Parts that wore together should be reassembled together with the part it wore with.

There are valve train parts trays for this, but you can get by with labeling plastic baggies.

The heads you have are pre 1979 heads and intakes flow 152 CFM while the exhaust ports flow 93 CFM. They use the larger flat seat spark plugs.


As for the crank - depends how deep the grooves are - maybe can be turned, if not you should be able to get a seasoned useable crank from the machine shop. Many often buy cranks just for folks who have one that can't be turned to get it into a usable condition.

Mine is turned .010 under, so you just use matching bearings when you do the build. The machine shop can tell you if the crank is usable.

You need to decide which ring material you will use, and tell the machine shop. Moly rings require a different cross-hatch than chrome rings, etc... and seal different. If the shop needs to bore the block - then you need to buy the pistons first, because they will bore and hone the block to fit the pistons. If they say it needs bored 10 over, then you buy 10 over pistons. The shop mics them and bores the cylinders for the correct fit, then hones for the cross-hatch to match the ring type you intend to use.

If you have a machine shop assemble your heads, you have no worries. If you assemble them - there are a dozen things to sort out and check.

Those Performer Kits require bigger springs and the heads require machining and modification to out the parts on because the stocker springs are inadequate for the cam lift.

that was really helpful, i was wondering what all i should tell the machine shop and/or have them do, i am going to call my local junkyard guy this week to see if he has any vortec heads(i no i would need a different intake) and then drop the parts off at the machine shop, i figure i'll get them to check everything to see whats reusable and then have them install the cam bearings, pistons, ext. anything else i should watch out for, you guys are awesome